[Mk2] [Turbo] Steering wheel wobble above 70

[Demes]

Hi guys,

I have an elusive problem with a Rev3 import Turbo.
At and above 70mph, the steering wheel would sometimes start wobbling. Not too bad, doesn't happen every time, but when it does it shakes a little. Never happens below that speed, doesn't happen when cornering, pretty much only on motorways, high speed, going straight.
Despite the wobbling the car doesn't feel too unstable, it still goes straight, and there's no shaking of the chassis that can be felt. It doesn't really get any worse as speed increases.

Here's what we know/checked:
Tires, suspension, everything is OEM/OEM spec.
15" rev5 wheels with OEM sized tires, properly balanced.
Alignment was checked, and it's OK. I can post numbers if I find the paper.
Tie rod ends, springs, drop links were changed about a year ago as they were quite worn out.
Car has about 70k miles on it.

I'm worried it might be something deeper in the steering mechanism. Since the outer ball joints were quite worn out, are there others 'inside' that I should inspect? I'd rather not replace random parts aimlessly.
Wheel bearings don't make any sound, and that would be a constant wobble - this doesn't always happen. It's been like this for more than a year, and hasn't gotten any worse, but annoying nonetheless.

Any help is appreciated,
Demes

[Ryan S]

it'll be the 25 year old suspension bushes mate. I have the same issue above 60mph. I'm sure it's the bushes. You can get a full set of front polybushes off TCB parts for 40 quid.

[Demes]

Good point Ryan, those that we can see are quite worn.
I heard some bad things about poly bushes that even the softest of polys are much harder than the original rubber ones, and we're trying to keep it at least somewhat comfortable - are they really that stiff?

[Ryan S]

the issue is that toyota don't sell the bushes seperately from the parts they are mounted in. Polybushes is the only way. I've no personal experience with them but they will be better than old wrecked rubber. I have had folk say on here that polybushing is fine. I'm in the exact same boat bud. I don;t want polybushes either but it appears to be the only viable option.

[yokomomr4bx]

I know you're using genuine wheels and they're balanced, but...wheels centred on the studs rather than the hub flange will give you exactly this issue. I had exactly the same issue and it was rectified with some £3 his adapters. I can't see it being this because your wheels should be a direct hub fitment being Toyota...but just a thought

Another thought, it may be worth giving the contact faces on the wheel and the disc a good clean with a wire brush and some sandpaper just to be sure there's no corrosion that's stopping the wheel sitting nice and true to the hub.

[Demes]

Thanks for the suggestion! We'll check it out. It did have aftermarket wheels at one point, so maybe something was changed around the hub and we didn't notice it.
Or if there's nothing there, go with the change of bushings.

[yokomomr4bx]

Did you ever get to the bottom of this, always curious to hear the outcome of these kinds of issues!?

[Demes]

Not yet! It might be a couple weeks (months?) until we can try and fix it, but I'll make sure to report back

[HighwayStar]

Don't forget to check topmounts. ...lots of possibility for perishing there.

Fensport sell the TRD replacements cheaper than the oem items...

[Race Idiot]

can you still get the trd topmounts or have they just not stopped listing them on their website.

I'll be buying another set of em if thats true!

[HighwayStar]

They had loads left when I bought mine about 5 months ago (fronts only though).

Give 'em a call...

[Ryan S]

i just bought brand new coilovers and it has helped the wobble. it does still happen under braking (discs and pads are new) so i'm certain it's bushes.

[yokomomr4bx]

This may be a very late reply to these issues, but I too have recently been encountering shake in the steering wheel above 60mph and more so under braking. My issues are also tied with a mild pulsating of the brake pedal when braking from these speeds which exaggerates the wobble in the steering wheel. Clearly the braking and shaking/pulsating are linked, I replaced my front discs and still had the same issue - turns out my hub was actually warped from a particularly bad case of a seized calliper piston - I had hoped the damage was limited to the discs but unfortunately not. So in short...it may be a good idea to check the runout on both your hubs and discs!

[Chumbaside]

I have had this issue with two MR2's over a number of years! Each time thought it was a disc running out, each time turned out to be the hub flange / wheel bearing not running true. Swapping hubs and new discs cured the issue each time - so did changing the wheel bearing IF the hub flange was true. Cause was most likely seized callipers or worn bearings at some point.

I also got shake when braking due to worn front tie-bar poly bushes (on the non-adjustable castor arms on Rev3+). I was chasing for ages! Replaced the bushes, vibration gone

So a bunch of things to look at, as well as the usual e.g. properly fitting wheels (hub-centric), alignment etc.

[Demes]

Minor update on this - even though our previous set of tires were perfectly balanced, a new set has improved on this quite a bit. Same set of wheels, just a new set of rubber on them, and while the wobble is not entirely gone, it has gotten better.
Next is still to change all the bushing, (which is about to be done soon?) but we'd like to have them remade from rubber rather than use a polyurethane set.

On that note, does anyone have a spare set of bushings (either poly or rubber) that we could use for measurement, so we don't have to dismantle half the car to get custom bushings made?