Really bad knocking when goin over bumps

[Dalejones]

Ok so my mk5 GT tdi 140 knocks really bad when going over bumps and potholes etc, the car sailed through its mot which I was hoping they would identified what was wrong, on my mk4 golf I had the same problem and it was the ARB bushes but on this model you can't buy the bushes on there own! Not sure what else it could be! Any thoughts, I'm on a very tight budget so don't want to spend money on something it turns out is not causing the knocking noise.

[ChrisGT]

Most likely would be anti roll bar drop links but would have thought they would have been picked up in the MOT if they were knocking.

Another possibility is the front subframe moving slightly. You can buy a spacer and bolt kit that stops this from knocking.

This video will show you how to check and how to fit the spacers.

I got the spacers and bolt kit from darkside developments for about £15.

Chris

[Paradox1]

Also check top mounts and which bone bushes

[Dan_FR]

Same description, mine was the steering rack...... Could not find any play at all, could not replicate the issue on a static car, but driving over bumps it knocked like crazy

Subframe noises are usually an issue when parking, reversing, setting off etc. Not so much on the move

ARB bushes can be bought on their own from Powerflex for 20 odd quid.... Its a 23.6mm ARB on the GTI from memory and you need to reuse the standard brackets so the whole bar needs to come off the car and the original brackets split in order to replace the bush. Get a Digital caliper out and measure the thickness of your ARB before ordering.

I replaced the whole front end of my car chasing my knocking noise until I changed the rack as a 'hail mary' which thankfully paid off

[pudding]

Out of interest since you have a new rack...... if you flick the steering wheel left/right quickly and forcefully with the engine off, do you get clonking noises from the bottom of the column?

[Dan_FR]

It's a low mileage second hand rack i bought as part of my trial and error approach to find a knocking noise that no mechanic could find   

But yes I get a relatively small/quiet noise, It's the same on a few cars of this platform that I checked/tried/compared with mine...... apparently its common on electromechanical steering.

My old rack was significantly worse though, made quite the racket. I think I sent a video to @Pesky jones a while back with the noise my old rack made...

[Tazocin]

If you want to pin it down more take the drop links off then go for a drive. Lack of knocking and you've got your culprit but do note it eliminates both ARB and droplinks from the picture. Do be cautious though as the car will roll much more on corners (but generally knocking droplinks are most obvious at low speeds over bumps, not on rapid corners. Ease of removal of droplinks can vary depending on how much time they've had to corrode on :D.

[pudding]

It's a low mileage second hand rack i bought as part of my trial and error approach to find a knocking noise that no mechanic could find   

But yes I get a relatively small/quiet noise, It's the same on a few cars of this platform that I checked/tried/compared with mine...... apparently its common on electromechanical steering.

My old rack was significantly worse though, made quite the racket. I think I sent a video to @Pesky jones a while back with the noise my old rack made...

OK cool.  Mine makes the knocking when rocking the steering wheel back and forth, in fact all of my VWs have done that come to think of it, even MK2s, so must be normal.......or they all had worn racks / column UJs 

There is a slight wandering behavior under power and generally not settled on straight roads, and needs a lot of correction......but then again....that could just be lorry ruts dragging it around, it's so hard to be sure, as you say!   On a smooth and flat road, it's epic.    There's no play between steering input and the road wheels.  Maybe these cars are just naturally fidgety!

[Dalejones]

If you want to pin it down more take the drop links off then go for a drive. Lack of knocking and you've got your culprit but do note it eliminates both ARB and droplinks from the picture. Do be cautious though as the car will roll much more on corners (but generally knocking droplinks are most obvious at low speeds over bumps, not on rapid corners. Ease of removal of droplinks can vary depending on how much time they've had to corrode on :D.

I may try this tomorrow! Sounds like a good idea