Good Morning All, Before I lay out my hard earned $$$$$, I would like some feedback from you forum guys.:notworthy My hoe, with the hydrostatic power steering, is having steering issues. With the wheels on the ground, it is very hard to turn the steering wheel. Front wheels up it steers easy with full range. I hooked up a pressure gauge directly to the power steering pump, ran the engine for short 3 and 4 second intervals(I read that testing a pump this way, to not run a test more than 5 seconds). I didn't have the fittings to run the gauge inline. The pump showed less than 200lbs of pressure. According to my parts manual this pump should be pushing 1100lbs. Looks to me like the pump is a gonner?? Was my test proceedure correct??? Should I do an inline test to confirm??? Are these pumps worth rebuilding or should I just buy a new one? The tag on my pump says it is a "Plessey Dynamics", from Swindon, England.. I see new ones on the web for $600-$700. I am not afraid to rebuild mine, but sometimes the rebuild kits don't have all the parts needed. If I can even get a kit for mine?? Any thoughts would be appreciated:beerchug THS..AL
A "rebuild" kit would just be new seals. Probably, such as 90%, won't fix internal leaks. Do you have a diagram?
do you mean a diagram of the Pump? If so, yes my parts manual shows an exploded view of the pumps internals.
http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=rrtips&th=20564 Here's another guy fooling with a Plessey pump, he bought the O-rings at a bearing supply house. I looked in my service manual, the pump should flow 4.2 gallons per minute at 1000 rpm. There is a suction filter screen that is in the elbow on the left side hydraulic oil tank; this is where all the lines come together under the tractor. I would test the flow, just direct it into a clean 5 gallon bucket and see what you get. If it's low, pull the screen filter and test again after a cleaning. BUT, the PS only has 2.5quts of oil, so it will take about 5 seconds to pump that... I'm pretty sure the above is correct, my service manual covers every tractor Ford made in the 60's and 70's, so on my beast, I go and look at the pieces, and try to find the correct manual section. Can't do that with your beast. Good luck.
No offense intended, but just to clarify a safety point: UNLESS YOU ARE 100% SURE THAT THE PUMP HAS A RELIEF VALVE IN IT, DO NOT DEADHEAD THE OUTLET! Most power steering pumps do, the one time you get one that doesn't, it will either fail catastrophically or something will burst or explode, probably injuring or possibly killing you. Oil injection injuries are far worse than burns and can be fatal. Always, always, always tee gauges into the pressure line. There are alternate ways to test pressures, all of them include some way for oil to return to tank.
I agree with lantaxco, DON'T DO THAT. but now that you have, there's very little to lose by taking the pump apart and deciding how you want to procede.
Thanks Guys, I was leary about dead heading the pump. I am going to get the fittings and redo the test, checking the flow also. El Hombre, when I cleaned out my hydraulic tank a few months ago, I found that screen and it was DIRTY for sure. Unfortunately it made no difference in the steering performance. When I test the pressure again, I want to look at the pressure while turning the steering wheel right?? Not the pressure while the steer wheel is straight?
Your procedure might have been dangerous, but it was conclusive. No need to check the flow etc. I'd tear into it and see if you find anything in the relief valve, or continue and see how toasted the pump guts are.
I kind of wondered if further testing would be redundant. I will tear into it to see what I find.. Other than finding actual broken parts inside, I probably won't be sure what I am looking for. So I will probably be back with pics and questions.:beatsme THANKS to all that responded!! And for the danger warnings. :notworthy... I looked at a training manual from Brockwell Hydraulic Training Seminars that a friend took and there were pics of injuries from hydraulic explosions. Nasty and deadly for sure!!!! I usually don't take chances, and I am probably lucky my pump is toast!!!
Well I pulled the pump and dissasembled it. Found that the plunger looking valve, was stuck in one position. I polished up the plunger bore and the plunger so that it moves like it should. Pump looked fairly clean inside and the bearings seemed tight. I had hoped to get an o-ring kit, but doesn't look like one is available. I did a google search and found nothing. Anybody know of a source that I missed??????? My local New Holland guy says he can piece together most of the orings at over $120. Going to pass on that since I can get a whole new replacement pump for $500. For now, since it is fairly easy, I am going to throw it back together and see what happens....:drinkup Hopefully it will work well enough to get me by while I maybe find an oring kit or bite the bullet for a new pump....