Brake thud

[Zedhed]

Hi folks got a brake thud when i hit the brakes.steering wheel jerks and front drivers wheel moves.what could this be.

[Alan Gunn]

I had something like that and it was the bottom ball joint.
On first testing on the mot ramp and using the one man bit to rock the car nothing could be seen.
We then jacked the car up and the joint was hanging by a whisker. 

[Zedhed]

Thing is its just passed the mot so thats why i ruled out anything to do with bushes etc.

[Alan Gunn]

My car passed the mot as well.
We where both very surprised when we looked at it just hanging with the body jacked up and the weight off the suspension.
I used to be a tester and it was about the worse one i had come across.
I used to get a bit of a wheel wobble sometimes on a bend but not always. 
Worth a look i would say.
Look at reply 3 in this post.
http://xdrivers.co.uk/forum/index.php/t ... 551.0.html

[henrym3]

Make sure you check the caliper mounting bolts

[Zedhed]

Think i might have found the cause.there seems to be a lot more play in the upper control arm compared to the passengers side along with the rubber starting to give way.would this have anything to do with the 4x4 light being illuminated.still getting the sas permanent code :-[

[Smeeagain]

[quote="Zedhed"]
Think i might have found the cause.there seems to be a lot more play in the upper control arm compared to the passengers side along with the rubber starting to give way.would this have anything to do with the 4x4 light being illuminated.still getting the sas permanent code :-[
[/quote]

The 4x4 light is often (but not always) linked to wheel alignment. When did you last have wheel alignment checked?

It can pass the MOT but have loads of play, it is about the way they do the test

[Zedhed]

Had the car since august mate and we have never had the alignment checked.

[Zedhed]

Just a quick question but how does the steering wheel know what position the front wheels are in or vice versa.

[henrym3]

via the SAS which will be at 0 degrees in straight ahead position. if alignment is out then in order to drive in a straight line you will have to turn the steering wheel slightly in one direction or the other to compensate. Is your steering wheel straight ahead when driving on a straight road or slightly off centre

[Zedhed]

It is a bit off centre now after replacing the sas ::)i should have marked it really.

[henrym3]

Realistically you need to plug in a diagnostics machine and look at the sas live data. Turn the steering wheel till the machine reads 0 degrees. If the steering wheel is straight ahead then the track rod ends need adjusted,

[Zedhed]

So if i took it to be tracked up,they would do all this.

[henrym3]

Yes any decent alignment place will be able to put your steering wheel straight and have the wheels pointing in the same direction. I find it really irritating if the steering wheel is even the slightest bit out cos I know there's something wrong somewhere.