How much noise?

[Bill Radford]

On a previous thread we talked about my hydraulic pump problems and what we found when we got into it.
I wound up having the drive portion of the pump (gear, wobble shaft and bearings) replaced. We (me and the mechanic) decided that the pump half was ok .
Put her back together. Drive gear on back of cam looked ok and was solid. Could not get it to move or wiggle.
Lift is very strong, but I still have some noise when the lift is stationary that goes away when I lift an implement.
I realize that this is most likely coming from:
1: the new pump gear against the old cam drive gear
2: some looseness in the front cover gearset
In an ideal world where time and money were unlimited, I would probably want to take the engine off and replace the cam gear, crank gear and pump drive gear on the back of the cam.
The engine runs good, plugs look good, timing is spot on and the oil pressure is a steady 50-60 lbs.
No heating issues etc.
Tractor is only used for parades and light yard work.. no plows etc.
Since she's over a half century old I expect some clattering. Will it hurt anything to run the tractor?? (100 hours in last 3 years)
I dont have access to a comparable tractor nearby to listen and compare the way mine sounds to another one.

 

[Ecnerwal]

Noise might be coming from the relief/bypass valve? I'm not overly intimate with lift hydrualics, but if it's only happening when not working, it's got to be something that is involved with the flow of fluid when the lift is not being used. I don't know if that system runs full pressure and the relief is the bypass, or if there's a bypass no-pressure mode similar to how backhoe hydrualics usually work (being more familiar with them, though I do need to learn about 3-point now that I have one.)

 

[JMOR]

(quoted from post at 13:57:51 07/15/13) Noise might be coming from the relief/bypass valve? I'm not overly intimate with lift hydrualics, but if it's only happening when not working, it's got to be something that is involved with the flow of fluid when the lift is not being used. I don't know if that system runs full pressure and the relief is the bypass, or if there's a bypass no-pressure mode similar to how backhoe hydrualics usually work (being more familiar with them, though I do need to learn about 3-point now that I have one.)

is 641 has Ford's unloader design, which when not lifting (hold or lower) allows the pressure to drop down around 40 PSI, vs the lifting max of 2000.

 

[Hal/ Eastern WA]

First of all, I am not a trained mechanic, just an old farm boy who has tinkered with old machinery for nearly 60 years, and have usually been able to keep junk working, somehow.

I think if it was mine, I would remove the pump AGAIN! and figure out some way of seeing how the two gears are meshing. Maybe this could be done with clay, if you made sure the bits of clay could not fall down into the crankcase.

While you are in there, I would check the camshaft gear for any fore and aft looseness with a bar or large screwdriver, wondering if the gear could be rubbing on the block or cover when any thrust is taken up by the strain of operating the pump. It will probably move a little, but if it moves very much at all, I would be worried about whatever is supposed to deal with that thrust being worn out.

My experience with the hydraulic pumps on my tractors has been that I don"t hear anything from the gears meshing. But I have to admit that I sure don"t hear very well anymore. I am in the process of getting hearing aids. But I think I first removed and replaced my first hydraulic pump about 30 years ago, when my hearing was OK.

It would really worry me if there was much of any noise from 2 gears meshing, especially if one of them is brand new. Like you wrote about an ideal world, the best thing to do would be to split the tractor and put in a new gear on the back of the camshaft. But you MIGHT still have the noise after going to all that work and expense.

Sometimes it is hard to pinpoint the location of sounds. Maybe using a stethoscope might help. You want to be sure the noise you are hearing is really coming from the two gears you are looking at.

Another idea would be to continue to use your tractor as you have been, on light duty, and if the noise gets worse, maybe plan on replacing both gears. I also would probably plan on watching the oil I drained from the crankcase and the filter medium in the opened oil filter for steel particles. There shouldn"t be much of such evidence of wear, but you probably WILL find a little. If you find lots of filings, then fairly rapid wear is occurring and you probably need to deal with it SOON, or maybe something real bad might happen. I wish you luck in finding this gremlin!

 

[Bill Radford]

Hal:
Got a stethoscope cheap at Wally world, took off the round part at the end and stuck a small carriage bolt in the hose.
I'm an amateur but I think I heard something.
Most noise came from piston end of pump and traveled down the manifold toward the transmission. I could actually feel the vibration on the pump and down the manifold. Normal bearing noise in bottom end, normal in valve cover, no excessive noise in governor housing.
Front cover has some noise, but nothing like that on pump and manifold and doesn't change a lot when I raise the lift.
I know that noise would travel down cam and resonate down front cover.
Gear area of pump just rebuilt, no excess of normal gear noise at area of pump drive.No abnormal sounds in tach drive area.
Cam pump drive gear was solid, coudn't get it to move with a screwdriver from front to rear.
Do you think I would be wise to kit the piston part of the pump? I dont have the tool to remove the seats but most folks say this is usually not necessary..
Will post back after doing more homework.
Plan to take pump off soon and listen to engine running without pump.

 

[Hal/ Eastern WA]

If your mechanic friend said the valve parts of the pump looked OK and all the springs, balls and gaskets were where they were supposed to be AND the pump is not leaking, I don"t think I would take it apart again.

It might be interesting to see if you hear the same noises when the pump is not on the tractor. You might want to put a rag or cardboard over the opening to avoid oil being tossed about. I also would cover the hydraulic manifold to make sure nothing drops into the openings.

Obviously if the noise is still there, there must be a problem somewhere else and maybe the pump and its drive are OK. But just where? Unusual noises worry me. Good luck!

 

[Bill Radford]

Heres where we are now...
Took pump off... Much less noise, probably normal for age of engine.Gears show no wear. Checked cam gear on rear of motor..no front to rear thrust, solid in shaft.
Took pump end of hydraulic pump apart.. really nasty in there. Got kit and stripped the pump down. Gaskets were stuck to pump parts. Put everything that was not rubber in cleaning bucket overnight, then scraped off all gasket material.
Cleaned everything super clean with brake cleaner, dried with air.Put on bench after lightly coating all bare metal surfaces w/light coat of hydro oil.
Gonna put it all back together tonight.
Wish me luck that this is the gremlin I've been hunting.