What went wrong with rear diff bushing install? Pic attached

[janseny7]

Took my 2015 F82 to a local Indy shop specializing in BMW. Original rear rubber bushing was cracked so I ordered the 2018 New OEM polyurethane and brought to them to install. Part#33179503009

Mechanic called and said he got it in but it’s “way too soft” and the rear diff will move around too much. He also said he could pull it out with a screwdriver. Here is a picture for reference. It looks squished and torn up just from the install.

What do you all think the problem is? Did I order the wrong bushing? I know it’s not my year but everything I read online led me to believe the new poly bushing would fit. Or was it installed incorrectly?

We are ordering the original OEM rubber bushing from local dealership and will be here tomorrow. I’m not happy about using the original rubber one again even though it’s new.

Unfortunately I need my car and don’t have time to wait around until Monday or Tuesday to order a better bushing kit like powerflex etc.

[M3SQRD]

There are no pictures.

Most people replace diff bushings with aftermarket stiffer bushing as well as the dual mounting bracket to practically eliminate diff torsion as it’s putting down power/torque. However, I have not heard of anyone having an issue with replacing original bushings with revised stock bushings. The fact that he can pull the pushing out with just a screwdriver is scary and suggests something more than just your bushings are your problems. BimmerWorld’s website show the part you ordered is a diff bushing.

[janseny7]

Originally Posted by M3SQRD

There are no pictures.

Most people replace diff bushings with aftermarket stiffer bushing as well as the dual mounting bracket to practically eliminate diff torsion as it’s putting down power/torque. However, I have not heard of anyone having an issue with replacing original bushings with revised stock bushings. The fact that he can pull the pushing out with just a screwdriver is scary and suggests something more than just your bushings are your problems. BimmerWorld’s website show the part you ordered is a diff bushing.

Picture attached. The old bushing was not taken out with a screwdriver. He was saying that about new bushing he put.

[M3SQRD]

Originally Posted by janseny7

Picture attached. The old bushing was not taken out with a screwdriver. He was saying that about new bushing he put.

Yes - new bushing can be pulled out with a screwdriver. This suggests that there may be an issue beyond just a bad original bushing. The bushing OD is larger than the hole OD in the diff bracket and, therefore, requires a press of some kind (whether pressed/pulled in on the car or a standard upright press if done out of the car) to install the bushing in an interference fit hole. Did the tech tell you how much force (estimated) was required to press in the new bushing? Either you were sent a bushing that was improperly manufactured or there’s a problem with your diff housing.

Was the bushing damaged during install at 9-10 o’clock in the pic?

What did the old damaged bushing look like? Was it easy or hard to remove the old bushing?

[janseny7]

Originally Posted by M3SQRD

Yes - new bushing can be pulled out with a screwdriver. This suggests that there may be an issue beyond just a bad original bushing. The bushing OD is larger than the hole OD in the diff bracket and, therefore, requires a press of some kind (whether pressed/pulled in on the car or a standard upright press if done out of the car) to install the bushing in an interference fit hole. Did the tech tell you how much force (estimated) was required to press in the new bushing? Either you were sent a bushing that was improperly manufactured or there’s a problem with your diff housing.

Was the bushing damaged during install at 9-10 o’clock in the pic?

What did the old damaged bushing look like? Was it easy or hard to remove the old bushing?

Here is the old bushing. The tech did not say anything about how hard it was to get the new one in. He did use a press with the new bushing and the tears/cracks makes me wonder if he pressed it incorrectly. If that’s even possible. He did not mention if it was damaged during install but obviously it was.

[theweebabySeamus]

I'd probably look for a new shop before I looked for a new bushing. Looks like an install issue to me.

My shop installed the same issue with no issues. Do I wish I'd gone with a stiffer bushing, as I now have a PF dual mount bracket and PF purple bushings sitting on my floor? Different story.

[janseny7]

The more I think about it the tech didn’t use the right tool or installed it incorrectly causing the tear. Although it’s the new OEM bushing it should still fit. And when he said it had too much play in it and diff was moving around too much it’s probably because the bushing was tore during install.

[janseny7]

Originally Posted by theweebabySeamus

I'd probably look for a new shop before I looked for a new bushing. Looks like an install issue to me.

My shop installed the same issue with no issues. Do I wish I'd gone with a stiffer bushing, as I now have a PF dual mount bracket and PF purple bushings sitting on my floor? Different story.

I would definitely go with a new shop but I can’t take it anywhere until they fix it so I’m kinda screwed.
I don’t know anything about installing bushings from what I’ve read online online you can mess up a polyurethane bushing by not aligning it properly, using the right amount of lubrication or pressing it too hard

[hC1001]

Maybe they didnt lube it for installation?

Correct way to install is to lube the diff carrier bushing hole and bushing with circolight. Its a temporary lube that is slippery when wet but dries and becomes no longer slippery. Its suppose to be pressed in from the rear towards the front. The bushing orientation is correct in the pic. The flatter side with part#s are suppose to be seen from rear of car.

I can only speculate the bushing got damaged during pressing in because there was no lube used. It looks like pieces of the sides got caught and ripped off and is stuck between the bushing and diff hole wall causing the left side to roll back.

[hC1001]

I also wanted to add that the BMW instructions also say the poly bushings shouldnt be used on your car. They only recommend the rubber one on all cars before 7/2016. Anything after will need to check what rear subframe is installed on the car. So BMW used different subframes over the years and they specifically mention compatibility issues with specific subframes. I know a lot of ppl have installed the poly ones on earlier cars without issues but no one ever mentions BMW instructions on the compatibility of the subframes. Im guessing it might have to do with the carbon fiber driveshaft switch to steel. Maybe the poly bushing caused more NVH, i dunno. I went with powerflex so i cant comment if its fine to use the poly one on earlier F8X cars.

This is from the TIS:

Note:
For vehicles up to 07/18, the rubber mount with the BMW part number 7 852 495 is to be installed in connection with the rear axle support 2 284 640. Only the rubber mount with BMW part number 7 852 495 may be used for vehicles up to 07/16.

For vehicles from 07/2018, the polyurethane rubber mount with the BMW part number 8 094 690 is to be installed in connection with the rear axle support with the BMW part number 8 097 478. The polyurethane rubber mount with BMW part number 8 094 690 is used as a replacement from 07/16.

Before removing and installing the rubber mount, check which variant is or will be installed!

[M3SQRD]

Your other thread about this topic shows it was improperly installed and damaged during the press fit.

hC1001 information is extremely useful and suggests the wrong bushings were potentially used in your diff and that’s why it’s so easy to remove the new bushing. Installation damage certainly isn’t helping.

[M3SQRD]

Originally Posted by hC1001

I also wanted to add that the BMW instructions also say the poly bushings shouldnt be used on your car. They only recommend the rubber one on all cars before 7/2016. Anything after will need to check what rear subframe is installed on the car. So BMW used different subframes over the years and they specifically mention compatibility issues with specific subframes. I know a lot of ppl have installed the poly ones on earlier cars without issues but no one ever mentions BMW instructions on the compatibility of the subframes. Im guessing it might have to do with the carbon fiber driveshaft switch to steel. Maybe the poly bushing caused more NVH, i dunno. I went with powerflex so i cant comment if its fine to use the poly one on earlier F8X cars.

This is from the TIS:

Note:
For vehicles up to 07/18, the rubber mount with the BMW part number 7 852 495 is to be installed in connection with the rear axle support 2 284 640. Only the rubber mount with BMW part number 7 852 495 may be used for vehicles up to 07/16.

For vehicles from 07/2018, the polyurethane rubber mount with the BMW part number 8 094 690 is to be installed in connection with the rear axle support with the BMW part number 8 097 478. The polyurethane rubber mount with BMW part number 8 094 690 is used as a replacement from 07/16.

Before removing and installing the rubber mount, check which variant is or will be installed!

I just looked online at PowerFlex diff bushing and the same bushings are used regardless of the MY of f8x. Also, the p/n’s above don’t agree with what PowerFlex/BimmerWorld list as oem bushings which start with 3317…

[theweebabySeamus]

FWIW, my 2015 with an OE poly doesn't look like that at all. I DO have increased clunking, which started several months after the install, but I believe it's probably damage to the front bushings as the rear looks fine.

[hC1001]

Originally Posted by M3SQRD

I just looked online at PowerFlex diff bushing and the same bushings are used regardless of the MY of f8x. Also, the p/n’s above don’t agree with what PowerFlex/BimmerWorld list as oem bushings which start with 3317…

I just checked this.
The part# for the rubber one seems to be correct. https://www.ecstuning.com/b-genuine-...r/33177852495/
The part # for the poly one listed in the TIS was superseded by the the 009 part. https://www.pelicanparts.com/More_In...7-8-094-690-M9

Its also possible the bushing the OP got is wrong too. Cant really read the part# off the pic. I wish i could see one in person. To me the bushing looks like foam material on the outer part and rubber/poly inner core. it looks like it rips and squeezes like foam too from the OPs pic... maybe its neoprene foam and not poly?

[theweebabySeamus]

Originally Posted by hC1001

I just checked this.
The part# for the rubber one seems to be correct. https://www.ecstuning.com/b-genuine-...r/33177852495/
The part # for the poly one listed in the TIS was superseded by the the 009 part. https://www.pelicanparts.com/More_In...7-8-094-690-M9

Its also possible the bushing the OP got is wrong too. Cant really read the part# off the pic. I wish i could see one in person. To me the bushing looks like foam material on the outer part and rubber/poly inner core. it looks like it rips and squeezes like foam too from the OPs pic... maybe its neoprene foam and not poly?

The updated BMW bushing is not full poly, it's poly exterior with a foam core. Poly to resist tearing and foam for NVH, I'd assume.

[hC1001]

Originally Posted by theweebabySeamus

FWIW, my 2015 with an OE poly doesn't look like that at all. I DO have increased clunking, which started several months after the install, but I believe it's probably damage to the front bushings as the rear looks fine.

I doubt its the 4 front diff support bracket bushings. Mine were still good after 100K miles but i replaced them anyways with PF. Usually clunking right after diff work is from the driveshaft nut if it was removed during the work. Other things to look at is the tranny mounts(more likely) and then engine mounts.

I would try tranny mounts first.

[M3SQRD]

Originally Posted by hC1001

I just checked this.
The part# for the rubber one seems to be correct. https://www.ecstuning.com/b-genuine-...r/33177852495/
The part # for the poly one listed in the TIS was superseded by the the 009 part. https://www.pelicanparts.com/More_In...7-8-094-690-M9

Its also possible the bushing the OP got is wrong too. Cant really read the part# off the pic. I wish i could see one in person. To me the bushing looks like foam material on the outer part and rubber/poly inner core. it looks like it rips and squeezes like foam too from the OPs pic... maybe its neoprene foam and not poly?

I agree with you on the material composition of the bushing. Other thread shows you need a special tool that pulls in from the center, not pressed in by the OD, and a metal cylinder is used to stabilize the bushing OD as it is pulled into the subframe. OP’s bushing was pressed in, hence the damage to the OD of the bushing and its lack of radial preload from the lack of a proper interference fit (pulls out easily with a screwdriver).

Where I’m confused is with the TIS and the pre 7/2016 and post 7/2018 and 7/2016-7/2018 having potentially different subframes and/or bushing yet PowerFlex uses the same bushings regardless of MY.

[mapster37]

Looks like improper installation. There is a special tool for that bushing install.

[janseny7]

Originally Posted by M3SQRD

I agree with you on the material composition of the bushing. Other thread shows you need a special tool that pulls in from the center, not pressed in by the OD, and a metal cylinder is used to stabilize the bushing OD as it is pulled into the subframe. OP’s bushing was pressed in, hence the damage to the OD of the bushing and its lack of radial preload from the lack of a proper interference fit (pulls out easily with a screwdriver).

Where I’m confused is with the TIS and the pre 7/2016 and post 7/2018 and 7/2016-7/2018 having potentially different subframes and/or bushing yet PowerFlex uses the same bushings regardless of MY.

I bought the bushing from 7/18 on. Apparently there two different versions of the poly. Here is a pic after they pulled out the bad install.

[theweebabySeamus]

Originally Posted by hC1001

I doubt its the 4 front diff support bracket bushings. Mine were still good after 100K miles but i replaced them anyways with PF. Usually clunking right after diff work is from the driveshaft nut if it was removed during the work. Other things to look at is the tranny mounts(more likely) and then engine mounts.

I would try tranny mounts first.

Did the trans mounts a month ago, helped a little. I had my turbos replaced so next thing is rechecking torque specs on the engine mounts.

[M3SQRD]

Originally Posted by janseny7

I bought the bushing from 7/18 on. Apparently there two different versions of the poly. Here is a pic after they pulled out the bad install.

OEM has two different versions but aftermarket bushing have only one. Unlike oem, aftermarket bushings can be pressed in.

[janseny7]

Originally Posted by M3SQRD

OEM has two different versions but aftermarket bushing have only one. Unlike oem, aftermarket bushings can be pressed in.

That’s why I didn’t fight him too much about messing up the poly bushing. I couldn’t say with 100% certainty that both updated OEM poly bushings would fit.