steering has a mind of its own
 

for awhile now i've been trying to track down why my car wants to go to the right. finally got a chance to take it to a very reputable alignment shop. after 2 hours they gave me my car back

- the alignment was set to spec. they had no problem with getting every setting correct, the difference between the left and right were negible

- they switched tires to see if it could have been a tire problem

- they tried varying settings and under different conditions - braking, accelerating, cruising in. they don't think it's the diff or anything like that

the technician's best guess (although he admits he has no proof) is something in the power steering rack. basically the car goes straight, and then suddenly it's like the steering mechanism turns the steering to the right a little. he said to get the steering system pressurized (they didn't have the equipment to do this).

i called my mechanic and he said he's never really seen the steering rack go bad and that he doesn't have the equip. to do the pressure test either. and also warned me that a steering rack is very expensive.

anybody have any comments? anybody know what this special equipment is?

i guess the good thing is that since all my alignment specs are good the car handles fine except this magical force that turns the wheel a little.

He may be bullshiting you. I've never seen a steering rack be replaced. But hey, anything can happen.

well at this point it's my only lead. i've had the alignment done, i've had the suspension parts looked at, all my bushings have been replaced.

Does the steering wheel turn a little even while idleing? Like twitch a bit? I'm wondering if it stops if you were to remove the power steering belt. Might even try this while driving, though I wouldn't for long in that I would personally want to remove the power steering the "correct" way (loop line, or removal of hydraulic driven components). But for troubleshooting, it should be ok.

Anyway, if I recall correctly, our power steering system has a valve that moves when we move the steering off center, which then applies the hydraulic pressure to the rack. If that valve was damaged, or the seat leaked a little, the valve might move on it's own, causing steering rack movement with no steering wheel input (one reason why manual is preferred in racing situations). If it doesn't twitch at idle, it would be doing this only with elevated engine speed and elevated vehicle speed, which would indicate something in the speed sensitive mechanism. Pulling the power steering pump belt removes hydraulic pressure input to the system, so a slipping valve would no longer move the rack.

Any thoughts on this, 'yall? Pulling the belt is easy...

It's definitely the power steering.

Something is causing a variance in hydraulic pressure from left to right (that is how power assist works in the first place). Check the seals, check the fittings first.

Spurvo's advice is good.

It could be a loose tie-rod end or something like that, allowing the steering to be a little loose. You'd think the alignment guys would have caught it, but they may not have - I had a buddy who had tie-rod loose/worn and the alignment shop didn't catch it until he told them to check everything - it was causing some odd wear on the front tires (not an rx7 though).

Simon.

Alignment guys missing a loose tie-rod would be like a muffler shop missing an exhaust leak - they'd have to have their heads way up something.

Besides, the alignment people were aware beforehand.

ttb, just remove the entire power steering pump, lines, and plug the holes :P.

Jack up the front of the car with steering wheel straight. Start car and see if wheel moves. Rev car and see if wheel moves, that will tell you if the rack is messed up

I've had a similar problem w/ my first fd. Has your car been in an accident? sometimes if it is a bad accident it's almost impossible to get the car to run straight

I also had this problem w/ my Pontiac GP. After an allignment it still pulled to the right a little

I believe the steering gear is made by Koyo Seiko and has a rotary valve contolling pressure to either the LH or RH cylinder. The design is basically common across all steering gear manf - an input shaft connected to the pinion via a torsion bar. The valve sleeve is pinned to the pinion and relative rotary movement between the sleeve and the input shaft directs oil in the appropriate direction.
As has been previously suggested take off the pump belt (not too long) and see if it still does it. If it stops the problem is almost certainly in the valve - get a new/recon strg gear, DO NOT mess around with it.
If the problem remains with no power assist then the problem is mechanical, i.e. freeplay somewhere between the strg wheel and road wheels. Try column couplings, UJ clamp to the input shaft, inner & outer ball joints, Knuckle joints etc.
Hope this helps