TR7 steering wheel shaking/wheel wobble

[greasemonkey]

hi all,this has been a problem for the last 26 years at 50-60 MPH on my tr7 v8.did all the normal things ,balancing road wheels on/off car,changing tyres etc .only one thing stopped it,renewing steering rack when i got an advise on it at the mot because of slight play.that cured it for a year but then it came back.anyone got any ideas on this or is it new rack time again?,cheers greasemonkey..

[Stag76]

It can be caused by fatigue in the sub-frame resulting on zero or minus caster angle.
There are adjustable strut tops available that allow it to be corrected.
I made some saddles that moved the sway-bar forward by 10mm and increased the caster angle.
This cured the wobble and made the steering track straight instead of following
the variations in the road surface.

[Hasbeen]

The reason the new rack cured your wheel wobble for a time was it was a little tight, & added drag into the system. The drag dampened out the minor wobble you had. New tie rod ends, or ball joints can do this for a while in the same way.

A good on car balance should fix this, until you remove & refit a wheel. The problem is that our alloy wheels dont centre quite well enough on the hub. This can be cured by fitting a centring ring on the inside of the wheel. You would need a good machine shop to make a couple.

Alternately you could use wheels which centre on the studs, with conical nuts. My 8 has these, & has never had wheel wobble in 12 years.

Alternately you could fit a steering damper. These were very common before power steering, with it's built in drag eliminated the problem. VW beetles was one that had them as standard, & the things are virtually undrivable without one, as were some Alfas. There was a post on here many years ago with a tutorial on fitting a damper. A VW one could easily be grafted in.

They are simply a light shock absorber on a tie rod, just a bit harder to fit on a car with a rack than one with a drag link.

You could of course, do what I have done. I bought a used on car balancer from a tyre shop, whose staff did not know how to work it. They are about A$15,000 new, but mine cost only A$500. I did have spend another A$1200 to buy a 10 KVA diesel gen set to drive the thing, as 3 phase power is not available here due to shortage of distribution lines. This may be a bit extreme, but the wobble bugged me.

This has cured the problem for me. Now that few people can still drive these things, I could no longer find a shop offering on car balancing.

If you have read this far, congratulations, & good luck with fixing our wobble.

Hasbeen

[Hasbeen]

PS. You could also remove a shim from the rack, tightening it up a little. This would have to be no more than a couple of thou with a newish rack. This is not a desirable way of fixing the problem, but I think I would do it, if I could find no other way. The wobble annoys me so much in a car I have spent a kings ransom on.

Hasbeen

[Howard_B]

I had the usual 50/60 mph wobble with the original steel wheels, but when I changed to MGF wheels the wobble vanished - and has stayed away, so long as I keep them balanced

[greasemonkey]

thank you all for your imput,a lot of food for thought there.i wasnt aware this was a common tr7 problem until i joined this forum,the machining jobs i could do in my workshop.i have tried balancing the wheels on the car several times but it didnt help.i built up this car many years ago but fitted the work in between jobs at my garage,now i am semi retired, i am going through it sorting the jobs i never had time to do.so far i have panelled and fully carpeted the boot.i have the interior stripped at the moment.i am soundproofing and generally tidying up the interior and am just renewing the heater matrix..cheers greasemonkey..

[JeffLemon]

I bought my first TR7 new with 12 miles on it in 1979. Under warranty, the dealer could never fix the vibration issue, although an independent shop that had a hydraulic frame bench "tweaked" the tops of my strut mounts and that helped, but did not cure the issue. I drove the car that way for 13 years. I bought another TR7 about 20 years ago, same issue. I have read it is a fundamental design flaw, mostly due to using the sway bar as the front suspension link. Good Luck, JL

[FI Spyder]

My Tercel has a torsion bar as a front suspension link (same as the 7) but it doesn't have wheel wobble. On the 7 the near zero caster is the problem. Every thing has to be perfect. Tires balanced and if not round then shaved. Steering rack no play. Toe in right. Tie rod/ball joints tight. Wheel bearings set correctly. Probably other things I haven't thought of. If everything isn't right you can compensate with moving sway bar forward (changing caster), installing steering shock like the VW (had one of those) etc. My own personal experience: had violent shake at 50-65 when I bought it. Put on new tie rods/ball joints (old ones seemed good but did it anyways) and put on new Kumho tires (balanced off the car on their electronic machine). Silky smooth for many years except for last few with a slight wheel wobble around 60. When going over rough terrain like a field (when getting in position at a car show) you can feel the play in the system yet can't really see any when you wiggle the streering wheel and look at the tire. Think I might have to drop a shim in the steering rack but that'll have to wait until I get it up on jack stands next.

[busheytrader]

I had one bout of the steering wobble after my wedge had been laid up for a winter. The steering wheel shook noticeably around 55 and roughly doubled under braking. Everything relating to suspension and steering was in A1 condition.

My Ford Capri 2.8i brake discs were slightly scored and had become pitted so I decided to change them. I'd read about DTV and how any dirt etc between the disc and the hub makes the disc run out of true leading to high and low spots resulting in pulsing brakes accompanied by a wobbly steering wheel, when braking.

I replaced just the discs ensuring that every mating surface was 100% clean and free from corrosion. On the basis of replace or change one thing at a time to see if that solves the issue, I went for a road test. It should have just cured the braking wobbles but it solved the steering wobbles under all conditions........... Everything else including wheel bearings were untouched. The roadwheels were replaced in exactly the same positions.

I can relate to the previous post regarding steering play after replacing everything. I didn't think the steering column bush would make much of a difference but changing the worn out plastic item to poly makes it feel much better.

Adam

[BenTen]

Hi there. New to forum so just picking up on this thread. Rebuilt my '80 DHC Sprint over 20 years (that's another story) and replaced most relevant parts but not all. My replacement sequence might bring some light to bear on this problem. Everything was replaced including ball joints, bushes, track rod ends, tyres and balancing, struts, column bushes, brakes. Everything but steering rack and hubs with original bearings which I thought were ok. On recommissioning and MOT I had a few issues, as expected from being off the road and in bits for so long, so worked through these for few months. Slowly sorted most but had persistent distinct wheel wobble at 50-60. Very annoying. Felt like had a flat spot on tyre it was so forceful. Anyway a trusted friend and mechanical guru drove and said instantly "front bearings". He did not know that I had not replaced them so he was not just making a guess based on my list of jobs done/ not done. PROBLEM FIXED. While doing them, it struck me that getting the right amount of torque before fitting split pin is crucial, also confused by fact that castellated nut dictates where pin can go. I spent several hours "Playing" with various settings on both hubs, going for rins inbetween to get the hub settled and warm. 3 years later still fine. Also had to replace steering rack last year so doesn't look like that had any influence. Hope this helps.

[greasemonkey]

i know i am dragging up an old post but i have only just got around to sorting this problem.i thank all who have contributed to this thread.i have used Stag76's solution with the result i now have no steering wobble whatsoever.this worked for me,thank you sir, you are a star.i moved the antiroll bar forward 10mm by making two 15mm thick steel plates with two sets of tapped 10mm holes to fit under the a/r/bar mountings.one set is utilised by the bolts that come though the holes in the subframe.the other set are 10mm forward of the subframe bolts and these are used with the correct lenght bolts to secure the a/r/bar mounting.i would have made replacement alloy mountings as Stag76 has done but i didnt have the correct size material at hand.although i used my mill to drill and tap the holes using the indexing facility,it would be possible with care to make these plates with the minimum of metalworking tools,cheers all greasemonkey..

[prlee]

Just been reading this thread.

I introduced the 50-60 mph vibration when I rebuilt the car's suspension,tried to get rid of it by wheel balancing, but could it be from adding the anti-dive kit which lowers the anti roll bar?

Could it be that the anti roll bar is has not aligned equally on each side?

I also added orange poly bushes and rebuilt the struts using KYB inserts, I also removed an odd rubber spacer under the front spring which looked home made.

[Beans]

... Could it be that the anti roll bar is has not aligned equally on each side? ...

Can be a very time consuming exercise, but well worth trying to get the ARB (and thus the castor angle of the struts) aligned properly.

[prlee]

Thanks Beans, hopefully the TR will beback on the road in spring.

[dursleyman]

It can be caused by fatigue in the sub-frame resulting on zero or minus caster angle.
There are adjustable strut tops available that allow it to be corrected.
I made some saddles that moved the sway-bar forward by 10mm and increased the caster angle.
This cured the wobble and made the steering track straight instead of following
the variations in the road surface.

Bruce, does this mod cause any other changes to the steering/handling? I occasionally notice a very slight tremor but its nothing much to bother about and I really like the way mine handles so don't want to mess it up!

Russ