Mk5 IRS Installation, offset bushings

[CW_MI]

Getting ready to install the rear IRS differential in a Mk5 coupe and the rear bushings are offset, the manual doesn't mention this, and the pictures show a centered bushing. Are these incorrect ? I googled the part number and it referenced a Factory Five part number.

[michael everson]

Yes, its correct. I just installed a set. I put the hole up on both and then rotated until the bolts went. Not a great fix because it's nearly impossible to rotate once installed.
Mike

[CW_MI]

Yes, its correct. I just installed a set. I put the hole up on both and then rotated until the bolts went. Not a great fix because it's nearly impossible to rotate once installed.
Mike

Wow, this makes no sense to me. Myself and fellow forum member 8secDuster (usually in the coupe forum) installed the center section without the rear bushings, just to see if the rear attachment holes were offset requiring the need for the offset bushing. The center section is positioned so that we could basically slide the front attachment bolts in and out by hand, and looking into the rear mounts, the holes in the center section are pretty my directly centered in the chassis holes. Trying to use the offset bushing when it isn't needed seems like it's just going to cause issues installing the bolts, its like creating a problem when there isn't one.

I think I'm going to try and locate some bushing that have the hole in the center. There is no reason to have to struggle with the offset ones.

[Indy Shu]

I recently helped with installing these and it's really not that big of a deal. We put the holes to the bottom and were having a hard time getting one of the bolts to go in. We rotated one bushing just a little and were able to get it in. You have to rotate the diff up out of the way a little to get access to the front side of the bushing in order to move.

[2nd2none]

I'll be installing mine within the next week, hopefully, and was already reading ahead and it does mention the offset bushing. Page 112 of the build manual.
225390

[CW_MI]

I'll be installing mine within the next week, hopefully, and was already reading ahead and it does mention the offset bushing. Page 112 of the build manual.
225390

Thanks for posting this. My page 112 is completely different. When did you download your manual ?

[2nd2none]

Its Revision 1P from December 2025

[edwardb]

Yep, now see that in the build manual. Also revision 1P from this past December. I can see where that might help with the installation. Seems it would also change the pinion angle slightly if left in the bottom position as shown in the manual.

[CW_MI]

Its Revision 1P from December 2025

Okay, makes sense. I downloaded mine right after making my order in late November.

[CW_MI]

Yep, now see that in the build manual. Also revision 1P from this past December. I can see where that might help with the installation. Seems it would also change the pinion angle slightly if left in the bottom position as shown in the manual.

Agreed. Along with making it more difficult to run the bolts through, if everything lines up. Seems like it's creating a problem when there isn't one.

[2nd2none]

Agreed. Along with making it more difficult to run the bolts through, if everything lines up. Seems like it's creating a problem when there isn't one.

I wonder what brought about this change to the offset bushing. Just spent the past couple hours trying to get this done. Fronts lined up with temporary tapered bolts and I just got the rears down in the bushing. Such a tight fit and when lowering it down, the diff want to grab the hole in the bushing and yank it down with it. Rear diff holes look about centered in the mount buuuut these dang offset bushings are stopping me. Time to lift it up and out and start over after rotating the bushings

[CW_MI]

I wonder what brought about this change to the offset bushing. Just spent the past couple hours trying to get this done. Fronts lined up with temporary tapered bolts and I just got the rears down in the bushing. Such a tight fit and when lowering it down, the diff want to grab the hole in the bushing and yank it down with it. Rear diff holes look about centered in the mount buuuut these dang offset bushings are stopping me. Time to lift it up and out and start over after rotating the bushings

Kind of what i thought would happen. I don't even want to try finishing the diff installation until i get the 2128 centered bushing. I'm going to try calling Factory Five again, and see if they have any left. If not, i'll order them from Energy Suspension and wait the 4 to 6 weeks.

[CraigS]

Maybe I am off base since it's been about 8 years since I did my IRS retrofit in my MkII but...I had trouble getting those bolts in also. And I remember several threads about the problem. As best I remember the holes in the frame are a bit wider apart than the holes in the diff. So the fix has been prybars and ratchet straps to move the diff to get the bolts lined up. So maybe put the eccentrics in so the holes are further apart????

[Cobra roadster]

Hi guys. I am waiting to have mine delivered in March. What does Factory 5 say about this.

[CW_MI]

Hi guys. I am waiting to have mine delivered in March. What does Factory 5 say about this.

Great question. I sent and email , and left a message a week ago. If i get a reply, i'll post it.