Thread: D1 clunk on takeoff

I would 1st look at the rear A arm ball joint??

As Hook says - A-frame ball joint. The lower link rear bush or the A-frame chassis bushes usually give a duller sound, as do the front radius arm bushes. The front of the rear lower links usually click rather than clunk in my experience. And most suspension joint problems except the A-frame show up as steering wander before they clunk.

Other, less likely possibilities include free play on any of the splines in the drive train, and just possibly U-joints. In view of the seriousness of U-joint failure, I would check them anyway, although it would be unusual for them to have enough free play to clunk without severe vibration.

John

I 3rd what hook and jd have said.

cheers phil

I checked the uni joints last night - they seem to be OK. No rotational movement or play that I can find, and no drivetrain vibrations at any speed.

The vehicle does wander a bit, and has a tendency to oversteer but I'd put that down to tyres and 2" lift.

Whats the best way to check the A-arm balljoint for play?

yeah what he said ^^^^^ as I need to check mine

Steve G if it's not the A frame then look at the dampers/shock absorbers. Where the pin goes through the hole in the bracket on the axle - this can wear; if the damper bushes are worn the pin can slip backwards and forwards and makes a repeatable clunk starting and stopping with a bit of momentum and especially when wet. Has happened in various LR's of ours.

Originally Posted by steveG

I checked the uni joints last night - they seem to be OK. No rotational movement or play that I can find, and no drivetrain vibrations at any speed.

The vehicle does wander a bit, and has a tendency to oversteer but I'd put that down to tyres and 2" lift.

Whats the best way to check the A-arm balljoint for play?

There are two ways of doing it

1. Crawl underneath with a suitable crowbar or tyre lever and see if you can get any movement on the joint - there should be none.

2. Handbrake on hard, crawl underneath and get a helper to rock the vehicle back and forth as far as possible. This should not only sound the clunk, but you should see any movement, although it may be necessary to put your hand on the A-frame near the joint to feel it.

If inspection shows any signs of powdery rust coming out of the joint, you have found the problem (or a problem anyway) with no further tests.

Even with a lift, there should be no tendency to wander, although the tyres may help to make it wander. But I would check the entire steering linkage for free play, and all the suspension bushes for free movement, using a lever. Most likely bushes to cause wandering are the panhard rod and the rear bush on the lower link at the back, but just about any of them can cause it.

Other possible causes of wandering are loose wheel bearings or swivel bearings, but these usually have other symptoms as well.

John

Checked out the A frame joint and its OK. The rubber boot is still perfect and cant see or feel any movement while rocking the car.

Panya - I think you might be onto something. The rear shock lower bushes seem quite loose in the axle bracket. I can grab the shock and rattle it around in the axle hole a bit. I think I'll just pull the shocks off and do a couple of test takeoffs in my street to see whether it makes a difference.

Are the shock bushes just a generic part that I can buy anywhere, or are they a special shape/size for the Disco?