I have a 75 roadster. The power steering was rebuilt with new components,still tough to turn at low speeds (like parking).Can i install a larger (or smaller) pulley on the pump to speed it up a little to get some low rpm power assist? Every things o.k.once the rpm's are up. Thanx;jim

You don't say whether the pump is "new" and/or if it was doing this before the system rebuild. Sounds like your pump is not flowing enough at low speed, and not building up enough pressure. I would clean out and re-build the pump (watch out for the vanes falling out), and see if that was the culprit. Be sure the pressure relief valve doesn't have trash in it. If the pump is old and it wasn't doing this before, you may have some junk in there holding a valve open not letting the pressure be where it needs to be. In that case, maybe flush and clean the lines.

|UPDATED|9/10/2003 10:05:40 AM|/UPDATED|

did you replace the hoses also? these hoses can collapase internaly and not allow enough fulid to get to the cylinder . also check the cylinder under the car. check the shaft to be sure its straight with a good straight edge. also remove the hoses to the cylinder and push it in and out by hand(watch out for the mess). it should move freely with both hoses removed after all the fluid has been pushed out.

the pump,hoses,control valve and slave cylinder are new.(from Vette Brakes)

I had a similar problem when autocrossing. Not a good time to have hard steering. Read an article in either Corvette News or Vette Quarterly (now Vette) advising to replace the relief valve in the pump with one from a pickup truck. The stock valve can't port the fluid fast enough at low speeds and essentially you are getting a hydraulic lock effect. The truck valve has a lighter spring.
This was in the mid-70s and I have a '73. Worked great at low speeds however there is a very slight loss of on center feel at 70+ speeds. It's a pretty easy change.

do i have to tear apart the pump to replace the valve? if so wouldn't be easier to install a rebuilt pump from a pick up?

If you have installed new copoents as you said then you need to check the control valve for proper balncing to do this you have to have the front wheels off the ground disconect the power steering cylinder rod from the mount on the control valve there is a cap at the end remove the cap and there will be a slot where a scerw driver will fit start engine and watch the cylinder it will move in or out if it is moving toward either side you need to adjust it so it will stay in the center postion with out moving using the slot on the control valve turning it clockwise for ou couterclockwise for in my 75 had same problems afer I inslalled new control valve and cylinder after the adjustment to control valve stearing was great

It's been almost thirty years but I believe you can do it on the car. Disconnect the high pressure line where it attaches to the pump. Remove the fitting that it screwed into and the relief valve is right there. Remove it, noting orientation, and install the new one. Reinstall fitting and reattach high pressure line.

A GM service manual helps.

Good luck.