seriously, whats this damn noise!

[speedjunkie]

Ok hopefully someone can help. after fitting a set of konis i now have an annoying knock when i hit small bumps in the road, it seems certain that its coming from the shock top mounts in the boot area.

It not the exhaust as thats no way near anything and has a powerflex center and prima racing rear mount so isnt going anywhere. there is nothing loose under the car, ive rebuilt the boot lock, made sure the wheel liners and bumper arent moving of making noise and i currently have no rear seats, spare wheel or anything else in the boot area.

whats odd is i cant get the noise to happen with the car standing still, even with people in it and me jumping up and down in the boot (hanbrake on or off). also strange is the fact that the tighter i go with the shock top nuts the worse the noise gets. although this does point to the shock top mounts being at fault in some way!

i get no noise on undulating roads and the shock mounts are all in the right order: white plastic ring, bump stop, circlip, thick step washer sat on the circlip, large washer, rubber bush with flat side upwards, car body, tapered bush with wide part at the bottom, compression washer then the nut.

i have checked literally everything now and short of making some new bumpers from polyurethane to see if it will help im stuck. i am booked in to visit ktec on saturday for them to see if they can work it out but has anyone had a similar issue or got any ideas? ive seen a few threads where people have had issues with konis knocking in this way but theres never been a fix.

the compression damping makes no difference to the noise either!

help!!!!!!

 

[barker22]

1 thing to check if you havent already. i have literally just found this to be the case on mine after mashing my head for weeks. as you lift the tailgate, where it shuts there are two rubber 'bungs' to cushion the impact of the lid and to keep it in a 'tight' position. over time they wear down and dont hold the boot tight and as you go over bumps you get a slight knock, pull the 'bungs' out a little or put a small piece of rubber on top of them, just something to try.

 

[speedjunkie]

already tried that, even driven down the road with the boot open in case they werent firm enough :-( thanks though, everything is worth a try

 

[speedjunkie]

Ok, so a visit to K-tec later and I confirmed pretty musch what I thought, the noise is coming from the rear shocks and it is related to the tightness of the top nut! However, rather than being the rubber bumper at fault and compressing so much it's support is hitting the car, it seems that the shock itself is making the noise. From our discussions, it would appear that the piston in the shock is not able to move fast enough to respond to instant hits, so you get the klunk noise.

I had the shocks wound up to 180 degrees for compression damping and i have now backed off fully, whihc I guess has helped a 'little'! Howwver I am going to get the shocks swapped out by Koni and try another set as I am sure this cannot be right, especially as it seems that when you wind on the compression, you have no idea if the piston holes are lined up correctly for fluid to flow (those who dont know the konis - there is no 'click' or way to identify when you are at a compression setting, just 180 / 360 degrees ec) so you could wind it on and actually stop the shock from moving correctly at all.

I know a few people on here have had similar issues with knockign Konis, but it would be good to hear how many and possibly argue out with Koni that the design is a bit crap!

Comments?

 

[Dafthead]

haha this happened to my dad, he had mechanics looking at it, even replaced his real wheel bearings.

In the end I went out with him to listen to it, and laid down the back seats, then laid with my head in the boot, saw that the aerial was knackered and banging against the roof when he did 50+

 

[speedjunkie]

Its not that

 

[speedjunkie]

Ok after much messing about with the car and checking everything i took off the rear konis and realised that one of them had way too little compression damping. when pusing the shaft down from fully extended it took about a kilo of weight and dropped like a stone, which compared with the other was a huge difference. this was with both shocks set to minimum damping. a quick call to koni and i had a new set or shocks, fitte them up and the noise is now gone

if you have a similar issue and your new dampers knock, check this out first, its not what you expect from brand new shocks, but the guys at koni didnt argue at all and everything was sorted out for me in very little time. just got to fit some new steering rack bushes now ans the car will be spot on.