budget76
06-24-2012, 10:57 PM
Ok guys, lets help me try to figure this one out. 95 318TI, going to cross-post in the e30 section since the rear is e30.
It sounds like a metal-on-metal knocking/clicking upon acceleration. I am 95% sure it's from the drivers side rear, but I haven't ruled out driveshaft u-joint yet. What I've figured out follows:
1. Happens only with torque on the rearend. Much more noticible upon acceleration no matter how hard or soft, but I sometimes hear it upon deceleration. Push clutch in and no more sound.
2. Sound seems to go away at high speeds. I can occasionally hear it at highway speeds, but typically only when in the left lane next to a divider so the sound bounces back at me. Maybe I just can't tell it's there with all the ther road noise at speed.
3. No pattern to when the noise is there. It has been every morning, but only sometimes after work. Comes and goes, but has been noticible more than not as of late.
4. I recently had the rear sway bar mount on the drivers rear fail, and welded it back on. It is tight and I do not believe the cause, though it made a similar noise when it was broken off and hit agains the rear trailing arm.
5. Oddly, the noise seemed to be much less noticible/go away when the temp was >90 out last week. Also seemed like it mostly went away after a 40mi highway drive at ~70mph.
6. I have crawled underneath. Nothing visibly loose, the CV/axle shaft didn't seem to have any more play than the passenger side, shock mounts tight, sway bar mount tight, felt no play with the wheel in the air like you would expect with a bad wheelbearing. All lugs are tight.
7. What I found that could be the culprit. When smacking things with my palm to try to replicate the noise, I hit the brake caliper and though all bolts/attachments are tight, it seemed like the caliper allowed the pad to move a little bit and make a banging noise. I thought this was the cause, but applying light pressure to the brakes when accelerating did not make the noise go away. My rear pads have alot of life, but squeak horribly and will be replaced in the next two weeks. Don't think it will do anything though. Wondering if the rear rotor is warped and #7 is in fact the cause.
8. I have put 750-1000 miles on it with this noise coming and going. I have to drive it to get to work, about 100 miles/day, can't avoid it. No changes in handling or anything, though I do feel a slight 'chugging' at low speed, very slow acceleration with low RPM that I didn't notice in the past.
Thoughts guys? I did search. Rear shock mounts are new, guibo looked brand new when I was that far under the car last (not long ago), and I see no obvious signs of bad diff/subframe mounts, though it IS tough to see with no ramps and a low car.
Thanks, hopefully the audio clips below work. If not, I'll try uploading somewhere else. Edit: sorry but you'll have to download the clips. One is 14 seconds, one is 10. They're very small files.
rearend click 1.m4a
rearend click 2.m4a
It sounds like a metal-on-metal knocking/clicking upon acceleration. I am 95% sure it's from the drivers side rear, but I haven't ruled out driveshaft u-joint yet. What I've figured out follows:
1. Happens only with torque on the rearend. Much more noticible upon acceleration no matter how hard or soft, but I sometimes hear it upon deceleration. Push clutch in and no more sound.
2. Sound seems to go away at high speeds. I can occasionally hear it at highway speeds, but typically only when in the left lane next to a divider so the sound bounces back at me. Maybe I just can't tell it's there with all the ther road noise at speed.
3. No pattern to when the noise is there. It has been every morning, but only sometimes after work. Comes and goes, but has been noticible more than not as of late.
4. I recently had the rear sway bar mount on the drivers rear fail, and welded it back on. It is tight and I do not believe the cause, though it made a similar noise when it was broken off and hit agains the rear trailing arm.
5. Oddly, the noise seemed to be much less noticible/go away when the temp was >90 out last week. Also seemed like it mostly went away after a 40mi highway drive at ~70mph.
6. I have crawled underneath. Nothing visibly loose, the CV/axle shaft didn't seem to have any more play than the passenger side, shock mounts tight, sway bar mount tight, felt no play with the wheel in the air like you would expect with a bad wheelbearing. All lugs are tight.
7. What I found that could be the culprit. When smacking things with my palm to try to replicate the noise, I hit the brake caliper and though all bolts/attachments are tight, it seemed like the caliper allowed the pad to move a little bit and make a banging noise. I thought this was the cause, but applying light pressure to the brakes when accelerating did not make the noise go away. My rear pads have alot of life, but squeak horribly and will be replaced in the next two weeks. Don't think it will do anything though. Wondering if the rear rotor is warped and #7 is in fact the cause.
8. I have put 750-1000 miles on it with this noise coming and going. I have to drive it to get to work, about 100 miles/day, can't avoid it. No changes in handling or anything, though I do feel a slight 'chugging' at low speed, very slow acceleration with low RPM that I didn't notice in the past.
Thoughts guys? I did search. Rear shock mounts are new, guibo looked brand new when I was that far under the car last (not long ago), and I see no obvious signs of bad diff/subframe mounts, though it IS tough to see with no ramps and a low car.
Thanks, hopefully the audio clips below work. If not, I'll try uploading somewhere else. Edit: sorry but you'll have to download the clips. One is 14 seconds, one is 10. They're very small files.
rearend click 1.m4a
rearend click 2.m4a