Vibration felt through brake pedal

[blocke]

So my car has always had this sort of vibration. I can never figure it out, but it feels like a rubbing/grinding oscillating type of vibration. I only feel it when I am sitting at idle, with my foot on the brake pedal. I can actually feel it through the pedal. The noise cannot be heard outside the car, or inside. Simply felt. I highly doubt it's clutch/flywheel related, as I have had them out and replaced 3 times for various reasons.

I know this is super hard to diagnose over the net, but anyone else ever experienced any similar kind of issue?

[jlevie]

There are no hard connections between the engine and the brake system, but vibrations caused by the engine can be transmitted to the body and then to the brake pedal. The first things I'd check would be the motor & transmission mounts, guibo, and exhaust.

[blocke]

There are no hard connections between the engine and the brake system, but vibrations caused by the engine can be transmitted to the body and then to the brake pedal. The first things I'd check would be the motor & transmission mounts, guibo, and exhaust.

I was thinking the same thing, so perplexing. Motor mounts are OE for all I know, so they could be suspect. Tranny mounts are brand new, and exhaust is solid (been on an off the car 3 times recently). Guibo is also new, replaced it when I had my tranny out.

I might replace the motor mounts since they should be done anyway, see if that helps.

Just in theory, if there was a problem with the rotating assembly, how would that be apparent? Would a bad crank bearing or something cause this type of vibration?

[jlevie]

Replace the motor mount. The odds are that they are way overdue.

Most problems in the rotating parts will present symptoms other than what you describe. However, a bad pressure plate is a possibility.

[dogsbark26]

ABS pump?

[blocke]

ABS pump?

I suppose it is possible. It feel like a vibration that is caused by something rotating though. I'm going to replace the mounts, they are due anyway.
The pressure plate, clutch, TO bearing, Pilot, etc. all are brand new.

[u3b3rg33k]

ABS pedal feel is very distinct, and this description sounds nothing like that. You'd definitely be able to hear it as well.

[blocke]

Update: found the cause

Busted out the stethescope today and listened all over for the cause of this. Turns out the sound and vibration was coming from my power steering pump. I removed the belt, started that cAr and the vibration and noise was gone. I put the belt back on, a little looser this time. Noise and vibration are still gone. I think it was too tight, perhaps straining the bearings or pulling it slightly out of alignment enough to bind? Who knows, but I'm relieved it's not something major.

[dogsbark26]

Thank you for letting us know. Glad you've fixed it.

[bmwstudent]

the mechanics stethoscope, a very useful tool. congrats