Power Steering Pump Blowing Seals

[RickHawk]

I have a JINMA 354 tractor that keeps blowing the power steering seal. I have replaced the seal several times now and as soon as I turn the steering wheel, the seal blows and I end up with hydraulic fluid mixed with the engine oil.
My tractor has both a pump for the hydraulics and a separate pump for the steering. I have replaced the power steering pump, the steering gear box and the power steering cylinder. Also to check for any blockage, I blew air through all the hoses in the steering system.
I googled the problem and found where someone had a similar problem and posted: I simply dimpled or peened around the seals enclosure with a punch to tighten it up. It has not leaked since?
Am I missing any parts? I uploaded a few pics. Is there something I am missing? Any suggestions?
Thanks in advance
Rick

 

[murphy1244]

:welcome:

 

[puckgrinder85]

Is it blowing the seal right out of its bore? Is that what you mean?

 

[the old grind]

Welcome, RickHawk. That staking the front seal works for you says your seal bore may be oversized, and as little as .002" - .003" can make all the difference. 'Double lip' seals can pop out under excess pressure. A single lip (surely not what you have) would just leak. Sounds like you have the fix going on.

Check the 'Chinese Tractor' forum for Jinma stuff. There are recent questions about their pumps. I hope you have a good one in yours.

 

[MHarryE]

When I have seen this problem in the past it has been due to excessive internal pump leakage. Gear pumps generally have a flow Atha for internal leakage to return through the inlet side, but I the flow becomes too high, the shaft seal will low. It says, however, you have already replaced the pump. Is it possible you have a sticking relief valve that will cause the pump to hit a higher pressure than which it is capable of handling resulting in excessive internal leakage and the consequent blown seal?

 

[oldnslo]

Like HarryE said.
Check for flow path from the seal chamber to the pump inlet. Also double check to make sure the pressure balance seals (formed m shaped seals) are seated and orientated correctly. From what you are describing any pressure blows the seal which would indicate you have either a blocked case vent to the pump inlet or the pressure port is connected to the seal area.

Does the seal push in easily with your fingers or does it require a press?

good luck

 

[CJONE]

Like HarryE said.
Check for flow path from the seal chamber to the pump inlet. Also double check to make sure the pressure balance seals (formed m shaped seals) are seated and orientated correctly. From what you are describing any pressure blows the seal which would indicate you have either a blocked case vent to the pump inlet or the pressure port is connected to the seal area.

Does the seal push in easily with your fingers or does it require a press?

good luck

+1 sounds like the pump is not the correct rotation, like oldnslo said. The kidney shaped seals on the thrust plates always face the pressure side of the pump. If everything is correct then install a case drain back to tank. CJ

 

[RickHawk]

Problem Solved!

Thank you everyone for your advice and recommendations.

The problem was the pressure relief valve. I took the power steering pump apart and realized that the housing portion that holds the gears is reversible but in only one direction does the hydraulic fluid flow through the port into the pressure relief valve. I had it backwards so no fluid would flow into the valve, thus building up too much pressure and blowing the seal. I reassembled the pump correctly and now everything works fine.

I don't know if I assembled it wrong the first time I installed it or if it came out of the box that way. Anyway, all is good now. Thanks again

Rick

 

[CJONE]

Glad you figured it out. CJ