phenomeno

iTrader: (1)

Hi everyone, after my friend installed new megan adjustable dampening coilovers into my 93 LS400, there is a knock coming primarily from the front left strut tower when i drive over dips. Ive tried to do a search but cant find anyone having the same issue. My friend said we have to "Cut" holes by the strut tower so the thing thats causing the knocking has room to travel. Has anyone had the same issue after coilover install? Is this normal? Sorry for the newbie question, Im not very mechanically inclined. Thanks for any input.

RA40

iTrader: (6)

How low is the car ride height? If the upper control arm is contacting the body you'll see a dimple where it is hitting.

phenomeno

iTrader: (1)

Thanks RA40 for replying. Its low enough that when i slowly go over speedbumps it just minimally scrapes. Im pretty sure its not dumped down all the way. The knock doesnt happen all the time but maybe over the reflectors on the highway or at a dip if Im going too fast. How do I correct it if it is the upper control arm contacting the body? I dont want to cut a hole in the body, just got a weird feeling that it will weaken the body where the control arm and strut tower is. Im planning on going with a UAS bag setup using the same megan coilovers. Will that correct the knock if it is in fact the upper control arm?

dicer

Yeah it would be best to have it adjustable so when you need to go high with it you can, that's a good idea.

phenomeno

iTrader: (1)

After research on several groups on facebook LS400 pages, Ive found that this knock is common and others have offered several work arounds such as cutting of metal area around strut towers to installing rubber on metal part to lessen the knock. Apparently its the upper control arm that is knocking against the body of the car. You can buy the correct way of fixing it by buying front upper control arms like "SerialNine" but they go for $530.00....sheesh

PureDrifter

iTrader: (10)

the aftermarket UCAs don't resolve the clunk at all, especially if you're very low. the only way to "fix" it is to alter the suspension geometry by sectioning the spindle. That's been discussed here as well, though some time ago.

phenomeno

iTrader: (1)

Thanks PureDrifter, Im adding Air bags so hopefully that fixes the clunk. If not I guess I just gotta go a little higher on the coilovers. Thanks for ur input

timmy0tool

iTrader: (7)

you sure the knocking isn't a loose collar on the coilover itself? make sure everything is tight.

i hope you guys lengthened the coilovers because they are boxed at the shortest length so they fit in the smallest box possible for shipping purposes. they need to be lengthened for sure, or you will be very low, thus hitting the upper control arm to the wheel well.