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Sticking Brake Calipers & Bent Rim / In Neutral, do Driveshaft vibrations diminish?

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#1 · (Edited)
Sticking Brake Calipers & Bent Rim / In Neutral, do Driveshaft vibrations diminish?

Greetings,

Trying to distinguish between front end issues vs possible driveshaft issues after reinstalling DS with new guibo & CSB. (It could be multiple problems of course, and yes car was vibrating before I removed the driveshaft.)

From searching the forums, I saw some comments that pushing in the clutch will stop driveshaft symptoms, but did not see this for automatics also.

Can anyone advise? If I shift auto tranny into neutral and the symptoms/vibrations don't change, can I rule out driveshaft issues?

It's hard to tell whats vibrating, but if I messed up reinstalling the DS I don't want to confirm that by trashing the new guibo/CSB and eventually the u-joints.

Also, the DS was out to replace the tranny selector shaft seal so the whole engine/driveline has been moved around recently and put back this weekend ... and yes I am resigned to going back under and redoing everything. Que sera, sera...

Main question right now: Does the lack of change when going to neutral help narrow down or eliminate possible driveline issues?

SYMPTOMS - 04 325i, 107k miles, gm tranny -390r
Note, the front end was vibrating at highway speeds from 65 to 75/80 mph BEFORE I removed the DS, and is still vibrating after the reinstall but now I am noticing vibrations at lower non-highway speeds.

I swapped two good wheels (with the same Bridgestone tires) from my Dad's e46 to my fronts and no real difference (my rims on his car drive fine on smooth roads). Suspension is new (10k miles), but with original control arms, tie rods & end links. The CA''s & TR''s still tight with no play, but I have new end links on the way due to a torn boot.

Vibration is through steering wheel mostly, but some through my feet / knees (but not the pedals) and some through the passenger headrest. Seems to be at all speeds above 25 mph and is worse on highway at 65 to 75/80 mph. Does NOT seem load dependent, and it happens when coasting in neutral. There is no rythmic thumping sound, like an unbalanced washing machine.

It's also not that bad of a shake, e.g., the coins in the tray behind the e-brake are not rattling. Ive had out of balance tires shake much worse, but even so something just ain't right. The steering wheel vibrates for sure, but I really can't tell if the headrest "vibration" is just normal baseline vibration.

Sorry for the long post,
 
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#2 ·
In neutral, the speed of the driveshaft does not change. The wheels are still spinning the differential, which is spinning the driveshaft. In neutral, gears are uncoupled within the transmission. If there is a driveshaft issue, it will persist no matter what and change in direct relation to rear wheel speed, not motor speed
 
#3 ·
Not from an E46 but other rear wheel drive cars without independent rear suspension, pushing the clutch in or popping the transmission in neutral can often "unload" the driveshaft and vibrations will reduce or go away.

Also in the cars I had dealt with that had driveline vibrations, you could notice the inside rear view mirror would vibrate to the point the image in the rear view mirror would be fuzzy.

You need to first rule out bent wheels, even if you took wheels off a different car, you need to make sure they roll true and round. Do not forget to check the rear wheels as well.

http://forum.e46fanatics.com/showthread.php?t=1066399

http://forum.e46fanatics.com/showthread.php?t=999695

http://forum.e46fanatics.com/showthread.php?t=1048342

http://forum.e46fanatics.com/showthread.php?t=1045028&highlight=cracked+wheel

http://forum.e46fanatics.com/newreply.php?do=newreply&noquote=1&p=17268280
 
#5 ·
Not from an E46 but other rear wheel drive cars without independent rear suspension, pushing the clutch in or popping the transmission in neutral can often "unload" the driveshaft and vibrations will reduce or go away.
The search results I was looking at may have been for an older BMW e39 or e30, but I don't recall. What's important is that it doesn't help diagnose my problem. Thank you for clarifying.

Also in the cars I had dealt with that had driveline vibrations, you could notice the inside rear view mirror would vibrate to the point the image in the rear view mirror would be fuzzy.
Right, this is what is confusing me. I am no where near that level of vibration ... in fact the vibration I see and feel through the headrest appear closer to normal than not.

(Although, IF I did reinstall it wrong, maybe it would take time for things to really loosen up.)

You need to first rule out bent wheels, even if you took wheels off a different car, you need to make sure they roll true and round. Do not forget to check the rear wheels as well.
Ahhh ... might as well, ill have the car on jack stands anyways. And, there could always be more than one thing wrong at once. Could be more than two things wrong, for that matter.

Thanks for the urls to research as well, and for the feedback.
 
#7 ·
Change You Brake Fluid Regularly

Quick Update,

The left rear caliper had a gelatinous rusty blob near the bottom of the cylinder near the bleed valve hole. Under that blob, the rust was eating into the cylinder wall.

So, Im waiting on 2 calipers (RF & LR) and a new brake hose for the RF due to corrosion at the caliper end.

I'm actually glad to find a problem, to be honest. Hopefully, this means progress on the vibrations.
 
#10 ·
Update- brakes fixed, front right rim BENT, now shakes only on highway

I've really hit the lottery on this, so here goes:

After fixing the brakes, the vibrations now only happen at speeds above 50 to 55 mph with a lull around 70 to 75 mph, sometimes. Looking again, next I found a bent front right rim, which I think explains remaining symptoms. (I'll check rears too soon.)

So, I am tentatively calling the driveshaft reinstall a success for now, since no vibrating/fuzzy rear view mirror and it only has problems on highway. (I think it's more a 15hz vibration, not a 60 /120 hz vibration, and finding good rims should confirm this.)

Of course, finding a good rim is proving difficult but so it goes. The replacement I got today is also bent, but I can return it easily.

So, in the end I think it's going to be either new rim, if available, or used from Craigslist but checking each possible one on the car first.

Can anyone recommend reputable sources for new rims? Or for used rims, a good source locally in the SF Bay Area?

What a series of small obstacles, ha. I put the ugly details below for anyone interested.

Cheers

Brake Saga - Rebuilding The Rebuilds
I rebuilt my front left caliper and obtained 3 remand calipers for the others, only to find the left rear reman was frozen solid completely. Once around block, and had to put a box fan on full on that rotor (temp 300F +, burning brake fluid smell, very hot to touch wheel). Later, I put 80 psi of compressed air on that caliper & piston didn't move one bit. Rebuild date on the box was mid October 2015.

So, got a replacement reman'd caliper locally, but ended up rebuilding all three of them because one ran hot still & I wanted peace of mind. I found pinched dust boots in two and a shabby looking piston in the third:
Auto part Still life photography Circle Metal
Auto part Tool accessory Machine Machine tool Metal
Tin can Auto part Tin

The front right caliper with white boot was still running hot (also October 2015 reman).

Used 1200 grit sandpaper to clean rust off that piston and elsewhere. I did new seals, dust boots, slide pins & bushings, with new 9mm bleed screws and silicone paste.

All buttoned back up and the brakes I think are good now. Rotor temps on the ir thermometer seem normal & comparable to other e46, and no wobble/shudder when I hit the brakes. That and no more vibrations at low speeds on city streets.

In the end, the only caliper that worked properly for me, this time, was the one I was able to rebuild myself.

Replacement Rim Also Bent
Yes, why not at this point. I picked up a refurbished rim locally, tonight found it has a significant bend on inside rim and slight one on the outside rim.

Also one of the small holes, next to the bigger bolt holes, looks like it was chiseled or picked out from behind.

Auto part Wheel Rim Tire Automotive wheel system
Wheel Auto part Alloy wheel Rim Automotive wheel system
Alloy wheel Rim Wheel Tire Auto part


Do I even want to know why that happened? Looks like a rodent chewed on it, or an impact chisel was used to cannibalize alloy for welding ... wtf?

That shop sources their rims from junkyards and totaled cars and such.
 
#12 ·
Here you go ... what do you think?
Auto part Automotive fuel system Engine


It's really hard to tell from this pic, but each little triangle on the outside of guibo is pointing toward a flange (either on trany or driveshaft). Reused the bolts with new lock nuts.

I think you can kind of see a triangle near bolt on right, but very tough. I'll double check it though, and take better pic. Not taking anything for granted on this.
 
#15 ·
New rim from dealership / bent rim balanced fine though

So I returned that refurbed rim yesterday and the shop gave a refund without much trouble.

They did show me on the "Hunter" balancing machine the rim was balanced (.5 gram weight on inner & outer rims), and how you couldn't feel any wobble with a finger on the slowly rotating rim. He refused to spin the rim fast, however, claiming the machine won't allow it.

He sounded very convincing, but I can still see the red wd-40 straw perfectly still as the rim moved away and towards the straw. It was an interesting experience.

So, end result is I ordered a new rim from the dealership that should be in today. I just need to be done with it at this point.
 
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