Coilover Issue

[karter]

how can I tell if the shocks have been installed too short? They were installed when I bought the car and we've done at least 30k - I have all the previous owner's receipts but there aren't any for the coil overs so I assume they've been there for a while.

[scotty nm35]

Get it on a hoist, drop the shock and make sure it can still move longer than it is when bolted. If it extends past the mount at full spring travel you should be fine.

[LenBo]

Guys, FYI

I have 2002 ARX with standard suspension and I had this very same issue. It was definitely a fatigue crack. On my car the fatigue crack grew quite a long way towards the front and back of the car before the shock top finally ripped out on a pot hole just like Matthew. however for at least a year beforehand I could hear a rattling / tinkling sound coming from the back but could not for the life of me find it - until it ripped out of course!

about 6 months later the other side started tinkling, so I knew exactly what it was this time around.

As Matthew showed, there is absolutely no access from the top. structure of the car completely excludes access.

to fix, I snuck two bits of 5mm plate above the mount, with captive studs tacked to the plates, one each side. couldn't do it in one piece of plate since it won't go up the hole. in my case the fatigue crack had propagated towards the front and back of the car quite a distance and intersected the hole in the middle, which is stiffened by an upward fold. crack had progressed right through the fold. so gouged out the crack and welded it closed, added the plate above then added a strip of something like 4x10mm flat bar rolled into a cylinder and welded that to the inside of the hole to reinforce the folded edge.

it was fiddly, but not terribly difficult, certainly not nearly as challenging as fabbing the 3" the intake pipe

no problems since.

I'm about to order BC's myself since the standard suspension is ready for the bin.

my car has done about 180kms, the top mounts ripped out at about 150 and 160k's respectively.

I don't suspect lack of travel positive or negative travel on the BC's on Matthew's, since it happened on mine with standard suspension. you can even see the fatigue crack heading forwards on the photo posted earlier in the thread. What may be a more interesting coincidence is that no one else seems to have had this issue accept Matthew and I, and we both drive early ARX's. Is there a chance that this top mount is different on the ARX since it is a bit higher than everyone else?

How did the eng shop fix your top mounts Matthew?

Lenny.

[karter]

The guys welded plates on both sides - I'll post photos next week - the tinkling noise might confirm my mechanic's theory that the shock mountings had loosened over time - I was getting some metallic knocking in the rear (on the move) but couldn't find anything loose - the shock mounts get a thorough check at every 5k service now.

Matthew

[karter]

Pics of repair are attached - complete with 10k of road grime.

[rosella]

This has just occurred to my car. It's got BC BR coilovers and lowered. Running 19x9.5 +20 wheels.

I showed the information in this thread to the mechanic that is going to repair it. The information confirmed what he was planning to do anyway. BTW, he owns a R34 GTR and worked on the SAU NSW ex-president's N1.

[datmoo]

Second car with BC's to have this happen, maybe look at the way they are set up. Looks like suspension is travelling beyond the shocks limits.

....cough MCA's. 

[rosella]

Matt, you're pretty much on the money. It appears the forces are concentrated downwards rather than upwards. The mechanic suggested that even going in and out of driveways on an angle would cause the issue. The shock couldn't travel much as the coilovers were compressed to produce a lowered effect. I crushed the middle muffler going over a speed hump in an industrial estate a few years ago. I'm also chewing out tyres like no tomorrow and inner tie rod end on the left. I've replaced the item 4 times in the last 2 years. The car is now sitting 25mm higher and may need to go higher.