840 Accelerator pedal sticking--solved

[ltbrett]

Apparently, this is a common problem and it applies to both 840's and 850's. My symptom was an occasional stubbornness to return to idle--RPM's stayed a little higher than they should have been. I could hook a foot under the gas pedal to return to idle. The culprit turned out not to be a sticky cable or weak spring as I expected, but a failed bushing on the accelerator pedal, allowing the pedal shaft to float away from the recess in which it resides. 850's use the same mounting system, but without the throttle cable.

There are two number 8 bushings, but the one that failed is not shown. It sits next to spring number 11. It looks like my lead foot pushed on one end of the accelerator shaft, levering out the other end, destroying the bushing and allowing the shaft to float around a little. The system is not particularly well designed--too fragile, with only thin plastic bushings retaining the shaft. I was only able to recover two small pieces of the bushing, which leads me to believe that the bushing was shattered for some time before symptoms arose. If these bushings degrade with age as I suspect, more cars will exhibit this issue. The replacement is part number 35411154172.

Anyone opening up the footwell for GM repair, brake booster repair, or any other reason should check these bushings. I could have caught this last year when I did my GM repair but there were no symptoms and I didn't know to look.

Hope this saves someone some time!

Brett

[Timm]

Thanks Brett, that's great information!

[JDP530]

I found those bushings in pieces on my car a couple of months while removing the GM. Thank goodness the parts are still available so I have already replaced them. I did have a bit of trouble getting the darn spring back in place!

[shogun]

already replaced them in my E32 750 8 years ago, should last with new bushes another 15 years now.
In 2010 we did it on 3 cars in our wrenching group http://alpinakozou.web.fc2.com/file/.../20100103.html

[kiwiCSi]

This issue has been previously reported, quite recently, on this forum:
https://www.bimmerforums.com/forum/s...hlight=bushing

[ChrisFuture8]

Agreed, and thanks to Dragon850's DIY write-up, it was a breeze to repair/replace. Not hard to do, just time consuming. The difference is night and day in terms of pedal feel, engine response and acceleration. No more lags.

Anyone tackling this job, remember to order a quantity of 2 of the part #8 as listed by the OP. I made a mistake of ordering just one and then had to do a reorder and paid the dumb shipping fee twice.

[bencrossman]

I recently did this to my 840ci
First time I've done anything like this so was a bit worried but was pretty easy. My pedal was a bit sticky every now and then so I ordered the parts. They arent expensive and I was fine them taking their time arriving.
Three things to take off:
- leather cover
- pedal plastic cover
- an air flow plastic bit (kinda fell out)

I was indeed correct, one of the bushing was in two pieces.
All easy to get out. Only thing that had me stumped was the detaching the accelerator cable from the bar. Eventually worked out you just push it through.
Gave it a clean. New bushings. Greased up and put back in. Putting the accelerator cable back in again very difficult.

Hope this helps
Ben