[s-cars] Power steering pump resistance?

McCall, Randy rmccall at nexant.com
Thu May 29 13:54:04 PDT 2008

Hey Aaron,
Tom Green put up some great info on the pump operation and possible
reasons for your problems.  I'd have to agree that it might be a
blockage - based on his comment that there are essentially two hydraulic
circuits with a variable output for steering and low flow/high pressure
for the bomb and braking system, that gives you three pathways of
potential blockages (including internal problems).  Given that the pump
pressurizes a non-compressible fluid, if there is  system blockage to
fluid flow, you're going to see that as very high resistance at the pump
- that additional resistance at higher rpm when the engine's actually
driving the pulley could well be eating up the ribbed side of your serp
belt; might also be putting a bit of "water hammer" on the system,
except at a high frequency for each piston stroke of the steering pump.
Might even explain hoses starting to leak as the pressure waves could be
very high intensity and repeated.  Why that would affect the tensioner
(or pensioners for that matter) roller's bearing isn't clear to me
though. I can see pretty big changes of tension in the system leading to
rapid movement of the tensioner and possible destruction of the spring
in the tensioner, but the roller bearing should be ok with the changing
load on it.   

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