Hey everyone,

I recently had some BCR coilovers installed on my 07 350 and noticed that the rear passenger side makes a soft thud type sound when going over bumps that the other sides do not. It does not feel like a bottoming out of any kind, just more of a deeper thud, almost like something is a little loose. Anyone have any idea or experienced this. I am going in for an adjustment next week and would like to try to get this fixed too. Thanks

 

I would say check everything to make sure it is tight and secure.

 

The proper way to set preload on a coilover-

-Loosen both lock rings under the spring (spring seat ring(top) and spring lock ring(bottom)) so that the spring is loose and can move up and down slightly.

-Tighten up the spring seat ring so that the spring is snug, but do not tighten it down past simply holding the spring snug, this will be "0" preload.

-Now bring the bottom lock ring up so that it is just touching the spring seat ring, but do not tighten to lock, you will be moving the spring seat ring next.

-Now tighten up the spring seat ring so that you are now preloading (compressing) the spring.

-Measure the distance between the bottom ring and the top ring as you are tightening, once there is a 3mm gap between the two rings, you have 3mm of preload on the spring.

-Tighten up the lock ring to lock your preload in place

-Repeat for all 4 corners.



You also want to check and make sure the top 17mm center nut is tight, it's best to check it with an impact gun if you have access to one, a wuick hit is all it should need. A few other areas to check are the lower mounting bolts, the 4 allen bolts that adjust camber, and the 4 lock bolts underneath the pillowball bearing, make sure all of these are tight.



Sometimes noise can come from somehwere else, endlinks, swaybars, and chassis contact can all be problems. Make sure now that the car is lowered and stiffer that you don't have exhaust contact anywhere. These are all common noise issues.

 

thanks so much for the info, ill take it in and see what they say

 

I fixed a clunk like that in a crappy old Ford I used to own when I discovered one of the swaybar linkages rusted right through... something like 10 bucks and 10 minutes of work fixed it.

 

it seems to be a common problem with the BCRs. I dont think anyone has figured out what causes it as some people have it and some dont. Best thing to do is make sure all the bolts are tight and that the preload is set correctly.

 

thanks, ill make sure i mention the preload to them. I did a pretty good amount of research and don't remember anyone complaining about BCR's making noise, good to know its not just me. THanks

 

Thanks for that info CircuitMS, I'm about to have my coilovers installed this week!

 

i believe there was a huge thread in the 2IS suspension forum

 

I'll take a look, thanks

 

so i took it in and they checked everything and said everything was tight, still have the noise.

I also made it 2 clicks softer from the middle cause it was a little jarring on potholes but its still a little stiff, anyone have any experience with the softer settings and if going a lot softer makes a world of difference or should i leave well enough alone? Thanks everyone

 

Yes I also do have experience with this with my Lexus GS 300. Sometimes it really annoys me especially when I go to my party store daily.