I have been aware that the P/S pump on our '78 has been making a few squealing/groaning noises on occasions when "under load" and warm. During our recent 1385 mile trip to the south of France in 30+ degree C heat it was doing so quite a lot! I also get the impression sometimes that the P?S is not giving me the assistance that it maybe should be.

I'm now wondering if maybe a rebuild or replacement of the pump is on the cards. But a few questions first:
Is it likely that the pump would in fact not be actually pumping enough to give it's full potential?
Would a rebuild with a "normal" kit solve that?
How doable is a rebuild - will I need a puller, or can I leave the pulley on thge shaft and just remove that whole part?
Or, is a new pump a better idea in any event?

I should say that I have eliminated the belts as the origin of the noise and, I am not thinking at all about installing a Borganson system.

Any thoughts and/or suggestions most welcome!😄

 

Upgrade to later GM Saginaw II pump

 

When was the last time you changed the fluid.

 

that one seems pretty small.. anyone adapted this pump? pressures ok etc? mods?

OP they do come apart pretty easy but am very curious what the fix is for you as occasionally mine also groans when warm and under pressure..

my leak link
https://www.corvetteforum.com/forums...leak-79-a.html

also see Jim Shea's papers here go to post 7
https://www.corvetteforum.com/forums...is-papers.html
pic @bmotojoe

 

September 2024, when I had to change a hose that was weeping a little.🙄

 

I've just a look at one of these - it looks like a little more work that a "bear of little brain" like me could get involved with!😄

 

Interpon - Thanks, I'll check out both threads.

I confess that I'm not really sure how the pump works, or why they "squeal", and therefore don't really know if a build is the answer or not. I may be imagining it, but as I say, I sometime feel that the assistance level of the P/S isn't quite what it was, maybe?

There is no leak (at the moment! ) and the fluid is up to the correct level. I am, and for the 36 years we've owned the car, always have used ATF in the P/S system, If I were to change now to actual P/S fluid, I'm guessing a complete flush would be required?

 

Just a supplementary question - would the PSCV be responsible for what I perceive as a lack of assistance on occasions?

 

Jim Shea i know mentioned to use GM power steering fluid.. i would think you do not need to empty.. maybe a few dump (suck) and fills..

 

The pumps are capable of 1300psi, but honestly seldom go over a couple hundred.
You need a corvette specific pump with a 900psi max psi valve on it so you do not blow the hoses. So replace it with another pump very cautiously, it will likely be just a std (high) psi pump. Even if you change it, #21 & 22, flow orifice and psi spring, are the C3 specific parts, and you should swap the originals into your new pump. Easy..

The pump part is just sliding vanes. When severely worn they do not make max psi. Suggest that is not likely your problem. Max psi is seldom used and not that important, unless too high.

Rubber seal leaks are much more likely.

Incorrect flow orifice is possible. Highest psi is when turning steering in parking lot with car barely or not moving. If it "jerks" doing that, pump could be weak. Alternative is you wound up with the wrong flow control valve somehow over 50 years. In that case it could need more flow, bigger orifice. If it is overheating, it will foam, and make noise, and/or puke fluid. That means too big of an flow orifice. Turn One Steering sells flow calibrated orifices. You can measure your orifice size with a drill bit.

Never continue to apply steering wheel psi while the front wheels are already fully turned. That dead heads the pump, and psi spikes very high. Bad for pump. Yeah it may make noise when doing that. It is telling you to stop it.

Most noise is air bubbles trapped in fluid.
Suggest you use GM power steering fluid for correct lubrication properties, and it likely traps less air bubbles by design, and then purge air carefully by going lock to lock several times, with wheels off the ground.

Sticking PSCV could be due to wear or varnish, and would reduce assist psi. Could cause "jerking" if sticking. If it is not leaking, I would not mess with it. New GM fluid may help clean/lubricate it.

 

Saginaw II have increased capabilities and that's what virtually all performance PS pumps are based upon. Many Saginaw II pump bodies are Aluminum.
https://sweetmanufacturing.com/produ...egories/pumps/