Hydraulic Pump screen filter element location

[[email protected]]

Frankenhoe is coming along well. I actually got the motor running. So now it’s on to hydraulic stuff. I’m using Tech Manual-1068 and parts manual pc-972 page 50-14. JD 300 backhoe.

I added some hyd fluid and I moved ever so slightly the buck, because I don’t want it falling off the stands and blocking. Blew the bottom hyd cooler line and noticed the milky color of the fluid.

In research I found out there are 2 big filters to replace AR 75603 and hidden in 2 other unfortunate locations are round wire screens that go in holes. AR 26375 in the transmission case, once located, it wasn’t too bad.

And R27173 hiding somewhere in the hyd pump stroke control valve. I have the 3.01 cu. in. AR56160 hyd pump. I have spent the last 3 days researching changing hyd oil and filters.

Picture 1. I removed 2 of the plugs this morning looking for the filter. Both on top and the easiest to get at, I believe I removed (1.0 in size) plug 11 that says it’s a drain plug and seemed to be an empty hole, it’s right next to a small finger turn valve I didn’t want to mess with, it’s also not shown on my drawing pg.50-14. I did see this valve in a video that said it had something to do with ‘stroke and pump pressure?’ The diameter of this hole is smaller than the filter, so it can’t be the right place.

Picture 2. So next on the side that would be easiest to access with air cleaner installed was a nice big 1 ¼ in plug. I removed it and was just an empty hole. I really expected to find the stack up assembly shown on the right side with part # 33 screen R27173 filthy and waiting to be changed. But just an empty hole with a plug in it. Picture 3.

Picture 4 and 5. So I looked at the bottom, I think I see part 20 bushing, 37 set screw, and 17 lock nut, I think 1 ¼ in, as shown in left side stack assembly and next to it is a plug, looks to be 1 ¼ in.

Shouldn’t the assembly and screen be in the empty end hole?

Could it work with that assembly missing?

Would john deere locate a filter in a place that requires removal of the hyd pump to simply replace?

And it’s really hard to see but it looks like those 2 nuts end up being so close to each other there isn’t enough space for a socket to fit over either one. It is a very tight squeeze with no room to work of course. Anyone know the trick?

It would be great if the fix was just rebuild that assy with the 12 or so parts it would take for that empty spot.

Thanks ….. bob

 

[M-MAN]

The little turn valve you mentioned in picture 1 is the destroke valve which is used for cold starting. Sometimes a piece of trash will get stuck in there and you can free it by screwing it in. Can't help with the rest.

 

[Jim.ME]

From the pump breakdown in the online parts catalog PC972, the filter should be above the hex head plug on the right-side bottom of the pump housing.

It also appears some of the pumps (with serial plates) did not have a filter, there is a valve above that plug.

 

[[email protected]]

The little turn valve you mentioned in picture 1 is the destroke valve which is used for cold starting. Sometimes a piece of trash will get stuck in there and you can free it by screwing it in. Can't help with the rest.

noted .... thanks

 

[buickanddeere]

A big win to have that de-stroker already installed in there .

 

[[email protected]]

From the pump breakdown in the online parts catalog PC972, the filter should be above the hex head plug on the right-side bottom of the pump housing.

It also appears some of the pumps (with serial plates) did not have a filter, there is a valve above that plug.

thanks ... you were 100% correct, no riveted-on plate so not one of those, so i took the pump out, about 3 hours, a socket will fit, popped it open and there it was... i'm not sure how often you need to change this screen but i wouldn't want to have to do that each time. i have the front axle, spindle and knuckle type front as on page 60-5, the center part of the casting that holds the pivot (with parts 9-12) needs a access hole so you could get to the bottom easier, i don't think it would weaken it too much , but that plate does take all the weight for the front end and i'm not working at the machine shop anymore, so no access to a mag base drill and core drill. thinking maybe cut down a socket to make it thinner and make some kind of tool to be able to reach into the thin space to get the plug out, then you would have to see if you have enough room to get the old one out and new one in.

so, thanks again and i say you know your stuff .....

 

[Jim.ME]

thanks ... you were 100% correct, no riveted-on plate so not one of those, so i took the pump out, about 3 hours, a socket will fit, popped it open and there it was... i'm not sure how often you need to change this screen but i wouldn't want to have to do that each time. i have the front axle, spindle and knuckle type front as on page 60-5, the center part of the casting that holds the pivot (with parts 9-12) needs a access hole so you could get to the bottom easier, i don't think it would weaken it too much , but that plate does take all the weight for the front end and i'm not working at the machine shop anymore, so no access to a mag base drill and core drill. thinking maybe cut down a socket to make it thinner and make some kind of tool to be able to reach into the thin space to get the plug out, then you would have to see if you have enough room to get the old one out and new one in.

so, thanks again and i say you know your stuff .....

What was in that screen, anything? Good for you doing it. I will bet many of those never get checked or replaced. Cleaning, not replacing is a standard practice for a screen.

 

[[email protected]]

A big win to have that de-stroker already installed in there .

okay, not exactly sure why? the youtube i watched about that, the guy said he didn't think he was getting the correct pressure, so he hooked up a pressure gage and tweaked it in, but i didn't get the impression it was something that needed messed with very often? but i thought an installed pressure gage might be nice to be able to keep an eye on it, and might tell you if the filters are getting clogged ... thanks for the info

 

[[email protected]]

What was in that screen, anything? Good for you doing it. I will bet many of those never get checked or replaced. Cleaning, not replacing is a standard practice for a screen.

didn't notice any metal, wasn't blocked off but wasn't clean, i set it aside so the oil would drain off then i will be able to see the dirt, have totally redone this thing from the reverser to the fuel tank, taking forever 1 year tear it apart, 2 year find a short block and get all the parts, this year put together, it seems to be turning out very well, just a hobby i don't need it so i'm not in a hurry to get it fixed so when i find something i have the time to wait and get the parts, the learning curve has been steep, it would have been very easy to have done this (if i had only know it needed done) before i put the radiator and fuel tank and all that stuff back in, but i only had to take the radiator out to get the pump out, and i don't like the way it's mounted so i'm going to change it a little....... thanks for the help and interest it's really great to have someone to bounce ideas and ask question ...

 

[buickanddeere]

okay, not exactly sure why? the youtube i watched about that, the guy said he didn't think he was getting the correct pressure, so he hooked up a pressure gage and tweaked it in, but i didn't get the impression it was something that needed messed with very often? but i thought an installed pressure gage might be nice to be able to keep an eye on it, and might tell you if the filters are getting clogged ... thanks for the info

Way back when on a previous line of posts . The de-stroker was discussed . It reduces the load on the starter by de-stroking the front pump .

 

[matthies]

The bushing and nut picture, the nut locks the allen head bolt inside of it. This is where you adjust your hyd pressure at. Loosen the nut(3/4 inch wrench) and slowly turn in the allen head until 2100 psi is acheived, engine running at fast idle and a gauge in a pressure line.

 

[Tx Jim]

Factory stand-by pressure setting is 2250 psi

 

[[email protected]]

Okay, the hyd pump / front end is done and back together. The old screen in the pump had some crud mostly on the inside but the metal screen along about 80% of the length had torn open (blew out) and so I’m not sure how much screening it was doing. But everything looks good now.

Now moving on the transmission case and screen ar26375, the old one really had a lot of crude and was stuck in there real good, I had to twist it about 360 degree and pull big time to get it out, at one point I thought it was coming out in pieces, but it came out. I noticed a lot of sludge in the bottom, took off the rockshaft housing to look down in, and it still has some pockets of milky old oil and a lot of junk in the bottom.

Questions;

• Best way to clean as much sludge from tank bottom as is possible?
• I didn’t see a magnet anywhere, seems plenty of room at the bottom of those 2 tanks to add one in each side? If it wouldn’t interfere with anything.
• As I was standing there looking at those gears, I noticed that about 15-20% of the inside of the trans housing still had JD yellow paint on it (new at factory) and I wondered where the rest of the paint went?
• So all the paint missing has been trapped by filters through the years and removed or is still currently at the bottom of the housing and whatever paint is still there will keep coming off until it’s all gone and go into the system to be filtered or settle to the bottom?
• Can I run the motor and pump with the rockshaft housing (cover) off to see inside when running?
• How about with the transmission and shift lever cover removed?

The plan is to

• clean up things as much as possible
• reassemble
• put new oil in
• start the motor so the pump will run
• run thru the gears to see the axil turn

thanks….bob

 

[Tx Jim]

I've read where several people have installed magnets designed to control hardware disease in cows. If you attempt to operate engine with rockshaft housing off you will have a major oil leak on RH front of opening in trans case. Operating with trans shift cover removed will also be a major hyd oil leak. Loose paint inside trans case should get trapped with hyd filter & suction screen.

 

[[email protected]]

I thought it would leak hydraulic oil without the covers.

Maxi-Pads with wings, so today I cleaned a lot of the sludge from the bottom of the transmission case. The rear or back half of the case has the most room to work. Looking for some way to get this done I ended up going with Maxi-Pads, they worked surprising well, and have several interesting qualities, so I packed 4 into the bottom of the back half absorbent side down with a small dowel and was able to get two into the front part, sort of, don’t pack to tight. Had lunch and about an hour later dug then out with a wire hook and some long pliers. Only had one stick up a little, was able to push it around and it came right out, they all came out in the same whole condition they went in, none ripped or came apart in any way. In the rear half with the second cleaning, I was able to get a great deal of that black sludge, I was very happy with the results.

Then I took the bore scope to the transmission bottom screen hole to take a look around, didn’t see anything loose floating or moving around. Lots of sludge. Cleaned out as much as I could with rags.

But while I have the covers off, I was going thru the shift pattern, the right (speeds) seems to all go into all four gear positions and work fine. However, the left selector with Park, II, and I, Reverse, seems maybe have some issue.

Is there some kind of safety that keeps or controls the left shift lever?

All safety circuits have been removed, the old wires and harness were toast, and those existing components toast too and were removed.

All I have right now is a battery connected to the starter and a starter button connected to the solenoid to start.

The fuel pump will turn off motor at its slowest / off setting, to stop motor.

It’s well blocked off the ground with back wheels off for safe testing.

Thanks….bob

 

[Tx Jim]

IIRC trans shifter will only go into reverse when high/low gearshift is in low speed location. RH gearshift lever must be in a gear selection for LH lever to go into "P".

 

[[email protected]]

IIRC trans shifter will only go into reverse when high/low gearshift is in low speed location. RH gearshift lever must be in a gear selection for LH lever to go into "P".

thanks, i will try that this afternoon, subject to rain.........

 

[Jim.ME]

What is the "issue" with the left selector?

To be clear, does your 300 have the hydraulic reverser (lever below the steering wheel on the left side) transmission? I know on the 401C there was no reverse in the range gear box (left shift lever on the transmission), with the hydraulic reverser only Park, I and II and I expect yours would be the same. If yours shows reverse on a decal next to that lever it is likely the wrong decal was applied. They block reverse out when in High (II) range for safety reasons (speed control). Below is a clip from a 300 Operator's Manual.

 

[Tx Jim]

Thank for correction/clarification. I forgot most JD industrial tractors have hyd reversers

 

[Jim.ME]

Thank for correction/clarification. I forgot most JD industrial tractors have hyd reversers

No problem. I just thought it was time to get clarification on the transmission. I don't think he has ever said if it has a reverser (or the hydraulic HI-Lo) or not. If it has the reverser there is no reverse in the range gearbox.