Steering rack question... Options

[MikeM]

Hi all....
I'm still searching for the cause of a shimmy, and I've done everything on the back of the car so I'm now looking at the front. Today, I noticed that there seems to be a couple of clunks or slightly dead spots in the travel of the steering rack. I can't tell if it's coming from the rack or from one of the couplers, although they all seem to be tight with no play. Should the rack be smooth in it's travel range? Could this cause the car to shimmy? I should add that it shimmies at just below 30 and just below 60 mph.
Thanks,
Mike

[Cap'n Krusty]

If it's happening at those speeds, first thing I'd look at is tire balance. You don't say what year 914 you're talking about, but early (lug centric) cars are prone to non-centering issues, something hub centric cars don't have a problem with. Steering rack wear isn't one of the more common issues we face, but it can happen.

The Cap'n

[MikeM]

Hi...yes, I've had the wheels balanced several times. I've also tried 3 other sets of wheels and tires. Given that it occurs at those speeds I didn't think it would be the rack but I'm trying to rule things OUT!!!
Mike

[bdstone914]

Sounds like the rack. Check the inner tie rod ends. They can get soft and worn. I have many good racks if that is what is the problem.
Bruce

[MikeM]

Sounds like the rack. Check the inner tie rod ends. They can get soft and worn. I have many good racks if that is what is the problem.
Bruce

Bruce...can you send me a number where I could call you?

[Cap'n Krusty]

You STILL haven't given us enough information to properly answer your question! I guess subtle prodding doesn't work with some people. As for worn inner tie rod ends, new ones are readily available (sorry, Bruce!).

The Cap'n

[bdstone914]

You STILL haven't given us enough information to properly answer your question! I guess subtle prodding doesn't work with some people. As for worn inner tie rod ends, new ones are readily available (sorry, Bruce!).

The Cap'n

I meant a used rack. I would not sell used tie rod ends. Half of the ones I have on racks are shot.

[MikeM]

Apologies....
It's a 74,and I have the rear centering rings from Tangerine. I've also replaced the rear rotors,wheel bearings and trailing arm bushings,trans mounts,new rear shocks and springs, and recently 2 new axles and cv joints from Tangerine. The car SEEMED to vibrate when driven on a hoist so I thought it was the back end. I'm now looking at the front. There seems to be a couple of clunks in the travel of the steering rack.
Is this normal? Would it cause a shimmy?
Mike

[pcar916]

The source of my persistant shimmy turned out to be loose front wheel bearings. It seems I wasn't tightening them quite enough.

Once I had the right torque the shimmy went away. I'm talking about just a wee-touch more torque than I'd like because the washer doesn't move quite as freely as I'd like.

But with synthetic grease they never burn or gall the races.

Good luck

[MikeM]

Thanks for that. I've adjusted them before but I'll look at them again.
Mike

[MikeM]

Any more thoughts gentlemen?

[Dave_Darling]

Shocks, ball joints, A-arm bushings... Probably more as well.

--DD

[SLITS]

The rack should run smooth from lock to lock.

If there is a catch / glitch in the travel of the rack, it is a worn spot from many miles on the road or lack of lubrication. Not much to go wrong with a manual rack.

2ndly, if the boots were broken / missing, foreign material could get in and cut the seals which would result in a loss of lubrication and accelerated wear of the rack against the pinion.

[Mike Bellis]

The fact that you state the shimmy at 30 & 60 mph sounds like harmonics of rotating mass.

I would look at bearings and brake rotors since you have tried multiple wheels.

A bad steering rack should shimmy at various speeds.

[bdstone914]

You can try to isolate if it is front or rear by lifting the rear wheels off the ground and running the wheels up to the speeds where the shimmy occurs.
It does sound like a rotating problem. Do check to ball joints and outer tie rods too.
Bruce

[MikeM]

Ever heard of a clutch or flywheel causing that shimmy?
I swapped out the transmission but not the flywheel.
Still can't tell if this clunking is coming from the steering rack or couplers.
I have driven up to speed with the back end raised and it vibrates. That's why I've been concentrating on the back end.Maybe vibration in the scenario is normal.

[SLITS]

With the ass end in the air, the angularity on the CV joints is out of whack and it's going to vibrate.

Put jacks under the trailing arms and bring the suspension up to normal level and check for vibration.

My opinion.

Flame on!

Swapping the tranny should have nothing to do with it if it didn't do it before the swap.

An out of balance clutch / flywheel assembly would vibrate the drive train and get worse with higher RPMs.

[MikeM]

Yes, I took that into account. Up in the air everything is hanging and out of whack.
I swapped out the tranny to eliminate it as a source of the vibration. It does not vibrate when revved in neutral in the garage, only with road speeds of 30 and 60.
Mike

[Mike Bellis]

Maybe you have a bent axle or CV problem.

Jack it up and let it run in gear and look for the vibration.

[MikeM]

Mike...just installled new axles from Chris Foley....no change!!
Now I'm getting frustrated....
Mike