Oil & Fuel Power steering pump bypassing fluid to crankcase

[dawilli]

I have an older model 285 MF that seems to be dumping power steering fluid into the crank case. I have refilled my reservoir 4 times only to have it be empty again with no trace on the ground. However, I thought about it and sure enough my engine oil level is coming right on up the dip stick when I checked it. This is supposed to be a new pump. Where in the pump is it bypassing? Or, am I on the wrong track.

In addition, the steering pump pressure never gets any where close to the 1650 psi (more like 700 psi) that it should and it took way too much effort to steer even before this sudden fluid loss.

I'd appreciate any help as I'm not a mechanic by any means......thanks. David

 

[JoeBuyer]

I know nothing about the MF285 but would it be leaking around the seal where it is gear driven into the engine?

 

[dawilli]

That makes sense since that would be the likely route to the crank case. I'll know soon. I may get a rebuild kit and try the new seals....if I can get my nerve up. the kit only runs about 50.00 bucks versus a new pump at around $350.00 to $400.00.

 

[jenkinsph]

The seal on the end of the shaft is the likely problem. Does it have anything else such as a hydraulic oil cooler on the side of the engine that could leak into the crankcase?

I would not run the engine in this case until the problem was fixed and fluids were changed.

 

[Soundguy]

that's where a ford PS pump on a 65+ would be leaking.. at the front drive..e tc.

 

[wing98]

i have replaced several of the pumps you can get them on ebay for about 280
i work for branson dealer and i did work for a massey dealer
never had any success rebuilding these pumps , so we just started replaceing them
the ones you buy on ebay are new ones

 

[Soundguy]

i agree.. when the front housing of the pump gets damaged.. new seals etc, rarely solve the issue for long.

 

[wdchyd]

i agree.. when the front housing of the pump gets damaged.. new seals etc, rarely solve the issue for long.

X 2..........My experience is wear internally in the gear set, housing and wear plates more than 50% of the time.......best to replace

 

[wdchyd]

I have an older model 285 MF that seems to be dumping power steering fluid into the crank case................................ This is supposed to be a new pump. Where in the pump is it bypassing? .....thanks. David

When this pump was changed did you do the mandatory house-keeping (drain, clean reservoir and screens, new oil and filter).....??

 

[MHarryE]

My experience has been a worn pump will cause the failure. Gear pumps usually have a leak path for internal leakage that directs that oil back to the inlet side. If internal leakage gets too high due to wear, it can blow past the shaft seal. Some pumps have a double front seal with a drain hole between the seals so this leaked oil cannot get through to the engine. The front shaft seal is usually reversed so it seals against engine oil. Yours sounds like a single shaft seal with the leak path into the crankcase. Re-sealing might work but be prepared for a new pump.

 

[jenkinsph]

X 2..........My experience is wear internally in the gear set, housing and wear plates more than 50% of the time.......best to replace

I agree with this too.

wdchyd, What do you think of Commercial Shearing brand?

 

[wdchyd]

I agree with this too.

wdchyd, What do you think of Commercial Shearing brand?

Commercial (now owned by parker), Permco, Lynch (and other copycats) are good pumps for cast iron larger displacement/mutiple gear units with roller bearings

Very common with mobil equipment applications, easy to rebuild/repair......tough for small tractor-like uses cuz of the space requirements......most rated for 2000psi (unless premachined with dowels in the housings for 2500psi)

Parker has been buying up other hyd mfgs to add to their cataloges the last few years..........but overall not a bad fixed-displacement pump for simplicity and versatility if you're looking for a "dumb pump" (one without pressure controls and such)

 

[TractorTech]

Generally, if the the pump pressure is adequate to deliver decent power steering, then the problem is the pump seal which can be replaced without getting into the pump. A wear groove will probably be apparent on the shaft where the seal lip rides. When installing a new seal, either reposition the new seal not as deep in the bore OR measure the shaft diameter and get a Speedi-Sleeve for the shaft to renew the wear area.