power steering getting stiff when warm at odd times fixed...

[ScottJackson]

I haven't posted on here for a while but I haven't been driving the Q either. Something about having the bmw 540 that makes the Q get rusty brake rotors. Anyway, now that the 540 is down for a while to get new front suspension parts and an M5 differential, the Q is my transportation. The power steering would work fine when cold but then go extremely hard when warm, most of the time. Sometimes when warm it would work perfect. There was no in between and revving the motor made no difference when it wasn't working. Speedo always worked fine too. Long story short I pulled the "control valve" of the pump which is number 7 in the exploded pic in the service manual. It looked good but there was some junk that came out when I flushed the fluid out with a quart of kerosene. I took the proper pressure line off the pump and blew with my mouth into the steering fluid reservoir to push the control valve out (obviously a pressure control valve) and left the line off, started the car, and poured the kerosene in the reservoir and let the pump push it out into an oil pan. After putting it back together and filling with DexronIII, it has worked perfectly since. I'd sucked out the old fluid several times before from the reservoir and put in new but it didn't fix it. SOOOO, if someone else experiences this, check the control valve in the pump.

[squeefoo]

Thanx Scott !! This is something I will try next.

Did you examine the "junk" that came out ?

I did the voltage test at pin# 7 and wound up replacing the brake switch, which had a burnt contact. The steering still seems a little stiff at lower speeds, but I get a different stiffness at higher speeds....

BTW: for future repairs the brake switch has the thicker wires of the two, the FSM had mine reversed. I went by the book for position since I couldn't jam my head up there. It seems the positions can be reversed between the cruise cut-off and the brake switch.

[maxnix]

Curious as to the color of the PS fluid.

Best argument I have seen for a mechanical fluid exchange. The PS fluid capacity is very small and the temperatures can get quite high, especially in town.

This is a nice solution as long as one doesn't engage the PS while the kerosene is in it. Unfortunately, going lock to lock several times is required to extract all the old fluid out of the system.

[squeefoo]

Tonight I pulled the pump, took it apart and it was spotless inside.Well I'll find out what it feels like tomorrow...might be one of those take it apart and put it together and it fixes itself deals.

There is a pressure sensor/switch? in the PS hardline I don't have a spec for in my FSM, looked all over and don't see a thing (maybe looking too hard). Two wires, aims forward, welded right onto the hardline adjacent to the PS solenoid (not the solenoid ) What is it? -Anyone ??

[ScottJackson]

The fluid was red as it should have been. There were just some small black specks that came out with the fluid but I couldn't really inspect the fluid in the pan as the pan wasn't perfectly clean before having the fluid in it. My valve looked clean and the little screen in the middle of the valve was clear also. The only other odd thing was there was a little milky fluid on the valve so there was at least some water in the system. I didn't turn the wheels lock to lock and I doubt it would hurt the PS system if it was only done once to flush the fluid from the rack. By the way, it's still been working great so I'm 99% sure that was what fixed it.

[squeefoo]

Used to be stiff steering all the time, now it's just when it's warm. Is it getting better or worse?

[ScottJackson]

sounds like you're on the right track. did you pump some sort of solvent thru the lines and reservoir too? If not, you could try that pretty easily. I didn't take my pump out when I flushed mine and checked the control valve. So the pump vanes all looked good and the bore they ride in was nice and smooth too? If so, you could try ordering a new valve and spring for your pump to see if that fixes it. I don't have any other ideas. If it's working somewhat now, I'd be very inclined to think the problem still lies with the control valve/spring or the pump vanes or housing. If the vanes were good and the housing smooth, it's about gotta be the control valve. The only other option would be maybe a blockage in the line(s).