When to rebuild coilovers?

[Notan_S54]

Hey guys, I’ve had BC Racing coilovers on my M3 for about 3 years now (sat most of the time until recently), and am now experiencing a weird hallow noise when going over bumps in the rear. I don’t recall ever hearing it in the past, but now I daily the car and am now questioning if they already need a rebuild.

[S54330Ci]

Not sure about BC, however MCS suggests these intervals. I am sure they can be applied to most any high quality coilover.

• Street : 25,000 miles
• Street/HPDE: 15-20,000 miles
• Sprint: 150 hours
• Sprint/Enduro: 125 hours
• Endurance Race: 75 hours
• Every 5 years

[Wernd]

I had over 50k miles on a set of KW Club sports before they needed a rebuild due to leaking, maxed out settings, and loss of dampening control. I basically drove them into the ground... MCS seem to pride themselves on building better coilovers than most and hopefully they last longer. I doubt I'll experience if that's true or not now that I trailer to and from the track.

Can you recreate the sound if the car is up on jackstands? How do you know it's not the sway bar or rcabs? Good luck

[Notan_S54]

Not sure about BC, however MCS suggests these intervals. I am sure they can be applied to most any high quality coilover.

• Street : 25,000 miles
• Street/HPDE: 15-20,000 miles
• Sprint: 150 hours
• Sprint/Enduro: 125 hours
• Endurance Race: 75 hours
• Every 5 years

Thanks for the reply! This car is the first car I’ve had coilovers on and will be using this as a sort of gauge for coilovers from here on out.

[Notan_S54]

I had over 50k miles on a set of KW Club sports before they needed a rebuild due to leaking, maxed out settings, and loss of dampening control. I basically drove them into the ground... MCS seem to pride themselves on building better coilovers than most and hopefully they last longer. I doubt I'll experience if that's true or not now that I trailer to and from the track.

Can you recreate the sound if the car is up on jackstands? How do you know it's not the sway bar or rcabs? Good luck

I plan on getting them up on jack stands tomorrow on my day off to figure that bit out. Good call on checking the sway bars and rcabs. Normally when a sound like this happens my first thought is shocks/coilovers and didn’t think to much of anything bushing related because I replaced/upgraded the diff, subframe, and rtab bushings while I had my subframe reinforced.

[bigjae46]

I’m going 12 years on my TCKs. No leaks or any issues yet. I’m sure there is a loss in performance…probably about time.

[usdmej]

I called TCK directly and they didn't give much merit to rebuilding just based on time passed


They recommended easiest way you can know is to jack up the car, remove the rear lower shock bolt and manually push the shock upwards, if it's slow to return to the original position or doesn't return at all then the seals are shot and time for a rebuild. Other shops have told me this too

Of course a leaking shock means rebuild time as well

[cobra]

Depends on quality of the shocks, use case, age, etc.

You can run some tests on the shocks if you take them off to see if the oil and air has mixed and if there's no damping.

For a street car I think 30k miles is a reasonable rebuild interval if you want them performing at top level.

[EthanolTurbo]

BC Racing only lasts 15-20k miles at most. You can put new cartridges in but I would just swap them out for Bilstein PSS.

[bigjae46]

I called TCK directly and they didn't give much merit to rebuilding just based on time passed


They recommended easiest way you can know is to jack up the car, remove the rear lower shock bolt and manually push the shock upwards, if it's slow to return to the original position or doesn't return at all then the seals are shot and time for a rebuild. Other shops have told me this too

Of course a leaking shock means rebuild time as well

You could do a shock dyno…but might as well just rebuild them at that point.

[mrgizmo04]

FCP Euro warranty

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