Have an odd problem here. Power steering works great turning right, but is jerky when turning left. It still assists, but pulses between easy and hard.

I pulled the pressure line off, fired it up, and the pump was pumping. Emptied the whole reservoir in a few seconds with a healthy spray.

No kinks or clogs in the lines, I checked and blew through them with compressed air.
Could it be the box? I thought it was just a big worm gear with ball bearings inside there. Not sure what could intermittently block it up.

Belt is tight, no screeches, and no pump whine. Seems to be doing well.

 

Well, there are only two possible causes I can think of. The first is a bad control valve in the steering box. I lean towards this since it only happens in one direction. The other, which did happen to me on my 69 H/O, is that the pressure control valve in the pump has come apart. This valve is inside the output fitting on the back of the pump. In my case, the nut that holds the spring on the valve at the correct force had come loose, causing the jerkiness. It took me a while to find this. Note that in my case, however, this happened when turning in both directions.

 

I just installed p.s. on a 1965 cutlass that had manual steering. Bought a p.s. gear box from RockAuto. After installing ,bleeding,it did the same thing your car is doing. After talking to Rock Auto they said something was wrong in the gear box. Something about check valves or springs that were hanging up, They sent me a second gear box and it works like a champ. A rebuilt gear box shipped for my car was around $90 dollars.

 

Another note, this is a 76 350 with stock 3 groove pulleys, and the steering pump came from a 69 AC cutlass.

The original pump and 2 groove pulley was thrown away at some point in its life so I am unsure if this setup requires a smaller diameter pulley to keep up with itself.

 

Thanks guys. I'll try the easy one first. I think I have an old 60's chevy pump I can rob the valve from.

 

Parts have been pirated from another pump. An 89 chevy van pump to be exact. I will do the swap and report back. I do not see a nut however that you spoke of, Joe.

just a Spring on a piston, and the fitting that compresses the piston/spring combo.

I have a metric steering box, so there is a metric fitting in the old 69 pump to make the lines work. Possible interchange problem?

 

No dice on the swap. Same problem. I did see the piston nut. Both units had 2 shims under the nut.

Time to swap the box.

 

I just had the same problem with a box I sent to Chip Woyer @ power steering services. He said it was the control valve in the box. I had to pull it out and ship it back to him for repair.

He said the valve is quite sensitive and that a small piece of dirt or shrapnel will cause it to malfunction. He was quick to blame me.

Clean your pump out very well and put all new seals in it to assure there is no contamination. Clean out the lines and assure everything is very clean when you assemble it.



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