THE DEATH WOBBLE THREAD

Casey wrote: Concrete on a plate, concrete on a plate... That's right, unlike jelly it doesn't wobble.

My new steel wheels and tyres were delivered this afternoon, so I went straight out and replaced my alloys.
I decided to go for steels with General Grabber ATs 205/75/15, which came already ballanced. They weren't cheap but this is the only thing I've done to my Jimny since buying it last October. When I saw them I was seriously worried they weren't going to fit under my unlifted arches as they looked much bigger than the 205/70/15 I had on. Anyway I needn't have worried there was plenty of space and no rubbing at full lock.
But what's more I just took them for a spin and NO WOBBLE. I could hardly believe it, in fact about an hour later I took it out again and not the slightest shake. It feels so much better. Hooray...

These are they.

Can't believe it. Just when I thought all my problems were over, I took it into Quickfit for an MOT Thursday, it flew through but next day the wobbles back. I can only think it's got something to do with them taking the wheels off to check the brakes. Took the two front wheels off and cleaned the hubs but made no difference, still wobbling at 45.

They are not allowed to remove anything on the MOT. Check to see if they have pinched a balance weight off the wheel.

Took it back to them today and got them to balance front wheels, which to be fair they did for free. This made it batter, but now only wobbles when braking at 40mph. They said the only thing that could cause this is a warped disk. Is this true? What I can't understand is if that's the case why didn't it wobble before I took it to them?

Here's a quick 101 on "warped discs", then.

Discs rarely warp. What seem to be warped discs are nearly always discs with serious runout or, more likely, disc thickness variation (DTV). This is caused by the discs, or sometimes the wheel, being incorrectly fitted - disc to dirty hub, or wheel nuts not tightened progressively and in the correct pattern. This means that the disc is fitted with a small amount of runout, not enough to cause pedal pulsing but still outside the manufacturer's specification. As the disc rotates millions of times over the next few months, the pads "kiss" the disc at the high spots. There is no real pressure involved and no impact on fuel consumption but this is enough to wear the disc excessively a tenth of a millimetre or more at those points. after about 3,000 miles you get the pulsing brake pedal. The only cure is new discs (and pads, of course), correctly fitted this time.

Vibration that first occurs mmediately after the fitting of new discs or the removal of a wheel can be fixed by removing both wheel and disc and refitting correctly. The damage takes a few thousand miles to build up.

When fitting new discs you MUST clean all dirt and rust off the hub. A rotary wire brush is the usual tool. In an ideal world you then fit the disc and check for runout with a dial test indicator, but it's near-impossible to use a DTI on a car where the disc is retained solely by the clamping force of the wheel.

Wheel nuts should never be tightened in a circle, never witrh an air tool and never to the full torque on the first go. With 5-stud hubs, first tighten enough to allow lowering the car to the ground without pulling it off the jack, then use a torque wrench to get the nuts to about 70Nm, skipping every other nut as you work your way round the hub (this is as close to "opposites" as you can get with 5 studs) until all five have been done. Then repeat with the torque wrench set to the full torque, which is 110Nm-120Nm for most cars.

When you've finished, spin the wheel and listen to the noise of the pads on the disc. Runout is obvious with experience; you're listening for a more-or-less constant noise, not an intermittent scraping.

It is possible to ruin a disc simply by fitting the wheel with an air tool wound up to 120Nm and going round the hub in a circle. The big tyre places are very bad for this, and as I have two sets of wheels I always take the loose wheels in for tyres, rather than allow them to fit them to the car.

The reason for the prevalence of death wobble is basically that front beam axle suspension (it's cart suspension, as in horse-and-cart) is incredibly fussy about any out-of-roundness in the rotation of the wheels. This is also why it's so hard to track down and fix the untilate cause, because it could be anything from play in a component to balance to eccentricity.

Don't rule out the simple possibilities like flatspotted tyres. Jimnys run very low front tyre pressure and a car that has been sitting round for only a week, especially in the cold, could have developed a bit of a flat spot on each tyre which will take a few miles to even out. i wonder if this was the case with the green Jimny above, which wobbled after being unused for a while?

Thanks for your comments, but it wasn't unused. The day before taking it for the MOT it was fine the day after it wobbled worse than it had ever done. They balanced the front wheels while I watched and it showed they were out of balance. They added weights and it improved but not to the state it was in before I took it to them. I must admit I'm totally confused.

I have the death wobble too and have gone for swapping out the king pin bearings which was a good thing to do as they were packed with way too much grease, in fact the swivel hubs were almost full, must have pulled about a litre from each hub! Along with water and rusty bearings. Didn't solve the problem but I have noticed a front brake issue. On axle stands I can't hardly rotate the front wheels as the brakes seem to be binding. Removed calipers yesterday and wound the pistons back in a little way with a trusty "G" clamp and they move albeit quite stiff but I put this down to the fact there's hydraulic fluid behind them . Backed the pads away from the discs and checked for disc wear and all looks pretty good and they seem relatively new. Refitted the calipers and then stamped on the brake pedal a few times to bed the pads back in and back to square 1. Brakes don't seem to be letting off fully on the front wheels, which means higher fuel consumption but more importantly, if they are permanently "on" and there's a slight bit of ovality on either or both discs then this would probably cause a slight death wobble feel....Am I on the right tracks? For £60 each + VAT I can get new calipers so is it worth it or do I get a seal kit for £25 + VAT and hope I can clean the piston and slides with a piece of emery cloth?!
How is the piston supposed to release the pads anyway? there must be an opposing force to release it after you use the brake pedal. Stand on the brake pedal and fluid pushes piston....release pedal and ??? isn't the fluid still there behind the piston, in the brake hose forcing the piston against the pad? Confused dot com!

If i was you i would get the brakes seen to by some one who knows what they are doing, your life depends on them.

don't know if this has been said in here but rear wheel bearings are a cause mine are shot and have terrible wobble have to change them soon as crap robbstorr rear locker fitted buy a idiot cause mine to fail i think

ive got new kingpin bearings and still have abit of wobble, we are in the process of changing both rear wheel bearings done one friday and will hopefully do the other tonight (the one friday had cracked the whole way around the bearing case!!). also fitted new rear shoes saturaday. will report back if the wobble goes.

if the vehicle has been lifted and you have the wheel wobble, a 4 wheel alignment has to be carried out. ask for a camber and caster read out, the problem will be with the castor read out after the lift. if lifted 40mm or more in my opinion castor corrector s are needed and put the castor back within specification.......think of a shopping trolley wheel when pushing it down the supermarket at speed, its the same as a car when the castor is out.