re: Re: Central Hydraulic Pump - ...

[Scott=John=Mockry%Mktg%TM@banyan.bv.tek.com]

Hello,

Halsey Imports 1-800- 792-0081 had a rebuild kit for my 86 5000CST pump for $20. When I went to 
rebuild the pump , I hoped to only replace the 8  O-rings under the large slotted screw heads to cure
the slow leak that was getting worse. After I changed the O-rings the leak was reduced but not 
cured. 

I took it apart again and this time separated the back end of the pump and replaced the one
large O-ring around the rear shaft support and also the 6 smaller O-rings sealing the piston ports to
the rear section. 

Of course after doing this the pump "REALLY" started leaking much worse than before. Someone from
the group mentioned that the rear housing of the pump sometimes gets warped and can not be 
sealed very well even with new O-rings. I thought this might be my problem as well.

I could not bring myself to purchase a rebuilt pump for $200-300 so I took it apart again. 

I found the reason for the leak and neither the Bently manual nor the service bulletins provided much
detail my problem. The rear section of the pump has a round support for the main shaft that is 
connected to the pulley. In the center of the rear support is also a pressure relief valve. 
The round rear support is aluminum and screws into the aluminum rear housing of the pump.   
My rear support had come unscrewed slightly so I removed it and found that there is  an O-ring 
"behind" it as well as in front of it to seal  the high-pressure fluid from leaking into the area where 
the two pump halves are joined together.

I  replaced the O-ring, tightened the rear support  using the allen in the pressure relief valve and it 
stopped leaking!  So far the pump is free from any leaks and works great. Rebuilding the pump "should 
be" fairly straight-forward if you have worked on other power steering systems.
Scott M.