Power steering problem

[larryboy_3t5]

I have a 70 Jimmy 4x4 with factory power steering. Put on a new pump and now when you start the engine it pulls violently to the left till it hits the stop. It will pull the steering wheel right out of your hands if you're not holding on tight. It stops when I remove the return line. Pump manufacturer says I have air in the system and advised to attach a vacuum pump to the reservoir and pull about 20psi of vacuum while working the wheel back and forth with the engine off. Did this till my arms fell off but the issue persists. Now they say it is a stuck valve or other problem with the steering box.

Anyone else run across this? I feel like the guy is just avoiding the issue of selling me a bad part but I've never seen this issue with power steering in the 40 or so years I've been working on GM cars and trucks.

[wannabefastcrf]

are the lines crossed ? Only reason I ask is because I have did that before on derby cars and I recall the wheel going crazy

[larryboy_3t5]

The high pressure line is threaded into the back of the pump like a brake line or trans cooler line and the return line slips on and secures with a hose clamp so I don't see how I could cross them.

[SeventyOne]

What do you mean it stops when you remove the return line?

Also to the questions about having the lines swapped - you are correct you cannot install the lines incorrectly AT THE PUMP...but what about at the steering box? I don't recall if they are the same thread or not.

[67Steven]

Should be different threads at the steering gear box as well- I don't think you can cross them, but never tried.

[larryboy_3t5]

It stops pulling to the left when I disconnect the return line.

[franken]

What did it do or not do before the new pump?
All the pump does is pump fluid so I'd guess the problem is something stuck in the box.
Maybe try cranking lock to lock w/ the engine off a few times to see if something frees up?
I'd do some searching of the internet. There's also a great writeup out there on rebuilding the box.
Heh, I didn't have to hunt too far. See the link in post #3: http://67-72chevytrucks.com/vboard/s...d.php?t=397446
If you rebuild the box, you may want to get a kit for the pump so you can pull it apart and clean it. or just pull it apart and reuse the O-rings. Also clean out the hoses and replace at least the return hose.
There's a recent discussion about the old topic of using a Jeep XJ steering shaft to get rid of the rag joint you may want to look into...

[larryboy_3t5]

The truck was a barn find and I didn't try to run it before I changed the pump. I called BBB Ind. (they sell rebuilt pumps and steering gear boxes) and they felt the problem was in the steering box. Most likely a Teflon seal in the valve. They say that valve is the only thing that can cause it to turn like that on it's own as, like someone just said, the pump just supplies pressure. Makes sense to me. After watching a few people do it on Youtube, I feel confident I could rebuild the steering box but the valve itself might be another story. Since this is such a safety item I've decided to replace the box. BTW, $250 at LMC truck and $150 at Autozone. Jeeze! Before I return the core I will disassemble it and educate myself a little. I'll post what I find here for future info.

TTFN