For those with E46 M3 differentials that have STRIPPED the side mounting hole (caused from driving around with a loose bolt), one repair is to drill it out and re-tap the hole to M16 (from the original M14x1.5).
Rogue Engineering's bushing "Fix" is our RE.484
urethane subframe bushing, modified to accept the appropriate sized M16 x 2 bolt (included).
Installation of this requires removal of the differential anyhow, so the new subframe bushing can be installed.
Included in the kit:
- Specially modified RE.484 differential bushing (for subframe)
- M16 x 2 bolt, 65mm length
- M16 tap (optional)
- M14 drill (optional)
Required tools for differential modification not included:
Modifying the Bolt Hole
- Removal of the differential is required to modifying the bolt hole accurately.
- Once the differential is removed, use an end of a screwdriver to determine the depth of the hole. Using a piece of tape, you can now mark the M14 drill (not included) to determine how deep you need to drill to clear the hole. Yes, you are drilling with an M14 drill to tap for an M16 bolt. Drilling with the M14 drill bit allows for the correct amount of material required to allow for threads to be cut by the tap. If you drill the hole too big, the threads will be too shallow and the bolt will not hold sufficiently. If you drill the hole too small, you will not be able to tap accurately.
- Once the bolt hole is sufficiently drilled, you can start tapping the hole with the required M16 x 2mm tap (not included). Marking the tap with tape will show you how deep to tap the hole. Using tap fluid and cleaning out the hole during the process will help.
- Once the tapping is completed, clean out the hole (compressed air blower is recommended), and test the new bolt in the freshly cleaned, tapped hole (by hand). Using the aluminum portion of the RE.484 bushing will give you the idea that sufficient depth had been reached.
- Factory recommended torque spec of this bolt (when it was an M14 bolt) is 128 ft lbs. We do NOT recommend this torque spec! We recommended that Loctite 262 (red) be used on a few of the threads on the end of the bolt and to torque no more than 75 ft lbs. Because these threads are newly cut and NOT hardened like produced in production, they do not have the same strength as stock.
The M16 tap and M14 drill bit are NOT common sizes found at Home Depot or Lowes. We offer them both as a convenience to our customers. Will you even need them again? Probably not.