Help Support SkidSteer Forum:
What seal went?
Was it the main shaft seal or the ones on the swash plates (where the steering levers attach)?
Can you check your charge pressure too? There is a sender on the filter housing, it should be about 200 PSI from memory, no higher. I was thinking high charge pressure may have blown the seal lips out.
Was it the main shaft seal or the ones on the swash plates (where the steering levers attach)?
Can you check your charge pressure too? There is a sender on the filter housing, it should be about 200 PSI from memory, no higher. I was thinking high charge pressure may have blown the seal lips out.
It was the main shaft seal, how do you check the charge pressure?. Can I do that with the seal leaking?. Thanks
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There will be a sender on the hyd filter unit (maybe 2) T into that with a 250 psi guage.
Unless the seal is really pouring oil out it won't throw the reading off too much.
Ken
Borrowed a gauge, charge pressure is about 80psi. I see the case drain for one wheel motor goes into the pump, would that have any effect? I will pull the motor and pump this week, but would be nice to know what is causing this. Thanks for the help. Roger
The case drain will not be a problem, it runs to the pump but the flow is so small it won't create too much pressure.
Pulled the motor/pump today, there is a split in the face of the seal. looks like too much pressure to me?
I have pulled the front half of the pump down, can't see anything obvious. I am assuming that any excess oil from the wheel drive pumps is scavenged by the gear pump for the hydraulics.
I could replace the seal and check the charge pressure when I re-assemble, but I would like to find something now than repeat this, any ideas?
Thanks Roger
Excessive pressure i would assume would push the seal lips out. The flow from the case drain ports is too low to cause any problems and plus, there is a relief inside the pump and if they were geting high enough it would simply go back to the tank.
The front half? you are talking the gear pump? or the piston pumps? or the gap between the 2 sections?
Bad seal maybe?
I have split the piston pump apart (pulley end) so far. The seal damage is the same as the seal that I replaced the first time, (1/8" split in the face of the seal). Not sure 2 seals would be faulty?.
I will pull the other piston pump apart and see if I can locate the check valve you mentioned.
Thanks Roger
Don't pull the pump for the valve. Its screwed into the valve section of the pump (the part where the oil comes out to the motors) There should be a 1" plug, there will be a spring and poppet for it.
You checked your charge pressure already.... So the valve should be working just fine...
I don't have a manual yet, had one for the M610 but hav'nt felt up to parting with all that cash for the 753. Tazza I am assuming that the oil flows from the valve block throught the filter and cooler to the pump, or is the other way round?
E-mail me "taz38sup at yahoo.com.au" at = @ and i'll send you a manual. From what i understand about the cooling system is the oil goes from the return line through the cooler to the back of the pump where its restricted to hold charge pressure. Any excessive pressure bleeds off to the inlet side of the hydraulic pump. I thought i had it all figured out when working on my 753, but now i can't remember how it all worked exactly.... But essentially the flow goes through the cooler FIRST then the filter so it can't be a problem with causing higher pressure damaging the seal. The charge pressure is all managed by the relief on the pump so i can't see how pressure is the issue....
Does the shaft have ANY play?
Pump is back together and Bob is up and running again, I had replaced the seal with one with too lower pressure rating. thank you for your help Tazza.
More than welcome, got your e-mail too
Glad its back up and running!!! and that LPS helped you out with the seal. I was always told never use non-genuine seals, now i know exactly why. You are now an expert in engine/pump removal though!
