How to inspect upper strut mounts?

[JPR10]

• Been dealing with a nagging chirping sound that is apparent when braking above 30mph to 0mph
• Thought it was my brakes so changed out all 4 rotors and pads (was due anyway), the sound remained
• I recently heard the sound while taking a corner at a faster than normal speed... affirming that it isn't an issue with brakes?

Upon reading other threads online and on different forums, there is a possibility that I have shot upper strut mounts (sounds like it's coming from front).

Is there an easy way to test/inspect these without having to drop the front suspension?

This is the noise:



I gathered that the noise can happen when braking hard, or when cornering (without brakes applied).

Any ideas?

[Dave Sal]

Have you considered that it might be a wheel bearing? Wheel bearings going bad usually make noise when turning.

[ross1]

That has nothing to do with the strut mounts.
Sure sounds like simple brake noise from here.
Things to check are; anti rattle clips intact and bearing on a clean, lightly lubricated surface, clean and lubricated caliper slide bolts, pads fitting correctly in caliper, pads wearing at an angle, loose wheel bearings, backing plate rubbing, incompatible pads/rotors.
I have found that some fancy schmancy slotted, drilled hoo-ha rotors to be noisy and have a grinding pedal feel.
Just because your brake parts are fresh doesn't mean they are compatible or working like they should.
Me, I'd take it all apart and clean lube everything, scuff the rotors and pads.

[geargrinder]

^^^ true dat. Meticulous workmanship is as important as parts in a brake job IMO.

[JPR10]

That has nothing to do with the strut mounts.
Sure sounds like simple brake noise from here.
Things to check are; anti rattle clips intact and bearing on a clean, lightly lubricated surface, clean and lubricated caliper slide bolts, pads fitting correctly in caliper, pads wearing at an angle, loose wheel bearings, backing plate rubbing, incompatible pads/rotors.
I have found that some fancy schmancy slotted, drilled hoo-ha rotors to be noisy and have a grinding pedal feel.
Just because your brake parts are fresh doesn't mean they are compatible or working like they should.
Me, I'd take it all apart and clean lube everything, scuff the rotors and pads.

Rattle clips weren't lubricated... is that a thing? all brand new and greased guide pins. crc brake quiet applied to pad backing. compatible rotors/pads (meyle rotors/akebono pads).

Why would the sound be apparent while turning if it is brake noise?

My indy was also mentioning something about a possible ABS malfunction where it is unevenly apply to a corner etc, but isn't throwing any lights?

RE: wheel bearing. I should remove the rotors and inspect to see if wheel bearings are an issue.

[AnotherGeezer]

My struts mounts clunked and made turning the wheel a bit more difficult. No squeal that I can recall.

[jicaino]

Could also be caused by oily fluid being used to wipe the rotor or the pad, or some contamination like that. Most definitely NOT strut mounts symptom and that indy suggesting ABS malfunction would cause me to stop taking the car to him for service.

[computiNATEor]

Huh. That also sounds like my M5's blower motor. If I brake firmly, the blower motor squeaks. If I turn the blower motor off, the squeak goes away. If I brake more softly, the squeak doesn't appear. Just a thought.

[geargrinder]

Huh. That also sounds like my M5's blower motor. If I brake firmly, the blower motor squeaks. If I turn the blower motor off, the squeak goes away. If I brake more softly, the squeak doesn't appear. Just a thought.

Sometimes as the blower is going out it just squeaks on turns too. Mine would do that. Ironically makes the old overblown claims of "E39 has MOST RIGID CHASSIS IN THE WORLD!!!!" a little bit suspect...

[computiNATEor]

Sometimes as the blower is going out it just squeaks on turns too. Mine would do that. Ironically makes the old overblown claims of "E39 has MOST RIGID CHASSIS IN THE WORLD!!!!" a little bit suspect...

Haha. I think the bearings in the motor are more suspect than the chassis flexing.

[mattmar1]

i remember one quite some time ago about the same issue on the fest forum, THEANGRYBEAR jumped in suggesting blower fan as a possible source of the squeak when turning/braking, sho 'nuff that was it.

[geargrinder]

Haha. I think the bearings in the motor are more suspect than the chassis flexing.

Of course, no the bearings are making the noise, what I'm saying is IMO clearly the cabin structure flexes just enough to make tiny little differences on the blower motor and make it squeal/not-squeal.
DOn't get me wrong I don't think this takes much but when the BM squealing changes going around a turn I'm pretty sure its some microflexing in the whole dash console that's doing that...

[computiNATEor]

Of course, no the bearings are making the noise, what I'm saying is IMO clearly the cabin structure flexes just enough to make tiny little differences on the blower motor and make it squeal/not-squeal.
DOn't get me wrong I don't think this takes much but when the BM squealing changes going around a turn I'm pretty sure its some microflexing in the whole dash console that's doing that...

I'd put my money on the blower motor shaft/fan trying to stay in the same position, like a gyroscope, and the bearings allow some play that cause the noise. Is there dash flex? Sure. But I think if you took the motor out of the car and accelerated it in the same manner, it would make the same noise.

Anyways. Sorry for the hijack

[mattmar1]

but when the BM squealing changes .

a definite flexing problem

[JPR10]

Huh. That also sounds like my M5's blower motor. If I brake firmly, the blower motor squeaks. If I turn the blower motor off, the squeak goes away. If I brake more softly, the squeak doesn't appear. Just a thought.

Interesting.... I will try the same driving conditions but with the motor completely off and report back.


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[jicaino]

I'd put my money on the blower motor shaft/fan trying to stay in the same position, like a gyroscope, and the bearings allow some play that cause the noise. Is there dash flex? Sure. But I think if you took the motor out of the car and accelerated it in the same manner, it would make the same noise.

Anyways. Sorry for the hijack

Not only this, but also when you brake your alternator stops sending a strong juicy signal and some other consumers stay on, causing the entire electrical system to "slow down" a bit (AC compressor, lights, and so on) probably what's happening in addition to the gyroscope that Nate very cleverly points out is that the current supply fades out some.

[ross1]

Rattle clips weren't lubricated... is that a thing? all brand new and greased guide pins. crc brake quiet applied to pad backing. compatible rotors/pads (meyle rotors/akebono pads).

Why would the sound be apparent while turning if it is brake noise?

My indy was also mentioning something about a possible ABS malfunction where it is unevenly apply to a corner etc, but isn't throwing any lights?

RE: wheel bearing. I should remove the rotors and inspect to see if wheel bearings are an issue.

Anything that makes the pads vibrate can cause an audible sound.
Dampening these vibrations is the reason for rattle clips, backing on the pads, etc.
The rattle clips need to be able to move on the cast caliper so I always make sure sue those surfaces are clean and put some silicone greezy grease on the caliper where they touch.
Any place the pads touch something else needs to be clean and smooth too, as do the portions of the caliper where they are in contact.
A sloppy wheel bearing can cause rotor movement which in turn will cause the pads to be pushed back a bit and allow the pads to flop around a bit.
Attention to detail means a lot when doing brakes.

[JPR10]

Interesting.... I will try the same driving conditions but with the motor completely off and report back.


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Sound remains with blower motor on/off and at any speeds... no changes.

Sound also seems to be more audible when window is rolled down and is coming from the front right corner? It’s hard to pinpoint exact location.