update on 1755 hyd pump

[pa dave]

started on pump problem by r&r the pressure control valve, ball, springs , o-rings all fine , next i r&r the hyd pump bearings , and all internal parts looked fine , no nicks or gouges or groves from wear, r&r compensator valve all lookes fine , reinstaled all parts, instaled gauge according to manual , it states to set pressure at 2450 psi at 2400 rpm , i noticed at idel it still carreys 2450 psi , would this be correct or should gressure drop with rpm? also the hotter it got the noiser it gets , closest dealer (white) 100 miles , spoke to them they simpley said bring it in,not to willing to give advice, i,am really trying not to ruin this pump , i,am afraid i still have same problem ,any ideas would be appreciated

 

[Wrenchbender]

Yes the pressure remain constant at all RPMs. Where and how are you checking the pressure? Are you setting the pressure by turning the compensator valve? There are really two different pressures you need to check. First turn the compensator screw all the way in and see what the pressure is, this is the main relief valve setting, that is the 2400psi setting. If that is OK, then turn the compensator screw out to lower the pressure to about 2200psi. There needs to be a difference in the two pressures of about 200psi. If your operating pressure and the relief pressure is the same you will be bypassing the relief and causing the oil to heat. Hopes that helps, WB<><.

 

[ollie gm]

Thanks for the great information.

 

[Anonymous-0]

As is usual Wrenchbender has given you good advice. You need to check how much oil is leaking back thru the case drain line. Does you manual tell you how to check this? I think you have an internal leak somewhere. We had one where we had to re-shim the relief valve.

 

[pa dave]

i will have to reset the psi as wright now it is set at 2400 , my manual does explane how to check bleed off , something else i noticed when hyd oil got up to temp the oil cooling lines and pump wern,t even warm , could the cooling pump loose prim and if so how could you reprim it , manual mentions about loosing prim but doesn,t explane how to reprim ? thx for sharing your skills Dave

 

[Anonymous-0]

The cooler pump was mounted in 2 different places. The lower mount is the better location. If the front seal on the cooler pump is leaking AIR the air will get in the system and will cause heat as well. Do not run the cooler pump with a belt that is too tight. How about a picture of how your cooler pump is mounted?

 

[pa dave]

i did prime cooling pump and now oil is flowing trough oil colier , did notice on hi-pressure valve on the Tee fitting it is leaking as i can see little bubbles around fitting , my next step is to tighten all fittings on hi-lo valve , then we will go from there , the bubbles didn,t seam to be leaking oil out so maybe it is sucking air in , i had replaced seal on cooling pump some years ago, an i always leave some slack in belt , i,ll let ya know thx DAVE