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.

[SeventyOne]

If you disconnect the return line I am guessing that there is no longer fluid flowing through the steering box (i.e. manual steering) so this tells us nothing really.

The issue is with the new pump. I recall reading instructions awhile back that involved jacking up the front tires, starting the engine and working the steering wheel back and forth, lock to lock, to get all the air out of the system and then topping up the fluid. It may take several tries.

Do you notice any cavitation of the fluid?

[larryboy_3t5]

I've probably installed at least 15 - 20 power steering pumps in my lifetime and that is the procedure I always use. It has always worked in the past so this is a first for me. The front was on stands, the pump was filled with fluid, and I started it up. It made the usual noise until the fluid made its way into the rest of the system then the wheel spun to the left. I shut it off, refilled the pump, and worked the steering back and forth a few times. With the wheels centered, I started the motor and it spun to the left again. I was able to force it to the right but it strained and hummed the whole time (like it will when you force a normal working system against the stops). As soon as I let go of the steering wheel, it spun all the way left again.

[larryboy_3t5]

It did spurt a little fluid out of the hole in the cap. Is that what you mean by cavitation?

[SeventyOne]

cavitation would be bubbles and frothy fluid - meaning you still have air in the system and the pump is essentially mixing air into the fluid.

Did it throw the wheel to the left from the start with the new pump or only after adding more fluid after initial startup?

[larryboy_3t5]

First start-up

[larryboy_3t5]

no bubbles

[SeventyOne]

You just replaced the pump, right? didn't touch the lines or steering box?

I would do the jack up and turn lock to lock thing again, adding fluid while you do it - check for fluid cavitation. Everything I'm reading tells me it needs more fluid and has air in the system.


check this out: https://www.youtube.com/watch?v=pW0Rt_yJTow

Also: some of the stuff below I think you can rule out but this is stuff I found online:

Noises from the power steering unit:
You notice a whining or moaning from the steering when you turn the steering wheel all of the way in one direction. Everything else seems to be fine except for the noise. The problem seems to be getting worse over time.

Possible causes:
The power steering drive belt is damaged or loose: Tighten or replace power steering drive belt as required.

The fluid in the system has air in it: Bleed power steering system.

The fluid level in the power steering reservoir is low: Fill fluid to proper level.

The mount for the power steering pump is loose or damaged: Repair or replace power steering pump mounts as required.


Steering wheel jerks:
When you are driving slowly or at an idle the steering wheel jumps or jerks. You don't see any other problems as far as steering and handling go. As time goes by it seems to be getting worse.

Possible causes:
The power steering drive belt is damaged or loose: Tighten or replace power steering drive belt as required.

The fluid level in the power steering reservoir is low: Fill fluid to proper level.

The engine is idling too low: Adjust idle speed.

You have a problem with the power steering pump: Repair or replace power steering pump as required.

The steering linkage is rubbing against something: Inspect steering gear and repair the interference.


Other stuff I found:
different cars but similar issue.

http://www.forums.turbobricks.com/sh...d.php?t=275458

[87Skier]

Might consider flushing the steering box.

When I replaced mine, I put the new pump in, replaced the lines (they were leaking), and disconnected the return line.

With the front wheels off the ground DO NOT START THE ENGINE, turn the wheels back and forth while hitting the end. Keep going until new fluid comes out (took me about 20 minutes). Reconnect the return line, top of the reservoir, and start the engine.

Also, it sounds like there may be an issue with the steering box. Why were you replacing the pump anyway?

[larryboy_3t5]

The truck is a "barn find" (I know, a much overused term to describe an old truck that has been left for dead). Anyway, seller, supporting paperwork, and DMV history indicated a truck that had been sitting since 1987. Engine turned over (by hand) smoothly and compression was good. So I decided to make it a running driving truck but save the "patina" (sorry) of a truck that has aged gracefully. I replaced the entire brake system, the entire fuel system, and decided to also replace the water pump and power steering pump "just to be safe". The pump was dry and the return line looked like it had leaked the fluid out. The pressure line looked ok. In hindsight, maybe I should have tried to run the stock parts in case there were problems that might stand out. That way, if I replaced the pump and the same symptoms existed, I would be fairly certain if was not the pump. So now I suspect the new pump may be a bad part. I've had that happen more than once. but I guess it could be the steering box.

Also, I probably should mention, I drew out some fluid yesterday and it has the look of coffee with a lot of creamer in it. It's not frothy, just has a light tan color. Today's plan is to remove the return line and purge the system. I'll see if I can get it full of nice clean fluid then start this all over.

[Chulisohombre]

The creamer is water and the black Is junk that was sitting in the steering box until You Ran the new box through It. Hopefully flushing will get it going again. Sounds like you May end up Replacing the rest of the system though. With all That crap running around it can Block The pressure ports and not let the system circulate and may wreck that new pump.the pump gas a pressure valve in it to that can get blocked and drop the pressure if it gets blocked with that junk flowing around too.

[larryboy_3t5]

Re: the last post, there was no "black junk", just the creamer color.

Well, I finally got back to it. I flushed the system until all the contaminated fluid was out. Went through almost two gallons of fluid. So now it has fresh fluid and no cavitation. But still has the same problem. Unless I find some instructions on how to rebuild the steering box, I may just give in and buy another new pump and a new steering box so I can start fresh.

Thanks to everyone who helped with advice. It is very much appreciated.

[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