D1 clunk on takeoff

[steveG]

My D1 300tdi auto has developed a clunk on takeoff.
Best way I can describe it is its like the sound you get from the drivetrain backlash when changing from reverse to forward with the auto - but its a much heavier sound and happens maybe a second after putting your foot down to take off. Probably happening as the the boost comes up and you start to accelerate more quickly.

Its repeatable and happens whenever you take off from stopped, and seems to come from the LH side of the vehicle (hard to tell 100% from inside while driving).
I had a look around underneath last night but without jacking it up. Levered all the bushes/suspension parts with a large screwdriver but nothing obvious.

I'm thinking its suspension somewhere rather than transmission, and when you stop it moves rearwards due to braking, then moves forwards again when you take off.

Any likely places that wear or come loose, or other suggestions on how to track it down?

Steve

[hook]

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

[JDNSW]

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

[discowhite]

I 3rd what hook and jd have said.

cheers phil

[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?

[dullbird]

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

[Panya]

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.

[JDNSW]

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

[steveG]

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?

[Panya]

Hi Steve I generally use the genuine bushes I think they last longer than the cheaper ones. You may need the metal washers also. If the hole in the bracket is badly worn you may need to get it welded closed and re-drilled. A quick fix (but makes putting the shocks on a bit more difficult) is to have a 3-4 mm steel washer made & drilled to fit the damper pin then just weld this onto the bracket where the worn hole is - on the upper face. Worth having it done properly if you have the time though!:p

[justinc]

Try also the front Radius rod bushes, or the rear trailing arm bushes. Have a good look for signs of movement, better still grab a ring spanner ,socket and long bar and get tightening. For the panhard rod bolts you'll need 7/8" spanners, the radius rod and rear trrailing arm to diff bolts a 15/16"(24mm), the rear of radius rod and front of trailing arms is 30mm, and the upper A frame bolts are 1 1/8".

I'll bet some are loose.

JC

[Dis_kuv_or_e]

1st of all get under it with a crow bar or length of water pipe and see where the movement is comming from. My case was the A frame ball joint.... Holy cow.... take some steroids (jokes guys, dont ban me) amd a big hammer and be prepared... seroiously its not that bad. let me know if you need the tricks (i mean steps) to get that sucker out

[jonpp]

Hi Steve,another thing you can check is the engine mounts becasue if the rubber has seperated from the steel backing as you go to take off the engine torque twists & if the mounts are worn out the engine suddenly moves against the mounts making a clunking noise.Way to check them is to get someone in the car wioth there foot hard on the brake & carefully put it in gear & rev it up slightly & if the mounts are worn you will see the steel backing move & the rubber stay still as the engine tries to move.Hope all goes well,Jon.

[disco joe]

my d1 does it as well i found it to be a bit of movement in the transfer case which apparently is not a poblem

joel;)

[dullbird]

mine does it as well......but only started recently.

I have a bush kit to fit...and an A frame ball joint. will check the shockies like suggested and I have been wondering how to check the engine mounts.

[steveG]

my d1 does it as well i found it to be a bit of movement in the transfer case which apparently is not a poblem

joel;)
Was the movement in the transfer case mount or in the case itself?

I took mine into the local Pedders place for one of their $14 suspension checks - much easier for them to swing on things with it up on the hoist than me trying to do it lying on my back in the garage.
The confirmed that the A frame ball joint is OK, but reckon pretty much every other bush is pretty tired - either starting to tear away from the center bushing (in the case of the radius rod to front axle bushes) or just generally old/worn/deformed.
They also commented that everything apart from the RH swivel I've rebuilt looks original.
Probably time to just work through it and slowly replace all the bushes - starting with the worst ones first.
I'll just add that to the growing list of things to fix/replace/add :o

DB - jonpp gave a description earlier in the thread of how to check the engine mounts.

Steve

[dullbird]

Yes I saw that......bit concerned on the whole having some one with head in engine bay while you try to have the car pull forward while under breaking just seems a little risky to me :)

[steveG]

Yes I saw that......bit concerned on the whole having some one with head in engine bay while you try to have the car pull forward while under breaking just seems a little risky to me :)

Just lie really flat on the ground so the axle housing will go straight over the top of you if the brakes let go :p

But seriously - you DONT want the car car to move - just to load it up a bit so that the engine mounts are trying to resist the torque.

Steve

[dullbird]

Just lie really flat on the ground so the axle housing will go straight over the top of you if the brakes let go :p

But seriously -
you DONT want the car car to move - just to load it up a bit so that the engine mounts are trying to resist the torque.

Steve

yes i know but in the unfortunate event of something going wrong with brakes you have the chance of killing someone.

[steveG]

Put it in reverse - the torque effect on the engine is the same, and no chance of getting run over.

Steve

[dullbird]

OK sorry to high jack the thread........

checked engine mounts seem fine checking them the way it was suggested above but in reverse.

Fitted complete poly bush kit.......only bushes that need to be fitted are the a frame ones but the Clunk has gone (well for the moment) its only my first day of driving it so I'm keeping my fingers crossed it will stay that way once everything settles so we shall see:)