Gringing/Clanging/Crunching noises from front end :( Mechanic could not find issue

[RubAVeeDubDub]

Hey folks,

Own a Bora 4-motion and been having horrible troubles with noises from the front end. The noises range from grinding noises, to clanging to rotational banging. Sounds like a wheel is loose but it isn't. You can feel vibrations of it through the car and it's quite audible from outside the car. Seems to develop when the car heats up and only after about 10-15kms of driving.

It happens while turning, especially at slow speeds, it happens when the clutch is both engaged and disengaged, it happens when braking and it happens when the car is coasting but not under acceleration strangely. The only other times it seems to not happen is when the car is cold and/or is given a bit of a boot. I've had my mechanic look at it (not a VW specialist but a JDM tuner) and he can't identify the issue.

As a bit of a background of the car:
1) Front end parts have all been changed in the last 5,000kms. This includes the ball joints, wheel bearings, tie rod ends, sway bar links, discs, stub axles and the driveshafts were only just inspected and given a clean bill of health by a pro.
2) The car has had new coilovers installed before I bought it - should only have 20,000kms of wear on them.
3) I did swap in some Audi S3 Quattro suspension to test and the noise was still there. I thought that the audi struts may have been shot as the wreckers banged it hard with a hammer to get it out of the hub and well the bora is a much heavier car so it may not have been built for the weight of it.
4) I've had issues with dodgy aftermarket driveshafts that the previous owner fitted, and found out they were too short (poor manufacturing). This would result in the driveshaft basically undoing it's driveshaft nut and and the driveshaft would fling around in the hub. I eventually caught wind of what the problem was when I tightened the driveshaft nut incredibly hard and the pressure of the shorter driveshaft resulted in the end snapping off. After that I found genuine driveshafts (2nd hand), had them inspected and they are now fitted to the car

I read somewhere that a bad brake master cyclinder can cause some nasty grinding noises? The noise does seem more to arise when the car is braking but the pedal isn't spongy nor is the noise isolated to only when braking plus the car seems to brake fine. That being said, at one point all the fluid was drained as I had to change brake hoses and replace the bushes in the rear control arm. I drained it by lightly pushing the brake fluid while the hoses were off and I tried to replace the fluid the old fashioned way until I realised I needed to turn on the ABS pump and get rid of the air in the system. My mechanic did this for me.

Has anyone got any ideas? Desperate here! My cousin wants to buy the car and I would like to get rid of it now that I have a new car and a company car.

Appreciate any and every help here!

[JustCruisn]

Gearbox. Rivets on the diff crown wheel snap.

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[RubAVeeDubDub]

Gearbox. Rivets on the diff crown wheel snap.

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****. You're kidding?

Best way to find out?

[JustCruisn]

Drain box oil and see what falls out.
Was common on 1.6 manuals and 1.8t manuals. Have not heard of 4mo having issues but vw have a history of weak rivets.

This happened on my gti and it sounds a lot like your description. Often the diff exploded and takes out the casing.
I needed new bolts to replace the rivets, arp brand about $300 parts.
Then found 1st gear a syncro and some other odd bits inc speedo gear needed replacement too.
If you do have the busted rivets I would recommend a recon box it will be quicker and give more peace of mind.


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[Bora Sport]

Are you sure it isn't a CV joint? If it is the gearbox, I have a low k gearbox that I could sell you. I am in Queensland so there would be freight involved but that shouldn't be too much of a worry. I guy in South Australia id buying my ABF engine and is happy to pay the freight.

[drucejnr]

Are you sure it isn't a CV joint? If it is the gearbox, I have a low k gearbox that I could sell you. I am in Queensland so there would be freight involved but that shouldn't be too much of a worry. I guy in South Australia id buying my ABF engine and is happy to pay the freight.

more info on the gearbox please - is it a 6sp to suit 4mo?

[Bora Sport]

I bought it some years ago off a forum member. I have suffered the above diff rivet failure on two of my cars over the years so when Jason was heading back to the UK he was selling all his stuff. He had picked up a low mileage Bora 4 motion gearbox and rear diff with Haldex to use to convert one of his Corrados to V6 AWD. I bought them off him as at that time my Bora was getting close to 200,000k's so I thought it might be good to have some spares. Thankfully over 100,000k's later I haven't needed them.

It is gearbox code FMP which apparently was in early Bora and R32's

.

[RubAVeeDubDub]

Thanks heaps for the advice and help guys. This couldn't have happened at a worse time full of bills and I have no garage at the moment to do the work as I'm storing my parents stuff as they go through a divorce.

Anyway - Bora Sport - I'm probably going to have to buy that box off you if you don't mind. I'll PM you about it. Can't seem to find a box in Vic right now.

I'm taking the car to the mechanic who rebuilt my driveshafts to get his opinion but haven't got my hopes up.

How hard is it to replace the rivets on a box?

[RubAVeeDubDub]

Anything special to note with removing the gearbox from a 4mo? I've done a few transmission swaps in the past but they were on fwd and rwd jap cars not awd euro ones.

Also - with regards to the clutch on the 4motions:

1) Are they push or pull type?
2) Does the throwout bearing have to be disengaged before the box will come off?
3) Can the pressure plate & throwout bearing be reused ?
4) Is it possible to remove the gearbox without having to take the front end off?

Thanks for the help again guys!