New sprocket for front mount hydraulic pump is super tight fit

[Delgriffith]

Not really a Ford question, but it is a pump on a Ford 860, 3/4" drive shaft. I had the splined hub on the engine wipe out from wear and when I disassembled things I noticed the keyways were messed up on the pump drive sprockets. I bought a new set of sprockets and tried to put one on the pump shaft. After slugging on it with a rubber hammer and not making any progress I figured I need a new approach. I pulled it off and noticed the mark where I had driven it on. It looks like I was actually digging into the sprocket metal slightly as I drove it on.

I'm debating heating the sprocket or sanding the pump shaft until it goes on. I don't like either option. Just wondering if anyone has dealt with this kind of thing and how it was resolved.

 

[TheOldHokie]

Not really a Ford question, but it is a pump on a Ford 860, 3/4" drive shaft. I had the splined hub on the engine wipe out from wear and when I disassembled things I noticed the keyways were messed up on the pump drive sprockets. I bought a new set of sprockets and tried to put one on the pump shaft. After slugging on it with a rubber hammer and not making any progress I figured I need a new approach. I pulled it off and noticed the mark where I had driven it on. It looks like I was actually digging into the sprocket metal slightly as I drove it on.

I'm debating heating the sprocket or sanding the pump shaft until it goes on. I don't like either option. Just wondering if anyone has dealt with this kind of thing and how it was resolved.

The specifics of what pump and implement you have would be helpful.

What sort of "sprocket" are we talking about? Is it one half of a roller chain shaft coupler? If so it is supposed to be a slip fit. Pounding on the pump input shaft is a recipe for early pump failure.

Dan

 

[Delgriffith]

The specifics of what pump and implement you have would be helpful.

What sort of "sprocket" are we talking about? Is it one half of a roller chain shaft coupler? If so it is supposed to be a slip fit. Pounding on the pump input shaft is a recipe for early pump failure.

Dan

It is that type of sprocket. The output shaft from the front of the engine has a sprocket on it and the pump has an identical one. They are coupled by a double wide chain. I don't think I hit it hard enough to damage anything but I'll find out I guess. Seems the only option to have it slip on is to sand the shaft smaller... or mount the sprocket in a lathe and bore it slightly larger.

This is the same pump we were discussing in the other thread from a month ago. It was working well enough to run the backhoe and so I had a job I was working on with it and the splines wiped out on the hub during that project. I finally got a loading valve about the time the hub went out and so I still haven't been able to test the pump. Just trying to get it back together now. I think there was some misalignment as well as one stripped bolt hole that caused an early failure on the hub splines. I put in a helicoil thread repair and I'm going to try to get the alignment with everything better to avoid having it tear up the hub splines again.

Ford 860 front mount Eaton 26013 hydraulic gear pump

I installed an aftermarket power steering system on my 860 and I am concerned I may have damaged my hydraulic pump that had been working fine for my loader. During the plumbing of the new power steering I accidentally left no route for the pump to circulate under no load and started the tractor...

forums.yesterdaystractors.com

 

[TheOldHokie]

It is that type of sprocket. The output shaft from the front of the engine has a sprocket on it and the pump has an identical one. They are coupled by a double wide chain. I don't think I hit it hard enough to damage anything but I'll find out I guess. Seems the only option to have it slip on is to sand the shaft smaller... or mount the sprocket in a lathe and bore it slightly larger.

This is the same pump we were discussing in the other thread from a month ago. It was working well enough to run the backhoe and so I had a job I was working on with it and the splines wiped out on the hub during that project. I finally got a loading valve about the time the hub went out and so I still haven't been able to test the pump. Just trying to get it back together now. I think there was some misalignment as well as one stripped bolt hole that caused an early failure on the hub splines. I put in a helicoil thread repair and I'm going to try to get the alignment with everything better to avoid having it tear up the hub splines again.

Ford 860 front mount Eaton 26013 hydraulic gear pump

I installed an aftermarket power steering system on my 860 and I am concerned I may have damaged my hydraulic pump that had been working fine for my loader. During the plumbing of the new power steering I accidentally left no route for the pump to circulate under no load and started the tractor...

forums.yesterdaystractors.com

DoeS the pump have a round shaft with square key?

 

[LarryMaine]

Have the same set up on my 850. The sprockets should both have small allen head set screws. The sprockets should fit onto the shaft easily but not be wobble loose. The set screws are used for the initial alignment, ie space between the two sprockets that matches the spacing of your double chain. Assuming you got the alignment right, it is the chain that keeps the spacing correct. The sprockets are kept from rotating on the shaft from torque by the longish square or rectangular key and the matching keyways on the sprockets and shaft. The set screws can just keep the sprockets and chain walking back and forth on the shaft during operation. Just make sure the sprockets and shaft have matching keyways, because if the key is not tight within the keyway, you are sure to rip it up and ruin the sprockets, chain, and shafts. As said above, do NOT hammer on either of the two shafts. You can gently sand away some metal to get the sprocket to fit better onto the shaft, however, all the ones I have worked on; the sprockets do not bind on the shafts. I would remind you, this is a high torque and high wear area prone to damage, so the initial alignment and fit is critical.

 

[TheOldHokie]

Have the same set up on my 850. The sprockets should both have small allen head set screws. The sprockets should fit onto the shaft easily but not be wobble loose. The set screws are used for the initial alignment, ie space between the two sprockets that matches the spacing of your double chain. Assuming you got the alignment right, it is the chain that keeps the spacing correct. The sprockets are kept from rotating on the shaft from torque by the longish square or rectangular key and the matching keyways on the sprockets and shaft. The set screws can just keep the sprockets and chain walking back and forth on the shaft during operation. Just make sure the sprockets and shaft have matching keyways, because if the key is not tight within the keyway, you are sure to rip it up and ruin the sprockets, chain, and shafts. As said above, do NOT hammer on either of the two shafts. You can gently sand away some metal to get the sprocket to fit better onto the shaft, however, all the ones I have worked on; the sprockets do not bind on the shafts. I would remind you, this is a high torque and high wear area prone to damage, so the initial alignment and fit is critical.

Maybe the OP needs to back that set screw out a few turns....

Dsn

 

[Delgriffith]

Yes, it is a round shaft with square key. And no, the set screws are backed out. Guess I'll sand down the shaft. That's easiest anyway.

 

[Destroked 450]

Measure the shaft and the hub, also check the end of the shaft to make sure it’s not swelled out a little

 

[TheOldHokie]

Measure the shaft and the hub, also check the end of the shaft to make sure it’s not swelled out a little

And maybe run a 3/4" drill bit through the hub....

 

[Delgriffith]

After sanding on the shaft for a while I think I know what happened. The key sheared and slippage apparently friction welded metal onto the shaft. I could see outlines of irregular shaped metal circumferentially wrapped around at the end of the key way. Once I sanded those away the sprocket slipped on.

 

[LarryMaine]

FYI - Not sure why the key sheared, either over torque which can happen if the engine is still turning and the pump freezes up, or bad initial alignment. Sounds like you figured it out, but if it does happen again, there are other methods of marrying the pump to your engine output shaft, i.e. using a hub that has rubber bushings around the bolt holes. I presume you have a hub that bolts onto the front pulley, and that should have some rubber bushings, but you can change out the chain and sprockets for a different splined shaft that will work with a different style of connector to the pump shaft and which will have some built in means of buffering the torque on startup.

 

[TheOldHokie]

After sanding on the shaft for a while I think I know what happened. The key sheared and slippage apparently friction welded metal onto the shaft. I could see outlines of irregular shaped metal circumferentially wrapped around at the end of the key way. Once I sanded those away the sprocket slipped on.

The discharge pressure test of that pump may tell you more. The sheared key is another sign it may have been severely over pressurized....

Dan

 

[Delgriffith]

FYI - Not sure why the key sheared, either over torque which can happen if the engine is still turning and the pump freezes up, or bad initial alignment. Sounds like you figured it out, but if it does happen again, there are other methods of marrying the pump to your engine output shaft, i.e. using a hub that has rubber bushings around the bolt holes. I presume you have a hub that bolts onto the front pulley, and that should have some rubber bushings, but you can change out the chain and sprockets for a different splined shaft that will work with a different style of connector to the pump shaft and which will have some built in means of buffering the torque on startup.

Yes, the hub has rubber bushings in it. I think alignment was the major factor. It had one totally stripped hub bolt and another with barely any threads left. Helicoiled both. The sprocket faces were not on parallel planes as well. I think it was wandering and working around as it rotated just wearing parts hard. The new hub has a larger shaft diameter at the hub, and larger sprockets on the other end with the 3/4" dia. I've taken pains to align them to be plane parallel and as close to coaxial as possible.

 

[LarryMaine]

Great, now as Dan suggested in your other thread, replace the pump and re-plumb your system.
Good Luck.