luerja

I need to replace the power steering pump on my non-NCRS 1972 Small block car and not sure whick one I could use? I don't even know what brand came with the car originally?

Any suggestion on a chrome pump to replace this, and has anyone know the correct billet aluminum lower bracket that would work on a SBC setup?

Would this pump be a direct fit? http://store.summitracing.com/partde...5&autoview=sku

Jim

67-73-76

The Corvette PS pumps produce a lot less pressure than the pumps from other model lines. Make sure you get a pump that is specific to the Corvette.

Jim Shea

That summit pump should work acceptably. A couple things to be aware of.
1). They mention that the threaded holes in the front of the pump are metric. All GM pump housing mounting holes were changed to M10x1.5 metric in 1980. So there are millions and millions of GM vehicles out there with metric pump mounting fasteners. They should be very easy to obtain at a salvage yard. You can also use the stud(s) that are on the back side of your original pump. They should exchange onto your new pump with no problems.

2). Also, you should use the discharge fitting, the flow control valve, and the spring from your original pump. Since the flow control valve has the pressure relief setting built into it, you will not have to worry about too much pressure in your system.

3). They mention that the pump driveshaft has a threaded end with a keyway. That should be the same as your OEM pump so the pulley should change right over.

BTW, I always recommend that you use genuine GM power steering fluid. It is available from any GM dealer. It is the only fluid that is specifically formulated to operate with the GM pump.
Good luck,
Jim

Durango_Boy

If I may add a question. With a car with Hydroboost, is it still important to maintain the proper Corvette pressure or will the Hydro buffer that some? I ask because I will be installing a motor that has a '92 Camaro pump. Right now I'm using my Corvette pump and I need to know if I should transfer the pressure valve or not. Thanks.

sperkins

Durango_Boy

Also, is there anything wrong with using Valvoline MaxLife trans fluid? It's had a lot of good reviews.

Jim Shea

The weak links in the C2/C3 power steering system are the power steering hoses. They do not like pressures above 1100 psi. I would swap the flow control valve out of your Corvette pump and put it into the pump on your new engine. That will insure that the pressure does not exceed 1100 psi.

The Saginaw pump(s) have been and are used throughout the world by many automobile manufacturers. Many of them use their own hydraulic fluid. The fluid that you suggested may work very well. I KNOW that the GM power steering fluid works very well with the Saginaw pumps.

Jim

I'm Batman

Are there any replacement PS pumps available with a lower output pressure? From what I hear, a slight reduction would be nice with the Jeep box.

MN80Vette

VB&P sells a shim kit for the Saginaw pump that restricts the output pressure. I think it costs about $20. Give them a call. Other CF members bought them to reduce the power assist for Steeroids. That's on my list of TTD this spring.

Jim Shea

Trust me. Going from something like a 1400 psi pressure relief setting in a steering system and changing to a lower 950 psi setting will NOT increase the effort or change the feel of your steering. The correct maximum power steering pressure relief setting is the amount that allows you to turn the steering wheel full lock to lock with your car stopped and your foot on the brake. You don't need any more pressure than that! The pressure relief setting can be changed to a lower setting by adding very small shims underneath the hex head fitting on the pump flow control valve inside the pump.

Now here is another approach. If you greatly reduce the flow of your pump, you will change the response of your steering valve and that will change the feel and apparant effort of your steering. You change the flow by going to a discharge fitting (the part on the back of the pump that the power steering pressure hose screws into) with a larger or smaller diameter throat.

The correct amount of flow is checked by trying to make a very quick evasive maneuver. You do that by driving the car at 15 mph in a wide open space (such as a vacant parking lot). Then whipping the steering wheel 180 degrees (as if you are suddenly trying to avoid something appearing in the road). If you do not have sufficient flow, you will feel a very sudden, abrupt, increase in effort. (Some people mistakenly think that their steering has "locked up" and quit steering even though full assist quickly returns.)

As I review the C3 pumps that were in production through the years I find a number of different flow settings. (I have no idea exactly why.) The change in 1982 was because of the push for improved fuel economy.
1967-1969 1.75 gal/min
1970-1973 1.60 gal/min
1974-1981 2.90 gal/min
1982 1.9 gal/min

So the 1970-73 Corvette pumps actually have less flow than any of the other C3 pumps. I don't know how much difference in steering feel you would experience with a lower flowing pump.

Many rebuilt pumps are supplied without a discharge fitting. So you are instructed to use your original discharge fitting, flow control valve, and spring. By using those original parts, you should retain your original pump flow and pressure relief settings.

NOW I AM TALKING ABOUT THE CONTROL VALVE & ADAPTER THAT IS LOCATED ON THE STEERING LINKAGE
It is interesting that the control valve on the linkage had an internal spring change in 1976. The control springs in use up to that point had a 55 lb rating. Starting in 1976 the spring was changed to a 40 lb rating. I have a drawing of the valve with the 40 lb spring. The valves before that time had "C" stamped into the end cap. The "C" was removed in 1977 (probably because the Corvette was the only car with the control valve type power steering.) So most valves with the "C" should have the 55 lb spring. I am fairly sure that all of the control valves that are being sold today are most likely with 40 lb springs.

Now I am not saying that just changing to the earlier 55 lb spring will dramatically change your steering effort.

A couple years ago I talked with a person in the Technical Service Department at Vette Brake and Products. At the time he stated that his company could special order a control valve with a 55 lb spring if you would contact the Tech Service Dept. They could rebuild your valve or supply you with a new one (the valve would have a 5 year warranty). He didn't recommend it but you could also purchase a rebuild kit with a special 55 lb spring. I hope that their offer still stands.

It would be interesting to run a controlled test with power steering pumps with known flows of 1.6 and 2.9 gal/minute. And then compare control valves with known 40 lb and 55 lb springs.

Jim Shea

Durango_Boy

Jim - What is it about the Hydroboost together with the Steeroids that cause the stock C3 pumps to fail?

Jim Shea

I am not aware of C3 pumps failing (with or without Hydraboost.) Do you have some information?

Adding a Hydraboost unit does not greatly affect the overall duty cycle that the pump experiences.
Jim

Durango_Boy

Nothing specific, but several members, have noted pump failure. They said it wasn't the Hydro specifically but the Hydro with the Steeroids broke the back.

Jim_Harrison

Jim;
This is some interesting information. When AutoXing my 72, sometimes on very tight courses where a lot of severe right to left steering input is needed I loose the power steering. Would a higher volume pump from another year help the problem?

I'm Batman

I think Norval said he burned up several stock pumps with Hydroboost and the Jeep box.

NewbVetteGuy

I'm resurrecting this because as I read the Speed Direct article on "Steeroids & Steering Feel", their article specifically recommends against using a pump that exceeds 2 gallons per minute:

"The pump cannot have a max volume exceeding 2 gallons per minute UNLESS you have a system (such as Hydroboost braking systems) that includes an additional amount of fluid over the stock amount. Why? If you run just from the pump to the rack, then back to the pump, excessive heat is the enemy. Any more than 2 gallons per minute could damage the rack. Systems with additional fluid and routing allow the fluid to cool, allowing some pumps with higher outputs. Unfortunately, higher output pumps may result in slightly less resistance in the steering wheel. This, of course, is a matter of preference for the driver."

http://www.speeddirect.com/index.php...-steering-feel


They also state that the Steeroids racks can handle between 800 and 1400 psi but recommend the 900-1200 psi range.


It's just really tough going to turn my wheel at low RPMs even on my epoxy floored garage with my 850 or 950 psi 1979 pump.... Can't quite figure it out... Seems fine at any decent RPM but at idle it's pretty awful!



Adam

terry82

does the gm fluid work better ?I have a 1982 vette that I just replaced the control valve in but I used cheap power steering fluid.