question on rear shock tower..

[jw 325ic]

what kind of metal is the rear shock tower or whatever its called, where the shock mount mounts to the body...is it aluminum or steel? reason i ask is i had to overload the suspension about once a week for a month for work and i have sport springs and the rear shock mount busted through the metal, which is now cracked. need to have it welded up but i need to know if its steel or aluminum. thanks.

[Beej '86 325es]

I have a similar issue: the welded seam that attaches the shock mount portion to the wheel well is split.

It's probably partly due to the really soft springs GC originally gave me which caused a lot of bottoming out the spring and the rusting in my wheel wells didn't help the situation.

I have to have this repaired as well. Good luck, keep us posted how it goes...

[John in VA]

I'd imagine it's made of whatever the rest of the body is, not aluminum.

[der affe]

it is just steel.

look into upgraded RSM's while you are at it, if you don't have them already. there is a member on here that is selling billet RSM's with urathane insterts AND the shock tower reinforcement plate for a really good price

[der affe]

here's a link

http://www.r3vlimited.com/board/showthread.php?t=128041

[jw 325ic]

already have the bmp billet/urethane rsm's. so its just steel then..?

[der affe]

do you have the reinforcment plate also?

i think some of the problem is caused by the stiffer RSM and the overall age/mileage of the car of the car. it takes a lot of abuse over time, add in a stiffer than stock part and that may be the cause.

remember that the steel there is pretty thick too, buy the appropriate thickness

[jw 325ic]

i dont have the reinforcement plate. i need to get one though, where can i find those, its been awhile since ive looked into it...turner or bmp? my car only has about 140k miles, but i have the billet/ure shock mounts and h&r sports. im in college and for money i throw papers, on sundays theyre huge and overload my suspension so i think after too many sundays overloading it, its just taken a toll on the metal. we got a e32 now, so thats my work haus but i need to get my cabby fixed for the gas miles.

[der affe]

somewhere on here there is a thread with the BMW part number. it is actually a factory part. IIRC it was $5-$8 each

[Gooch]

Found this info when I did mine:

Z3 Reinforcement Plates (Part Number 51-71-8-413-359)

http://home.comcast.net/~matthew.c.smith/mods/rear_shock_mount/index.htm

[der affe]

that is what i was talking about ^^^^^

[jw 325ic]

had it welded earlier this week and so far its great. already ordered the plates from the dealer, got a good deal on em from a hookup i got there. was going to go to koalamotorsports.com and get theres but shipping would have doubled the price at the dealer.

[Beej '86 325es]

Glad to hear you got it all buttoned up.
I'm going to install the Mason rear strut bar to help reinforce that area so it doesn't happen again to me.