A question about overhauling a C3 power steering pump.

What needs to be replaced usually . I see most vendors only sell seal kits...

 

thats all you need , and a puller for the pulley

 

 

Is your pump noisy? Or just leaking?
When you disassemble the pump to replace the seals and o-rings, take a look at the cam ring surface where the pump vanes slide. If you can see chatter marks, you will need a new ring. Look at the plates on either side of the ring. If you can see spall marks where the rotor spins against the plates, you need a new pump.

If you can feel a wobble when you press the pump driveshaft side to side. The bushing in the pump housing is worn and you need a new pump. As part of the manufacturing process, Nexteer (formerly Saginaw Steering), hones the driveshaft bushings with respect to some precision dowel pin holes in the housing. You do not get this precision operation if you just replace the bushings. You are best served with a new pump not a rebuilt one.

I always recommend that you replace the power steering fluid with genuine GM fluid. It operates best because it was designed to work with the Saginaw line of pumps and helps prevent the above wear conditions.

There has been a push to use Dex 6 automatic transmission fluid as a "universal" fluid in the power steering system. Saginaw engineers indicate that Dex 6 is NOT as good as genuine GM power steering fluid. The GM part number for a quart of power steering fluid is 89020661. The previous GM part number for power steering fluid was 1050017. Both fluids work equally well.

Jim

 

Actually I have 2 pumps here. One has a heavily dented housing, the other (my original seems) to turn a whole lot lighter than the one that is dented. The shaft can be pulled in or out a little. It doesn't seem to wobble from side to side.

What is a source on new pumps. I only seem to find remanufactured (rebuilt ?) ones.

 

thats a real simple unit, get a rebuilt from a good vender, they are tested when rebuilt and are very simple to do,, those of yours sound like junk.

 

The poster is in EUROPE! how does he run down to the NAPA store in Belgium?

 

rock auto and several other online venders ship internationally,


your rudness shows a lack of masculinity and inability . try to man up

 

Had the same problem. In the end I just ordered an A1 Cardano replacement for about € 75,- (incl. shipping) via SixPack Speedshop (in BE). Fine so far, though the irony (of course) is that now my control valve leaks...

Otherwise check out stepaside.nl They might deliver Rockauto parts a tad cheaper than ordering yourself.

 

Was that a new or rebuilt one ?

I just dismantled the pump and sure enough the ring has radial marks in it.

 

Saginaw had a process where the cam ring was plunge ground. The surface contour ended up smooth but you could actually see a waveyness in the surface as the grinding wheel moved axially with the contour. If you can actually feel chatter in the ring contour, the ring is no good.

Sorry, I just don't have information on where to purchase a new Saginaw (now Nexteer Automotive) power steering pump. I assume that a number of rebuilders probably purchase new rings, plates, etc directly from Nexteer in order to rebuild pumps.
Jim

 

Way preferable to doing it yourself. I am sure you can get rebuilt parts sent to the NL.

In fact, when I was stationed there in the Army, I used to go to Antwerp to a shop for parts all the time. Been a few years (decades?) now, and I don't remember exactly where.

These rebuilt units can be had with and without the fluid tank.

A1 Cardone is a good rebuilder of all that stuff. Same with starters, alternators, compressors, everything.

I would think it's definitely worth looking into.

 

Yes, i can feel the wavyness.

Untill now, I only found AGR Performance that sells new pumps.

What is the rated pressure and flow of a Corvette pump ?

 

A 1979 Corvette power steering pump had the following specifications;

125 Series Saginaw P-pump
Rated at 2.9 gallons/minute max flow control setting
950 psi pressure relief setting

There are a lot of different types of Saginaw P-pumps with flow ratings similar to the above.

The pressure relief setting is important because the pressure hoses from the control valve to the assist cylinder are not durable if exposed to higher pressures. Most General Motors steering systems have pressure relief settings in the 1500 range. The Corvette C2/C3 pump relief setting is much lower pressure (950 to 1000 psi).

The pressure relief setting is controlled by the small linear valve (6) that is located just behind the discharge fitting (24) on the rear of the pump.

The flow control valve has a hex nut with a small screen on its face. The hex nut is on the forward end of the valve (pointing into the pump and against the spring (5). There should be two or three shims under the hex head. The several shims should cause a small spring inside the valve to relieve pressure sooner.

Jim

 

If using an integral power steering box such as the Delphi 600 (Jeep or Borgeson steering), what is the best pressure relief setting? (Assume uprated supply hose.)

 

I'm not sure actually. But it definately had a new housing.

I happen to have it off the car right now, so I'll check out that valve thing to check pressure settings.

Any way I can check for rebuilt/new?

 

Why are you replacing or rebuilding the pump? Was it noisy? Did it just leak some? Was it malfunctioning?

If the P/S system was working OK, just install the re-seal kit for the pump. Everything runs in oil inside it, so unless it was run dry or had cruddy oil in it, the existing unit should be fine with new seals.

You also want to install new hoses and it would be best to do a simple rebuild of the control valve...if you can get the kits in Europe. Very inexpensive and about a 3 out of 10 on the 'difficulty' scale to rebuild it.

Unless the assist cylinder is leaky, there is no need to work on it. If it is leaky, there is only the ram-rod seal set that can be replaced. Again, cheap and easy. The most difficult part of this entire P/S rebuild process is removal, cleaning and repainting the parts. The rest is easy.

 

So I can just loosen the hex-nut to add shims?

Jim; you say there are supposed to be 2 or 3 shims under the hex-nut. To drop pressure to the proper level for the corvette?

 

For many years the pressure relief setting was controlled by the number of shims under the hex head screw on the rear part of the flow control valve. You could remove a shim and increase the pressure relief by 100 to 150 psi (if I remember correctly.) Sometime later, (and I don't remember when, sorry) Saginaw began using locktite to hold the hex head screw in place at a particular pressure relief setting.

Remember that the Corvette C2/C3 power steering system was designed to operate a relatively low pressure relief settings (900 to 1000 psi) because the cylinder line hoses would leak at higher pressures. These settings are lower than most other GM systems.

All I can offer is for you to create a small system where you have a pressure gage and dead head your system for a few seconds to actually measure the pressure relief of your power steering pump. You will have to cobble a line from your pump discharge directly into a closed end with a pressure gage. Make sure that you purge the air from the line and then just run your engine long enough for the pump to go directly into pressure relief.

Hopefully you will be able to add or subtract shims to bring your pressure relief setting into the 950 psi range.

Jim

 

Thanks Jim! I have my old pump lying around somewhere, so I'll dismantle that one first. Perhaps I can swap valves, hmmm...