Re: Central Hydraulic Pump - '89 100

[zm@mhcnet.att.com (Zafer Mehmood [209])]

> 
> The central hydraulic pump is leaking, apparently thru the housing.  I 
> had a hose replace 6 months ago so could overtightening been the cause.
> 
Very doubtful that overtightening could be the cause. On the other hand,
I've read that one of the banjo bolts that connects the hose to the pump
has a screen mesh that could get clogged. This makes the pump work
harder and causes it to leak in the center of the housing. Why was the
hose replaced? If it had disintegrated, then the screen could very well
be clogged. I also have a leaky pump and am planning to remove this
screen in the banjo bolt (on the recommendation of my Audi dealer parts
person) to see if the leak slows down or stops. He claims that this
screen provides no useful function since its in the output side of the
pump; more critical is the plastic filter in the reservoir since its
in the suction side.

> 1. Anyone know where I can can get a rebilt at a good price
> 
Check the archives. Someone had posted about the advantages of buying
only ZF rebuilt pumps (ZF is the manufacturer of these pumps, btw).
If I remember correctly, ZF rebuilt pumps are around $300. Try Halsey
Imports or IPC (phone numbers are the parts vendor list). PAP was selling
a locally rebuilt pump for ~$190 on a sale a few months back.

> 2.  What's involved in putting one in yourself
> 
According to people who have done it, not too hard. Drain the fluid,
unhook the hoses, remove pump from bracket and reinstall. You need to
prime the pump with fresh oil and clean the screen in the reservoir
and use fresh fluid. New banjo bolt (w/ the screen) and washers are
needed too. The Bentley manual has details.

> 3. Any chance of stopping the leak with epoxy's etc??
> 
No. The pressure generated by the pump is much too high to be sealed
by epoxy or any other "band-aid" methods. You can rebuild the pump
yourself with a rebuild kit thats available. Alan Cordeiro, who did
this has posted his experience recently. The job is quite involved and
the success rate hasn't been too high, though Alan's pump seems to
be holding up well so far...

-Zafer