Steering wheel jerk while applying brake

[Mattn1192]

While driving, if I tap my brakes, my steering wheel would jerk after each tap. That’s never happened until now.. Not sure what it is. Pads & rotors are fairly new. Car gets driven once or twice a week. FCAB (AGK Poly) have only been on a month or so (improperly installed?). Anyone ever have this problem before or know what’s causing this?

[sapote]

FCAB (AGK Poly) have only been on a month or so (improperly installed?).

I would check the FCAB and if it flexing too much under braking then it could cause the symptom you have. The other reason is somehow one of the front brake grabbing brake rotor too much but I don't see why suddenly this happens as it was not touched on recently.

[bigjae46]

Poly = trash. Check the passenger side FCAB. Likely melted.

[Mattn1192]

Found the problem. The inner part of the bushing fell out. Don’t know how that happened. Driver side fell out, passenger side is still in.

[Mattn1192]

Both sides

[bigjae46]

Pretty sure the bushings are pressed in backwards.


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[Mattn1192]

This sure blows.

[jbfrancis3]

Good opportunity to put non-poly's in. You may consider monoballs such as Turner's - I'm biased and have them but if you search you can understand other preferences. To get back on track quickly, and if DIY, consider the option already pressed into housings.

https://www.ecstuning.com/b-turner-motorsport-parts/front-upper-control-arm-monoball-upgrade-left-and-right-e46-m3/013276tms~a/?gclid=CjwKCAjwr56IBhAvEiwA1fuqGpAUISyMn4hKhJVEu7efRknsScPmB16Bk1cbBWIYSf3SPmsOoecdDBoCMsMQAvD_BwE

[Mattn1192]

What’s wrong with poly bushings? I’ve always thought highly of bushings from AKG.

[Mattn1192]

$323 for FCAB seems extremely expensive.

[bigjae46]

OE rubber is compliant, quiet but will wear out.

Solid/spherical needs maintenance, not compliant, but will last a long time if maintained.

Poly is compliant, noisy, and will wear out…if the passenger side doesn’t burn up and disintegrate.

OE - get kicked in the left ball, Spherical - get kicked in the right ball. Poly - get kicked in both balls.


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[FBloggs]

Good ol' powerflex.
Those bushings were purchased within the last 18 months?
Buyers of Their FLCAB/mount kits would be wise to double check the parts for correct assembly before installation.

[Mattn1192]

This is the one I bought

[bigjae46]

It’s installed backwards. The insert is flanged and should face the front of the car or the control arm. The flange prevents the insert from being pushed through the outer bushing.

The flange is on the back so the insert is being pushed through the bushing and will likely come off the control at some point. Handling will be very interesting at that point.


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[FBloggs]

It’s installed backwards. The insert is flanged and should face the front of the car or the control arm. The flange prevents the under from being pushed through the outer bushing.

The flange is on the back so the insert is being pushed through the bushing and will likely come off the control at some point. Handling will be very interesting at that point.


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lol! You can imagine what the faithful rear axle is going through as it tries to follow what the dodgy front is up to under the brakes.