Kinda bangs/pops/jerks then it will start moving........

[msubtech84]

The other day I jumped in the car threw the shifter over into reverse and went to back out of the garage but it felt like the parking brake was on.....I pushed the clutch back in reached for it to push it down but it was already down.......weird, I thought. I wondered am I hung up on something? I put it in first and tried to inch forward but the same response from the car it didn't wanna move (keep in mind I did not let the clutch all the way out on either occasion just barely to where it normally would get the car moving) I then put it back into reverse and let out on the clutch a little more and the car gave a little pop/bang from underneath somewhere and took off as normal.



Now a little history from the car so that maybe somebody will notice something in what I am writing that could possibly identify a potential culprit.

First and foremost I just bought the car about 4 months ago with 126,000 on the clock. When I purchased the car it had a vibration starting at the top of second gear through third gear. I ordered up a new guibo and center support bearing after doing some research. When I went to change it the center support bearing was obviously bad because the rubber was all ripped up. The guibo really didn't seem that bad. The driveshaft though seemed like it did have a tiny bit of play in the u-joints. (I don't know how much is too much). It's worth noting here that I found a receipt in the glove compartment for a center support bearing replacement last year. When I seen how badly it looked when I pulled it out of the car I questioned if it had actually been changed or not however.

After changing out these components and getting the car back on the road everything seemed to be running perfectly smoothly or for about 200 miles worth of driving until this event popped up. I know it's not an isolated incident because it has happened to me at various other times now multiple times a day while driving the car. It happens after coming to a complete stop and then either putting it into reverse or 1st and getting going and there will be just a little bit of jerk or pop or a very light bang and then it takes off as if nothing else it wrong. Something is binding up or something does anybody have any idea what it could possibly be?

[Mr Bingley]

Well, I would put it up in the air and take a look at the new new center carrier bearing for a start.

[msubtech84]

Thanks for chiming in to suggest something. I figured people would be all over this one. I am at a complete loss. I drove the car today and it did not do the jerk/pop thing to me. Maybe it was 2 day fluke?

[ProductUser]

As we say in the software biz, "Whatever fixes itself, breaks itself."

[Randy Forbes]

There's a procedure in the TIS for setting the preload on the CSB.

If the existing CSB is still intact, shift your gaze rearward about three feet (3'+) and inspect the sheetmetal structure above and to the left of the differential.

[RedconOne]

I've raised my car with a jack and placed it on Jackstands only once since I purchased, to inspect the rear diff, and the rest of the drivetrain. When I lowered it and went to back out of the garage, there was a loud Thunk from the rear.. almost as if the spring(s) had reseated in their perch or something. Scared the crap out of me so I put it up on ramps and looked, could see nothing wrong and it did not happen again.

Not sure related to your symptoms, just throwing it out there.

[msubtech84]

There's a procedure in the TIS for setting the preload on the CSB.

If the existing CSB is still intact, shift your gaze rearward about three feet (3'+) and inspect the sheetmetal structure above and to the left of the differential.

Thanks for the reply, what is the TIS? I set the preload to about a 1/4" it really is kinda tough to say where it starts and where it ends because the rubber is kinda a continuum rather than a black and white type of thing if you get what I am saying. Can I ask why you think this sheetmetal structure might be involved?

[msubtech84]

I've raised my car with a jack and placed it on Jackstands only once since I purchased, to inspect the rear diff, and the rest of the drivetrain. When I lowered it and went to back out of the garage, there was a loud Thunk from the rear.. almost as if the spring(s) had reseated in their perch or something. Scared the crap out of me so I put it up on ramps and looked, could see nothing wrong and it did not happen again.

Not sure related to your symptoms, just throwing it out there.

Thanks for the reply. That would freak me out too. I don't think this is the case with my car now but as a side note.......back in high school I rebuilt a 350 for a Trans Am anyways on one of her maiden voyages I punched it during a carb tuning and the counter spring for the window that sits inside the door broke and shot off making one hell of a racket. I thought I blew something up lol.

[Vintage42]

... It happens after coming to a complete stop and then either putting it into reverse or 1st and getting going and there will be just a little bit of jerk or pop or a very light bang and then it takes off as if nothing else it wrong. Something is binding up or something does anybody have any idea what it could possibly be?

Post #5 said "inspect the sheetmetal structure above and to the left of the differential." That would be to look for torn sheet metal in the differential mount and the trunk floor that it attaches to. It appears that you have not looked for that.
Rear subframe failure is a possibility:
https://www.bimmerforums.com/forum/showthread.php?1979601-Subframe-trunk-floor-differential-mount-failure
Pictures:
http://forums.bimmerforums.com/forum/showthread.php?2113938-best-place-to-get-a-drive-shaft&p=27765432#post27765432

[msubtech84]

I am back to report what I have found. I had the car up on jacks and could not find any problems with sheetmetal structure around the differential. The problem went away until today. It came back. When I was pulling it into the garage I realized I had not pulled in far enough and I released the brakes to pull forward some more. It popped again! I hit the brakes again and let off immediately tried to pull forward a little bit....another pop! It has been coming from the brakes this whole time. I wanted to let everybody know in case they run into the same problem. Anyways, it looks like I will get to inspect the brakes now.

Does anybody have any ideas what could be causing a temporary sticking of the brakes intermittently? Thanks in advance.

[KJ79]

I had a very similar problem that occurred intermittently over the past year. Very noticeable after rains or washing and sitting for a day or two. I just figured it was a little rust build up in the wheel/bearings..... and then one day my front left caliper completly froze up.

I read that water in your brake fluid can cause calipers to stick. After a new caliper and pads and a complete new brake fluid flush, I no longer have any of my prior symptoms.

[msubtech84]

I read that water in your brake fluid can cause calipers to stick. After a new caliper and pads and a complete new brake fluid flush, I no longer have any of my prior symptoms.[/QUOTE]I am

Yea I think your onto something here. I have not noticed if it does it more after I wash it but, it did rain the other day and it did not do it. I am unsure of what sets it off. I am having some serious problems with squeaking breaks too so I will just have to tear into the brakes and report what I find.

[msubtech84]

brakes*