JD2630 hydraulic pump seal failure

   / JD2630 hydraulic pump seal failure #1  

Minners308

New member
Joined
Aug 24, 2011
Messages
5
Tractor
1972 JD 2630
Gentlemen,

I have a 72 JD 2630 that has had a hyd. pump rear seal fail 2 summers in a row. It is not a fun job to change one out due to all of the stuff you have to take loose to get the pump out. What I would like to know however is what might be causing the failure. Is there internal pressure building up inside the pump due to another failure of a pressure relief valve or something similar?
Has anyone else had this problem? I would really like to know what it causing the failure so I can fix the root cause. Help!!!

Thanks
 
   / JD2630 hydraulic pump seal failure #2  
Gentlemen,

I have a 72 JD 2630 that has had a hyd. pump rear seal fail 2 summers in a row. It is not a fun job to change one out due to all of the stuff you have to take loose to get the pump out. What I would like to know however is what might be causing the failure. Is there internal pressure building up inside the pump due to another failure of a pressure relief valve or something similar?
Has anyone else had this problem? I would really like to know what it causing the failure so I can fix the root cause. Help!!!

Thanks

Usual causes of seal failure are over pressure or bad surface finish on mating shaft, housing, etc. When yoou say "rear seal" is this around a shaft or between pump housings? Since I believe this is the old JD Radial piston pump is there a chance the pump itself is getting worn which is allowing excess leakage into the case which could in turn cause excess pressure in the case? Not sure what type of test equipment you have but you might want to get the flow Vs. pressure checked on your pump. Tractor built in 72, that pump probabably has a few hours on it.

Roy
 
   / JD2630 hydraulic pump seal failure #3  
Minners308
By replacing seal are you referring to the inner quad ring or the external dust seal? If you're referring to quad ring did you shim correct end play of shaft and was the shaft area where quad ring rides smooth? Have you ever checked stand-by psi? It should be 2250 psi.
 
   / JD2630 hydraulic pump seal failure
  • Thread Starter
#4  
Wow you guys know your stuff. Yes indeed it is a radial pump, and the seal in question is the oil seal around the pump shaft where the coupling connects.
There is the possibility that the pump is getting tired, but it really seems to do a good job for me except for the leak. Admittedly when I changed the seal last summer, I did not check the end play and I don't have the equipment to check the stand-by pressure. The shaft was in excellent shape though. After reading through the manual again I'm wondering about the stand-by pressure. If that is set improperly (too high) could that cause too high of pump crank case pressure and force that seal outwards? Maybe I would be better off to take it to a dealer and check the tolerances inside the pump and the standby pressure and flow rate. I hate to pay their shop rates but I guess sometimes you just have to bite the bullet. Thanks for your help guys.
 
   / JD2630 hydraulic pump seal failure #5  
Minners308
Radial piston pump is the only factory frt hyd pump offered on a 2630. If you didn't disassemble the pump you only changed the "dust seal" and you didn't change the seal that's intended to hold 2250 psi!!!!!!
 
   / JD2630 hydraulic pump seal failure #6  
I may be wrong but if the pump seal drain line is plugged that can push out the dust seal as well can it not?
 
   / JD2630 hydraulic pump seal failure #7  
Yes a plugged seal drain could cause dust seal to leak. But if leak is very bad then inner quad seal replacement is the only cure.
 
   / JD2630 hydraulic pump seal failure
  • Thread Starter
#8  
Tx Jim is the winner! Admittedly I am trying to resolve the same problem again due to my own stupidity. Last year when I had the unit out I was unaware that that little quad ring was hidden down inside the groove that was only accessible from the inside of the case. Yes, the quad ring was cracked and deteriorated. That is definitely the problem. Now the only thing I am confused about is the end play in the shaft. I have about .014" more end play than the manual says is acceptable so I bought two new ones. The only problem is that they both are the same thickness as the old ones--about .089". If I put them in the end play is going to remain the same. I don't believe that JD offers them in varying thicknesses either. I guess I'll have to ask the parts guys that question.
Thanks Tx Jim you were right.

And thank you also to the person mentioning the bleeder line. I did check it to make sure it was not clogged up.
 
   / JD2630 hydraulic pump seal failure #9  
What are you referring to as .089" thick??? If the pump your tractor has is the 2.4 IN3 then these shims should correct the shaft end play problem.
R27478 SHIM AR 0.15MM (.006")
R27479 SHIM AR 0.25MM (.010")
 
   / JD2630 hydraulic pump seal failure
  • Thread Starter
#10  
Tx Jim,

My pump is the 1.38 IN3. There are two thrust washers at each end of the shaft that measure .089" each.
 
 
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