Rear end wobble

[Mez]

Hi all,

I've had my car lowered and ever since the back end wobbles when driving slow.

Mechanics have told me everything is straight, no damage, wheels and tyres fine too. Been told to get 4 wheel alignment done as bumped a kerb (Rear wheel) not long before it. Had new rear discs (which include bearings) too. They tell me that due to the car being lowered and the rear axle not being independent that the car will wobble side to side naturally as that's just how they all are. The car doesn't drive smooth at all when slow, is this normal then??

 

[Dumdum]

Without driving it it’s very hard to say, when lowered a car will tend to bump steer to a degree, which could be why your speaking of, although it’s not the rear of the car that does it

As for four wheel alignment, it can check the rear of the car but adjustment is done with shims and not easy like something with a riddled back end with wobbly eccentric nuts or adjustable length arms

I would be looking at maybe a rear wheel bearing or a wheel or Ive also had tyres do this

First thing would be a dial gauge on the rims to check run out

But again it depends what sort of wobble it is, does it feel like it’s steering by itself or a wobble like when your balancing is off and you get to 60mph and you can feel it through the car?

As a mechanic you take it as customers lie... albeit unintentionally... so find out for yourself on a test drive, one mans rattle is another mans wobble, is another mans clunk if you see what I mean

 

[Mez]

Sorry just to clarify, I'm not a mechanic. I work at a garage and the mechanics have told me everything is straight. They've had all the wheels off and on the balancing machine and said they're fine. The bearings are less than a week old. It's a wobble at the rear like I'm driving on rough ground even though it's smooth? No noticeable knocking and the feeling eases with speed.

 

[Dumdum]

Sorry just to clarify, I'm not a mechanic. I work at a garage and the mechanics have told me everything is straight. They've had all the wheels off and on the balancing machine and said they're fine. The bearings are less than a week old. It's a wobble at the rear like I'm driving on rough ground even though it's smooth? No noticeable knocking and the feeling eases with speed.

I didn’t mean you were a mechanic, I was speaking from experience... as in I am a mechanic

It’s still hard to pick up what you mean, is it a bit bouncy like your on rough ground... surely the mechanics would tell you if there was something actually up? Yes lowered cars do feel a bit bouncy at slow speeds, the stiffer springs will not track over bumps as well as non lowered springs

Just a thought... as it takes fifteen mins on a ramp, can you not just swap for standard rear springs and see if it does it then as that then rules out everything else bar the springs?

 

[Mez]

Ah okay, well I really appreciate your help though!

I can drive on the smoothest road possible and it's wobbles like one wheel is egged but I'm told it's fine?

I would love to try and swap the springs over but I wouldn't know how and the mechanics here are fed up of seeing my car now.

I really appreciate your help.

 

[Mez]

Update: Had the car 4 wheel aligned, no problem. Had a tyre company check the tyres, no problem!? Do 197's just feel bumpy once lowered, even on a pretty much smooth surface??

 

[Doogle]

Not mine, and I have lowering springs. Tried moving wheels from front to back to see if the wobble moves?

 

[Mez]

Yeah, still seems to be the rear passenger wheel. I did knock it before I had it lowered though on a kurb. Maybe stub axle is bent?

 

[Doogle]

Maybe, but that would show up on an alignment, both camber and toe. As above, difficult to suggest or diagnose without checking.

 

[Dumdum]

Where do you live? Perhaps someone near you with a 200 cup could come have a drive or even a lowered 197/200

I’m at j28 M1 if that’s anywhere near you?

Edit... Just seen your in Shropshire so perhaps someone may live nearby

 

[Mez]

I don't know anyone near me that has one unfortunately

 

[Foxspeed]

have you had the rear dampers checked? you can unbolt them at the bottom so they can be pushed up/down to see if they have resistance ie working correctly

 

[turkie172]

I've been watching this for some time and will have to go along with foxspeed on this I think one of the rear dampers is busted and the wheel is bouncing up and down on the spring with no damping. You describe it as wobble and the wheel is like egg shaped well that would be movement up and down, wobble well myself for one would say that would be movement left to right so what is it up and down movement or side to side.

 

[Mez]

I've pushed the car down on all 4 corners and as it's lowered I get no movement what so ever, could the shocks still be broken?

 

[turkie172]

Your pushing down on the springs it's how it comes back up will tell if the damper is busted or not. Do yourself a favour and take the damper out and try them before the really bad weather comes in and your standing in the rain or snow still not knowing what's wrong, is the wobble a vertical one or side to side you still have not said if you need any advice on how to undo the bottom rear shock bolts let me know give them a good spray with WD40 the night before and again some time before you start and work them back and forth as the exposed threads will be corroded just jack the car so the wheel is just almost on the ground to make it easier to refit the bolt. There should be some resistance pushing the damper to compress it and come back to length at a slow controlled rate and both should be the same of course.

 

[Mez]

Thanks for the help.
It's hard to tell really but I would say mostly side to side but does have a up down motion too. I'm not close to being a mechanic but I can do basic bits. Is this an easy job for a novice?

 

[Doogle]

Fairly easy bud, rears are quite simple. Do you have a basic socket set, WD40 and jack/axle stands?

If so, jack the car up and put onto axle stands, take both wheels off, pop the boot, pull back the carpet both sides in the boot, there will be 3 nuts for the shock absorber. The two outer ones loosen but dont undo completely. Then get under the car, undo the 1 bolt holding the shock absorbers on at the bottom and remove the bolt. With someone else holding onto the shock absorber remove the two nuts so it can be removed. Once off try compressing the shock down to see how quickly/slowly it returns. When modern shock absorbers get tired they become slow. If theres signs of leaking from the shock its fit for the bin. Use the WD40 if you need to for seized bolts and its righty tighty, lefty loosey.

When you are there you can check the rear springs arnt snapped and everything else looks fairly normal.

 

[Mez]

That's a great step by step guide, I really appreciate that! Thank you so much.

Quick question does the shock shoot down when you loosen it at the bottom? Is it difficult to put back on if it's fully extended?

 

[Doogle]

No problem Mez, no buddy, it shouldnt be under tension, that should be pretty much fully extended.

I think the lower shock absorber bolt is quite big like a 19mm, the top ones are probably smallish like an 8 or 10mm. You may need a breaker bar for the lower bolt to get it started.

 

[Foxspeed]

i wouldnt undo the top just the bottom so you can push up/pull down the damper see if its ok