Jump to content

rebuilding 55 olds power steering pump


Guest shirley

Recommended Posts

Guest shirley

anyone needing advice on how to rebuild your power steering pump and to get it working let me know. i have experienced all the major problems that could happen and you will even be able to bench test it without any tools and equiptment just tell me what you have already done to the pump and i will fix your problem on the forum.

dennis:o

Edited by shirley
left out word (see edit history)
Link to comment
Share on other sites

Hello Dennis, I have been having trouble with the rebuild on my 1957 Pontiac, see photo. I have taken it apart twice and replaced the large O rings twice, the second time using a complete NOS GM rebuild kit. All the vanes are in good condition, no visible wear or problems. I am getting no power assist. Any thoughts? Thanks, Todd C

post-31304-143138652971_thumb.jpg

Link to comment
Share on other sites

Guest shirley

Hi, Tod well i can see you are on the right track the problem is with the NEW O RINGS. the two large o-rings between the body of the pump have to be a flat

seal in order to work if you have the old seals reuse them they will work and solve your problem. call me and i can give you more info on how to bench test

the pump before you put it back on the car 440-884-9411 my name is dennis

Link to comment
Share on other sites

Guest shirley

Hi Todd hey if you find the old o-rings make sure they are flat on both sides. then when you put the unit back together do not put the top reseivor back on put the unit in a vice then fill up the front hole with trans fluid and put your thumb over the high pressure fitting on the back of the pump, then start turning the front shaft with

your hand and after 3or 4 turns you should feel pressure and not be able to turn

the shaft of the pump anymore now you know you have pressure and the pump

will work on the car Dennis and questions you can call me @ work 216-676-2589

Link to comment
Share on other sites

That's peculiar. I've rebuilt at least 4 50's GM pumps using new O rings with no problems what ever. O rings come in different gauge rubber as well as sizes and you must use the correct gauge so that it squashes and seals but still does not "fill" the groove. Rubber acts like a liquid and is pretty much un-compressable. If the ring is too large of a gauge it will fill the groove and not allow the mating parts to seat together. The old O ring is flat because it's old and has taken a set...............Bob

Link to comment
Share on other sites

Guest shirley

SORRY TO TELL YOU BOB BUT IF YOU LOOK IN THE O-RING BOOK O RINGS COMES FLAT ON BOTH SIDES TOO. THEY USE THEM ALOT IN TRANSMISSIONS. SO YOU USE WHAT WORKS FOR YOU AND I WILL USE WHAT WORKS FOR ME. THEY

DO NOT GET FLAT BECAUSE THEY ARE WORN. THEY ARE ALREADY A FLAT SEAL TO BEGIN WITH FOR THIS APPLICATION. I'VE REBUILT OVER 50 POWER STEERING PUMPS USING THE FLAT RUBBER SEALS WITH NO LEAKS. THIS WORKS FOR ME.

Edited by shirley (see edit history)
Link to comment
Share on other sites

No need to shout. They also come cruciform shaped for superior sealing compared to either flat or round . My point was that there is more to ring selection than diameter and the wrong ring profile will cause problems. Sorry you missed the very obvious point..........Bob

Link to comment
Share on other sites

Guest shirley

You are correct in that O rings come in different sizes & shapes & you must use the correct diameter to make it seal properly. That's why I use flat rubber seals when rebuilding vane operated power steering pumps. I did not miss your obvious point in your first statement. You contridicted yourself when you stated that rubber seals are pretty much un-compressable & that the O ring is flat because it's old & has taken a set. Bob, the only thing I was trying to do was to help this guy out with his problem as it appears that no one has been able to help him. You made me sound unreliable.

Link to comment
Share on other sites

No contradiction at all. The O ring is sized to fit in a groove that allows it to expand within the groove as it is squashed to make the seal. That does not "compress" the ring. Rather it "deforms" and flattens the ring to effect a seal. Big difference. Over a half century, or so, and fairly high heat, the ring takes a "set" and retains the flattened shape it was squashed into. A square O ring, properly sized, will work just fine as will a common O ring or the less common cruciform ring as long as it is properly sized to fit the retaining groove in both diameter and gauge or thickness. Properly sized is the key. Too thin and it will not seal. Too thick and it will not allow the parts to draw together, allowing any number of consequences. It was not my intention to make you sound unreliable but rather to point out alternative approaches to his problem. It's quite possible the selection of O ring has nothing to do with the problem "this guy" is having..............Bob

Link to comment
Share on other sites

Guest rsd9699

The "flat" o rings are called square cut o rings.

If using either square cut or round o rings, the compression must allow for the two metal pump parts to mate to reduce the clearances to the minimum for the pump to achieve its rated capacity.

Petroleum jelly is a great filler when packed into the vane cavity to provide the initial prime much the same as in an engine oil pump.

I always look for parts installed incorrectly, factory o rings will always work.

I think that if pictures are posted as the pump is disassembled, we will be able to point out the incorrectly positioned part(s).

But without pictures we can only guess.

Ron

Link to comment
Share on other sites

Well, thanks to everyone for considering my problem, I wish I were going to be working on it immediately but will probably not for a few weeks, so I hope everyone will take another look at the thread then. Will post photos after disassembly if there is no immediate fix.

I am certainly puzzled by this problem as this would not appear to be a complicated device. As you can see I had the factory diagram and service manual for reference and am quite experienced in old car work. The O rings I initially used were selected just by diameter and thickness as Bob said, and that is why I bought an NOS GM rebuild kit to replace them, just in case. But it has been a while since the second rebuild and I forget if there was a different profile. Thanks again for the discussion and hope to return soon.

Dennis, let me ask you a question. The service manual shows use of a pressure gauge for testing. I do not have a power steering pressure tester and have been unable to find one anywhere. Even professional mechanics I know have never used one. Do you think it is important and if so is there a commonly found gauge used in some other function that I could find? Or is your suggested bench pressure test sufficient? Thanks, Todd C

Link to comment
Share on other sites

TODD, i have the pressure gauge that you see in the picture it is made by

kent moore tools. it shows pressure and rate of flow. you can find them on ebay or if you need to use mine we could work something out? the bench test will let you know if the pump is building pressure and that should

be all you need to know. good luck DENNIS:o

Link to comment
Share on other sites

  • 3 weeks later...
Guest rsd9699

I have never had to use one - you either have pressure or not by turning the steering wheel to the extremes on a lift and listening to the sound of the engine slowing down under load or pump noise as it bypasses or the oil getting hot during bypass.

A place that sells a 1500 or 2000 pound pressure gage will most likely have all the parts to make you one.

I just rebuilt an Isuzu pump and knew I had power assist as soon as I turned the wheel.

I would think the older new car dealers have one to ensure that the pump met factory specs for warranty work and since everything is metric today - they would likely give it to you to just get it out of their way.

Ron

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...