Rear Knocking After Coilovers Fitted

[rix_1gp]

Hi guys, need help usual, fitted cobra coilovers , set to max low, and although the ride is pretty good, the problem is, and I've searched every possible solution to this, but, I keep getting a knocking noise, as if the whole back of the van is going to break off

I changed the rear shocks to standard, tried the cobra damper setting, changed rear shock spring rubbers, setting the chilies up ‘ down, etc... but the knocking sound just won’t go away, when you go over any bump, etc...

Please, what can be the issue?

 

[PaulE]

Hi!
Fitted myself -40mm H&R and I also get knocking, but wierdly only in rear left. It is 100% from the spring as we tested in the workshop.
I cannot see why are the springs causing this and cannot figure out what could be the solution either. Only temporary solution was to turn the srping approx. 30% degrees and this gives about 2-3 weeks quiet ride until the knocking come back.
It T30 Multivan with 8000km so the spring cup are not worn

Any ideas?

 

[rix_1gp]

Hi!
Fitted myself -40mm H&R and I also get knocking, but wierdly only in rear left. It is 100% from the spring as we tested in the workshop.
I cannot see why are the springs causing this and cannot figure out what could be the solution either. Only temporary solution was to turn the srping approx. 30% degrees and this gives about 2-3 weeks quiet ride until the knocking come back.
It T30 Multivan with 8000km so the spring cup are not worn

Any ideas?

Hi Paul

I see some guys cut the bump stops about 10mm but I can’t see this helping much

I will try this when I have time again to refit them

 

[Petehelmet]

Hi!
Fitted myself -40mm H&R and I also get knocking, but wierdly only in rear left. It is 100% from the spring as we tested in the workshop.
I cannot see why are the springs causing this and cannot figure out what could be the solution either. Only temporary solution was to turn the srping approx. 30% degrees and this gives about 2-3 weeks quiet ride until the knocking come back.
It T30 Multivan with 8000km so the spring cup are not worn

Any ideas?

I know there was a batch of H&R springs that knocked about a year ago but can’t remember if they were front or back

 

[Pauly]

It’s not uncommon for the H&R to jangle a bit in the rear on T32s that run empty (but it’s a jangle/rattle not knocking)
I put it down to the top three spring coils touching and when going over potholes/speed bumps the rebound separating the coils and then retouching if that makes sense
Mine does it all the time when empty and stops as soon as I put any weight in the rear

 

[PaulE]

I've got rhis noise only from rear left and this makes it wierd

 

[T6180]

Have you change the shock bolts when refitting?

There stretch bolts so may not be tight enough and it's this that is knocking under load

 

[PaulE]

The van has 10k km on the clock and the knocking is only heard when the is not loaded. If couple of passengers in the back then it's quiet and nice

 

[T6180]

The van has 10k km on the clock and the knocking is only heard when the is not loaded. If couple of passengers in the back then it's quiet and nice

As above mate

 

[zombie_T6]

Sounds like you may have too much pre load on the rear springs. If they are too loose they will obviously knock. Maybe just try raising the ride height and see if they still knock. Also make sure you have fitted the adjuster in the right position. My Vmaxx extreme has to have the adjuster at the top and not the bottom. If its fitted at the bottom it knocks.