MF275 live PTO cannot be shifted on

[Herb40]

Newbie here. My ancient MF275 was taken in for an engine overhaul (one blown cylinder liner). I use the PTO solely to turn a brush chipper using "live" PTO. The PTO had been working fine, but the mechanic decided to also overhaul the dual clutch (probably not a bad idea for a machine with almost 5,000 hours). After the tractor was returned to me, I found that live PTO operation worked fine with no load but could not be shifted on with a load attached.

After much reading online (most of it here), I decided to try to solve the problem myself. I noticed that the clutch pedal bracket was badly bent, thus stopping the pedal far from normal full travel. The bracket was replaced, the bushings in the pedal assembly were replaced, and a pedal return spring was added. I adjusted the clutch linkage according to the MF maintenance manual, although I was never able to "feel" the second stage pedal point at which the PTO could be shifted. After multiple linkage adjustments suggested by various sources, I was never able to find one that allowed live PTO to be shifted on.

Is it possible that a suitable internal adjustment can be made through the inspection port under the transmission? (I have the unfortunate complication that the tractor includes a MF236 front end loader, with its big support structure covering up the inspection port.)

Not to complicate things, but I find it interesting that my MF275 provides both "independent" PTO (lever down) and "live" PTO (lever up). The independent version works fine.

Thanks for any recommendation.


























































TO

 

[Jim.ME]

Newbie here. My ancient MF275 was taken in for an engine overhaul (one blown cylinder liner). I use the PTO solely to turn a brush chipper using "live" PTO. The PTO had been working fine, but the mechanic decided to also overhaul the dual clutch (probably not a bad idea for a machine with almost 5,000 hours). After the tractor was returned to me, I found that live PTO operation worked fine with no load but could not be shifted on with a load attached.

After much reading online (most of it here), I decided to try to solve the problem myself. I noticed that the clutch pedal bracket was badly bent, thus stopping the pedal far from normal full travel. The bracket was replaced, the bushings in the pedal assembly were replaced, and a pedal return spring was added. I adjusted the clutch linkage according to the MF maintenance manual, although I was never able to "feel" the second stage pedal point at which the PTO could be shifted. After multiple linkage adjustments suggested by various sources, I was never able to find one that allowed live PTO to be shifted on.

Is it possible that a suitable internal adjustment can be made through the inspection port under the transmission? (I have the unfortunate complication that the tractor includes a MF236 front end loader, with its big support structure covering up the inspection port.)

Not to complicate things, but I find it interesting that my MF275 provides both "independent" PTO (lever down) and "live" PTO (lever up). The independent version works fine.

Thanks for any recommendation.

Welcome to the forums.

Which Massy Ferguson maintenance manual do you have (what is the publication number)?

I don't think you have an independent live PTO. The PTO would either be independent, controlled by an internal hydraulic clutch (not the foot clutch), or a Live PTO driven through a dual (two stage) clutch. Do you feel three positions on the handle? Based on you description of what the PTO handle positions do, you do not have an independent PTO, you have a live PTO with the ground drive option. PTO handle fully forward (down) is ground drive, not independent PTO. In that position the PTO shaft will only turn when the tractor is in gear and moving. And you have to remember to take it out of ground speed when you back up because the PTO shaft will turn in reverse because the transmission is in reverse. In that position the transmission gears are used to turn the PTO at an rpm proportional to the tractor's ground speed. In the middle is neutral. To the rear (up) the PTO is driven by the engine. You need to have the second stage (below the top half of the pedal travel) of the clutch working to disengage the PTO clutch when shifting into or out of the engine driven mode. The PTO clutch is disengaged when the clutch pedal is fully down. The first half (top) of pedal travel only controls the traction clutch disc which stops the tractor from traveling.

The independent PTO handle has only two positions. It is out when the handle is forward (down) or engaged when the handle is fully to the rear (up). The PTO handle alone controls it; you do not need to use the foot clutch to engage the independent PTO.

Did your mechanic check the finger height adjustments when he installed the clutch?

If you have a Dual stage clutch, the release bolts for the PTO clutch may need to be adjusted, that info is in the Service Manual, MF publication # 1448768M1 or 1448768M92. The manual calls for .080" clearance on the PTO release bolts. Many find .070" - .065" clearance on the PTO second stage adjusting bolts works better.

Edit to add: Before you mess with this too deep, since you say you paid a mechanic to fix this you might want to talk to him about him getting the clutch properly adjusted, which should have been part of his service, if he overhauled the clutch.

 

[Herb40]

Thanks for your revealing reply. I've learned quite a lot already.

For manuals, I do not have the official MF manuals except for an "Operator's Manual and Assembly Instructions (1448 326 M8)." Instead, I have been using Jensales manuals throughout the 26 years I have owned the tractor, but primarily for general info and straight-forward maintenance info. I have a Jensales "Service Manual for MF255, MF265, MF275 (MH-S-MF255+)" and the Jensales "Parts Manual MF275 (MH-P-MF275)." I have never worked on any internal components of the engine, transmission, or hydraulic system, but have maintained them all without outside assistance except for an engine overhaul and two fuel injector pump and injector rebuilds. Although Jensales clearly states that their manuals are not MF manuals, I have found them to be very useful, and they obviously contain copies of many portions of MF manuals.

But one immediate difference related to my tractor is quite obvious: what the actual MF manual calls "Clutch Pedal Free Travel Adjustment," the Jensales manual calls "Adjusting Clutch Linkage" without ever mentioning pedal free play. So I've been lost in the dark on that one.

So I have a live PTO with a dual-stage clutch, with ground drive option. I have never used the ground drive and don't plan to. In use, the tractor is usually sitting still near some brush pile, with the live PTO running around 540 rpm to drive a brush chipper.

You asked about the mechanic: That's a long, sad story. After an engine failure, I finally found a farm equipment dealer in a nearby town to overhaul the tractor. The repair was to be done during two "slow" Winter months, by the in-house mechanic. That stretched out to almost six months, with no real explanations other than an occasional "mechanic has been ill." All communication was with the owner; never the mechanic, who I finally met well into the project. When the tractor was declared ready, I went to check it out. The engine ran just fine. With the machine sitting still in the shop, I "checked" the live PTO by engaging it and looking over to the rear of the tractor to verify that the PTO shaft was turning. It was, although I now know that wasn't a valid test.

When the tractor was delivered, I hooked up my chipper to the PTO shaft to try it out, but it didn't turn, of course. I called the dealer, who said that he would work with me to get the problem solved. I suggested that his mechanic come to my place to work on the clutch, but "the mechanic was very ill and in the hospital." While waiting, I overhauled the clutch pedal bracket and tried various versions of "adjusting clutch linkage," but to no avail.

Did the mechanic check the finger height adjustments when he installed the clutch? I don't know since I've never been able to talk to him. I doubt it, since it doesn't work, and he made no effort to replace the badly-bent clutch pedal bracket. The transmission works properly, but I doubt that anything at all was done to adjust the clutch. The owner hasn't kept me informed about the mechanic's status, and I need to follow up on that.

More than likely, the release bolts for the PTO clutch will need to be adjusted. To complicate things in a major way, the big mounting structure for the frontend loader will have to be removed first. All of this must be done here, since I don't plan to let the tractor be returned to the repair place.

 

[Jim.ME]

Thanks for your revealing reply. I've learned quite a lot already.

For manuals, I do not have the official MF manuals except for an "Operator's Manual and Assembly Instructions (1448 326 M8)." Instead, I have been using Jensales manuals throughout the 26 years I have owned the tractor, but primarily for general info and straight-forward maintenance info. I have a Jensales "Service Manual for MF255, MF265, MF275 (MH-S-MF255+)" and the Jensales "Parts Manual MF275 (MH-P-MF275)." I have never worked on any internal components of the engine, transmission, or hydraulic system, but have maintained them all without outside assistance except for an engine overhaul and two fuel injector pump and injector rebuilds. Although Jensales clearly states that their manuals are not MF manuals, I have found them to be very useful, and they obviously contain copies of many portions of MF manuals.

But one immediate difference related to my tractor is quite obvious: what the actual MF manual calls "Clutch Pedal Free Travel Adjustment," the Jensales manual calls "Adjusting Clutch Linkage" without ever mentioning pedal free play. So I've been lost in the dark on that one.

So I have a live PTO with a dual-stage clutch, with ground drive option. I have never used the ground drive and don't plan to. In use, the tractor is usually sitting still near some brush pile, with the live PTO running around 540 rpm to drive a brush chipper.

You asked about the mechanic: That's a long, sad story. After an engine failure, I finally found a farm equipment dealer in a nearby town to overhaul the tractor. The repair was to be done during two "slow" Winter months, by the in-house mechanic. That stretched out to almost six months, with no real explanations other than an occasional "mechanic has been ill." All communication was with the owner; never the mechanic, who I finally met well into the project. When the tractor was declared ready, I went to check it out. The engine ran just fine. With the machine sitting still in the shop, I "checked" the live PTO by engaging it and looking over to the rear of the tractor to verify that the PTO shaft was turning. It was, although I now know that wasn't a valid test.

When the tractor was delivered, I hooked up my chipper to the PTO shaft to try it out, but it didn't turn, of course. I called the dealer, who said that he would work with me to get the problem solved. I suggested that his mechanic come to my place to work on the clutch, but "the mechanic was very ill and in the hospital." While waiting, I overhauled the clutch pedal bracket and tried various versions of "adjusting clutch linkage," but to no avail.

Did the mechanic check the finger height adjustments when he installed the clutch? I don't know since I've never been able to talk to him. I doubt it, since it doesn't work, and he made no effort to replace the badly-bent clutch pedal bracket. The transmission works properly, but I doubt that anything at all was done to adjust the clutch. The owner hasn't kept me informed about the mechanic's status, and I need to follow up on that.

More than likely, the release bolts for the PTO clutch will need to be adjusted. To complicate things in a major way, the big mounting structure for the frontend loader will have to be removed first. All of this must be done here, since I don't plan to let the tractor be returned to the repair place.

Without seeing your Jensales manual, I am going to guess it is a copy of the MF service manual # 1448768M92, so it should be ok. "Adjusting Clutch Linkage" is the section title in the MF manual I have. Setting the clutch linkage per the steps should set the pedal free play. The adjustment info is the same in the Operator's manual 1448326M8. In the case of your 275 the 5/32" clearance between the clutch shaft arm and transmission is the free play dimension in the linkage, rather than giving a dimension measured at the pedal itself as many show. Pedal free play travel is what it is when the 5/32" dimension is set.

The external adjustment working out correctly is based on the clutch pressure plate being set up correctly to start with. If the mechanic did not adjust it correctly as part of the rebuild, the external adjustments may not solve your issues.

Please explain the PTO operation better than "it doesn't turn". I am only considering the engine driven operation (control lever positioned to the rear) of the PTO here.

1. With your chipper hooked up, can you move (engage the PTO lever fully to the rear (engine) position if you move it with the engine shut off? You might have to bump the starter with the fuel stop pulled to get the coupling splines to line up and let the lever move to the rear. Then start the engine, does the PTO turn the chipper?

2. With your chipper hooked up, when you try to move the PTO control lever to the rear position (engine driven) does it just grind when trying to engage the lever (with the clutch pedal fully depressed) when the engine is running? If that is what it does you might be able to adjust the PTO release bolts in the pressure plate from the .080" spec'd setting to .065' to .070" to get a better release of the PTO disc.

If you are traveling the tractor and you push the clutch pedal about halfway, does the tractor stop travel and you can shift gears? The PTO should not disengage until the pedal is fully pushed to the stop (the last half of pedal travel).

 

[Herb40]

Thanks for the early morning reply today. I am responding this morning after putting the PTO through the test steps you suggested.

I reset the clutch pedal free travel to the 5/32" called for by MF, after setting the linkage rod length to about 11-5/8". With this setting, the top of the clutch pedal itself is able to move only about 2" before resistance is felt. (I noticed that the linkage rod length is now about 1/2" longer than it was before the tractor was overhauled.)

1. With the engine shut off, I was able to move the PTO lever fully to the rear (engine) position with little effort. I did not have to bump the starter. After the engine was started, the PTO did turn the chipper. Later, on a subsequent try, the starter had to be bumped once to allow the PTO lever to fully move to the desired position.

2. When trying to engage the PTO while fully depressing the clutch pedal with the engine running, the PTO gears just grind. I am hoping that the PTO bolts can be adjusted from below through the inspection port to eliminate this problem.

3. To test pedal-controlled gear shifting with the PTO running, I backed the tractor out onto the driveway and shut everything down, including lowering the chipper to the ground. I started the tractor with the PTO engaged as in part 1 above and raised the chipper from the ground. Using the clutch, I shifted into gear and drove a short distance, used the clutch to shift gears, drove farther, stopped (shifted into neutral), and lowered the chipper to the ground. The PTO never stopped turning at the same speed, which I verified at several points by checking the chipper's RPM reading. I stopped the engine and disengaged the PTO. When the PTO finally stopped turning (because of the chipper's rotational momentum), I turned around and drove back to my shop.

Note: Starting the engine with the PTO engaged and with this chipper attached places a tremendous strain on the starter because of the energy required to get the chipper's "drum" up to speed.

 

[Jim.ME]

I am not advocating you make a common practice of starting it with the chipper connected and the PTO engaged. It is a way to confirm the PTO clutch was not disengaging, but that the PTO itself does work.

From your description and you indicating it travelled and shifted ok with the engine/transmission clutch (first stage) when the PTO was engaged it is likely that an adjustment of the three bolts in the pressure plate will get the PTO clutch working. Try setting them at .065" or .070" instead of the .080" called out in the manual.

The PTO pressure plate bolts can be adjusted through the inspection port, with a bit of effort.

 

[Herb40]

I am not advocating you make a common practice of starting it with the chipper connected and the PTO engaged. It is a way to confirm the PTO clutch was not disengaging, but that the PTO itself does work.

From your description and you indicating it travelled and shifted ok with the engine/transmission clutch (first stage) when the PTO was engaged it is likely that an adjustment of the three bolts in the pressure plate will get the PTO clutch working. Try setting them at .065" or .070" instead of the .080" called out in the manual.

The PTO pressure plate bolts can be adjusted through the inspection port, with a bit of effort.

Jim, thanks a lot for your skilled assistance in attempting to solve my problem, and for building my confidence that a solution may be available. I will follow your suggested remediation as soon as possible.

The tractor is normally stored outside, on dirt, under a lean-to roof. The work will be done in my shop, after I make room for the tractor. I may have to lower the rollover protection frame to get the tractor through the door. I will contact the shop that did the original clutch work to see if they will send the mechanic over to help; otherwise, I will do the job myself.

The manual for the MF 236 frontend loader suggests that the sub-frame can be handled with a single floor jack, so the removal should be straight-forward. I have the jack and the pneumatic tools suitable for handling the large fasteners.

I will post here again after I have had my initial glimpse of the innards of the clutch and perhaps have had a chance to measure the gaps that may need adjustment. And, of course, whether the bolt adjustments have solved my problem.

 

[miangus]

I would make sure the clutch pedal linkage is set in the correct position for PTO operation. If the pedal seems to be annoyingly high, it is likely in the correct position. Tractors used primarily as loader tractors often have the clutch pedal set in the low position. Remove the bottom cover and adjust the release bolts to .060 inch making sure they are even. Also check to make sure your mechanic didn't damage the extensions on the release plate. Improper disassembly of the PTO clutch can break the extensions. Sometimes to get proper release of a two stage clutch they need to be forced to slip under load. Get your chipper running under heavy load and depress the clutch attempting to release the PTO.

 

[Jim.ME]

I would make sure the clutch pedal linkage is set in the correct position for PTO operation. If the pedal seems to be annoyingly high, it is likely in the correct position. Tractors used primarily as loader tractors often have the clutch pedal set in the low position. Remove the bottom cover and adjust the release bolts to .060 inch making sure they are even. Also check to make sure your mechanic didn't damage the extensions on the release plate. Improper disassembly of the PTO clutch can break the extensions. Sometimes to get proper release of a two stage clutch they need to be forced to slip under load. Get your chipper running under heavy load and depress the clutch attempting to release the PTO.

The service manual for the MF 255, 265, & 275 I have shows there is only have one hole in the clutch linkage, so changing between pin holes does not apply to his 275. I believe the pressure plate was not adjusted correctly for proper release of the PTO disc.

 

[Herb40]

After adjusting the clutch pedal linkage as specified in the MF manual, the pedal IS annoyingly high. The transmission does not engage until the pedal is almost fully released, with only a couple of inches to spare.

I am in the middle of getting ready to adjust the release bolts. Yesterday, I removed the big loader frame covering the opening under the clutch and peered into the abyss. No, just kidding, but it does look kind of daunting:

1. I know that I need two 1/2" open-end wrenches with handles of some undetermined length. How tight are the lock nuts and the bolts themselves? Do the wrenches need to be ground down anywhere to fit? Of course, the answers will be known when I try something.

2. For the two bolts I can see (one well; one partially), the gaps appear to be different. I bought a caliper but don't know yet whether it will fit. I also bought a set of feeler gauges. It may be possible that I can stick some combination of them into an accessible bolt's gap to measure it. As for setting the gaps later, I was thinking of epoxying a nickel (or something else of the desired gap width) to a pencil-like handle, with an appropriate angle between the two. My caliper says that the thickness of a nickel is exactly 0.070". Is that suitable, or should I go smaller with 0.06 or 0.065? It's always possible to try something and then try again, but I'm afraid I would finally give up on this project if I had to do that.

3. But before any of that is going to be useful, how am I going to rotate the shaft to move from one bolt to the next? Of the techniques I have found, the "best for precision" technique was to turn the shaft via the bolt head on the crankshaft pulley at the fan belt. But that location is impossible to reach without removing much of the frontend of the tractor. Another suggestion was to raise one rear tire off the ground and turn it, but with less precision. I am wondering whether there is some way to engage the PTO shaft and turn it.

I'm off to the tractor to try some things.

Thanks for your ideas.

 

[Jim.ME]

After adjusting the clutch pedal linkage as specified in the MF manual, the pedal IS annoyingly high. The transmission does not engage until the pedal is almost fully released, with only a couple of inches to spare.

I am in the middle of getting ready to adjust the release bolts. Yesterday, I removed the big loader frame covering the opening under the clutch and peered into the abyss. No, just kidding, but it does look kind of daunting:

1. I know that I need two 1/2" open-end wrenches with handles of some undetermined length. How tight are the lock nuts and the bolts themselves? Do the wrenches need to be ground down anywhere to fit? Of course, the answers will be known when I try something.

2. For the two bolts I can see (one well; one partially), the gaps appear to be different. I bought a caliper but don't know yet whether it will fit. I also bought a set of feeler gauges. It may be possible that I can stick some combination of them into an accessible bolt's gap to measure it. As for setting the gaps later, I was thinking of epoxying a nickel (or something else of the desired gap width) to a pencil-like handle, with an appropriate angle between the two. My caliper says that the thickness of a nickel is exactly 0.070". Is that suitable, or should I go smaller with 0.06 or 0.065? It's always possible to try something and then try again, but I'm afraid I would finally give up on this project if I had to do that.

3. But before any of that is going to be useful, how am I going to rotate the shaft to move from one bolt to the next? Of the techniques I have found, the "best for precision" technique was to turn the shaft via the bolt head on the crankshaft pulley at the fan belt. But that location is impossible to reach without removing much of the frontend of the tractor. Another suggestion was to raise one rear tire off the ground and turn it, but with less precision. I am wondering whether there is some way to engage the PTO shaft and turn it.

I'm off to the tractor to try some things.

Thanks for your ideas.

I believe you said you can engage the PTO with the engine off. With the engine off engage the PTO. Make sure the engine stop remains held in the OFF position, wire the knob pulled out if needed, to be sure it doesn't decide to fire when you are turning the PTO shaft. It is not likely it would, but don't take a chance. Use a good-sized pipe wrench to turn the PTO shaft to bring the bolts to the bottom. for adjustment.

.070" is a good starting point. You will want to use feeler gauges or make a tool such as you described to check the gap; a caliper is not the tool for that.

You will want at least two 1/2" open end wrenches. You might want a couple longer ones as well as the shorter standard-length ones. Trying them is going to be what tells if you need to grind some off them or not.

Mark the pressure plate beside each one after adjusting to be sure. That will let you know that you didn't turn by one.

 

[Bob NY]

After adjusting the clutch pedal linkage as specified in the MF manual, the pedal IS annoyingly high. The transmission does not engage until the pedal is almost fully released, with only a couple of inches to spare.

I am in the middle of getting ready to adjust the release bolts. Yesterday, I removed the big loader frame covering the opening under the clutch and peered into the abyss. No, just kidding, but it does look kind of daunting:

1. I know that I need two 1/2" open-end wrenches with handles of some undetermined length. How tight are the lock nuts and the bolts themselves? Do the wrenches need to be ground down anywhere to fit? Of course, the answers will be known when I try something.

2. For the two bolts I can see (one well; one partially), the gaps appear to be different. I bought a caliper but don't know yet whether it will fit. I also bought a set of feeler gauges. It may be possible that I can stick some combination of them into an accessible bolt's gap to measure it. As for setting the gaps later, I was thinking of epoxying a nickel (or something else of the desired gap width) to a pencil-like handle, with an appropriate angle between the two. My caliper says that the thickness of a nickel is exactly 0.070". Is that suitable, or should I go smaller with 0.06 or 0.065? It's always possible to try something and then try again, but I'm afraid I would finally give up on this project if I had to do that.

3. But before any of that is going to be useful, how am I going to rotate the shaft to move from one bolt to the next? Of the techniques I have found, the "best for precision" technique was to turn the shaft via the bolt head on the crankshaft pulley at the fan belt. But that location is impossible to reach without removing much of the frontend of the tractor. Another suggestion was to raise one rear tire off the ground and turn it, but with less precision. I am wondering whether there is some way to engage the PTO shaft and turn it.

I'm off to the tractor to try some things.

Thanks for your ideas.

There are 2 adjustments that should be done while the tractor is split. One is the bolts in the clutch fingers that the throw-out bearing contacts. That HAS to be done with the tractor split. Your comment in the first line above makes me think that adjustment is out of whack. The second adjustment is for the second stage to disengage. I have one manual that recommends .090 and another that says .080. My 165 is set at .090 and my 65 is at .080. They both work fine. I had to close my 35 down to .070 to get the clutch to behave. I would recommend .090 or .080 to start with. I have done that adjustment up through the bottom with standard wrenches. Bear in mind that if the first adjustment isn't right, you probably won't be able to get the second right either.

 

[Jim.ME]

While not as good as properly setting the pressure plate fingers while the tractor is split one can make sure the fingers are in the right ballpark. Check to see that the adjusting bolt threads are flush to the back side of the fingers, or up to a couple threads out the back. Use a feeler gauge or such to see if the three adjusting screws are the same distance from the throw out bearing face. Ideally the gap distance will be within a few thousandth of each other. If they are way off, you can adjust the finger bolts. Keep the adjusting bolts fully threaded through the fingers, turn the others in if one is just flush to start with.

As Bob mentioned you should check the gaps of the second stage bolts to determine what adjustment to make. As I posted earlier the MF service manual for the MF 275 secondary release bolts to be set at .080". If they are a lot greater (.010 or more) than .080 I would adjust them to that setting and check the PTO engagement. If they are at .080, I would change the gap to .070 and test the PTO.

 

[Herb40]

While not as good as properly setting the pressure plate fingers while the tractor is split one can make sure the fingers are in the right ballpark. Check to see that the adjusting bolt threads are flush to the back side of the fingers, or up to a couple threads out the back. Use a feeler gauge or such to see if the three adjusting screws are the same distance from the throw out bearing face. Ideally the gap distance will be within a few thousandth of each other. If they are way off, you can adjust the finger bolts. Keep the adjusting bolts fully threaded through the fingers, turn the others in if one is just flush to start with.

As Bob mentioned you should check the gaps of the second stage bolts to determine what adjustment to make. As I posted earlier the MF service manual for the MF 275 secondary release bolts to be set at .080". If they are a lot greater (.010 or more) than .080 I would adjust them to that setting and check the PTO engagement. If they are at .080, I would change the gap to .070 and test the PTO.

You have me in a new ballpark here, speaking of making sure that the pressure plate fingers are in the right ballpark, in case they were not set properly when the tractor was split. So far, my attention has been solely on making sure that the second stage bolts are set properly. Where do I find the "back side of the fingers?" Am I now supposed to be checking the pressure plate finger bolts before working on the second stage bolts?

 

[Bob NY]

Go ahead and adjust the second stage bolts and see what happens. Be advised that if the second stage is pushed past the disengagement point, something in there can catch the rivet heads for the secondary clutch plate and start driving it again. That is why I had to back off my 35 to .070.

 

[Herb40]

Go ahead and adjust the second stage bolts and see what happens. Be advised that if the second stage is pushed past the disengagement point, something in there can catch the rivet heads for the secondary clutch plate and start driving it again. That is why I had to back off my 35 to .070.

OK, thanks. I did some checking and experimenting this morning and found the following:

1. I put the PTO in gear (lever back) and started the engine with the chipper attached. The PTO turned the chipper, as expected. When I detached the chipper from the PTO shaft, I was unable to turn the PTO shaft clockwise with an 18" pipe wrench. I plan to try again, but with a long cheater bar over the pipe wrench. Without some solution to this problem, I would be left with making hit-or-miss repetitions of the starting approach in order to ultimately expose all three bolts for adjustment, while also putting a big strain on the starter (and myself).

2. After the attempt above, one of the bolts that had not been exposed before was found to have a neat, chartreuse paint stripe from the side of the bolt head, along the shaft, across the lock nut, and onto the anchoring metal. This is not necessarily significant, but to me suggests the painting was done by the manufacturer and intended to alert the installer to the need for adjustment. I plan to color all three bolts so I can tell them all apart.

3. The gap for the bolt in 2. above exceeded 0.09". That's using the combination of the 3 thickest "feelers" on my feeler gauge. I could have measured more accurately with a different combination of 4 or more adjacent feelers, but that the gap exceeded 0.09" is all I need to know.

4. The gap for the other bolt that was exposed felt snug at 0.83 and again showed that no adjustments had been made. I saw no paint on what I could see of this bolt.

Using an actual feeler gauge for this work is too cumbersome. A series of tests with a caliper on three nickels showed that the measurements clustered in the 0.07 range, so I plan to make a feeler gauge with a nickel epoxied to a long pencil.

 

[Jim.ME]

Depending on compression it is not going to turn easy via the PTO shaft, you will need some leverage. Block the tires, transmission in neutral, and fuel stop pulled and held shut off.

Sounds like adjusting the PTO clutch bolts may solve the problem.

As for the finger adjusting bolts, you won't find the check I suggested in a manual. Checking how much of the bolt thread is out the back of the fingers is one of those thing people who have changed a number of these type clutches will notice. It is common that one will see about the same number of threads of the finger adjusting bolts showing on the clutch disc side of the fingers, after using the recommended gauge procedure for setting the throw out bearing side heads of those finger bolts. That should say they are about the right height with the second step that all three be adjusted to within .010" to .015" between minimum to maximum clearance to the throw out bearing face. Using the right gauge when the clutch is installed while the tractor is still split, allows setting both of these finger positions, what I posted is a way to see that it is close without splitting it to check.

 

[Bob NY]

Check the thickness of a hacksaw blade, or maybe 2 together. I think I remember someone recommending that for adjusting the second stage bolts.

 

[Jim.ME]

Check the thickness of a hacksaw blade, or maybe 2 together. I think I remember someone recommending that for adjusting the second stage bolts.

I believe a common hacksaw blade is about .025" so that would be like using feeler gauges. His idea of a nickel on a stick, should work.

 

[Herb40]

I'm back after a short hiatus to catch up on chores around the house and outdoors, search for longer 1/2" open end wrenches, wait on wrenches to arrive, epoxy a nickel to a wooden dowel, check out the turning of the PTO shaft to expose the pressure plate bolts, etc.

The PTO shaft can be turned fairly easily after a long "cheater" bar is placed over the handle of a pipe wrench gripping the shaft. Only a slight turning of the PTO shaft is needed to make a big difference in the turning of the pressure plate and the accessibility of the individual bolts, since the PTO system was designed so that at 1685 engine rpm, the PTO shaft is geared down to turn at 540 rpm.

In terms of the rotation of the pressure plate:
1685 engine rpm = 540 PTO rpm, and 1 engine rev = 1 pressure plate rev
1 pressure plate rev = 540 / 1685 PTO shaft rev = 0.32 PTO shaft rev
In degrees, to rotate the pressure plate 360 degrees requires only a 115-degree rotation of the PTO shaft.

Now, on to my experimentation. I call it experimentation because after several hours of trying to adjust even one of the bolts to my goal of 0.7" gap, I haven't managed to adjust a single one. The basic problem is that I cannot get my 1/2" open end wrench around either a bolt head or a lock nut. Of course, the heads are six-sided and the wrench end is slanted off at 10 degrees or so, and perfect alignment is required to slip the wrench onto a bolt or lock nut. I expected to find an example of this perfect alignment somewhere among the three bolt heads and three lock nuts, but no such luck. For some reason, all bolt heads and lock nuts have essentially the same orientation, so the wrench tends to fail to fit on all of them. I had carefully ground down the thickness of the wrench end quite a bit. Tomorrow, I will grind down the width of the two fingers that grasp the bolt and try again.