Ford 641 hyrdaulic pump problem

A couple of months ago I did the hydraulic cover service on my 641. I cleaned the sump thoroughly and replaced the fluid with CNH 134.
The lift is strong now and works properly. The "bobble" is almost completely gone.
The problem is that the pump is making a lot of noise now. The tractor sounds like a diesel.
I bled the system by screwing a barbed fitting into the bleed port and running a hose to the sump fill port under the seat. I cranked it up and allowed it to run for 15-20 minutes. No bubbles in fluid at all.
I can lift an implement and the noise disappears while the lift is going up and resumes when the implement is raised and held steady.
I can hear the clattering in the valve end of the pump and can pretty well isolate it there with a mechanic's stethoscope.
I removed the proof meter adaptor and checked the 7/16 bolt on the pump gear for tightness. I managed to snug it up very slightly, but there was no change in the noise.
The lift functions well as it is. Is there any risk of damage to the camshaft or other internal engine parts to continue running the tractor?
Please advise as whether to rebuild the pump or what else I may need to do. Tractor runs great, have adjusted valve train to specs last year when I had hood off.
Thanks a bunch in advance.. I have searched the site but have found only bits and pieces of what I need to know.
 
Bill, when you bleed the pump with the hose back to the fill hole, did the noise go away?

I'm thinking you might have a stuck closed pressure relief valve.
 
Then I don't think its the relief valve.

Inside of the front of the pump are 6 pistons, 6 springs, and 12 check valve balls and springs. Maybe something is going on in there. Not too hard to pull the pump and then the head off the pump. There is a pump rebuild kit available that gives you the springs and balls. Might be worth a try. Not too expensive. If I went in there I would put in new check valve springs and balls regardless of what I found.

I can send you the piston pump supplement manual if you want. Its for the very very early pump with ball bearings, yours probably has roller bearings, but the head end of the pump is the same. Just ask and I'll send it.
 
Kurt:
I've got the genuine original 1959 manual with
both pumps included.
I've never done a pump before, but have done lift
cover, carb and ignition services.
Think that I'll check with local CNH dealer for
rebuild kit. One of the older techs has been a
great source of info to me.. may get him to help
me with this (he does some work on the side on the
older iron).
If you think that the supplement will help, let me
know where to PM you and I'll get in touch.
Thanks again!
Bill
 
The check valve side of the pump is straight forward, but the the wobble shaft side is more involved. I would try the check valve side first.
Tisco makes a pump rebuild kit that is lot more affordable than CHN. YT has them as well as others. Your call.

Email me at kdmoser insert at sign here earthlink dot net and I'll send what I have. Do with it as you please.

Kurt
 
It is not hard to "kit" the piston pump. What I found to be difficult was removing the bearing race from the suction end of the pump to replace the seal underneath the bearing cone. I finally ended up cutting the cone with hours of work with a die grinder. There just was no way I could figure to pop that thing out of there with any kind of a drift. But once I got the new seal and new bearing installed, my pump quit sucking in air and my oil quit frothing up.

I would take the pump off the tractor and carefully disassemble it, starting with the head bolts. Be careful not to drop and lose any of the small parts. After the head (pressure side) of the pump is off, I would next remove the bolts that hold the suction side together. Once that is apart, you should be able to inspect the wobble shaft and roller bearings that move the pump"s pistons. I would look for broken springs or obvious damaged bearings or where the bearing runs on the wobble shaft. Most of the small parts were included in the kit I got from this site.

Unless your pump has been sucking air, you probably do not need to replace the suction side seal or the bearing and cone it rides on. I would sure try just doing the kit before I went to the considerable hassle of changing that bearing and cone.

I have had some problems with a gasket blowing in the pressure side of my pump. It would always blow in the same place, where the gasket is very thin. I always knew when that gasket blew, because oil would leak heavily out the side of the pump. After changing that gasket a number of times, I wondered if it would be possible to get a better gasket. I couldn"t find any, so I decided to MAKE a gasket out of polycarbonate. It probably took me 6 or 8 hours to fashion the much stronger gasket and make it fit exactly. But so far, after about 8 hours of operation, the pump is not leaking again.

I sure like your idea of adding a barbed fitting and a plastic tube to recirculate the oil while bleeding the pump. I have always just opened the pipe plug on the pressure side and let it run on the ground until the bubbles quit. Kind of messy. Good luck!
 
You mention blowing the gasket on the hyd pump. Take the pump apart and take the main body to a machine shop and have it planed like shaving the surface of a cylinder head
The noises in the pump are usually one of three things. A loose drive gear on the pump,(possible) a loose gear on the cam that drives the hyd pump ( not likely) or bad timing gears on the front of the engine. (Probably)
 

If you had a 640, as I do, I think I could help. But by the time the 641's came out all those problems were fixed! Are you sure you have a 641 pump? A picture would help.

Joe
 
I got thinking more about your problem Bill. I'm wondering if you might have a wobble shaft/thrust bearing problem. I guess you won't know until you get the pump apart.

Keep us posted
 
That is probably a good idea, and I might try it if my homemade gasket also fails. When I made the new gasket, I left more "meat" in the areas where the commercial gaskets would fail. The polycarbonate SHOULD be a lot stronger than the paper gasket it replaces.

So far it seems to be working fine. If the polycarbonate gasket fails, I might try making one out of soft copper sheet.

I have wondered why the gaskets kept failing. Maybe there has been erosion in that spot on the pump body, although I could not see or feel anything that worried me. Some years ago, I replaced the hydraulic relief valve with one from the aftermarket. I am wondering if that valve has stuck and the system is getting over pressurized. Then next time I drain my hydraulic oil I think I will put the original relief valve back in, assuming I can find it. When I changed the relief valve, it did not change the symptoms I was trying to fix.

Thanks for your input!
 
Kurt:
See my new thread "think I found my pump noise"
Think you were right all along.. bearing is toast.
Noise was pump gear scraping on housing.
 

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