P/S pump pressure
Thread Starter
Safety Car
Joined: Dec 2005
Posts: 4,270
Likes: 20
From: Central Michigan
P/S pump pressure
Anyone know what pressure the power steering on a 68 should operate at? The steering seems fine in the center(except for a small amount of play), but when I turn in either direction at any speed it seems harder than it should, as if the pump isn't building enough pressure.
The front end is completely rebuilt, I rebuilt the pump, then replaced it when I noticed a fine dark grey material all over the pressure relief valve as if the pump was self-destructing(found more grey stuff inside the pump reservoir). No change in steering. I'm on my second rebuilt control valve(first one had too much slop), no change. Rebuilt steering box, no change. Belt is tight, new hoses. The only part not replaced is the ram, I put new seals in, no leaks there. Am using Prestone fluid, thinking of flushing it out with GM fluid, as I read in the archives, and checking the pump pressure while I have the system open to eliminate the pump as the problem.Can anyone help me out here? Thanks in advance
The front end is completely rebuilt, I rebuilt the pump, then replaced it when I noticed a fine dark grey material all over the pressure relief valve as if the pump was self-destructing(found more grey stuff inside the pump reservoir). No change in steering. I'm on my second rebuilt control valve(first one had too much slop), no change. Rebuilt steering box, no change. Belt is tight, new hoses. The only part not replaced is the ram, I put new seals in, no leaks there. Am using Prestone fluid, thinking of flushing it out with GM fluid, as I read in the archives, and checking the pump pressure while I have the system open to eliminate the pump as the problem.Can anyone help me out here? Thanks in advance
Drifting
Joined: Oct 2003
Posts: 1,426
Likes: 1
From: VetteMOD
St. Jude Donor '05-'07
GM Power Steering Gear and Pump Manual states that the relief pressure for a Corvette is 900-1000psi. Did the pump make any noises when turning?
Last edited by BBShark; Mar 16, 2006 at 07:24 PM.
Thread Starter
Safety Car
Joined: Dec 2005
Posts: 4,270
Likes: 20
From: Central Michigan
No, the pump isn't making any noises at all. I was thinking about something this afternnon, I'm beginning to think the grey material I saw in the other pump was stuff that had settled into the ram, then puked back into the rest of the system once I had it up and running. I'm heading out to the garage right now(after making a detour by the fridge to grab a Bud), I'll pull the pressure relief and recheck if the screen is clogged again(like on the last pump), and see what else drains out. I'll check back in tonight with my findings
NCM Grand Opening Veteran
Joined: Sep 2005
Posts: 20,979
Likes: 384
From: South of giving a damn
St. Jude Donor '11, '17
BBShark is correct, Corvette pump is about 1000psi, truck pumps are about 1500psi. I was reading where some companies just basicly use ATF & call it PS fluid. From what I read GM PS fluid was developed for it's anti-foaming & heat capabilities.
Thread Starter
Safety Car
Joined: Dec 2005
Posts: 4,270
Likes: 20
From: Central Michigan
Thanks for the replys. Just came back from working on the Vette, and found some crud in the pressure relief screen and a kink in the return hose going to the back of the pump. Fired it up and began turning the wheels lock to lock to bleed the system, and yep, it's building pressure alright, straight out from the shaft seal! Fluid got into the fan, and you can imagine the mess it made 
. So I will take the pump back tomorrow and hope for better luck with the next one! Thanks again for the help
. So I will take the pump back tomorrow and hope for better luck with the next one! Thanks again for the help
