ok, another "what is this noise" thread - brakes
08-08-2012, 11:07 AM
#1
Rennlist Member
Thread Starter
ok, another "what is this noise" thread - brakes
the symptom: a metallic-y "creaking" noise when applying the brakes, coming from the front right wheel.
the observations:
---it only happens when applying brakes the first time after switching direction - fwd, reverse. i.e. after driving forward and applying brakes/coming to a stop, if i then drive in reverse and apply the brakes, there's the noise. and since it only happens on the first brake application in a given direction, i can keep backing up/applying brakes and i wont hear it again UNTIL i change direction, go forward again, and apply brakes for the first time. then i hear it, but again, only on that first brake application in forward direction. after that, i can go fwd and brake all day long with no noise. make sense?
---when trying to induce the symptom after changing directions as mentioned above, if i coast to a stop in either direction, then apply full brake pedal, no noise. i.e. i wanted to (hopefully?) rule out issues with the master cylinder, brake lines, calipers, etc when under full pressure. and car does not have to be moving fast. i can reproduce sound when stopping from 5mph as well as 30. it's like something is rotating or re-seating directionally, under load, that first time i apply the brakes when switching direction.
the troubleshooting:
---i swapped wheels and pads (to track wheels/pagids), swapped brake pins and spring clips with some extras that i have, and removed anti-squeal pucks. noise still there, unchanged so i doubt any of those are the culprit.
---i tightened the anti-sway and drop link. i checked the LCA, tie rod, top camber plate, spring, etc, and all seemed tight/ok.
---i took off under panels and checked subframe. seemed tight.
---i checked calipers, rotor, brake lines, etc and all seemed tight/ok.
---i checked for rocks in betw the rotor/backing plate. (but maybe i should check again, OR remove it to see if sound is still there.)
what i did NOT check/what could it be?
---wheel hub?? there is no play in the hub (it passed inspec just fine) but could this be a bearing issue?
---the bilstein coilover? but if it was that, why only do i hear noise the first time after switching direction - wouldnt i hear it all the time?
---a bushing somewhere that seems "tool-tight" but when under braking load, has lost enough elasticity or whatever to make that noise??
is this just "the sound a track-rat will make after being beating around tracks for a few years"? but if so, why only the right front?
sorry for the long post but any help would be appreciated, as i have a DE this weekend and need to solve this asap!
the observations:
---it only happens when applying brakes the first time after switching direction - fwd, reverse. i.e. after driving forward and applying brakes/coming to a stop, if i then drive in reverse and apply the brakes, there's the noise. and since it only happens on the first brake application in a given direction, i can keep backing up/applying brakes and i wont hear it again UNTIL i change direction, go forward again, and apply brakes for the first time. then i hear it, but again, only on that first brake application in forward direction. after that, i can go fwd and brake all day long with no noise. make sense?
---when trying to induce the symptom after changing directions as mentioned above, if i coast to a stop in either direction, then apply full brake pedal, no noise. i.e. i wanted to (hopefully?) rule out issues with the master cylinder, brake lines, calipers, etc when under full pressure. and car does not have to be moving fast. i can reproduce sound when stopping from 5mph as well as 30. it's like something is rotating or re-seating directionally, under load, that first time i apply the brakes when switching direction.
the troubleshooting:
---i swapped wheels and pads (to track wheels/pagids), swapped brake pins and spring clips with some extras that i have, and removed anti-squeal pucks. noise still there, unchanged so i doubt any of those are the culprit.
---i tightened the anti-sway and drop link. i checked the LCA, tie rod, top camber plate, spring, etc, and all seemed tight/ok.
---i took off under panels and checked subframe. seemed tight.
---i checked calipers, rotor, brake lines, etc and all seemed tight/ok.
---i checked for rocks in betw the rotor/backing plate. (but maybe i should check again, OR remove it to see if sound is still there.)
what i did NOT check/what could it be?
---wheel hub?? there is no play in the hub (it passed inspec just fine) but could this be a bearing issue?
---the bilstein coilover? but if it was that, why only do i hear noise the first time after switching direction - wouldnt i hear it all the time?
---a bushing somewhere that seems "tool-tight" but when under braking load, has lost enough elasticity or whatever to make that noise??
is this just "the sound a track-rat will make after being beating around tracks for a few years"? but if so, why only the right front?
sorry for the long post but any help would be appreciated, as i have a DE this weekend and need to solve this asap!
