Strut Clunk!!

[prasad]

Hello ,

Faithfully followed the superb instructions on the maintenance page and changed the front two shocks......I seem to get clunks from driver and passenger side on small bumps.....More on the passenger side. Looks like something is loose.....Should the strut tower bolts at the bottom be tightened using Impact Wrenches ??

I tightened the strut housing bolt (circular) to where it was before.....Tightened the control arm bolt......How tight should be the single (22mm) bolt on top of the strut bearing be ?
Thanks.....

-prasad :(

[Rory535i]

when i changed my shocks over i tightened the strut into the tower using an air gun and impact sockets. if they're not real tight it could cause the strut to move around slightly.

[MicahO]

Hello ,

Faithfully followed the superb instructions on the maintenance page and changed the front two shocks......I seem to get clunks from driver and passenger side on small bumps.....More on the passenger side. Looks like something is loose.....Should the strut tower bolts at the bottom be tightened using Impact Wrenches ??

I tightened the strut housing bolt (circular) to where it was before.....Tightened the control arm bolt......How tight should be the single (22mm) bolt on top of the strut bearing be ?
Thanks.....

-prasad :(

The top nuts on the strut housing (those accessed from under the hood) are not to be too terribly tight - IIRC the torque on them was in the 25ft-lbs range, and hitting them with an airgun will definitely break the studs.

The big nut on the top of the strut can/should be cranked down as hard as you can get it - it's going to be easiest with the spring compressed, either by the car's own weight or off the car and with the spring collapsed by a spring compressor.

Movement from either of those items should be noticeable with the hood open simply by getting the front end moving up and down - if that's the source of your clunk, you should be able to see it easily.

The big bolts on the bottom of the steering arm do get a very high torque value (don't have Mr. B in front of me), but again, it should be obvious if that's the source of your noise.

Where I got noise in the time immediately following a strut replacement was from the housing itself. I found that the insert had a bit of movement inside the housing. This was remedied by jacking the car up, taking off the wheel on the noise-producing side, and cranking down HARD on the big collar nut that holds the insert into the housing with a big effing pipe wrench. You don't need to remove the strut from the car to do this.

If it continues, you may want to take the strut back off the car, remove the insert, and put a few (very few) ounces of oil into the housing. The oil is there from the factory both for heat dissipation as well as to take up any slack space.

But the BF pipe wrench should be all you need.

[prasad]

Thanks a bunch Micah....
I tried using a 14" wrench with the wheels off, But couldnt get in enough between the springs to get a good grip on the collar nut on the housing.....THe springs prevent me from tightening the wrench nut....All I could do was a tongue and grove plier to turn the nut. I am not sure if the spring is compressed more that it needs to from the top nut on the strut piston/bearing.

-Prasad

[Kalevera]

I'm going to go out on a limb here and say that the sway bar links weren't retorqued and they're jostling around whenever you go over a bump.

That, or the bushings are shot.

Gotta read BMWe34.net -- it would've probably solved this issue completely.

best, whit

[prasad]

Lowell ..I saw your PDF posting on strut removal ....Good stuff..... Where did you find the box wench (22mm) that you used to hold the top nut while holding the shaft with a hex set ?

Thx,
Prasad

[stu1]

There's a very good chance this is a knackered upper control arm bush which is allowing the control arm to hit the steering rod leading to light knocking sounds (esp under braking). On mine I can see where the steering rod has been hitting the upper control arm.

Stu.

[632 Regal]

There's a very good chance this is a knackered upper control arm bush which is allowing the control arm to hit the steering rod leading to light knocking sounds (esp under braking). On mine I can see where the steering rod has been hitting the upper control arm.

Stu..

[prasad]

Cant feel it in steering wheel....

.

[Kalevera]

Hey Prasad.

I picked up a $5 chinese made 1' long box wrench at a local discount place. If you have a wal*mart around (and who doesn't?), I'm sure you can find one there as well. Box wrench = pipe wrench...same deal...same great tool.

I'm still thinking it's a loose sway bar link...I could be wrong, but I had the clunk-over-bumps for about two days after SLIGHTLY loosening one of the sway bar links prior to doing my sachs install.

I was SURE that I'd gone through a thrust arm bushing or something...but I got under the car and just started shaking things until I found the loose component...then felt really really stupid for forgetting to tighten it up the last time I was messing with it.

again, if you're getting a clunk, you should be able to reproduce it by putting the car up on jack stands and checking for play in the various components.

Good luck mate.

best, whit

[emw525E34]

Whit,

Thanks for the reminder on getting under the car and shaking drive compoents until you find the offending part. I must do that. That steering clunk when just pulling off is annoying. I dont get clunks going over bumps. Just the one when I pulled off the driveway or off a car park.

The PO used to have lowering springs which was restored to stock when I bought the car, so the springs were re-done. Thats where I should check first.

[prasad]

Thanks all....
I finally got a electric Kobalt impact wrench..Tightened the three nuts holding the strut housing at the bottom....Noice went away for some time but reappeared after some off road testing....Finally found that the nut on top of the bearing was loose by couple of threads....
No noise....but car runs stiff....May be I will change sway bar links some time soon....Any recommendations for the rear shocks ?
-Prasad

[Mobius]

All I could do was a tongue and grove plier to turn the nut.If you could turn the strut collar nut with a pair of pliers, then it's very definitely too loose. You should do what you can to get this tight - even if it's not the source of this noise, it will be in the future if this nut keeps getting more loose. I know, mine was loose for a time. I tried everything before discovering it.

As far as the rest of the suspension bits you talk about are concerned, here's a list of torque specs - go and check that everything is nice and tight:

Strut housing to steering arm (the three lower strut housing bolts) - 81 ft-lb
-Use loctite on these bolts (Bentley says Loctite 270) - if they loosen and fall out, it'll be an interesting ride.

Shock cartridge retaining collar - 96 ft-lb (how you measure this, I have no idea)

Upper strut mount to strut cartridge shaft -
(with internal hexagon) - 33 ft-lb
(with external hexagon) - 45 ft-lb

Strut assembly to body (three nuts on upper strut bearing) - 16 ft-lb (note very little torque here)

Stabilizer bar end-link - 43 ft-lb -Absolutely check this first. This would be the cause of 90% of front-end rattles.

[Kalevera]

Prasad - depends on what you want -- performance or ride quality? :) I love my sachs kit, which has the boge turbo gases on the rear. Everybody and their moms like the koni's, although you have to do a lot of work to adjust them on the rears once they're in the car. Also, it seems like people use the bilstein sports on the rear with few complaints.

EMW - If you've got a clunk in the turns, best thing I can think of is to first check the steering box mounting bolts (from below...in the subframe). If they come loose, you'll get a clunk in low speed turns (check bmwe34.net for details)

best, whit

[Mobius]

EMW - If you've got a clunk in the turns, best thing I can think of is to first check the steering box mounting bolts (from below...in the subframe). If they come loose, you'll get a clunk in low speed turns (check bmwe34.net for details)Steering box AND front subframe bolts. Tightening my subframe bolts just the tiniest bit cured my steering creak at low speeds.