Knocking/rattling Noise In Rear After Coilover Install

[alex.a]

hey guys, reeding a little help with an issue im having with my r34 gtr.

recently replaced the hks coilovers in my gtr due to both rears leaking and one was knocking like crazy.

so i picked up a set of TODA "fightex" coilovers from a local importer. were told they were low km and they sure looked like it.

These coilovers were obviously track orientated with both front and rear having upper bearing plates/top-hats instead of rubber bushes, nor did they have any rubber insulation between the springs and the top hats... All metal on metal so to speak

Both the front and rear upper top-hat bearings felt extreamly tight with zero movement, i removed all 4 spings and checked that the shocks were operating normally without the springs assintance.. everything looked ok. only thing i noted is when i had the coilover (rear) clamped in my bench vice by the bottom mount i could get around 1mm of movement in the shaft by pulling it backward and forward.

Seemed ok as the shock was at full extension and was a bit of leverage working against it.. maybe a little wear in the internal DU bush?

So after giving everything a good once over after reassembling i proceeded to fit them to the car.. all went swimmingly untill i test drove the car!

The rears were rattling sooo badly i swore i had forgotten to tighten the two 12mm nuts on the top hats!! almost a constant rattle whilest driving, nothing on really smooth roads but on any rough surface would result in a barrage of harsh noise!!

When going over any small potholes or bumps, the rattle would turn into a louder clunk/bang. under heavy acceleration the noise would lessen and when i was hard on the brakes and unloaded the rear coilovers the noise would drasticly increase.

i removed the rear seat and had a mate sit in the back while i drove around my estate with his hand on top of each strut, said he could feel the clunking through the coilover but it wasnt anything moving in the top area of the actuall pillow ball/top hat.

so i proceeded to remove the rear coilovers once again, inspected them from top to bottom.. nothing loose, everything done up!!!

Now through all of this i still havnt gotten a chance to fit the front units, it is still sitting on the hks's.

Now im starting to think that the rear coilovers may be ok? i have checked everything else in the car and the only thing i can find with a little wear is my rear hicas ball joints on the knuckle.

There would be maybe 1-1.5mm of movement in each rear wheel if i really wrench them from left to right while the rear of the car is on stands. the car seems to feel ok driving with no unusual movement.

i proceeded to refit my stock gtr rear struts and now there is zero noise! nothing at all, smooth once again.

what would it be? could that little bit of wear in the rear hicas really translate into so much noise with an almost solidly mounted coilover?

the hks units i removed have heaps MORE SLOP slop in the shafts and are pissing oil everywhere, but only one was rattling badly.

these also had pillow ball top-hats but there was rubber spring insluators between the spring and top hat, could this have made enough difference to hide the hicas rattle?

i have since returned the toda coilovers to the shop i bought them from for them to inspect. does anyone have any similar experience with a similar sitiation?

here is a pic of the toda coilovers i bought to show exactly what im babbling about

Any help would be greatly appreciated.

thanks, alex

[blind_elk]

both front and rear having upper bearing plates/top-hats instead of rubber bushes, nor did they have any rubber insulation between the springs and the top hats... All metal on metal so to speak

This may be answering your own question.

[GTSBoy]

Oh, yeah. 100% it's just that they have no isolation in there at all. 100% transmission of every little noise. Every jiggle and click will get sent straight into the metalwork of the car and ring like a bell (or like a shipping container of broken gearboxes falling down a mountainside).

[alex.a]

Hhhmm so the transfer of noise would be that bad? i think i will maybe place a thin piece of rubber mat between the top hat and the actual body of the car, if the noise is lessoned then i think that will prove this theory?

i have just never heard anything like it... its almost unbareable! but i guess thats the price i will have to pay then if i want to keep these coilovers

[GTSBoy]

Yuh, that's why stuff meant for track cars is not always a good idea for road cars.

[alex.a]

indeed GTSboy, but they were a price i couldnt refuse.

i can deal with the noise as long as its normal.

cant cant beleive the old hks ones i removed were 10x quieter just because of a 2mm rubber insluater between the top hat and the top of the spring.. but there ya go!

[ichi-go]

While having a solid top hat will transfer more NVH to the cabin but i'm fairly certain that's not your problem there, alot of people including myself run coilovers that do not have rubber hats or any rubber between springs but i dont have any sort of rattle on accel/deaccel/brake

I would hazard a guess and say that you probably didn't install those coilovers back properly as you said you took it apart

[alex.a]

no, i reassembled them exactly as they were.. they arnt a complex item

retaining nut--> pillowball plate--> spacer--> tophat--> spring...

as i said i too have run similar coilovers, just never encountered this issue without a top bearing being shot or something obvious

[Nissan-kid]

If you want to sell them I'll be more than happy to take them off your hands..

[GTR-N1]

And the outcome?

[jase-r34]

Mate I have the exact same issue with the coil overs I put in my gtt. No rubber insulate and very much track orientated suspension.... but again same deal, price was too good to pass up! I'm going to pull the rear out and put some rubber in there and see if it changes or hopefully fixes the sound.... will keep you posted!

[Phil Kadow]

Hi, I'm a new kid on the block and I to have fitted KShock coil overs all around my 2010 subaru Forester XT SH9. I also have a rattle, especially seems to be the left rear making all the noise. This is the first time using coil overs. My noise seems to happen on bumpy roads only. On good roads and Expressways etc they are as quite as a mouse. I am wondering if I have lowered too far. I initially wanted to lower the vehicle to make it easier for my disabled wife could get into it. My first thought was 50mm would be ok but I ended up going 70mm. The stance looks great but I don't know if this could be the cause of the rattle.I had the alignment done and the only thing that the aligner pointed out was for me to change the after market bolt that I used to replace the lower rear shock mount bolt that had to use to replace the one that I had to cut off to remove. I have since done that but the noise is still there. Any advice would greatly apprecited.

[niZmO_Man]

Might be the spring flinging around. How secure is it in the damper body? As in, did you lower the spring seat to lower it?

I'm assuming they're generic 'coilovers' so try swapping left and right?

[Phil Kadow]

The units are fully adjustable so I lowered the shock unit not the spring seat.

[KillmeImhere]

To OP: What you describe sounds like my same issue. Ended up being a blown shock on one of my rear coilovers. Replaced and problem solved. Most issues people describe appear to either be incorrect pre-load, a blown shock or are indeed using race style suspension with no rubber mounts. Hope that helps.