1968 Power steering not working after rebuilding pump

[admin]

I rebuilt my PS pump when I rebuilt my 289 a few months back. the new engine has been in the car and running fine with test drives around the block, but I finally got a chance to install the PS pump yesterday.

The problem is the car still feels like it's 100% manual steering. I turned the steering wheel lock-to-lock several times thinking I just needed to bleed air out of the system, but the steering never gets easier. The pump is full of fluid per the dip stick (about 1.5 qts) and no leaks. No squealing from the belt. No whine from the PS pump.

I did not mess with the control valve under the car yet because the PS system was working well before I started the major engine rebuild process about 2 yrs ago.

So I'm trying to figure out how to determine if the problem is with the pump, the control valve, or maybe with the lines between the 2.

 

[rvrtrash]

Jon, I was hoping that someone with more knowledge would check in, because I've only installed rebuilt units on my cars. I'll try to help using experience on hydraulic equipment. First, when you rebuilt the pump, did you buy a rebuilt pump assy. and install it in the housing, or actually rebuild the pump "cartridge"? I ask because I believe there would be a pressure relief valve in the pump. If that's sticking open, you wouldn't build pressure, or enough to make the system function. You'd have to do a pressure test on the pump, which would require hydraulic gauges and some sort of restrictor, to simulate a load on the system. You'd probably have to find a shop with the equipment for that. If you installed a rebuilt pump in the housing, that probably wouldn't be a factor, as I imagine they test them before shipping out. Another possibility is there should be a piston or check ball in the control valve that may be stuck or leaking past the seat or seal. Finally, the hydraulic cylinder itself may be leaking past it's internal seals. Sorry I can't be more specific. The same hydraulic test on the pump could be used throughout the system, to find where you're loosing pressure. Honestly, with shop rates what they are, you're better off rebuilding everything or replacing with rebuilt units.

 

[admin]

Thanks for the reply Steve. I did rebuild the pump myself, as opposed to buying a rebuilt cartridge. Honestly it was just gaskets, seals and O-rings, although I did have to replace the pressure plate because it was cracked in half.

1968 - Power steering pump rebuild - pressure plate cracked!

I opened up my PS pump to rebuild it (gaskets, seals, O rings) and got a little surprise when I took off the pump housing. The pressure plate was cracked clean in half? It's been a few years since I drove it, but at the time there were no issues with the power steering. Worked fine, no weird...

californiaspecial.com

Rebuilding was a pretty straight forward process in my mind, but it's certainly possible that I screwed up the pressure relief valve.

My local parts store actually has a PS pressure tester as part of their "loan-a-tool" program, so I picked it up yesterday and will try testing it this week. It's just a gauge with several different size fittings, so it should be easy (just messy pulling the lines off again and getting type F everywhere!

The most likely scenario does seem like the pump isn't building pressure. The fact that I'm getting zero power assist, but also no leaking, whining or other sounds from the pump is odd.

I'll test the pressure and report back.

 

[speedy02]

I reviewed your rebuild images. Your main shaft looks pretty good on the outside teeth. How was the rest of the shaft? Also, there may be a screen inside the pump. If the screen is clogged, it will affect the pressure. I added a link to a video in which he stated that if the screen is clogged, then you're better off buying a new pump. I think you could clean it with a sonic cleaner and a heavy-duty degreaser.

Fast forward to the 3:40 minute mark on this video.

 

[admin]

I had time this morning to hook up the pressure guage and the pump was creating ZERO pressure. Aarrggghhh!

So I bought a pump cartridge from my local parts store, installed it and now the power steering works fine. I was only able to test it in the garage because I'm also dealing with a brake issue, but the wheels turned nice and smooth and no leaks.

Mike, I do remember that screen and thought I got it cleaned out pretty well. But obviously I did something wrong to go from a pump that worked fine to one creating no pressure. I don't know if I reinstalled something in the wrong rotation or upside down and blocked off a passage or what. Or maybe the screen was the issue, but a blocked screen seems like it could reduce pressure, but not stop it entirely.

 

[Ruppstang]

If you have disc brakes, be sure that you have the calipers on the correct sides.

 

[admin]

Calipers are on correct sides. The brakes worked fine a few years ago before I pulled the engine, did body work, paint, etc.

I started a new thread on my brake woes: https://californiaspecial.com/forum...the-right-front-power-discs-rear-drums.14908/