I have a 73 corvette and was having a problem with no power assist at idle. In order to be able to turn the wheel with assist I had to rev the engine. I had a brand new pump sitting on the shelf from an 87 trans am that fit right in. (You probably know where I'm going with this) I put the pump in and it worked fine. Parked the car back in the garage and one week later I see fluid all over the floor and haven't had a chance to crawl underneath but I see no oil leaking from the pump and appears to be from the control valve. My question is do the C3 Vettes require much lower pressure than the mid 80's F-Body's? My guess is I may have blown the seal(s) on the control valve? If I were to switch out the pressure relief valve into the new pump would that have been the way to go?

Thanks

 

I took the stock '72 vette steering pump complete valve assy, and put it into a serp drive pump from an '87+++ vette, ran the stock steering just fine for years, later on I put in Rack steering, and so it's fine for that, and the Hydro boost brake setup also.....



I can't comment about pressures and flows though, I forget the numbers....

 

That's opposite to what he did.

 

First of all, the 1987 pump would have a metric discharge fitting. The 16x1.5mm female thread in the fitting was also designed for a pipe on the hose assembly with a metric male nut and an o-ring on the end. All General Motors pumps had conventional 5/8-16, inverted flare connections through the 1970 model year. All pump and gear connections were changed to metric o-ring the 1980 model year. So I would guess that if you didn't swap discharge fittings from your original Vette pump, you could have leaked fluid where the hose assembly with the inverted flare screwed into the metric pump fitting but did not seal properly.

Second of all, the hoses and control valve on the C2/C3 Vettes were designed for pressures around 900 psi. Most likely the 1987 pump would have a discharge fitting and flow control valve designed for 1400 psi pressures. Therefore, unless you swapped the discharge fitting AND the flow control valve right behind the discharge fitting inside your Vette pump, that in itself would probably cause those special Vette, 1/4 inch ID hoses to leak at their crimped connection fittings. I guess the lip seals in the control valve could have failed from the higher pressures.

BTW, a pressure hose assembly for a 1980 through 1982 Vette will have a 16x1.5 male nut and o-ring on the pump end. This hose should properly connect to your 1987 discharge fitting. You still need the flow control valve from your original pump however. It will work with the metric discharge fitting.

 

Thanks for the input guys. I did change the fitting over from the old pump but did not change the flow control valve. I just had knee surgery so I'm just able to get underneath the car tonight and see where the leak actually is. My guess would be one of the crimped hoses.