1975 BMW 530i - Clunking Noise from Front Right

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PatinaBeforePolish
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Re: 1975 BMW 530i - Clunking Noise from Front Right

Post by PatinaBeforePolish » Mon Mar 23, 2020 5:07 pm

I believe the stock sway bar can be removed without lowering the subframe. Larger diameter sway bars are a tighter fit and need more clearance. Remove the wheel for easier access and use a floor jack under the spindle to raise and lower the suspension as needed to install the links. The bar's only attachment points are the mounts and links. Tighten the links with suspension compression as if the car were sitting on the ground to where the bushings begin to just compress or mushroom. I'm sure there's a torque spec somewhere as it applied to bushings made in the 70's...

3" in circumference is slightly over 24mm which is the listed diameter for an M535i. Looks like the bushings are still available from BMW, I would go with those if practical.
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rishabhb
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Re: 1975 BMW 530i - Clunking Noise from Front Right

Post by rishabhb » Mon Mar 23, 2020 7:55 pm

For the life of me i cannot figure this out.

I put my body weight and move the car up and down on my US diving board bumpers and no clunk. Only happens when in motion.

I do not see any bruises on the chassis where the sway bar mounting points are to justify its hitting the chassis.

I think it happens with back and forth movement, when a wheel gets momentarily stuck in a pothole.

Back to thinking strut bearing. Just do not want to throw parts at it.

What do you think?

Realoem shows:

https://www.realoem.com/bmw/enUS/showpa ... Id=31_0028

The clunk sounds metal on metal.
Last edited by rishabhb on Mon Mar 23, 2020 7:59 pm, edited 1 time in total.

PatinaBeforePolish
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Re: 1975 BMW 530i - Clunking Noise from Front Right

Post by PatinaBeforePolish » Tue Mar 24, 2020 6:36 am

Online diagnostics usually evolve to throwing parts at it. It’s tough to find the exact issue without being there. My opinion is your car’s 45 years old and the newest e12’s are 39 years old- sometimes it’s good to throw parts at them!

But to keep going here, is your car rusted near any suspension attachment points? Is the steering box securely mounted to the frame rail? Check the wishbone and tension strut bushings as well as the ball joint and subframe bushings. Is the front bumper attached securely? Those are 40 lbs. of dead weight just hanging out there. Is your battery loose? Failure in any of these areas could cause the symptoms you describe.
78 F150
79 528i
81 528i parts car
01 540i
86 944
08 X3 don’t judge me it’s there to preserve the others

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528i-1981
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Re: 1975 BMW 530i - Clunking Noise from Front Right

Post by 528i-1981 » Tue Mar 24, 2020 8:05 am

You've probably done this, but because you mention that the struts were replaced, check that the mounting studs are tightened to spec at the shock tower and the self-locking nut on the strut insert piston rod under the dust cap is tightened to spec.
(oo=00=oo) Eric
1981 528i Manual

HB528i
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Re: 1975 BMW 530i - Clunking Noise from Front Right

Post by HB528i » Tue Mar 24, 2020 12:27 pm

My car clunked only when turning right, it was the tie rod end on that side. There was no other evidence of wandering either. I would also check tightness of the strut insert nut, pretty common issue.

rishabhb
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Re: 1975 BMW 530i - Clunking Noise from Front Right

Post by rishabhb » Tue Mar 24, 2020 2:32 pm

This car has no rust on the frame whatsoever. Removed the entire stabilizer bar and checked all other bushings under the car. Still clunks!
I am going to replace the strut mounts. Let's see what that does.

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Re: 1975 BMW 530i - Clunking Noise from Front Right

Post by HB528i » Wed Mar 25, 2020 6:45 pm

Check how tight the strut nut is before removing the struts.

rishabhb
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Re: 1975 BMW 530i - Clunking Noise from Front Right

Post by rishabhb » Wed Mar 25, 2020 8:40 pm

I thought of that. But to tighten it i need a 27mm hollow socket to hold the 11mm stud. I am thinking if i can use impact to tighten it, not usually recommended but worth a try maybe?

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Re: 1975 BMW 530i - Clunking Noise from Front Right

Post by HB528i » Thu Mar 26, 2020 6:55 pm

You can use an impact gun, much easier.

rishabhb
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Re: 1975 BMW 530i - Clunking Noise from Front Right

Post by rishabhb » Mon Mar 30, 2020 11:40 pm

So i figured out the issue.

It was a loose brake caliper.
When you trust a mechanic!

The bolts were loose and clunking is gone.

But what i have now is a sway bar from a M535i that will not go back on until the subframe is lowered.

Can someone please share a step by step on how to do that.

I have never dropped/lowered a subframe.
I have done engine mounts, shocks, struts, tie rods and that kind of stuff but always supported the car with jack stands on the frame. I know how to support a car but sub frame is something i have never done. I do not want to lower the sub frame without getting some inputs from you folks.

i am looking at this:
https://www.realoem.com/bmw/enUS/showpa ... Id=31_0005

Looks like engine mounts have to come out with a bunch of other stuff. I wonder if that's how BMW intended to replace subframe bushings. That would be bad engineering.

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Re: 1975 BMW 530i - Clunking Noise from Front Right

Post by 528i-1981 » Tue Mar 31, 2020 7:08 am

I replaced the stock sway bar with the ST one that required lowering the front subframe. It was the first upgrade I made to my E12 after I bought it. It was not complicated. With the car on jackstands (not under the subframe, obviously), simply back the two subframe bolts out to allow the subframe to drop about 1/2" (no more). IIRC the bolts take a 22mm socket, and an impact driver is helpful. From there, you can access the swaybar mount bolts to remove them, but it's cramped. Joe Boston gave me the hint of using the wrench in the trunk toolkit for that because it's low-enough profile, and that did work. Be patient when remounting the larger swaybar with its larger mounts and don't strip or crossthread the bolt hole. Ask me how I know. I'll also mention that you should use some silicone grease between the swaybar bushings and the swaybar itself.
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1981 528i Manual

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Re: 1975 BMW 530i - Clunking Noise from Front Right

Post by Lock » Tue Mar 31, 2020 3:28 pm

On recommendation from Eric I also bought an ST swaybar and installed it last weekend.
Lowering the front subframe is scary but not difficult, just takes time. The ST swaybar come with instructions. Once your car is on jack stands, place the floor jack under the subframe, undo the rear bolts two turns, and the front ones four turns. I found I needed to undo the fronts about six turns to get enough room, but as long as you don't remove them, and the subframe is fully supported you'll be okay.
I have a transmission jack and supported both the subframe and the engine to take pressure off the bolts, and used a 3ft extension bar to undo them - I wouldn't recommend using any kind of power tool because you don't want to remove the bolts or undo them too far.
I had to dremel out the bracket holes to fit as the new hardware was a little off, but once it was back together, greased it up and retorqued the subframe bolts to 60ft-lbs. I can post pictures later.
The ride is still pliant but it corners completely flat now. Highly recommend this upgrade.
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