DIY: Audi B7 RS4 Rear Differential Mount

[BenSti]

I already had done this before I did the DIY, however I had to go back and put loctite on some of the bolts so I figured I would do a DIY while I was at it. This is for the Apikol mount, not sure if there are any others or if they are any different if there are others. Keep in mind that this will look slightly different then what you will see on a stock car.

Time: 15-30minutes
Cost: ~$240

Tools:

• 3/8" Ratchet
• 8mm 3/8" Drive Allen Socket
• 16mm 3/8" Socket
• 16mm Box Wrench
• Blue Loctite

First off, get the back of the car up in the air. Ramps work perfectly for this.

1. Get under the car and break loose all 3 of the Allen bolts. They shouldn't be that tight. Once they are loose, remove them all. The diff will drop down a little bit, that is fine.





2. Pull down on the front of the diff to get room for the top bolt. Place the closed end of the box wrench on the nut of the bolt. Use the wratchet on the inside. Break the bolt loose and then remove it all the way allowing for the mount to come out.




3. Put in the new mount and reinsert the bolt. Tighten down the bolt until it is snug and allows for some movement of the mount.

4. Lift the differential back up and thread in one of the Allen bolts without loctite. Once it is in, tighten down the top bolt and then remove the allen bolt.

5. Crank down on the top bolt to get it really tight. You don't need to strip it, but you don't want any play.



6. Lift the diff back up again and thread in all 3 bolts with a moderate amount of loctite on each one. Tighten them down, not super tight, but tight, I would say 25lb/ft probably if you wanted to use a torque wrench.



7. Lower the car, clean up, and enjoy the new mount!

[NY07RS4]

In two of those pics it looks like you inadvertantly pulled the polyurethane bushing out of the mount a bit. You want to make sure it is flush in the casing at all times - including during install. It looks flexed in the pic above.

Good DIY though, thanks for taking the time!

[Zac]

Your tearin up the DIY's. Nice work!

[BenSti]

Hmm, looking at the photo, I see what you mean. It hasn't been pulled out at all, it just looks that was in the photo due to the shadow. The mount is nice and square to the car and fits perfectly. I am pretty sure it is correct, but if someone else wants to take a picture of theirs, we can compare it and see if it is off.

[PolishPete]

Thanks for the DIY.

[rs4 tony]

In two of those pics it looks like you inadvertantly pulled the polyurethane bushing out of the mount a bit. You want to make sure it is flush in the casing at all times - including during install. It looks flexed in the pic above.

Good DIY though, thanks for taking the time!

+1 doesnt look like mine....

[BenSti]

Hmm, I will take a look at it later and see if it can be adjusted.

[NY07RS4]

Hmm, looking at the photo, I see what you mean. It hasn't been pulled out at all, it just looks that was in the photo due to the shadow. The mount is nice and square to the car and fits perfectly. I am pretty sure it is correct, but if someone else wants to take a picture of theirs, we can compare it and see if it is off.

It may have just been pulled out during install while the diff was flexed and the bolts weren't secured all the way. Once you finished tightening everything down it probably put everything back in place correctly.

For reference, the pics I'm referring to are as follows: Pic 1 - bushing is not flush with cast. 2nd pic under number 2, looks good and flush. Pic under #5 = good. Pic under #6 = same as pic under #1.

[rs4 tony]

It may have just been pulled out during install while the diff was flexed and the bolts weren't secured all the way. Once you finished tightening everything down it probably put everything back in place correctly.

For reference, the pics I'm referring to are as follows: Pic 1 - bushing is not flush with cast. 2nd pic under number 2, looks good and flush. Pic under #5 = good. Pic under #6 = same as pic under #1.

hey do you have a pic of your busted rear diff mount?

[RAudi Driver]

Ben, your bushing does look cockeyed and it doesn't appear to be the shadowing.

Also, it appears that you got the old Apikol diff mount. Their new ones are cnc'd aluminum with their name stamped into it.

[rs4 tony]

+1^
get it checked out. better safe then sorry.

[BenSti]

I am going to take a look at it today. I haven't noticed any issues, but I will make sure everything is centered.

When I went up to 034 they did not have any of the new mounts in stock. I didn't really care as the cast one looks more OEM anyways.

[SoCalS4Avant]

Great work, Ben. This and your other DIY's have been copied over to the B6/B7 S4/RS4 DIY/Tech forum.

[SeKKeY]

any difference in feel after installing this mount?