Diff Driveshaft Alignment with Side Gears

[Hethel_Haus]

I am in the process of installing a rebuilt diff. into my Plus 2 and am noticing some troublesome alignment issues. The unit was rebuilt by others with a Quaife LSD. I trial tested the driveshafts before pressing them home into the aluminum carrier which is brand new from TTR. On the LH side, the driveshaft appears to fit nicely centered in the new oil seal. On the RH side however, the shaft is not centered in the seal. The fit at the bottom fits tight but there is a noticeable gap between the shaft and the seal at the top. I had some .065 wire and it slid thru the gap quite easily. I checked an old oil seal and I measured the ID to be approx. 1.231 inches and against the very tip of the oil seal at 1.125 inches. That gives a max. lip deformity of 0.053 inches which is well below what I measured with the test wire. It would seem that oil will pass quite easily past the top of the seal, let alone whether the new shaft would press home with a new bearing into the housing without galling.

Attached are some photos which depict what I am running into. There does not appear to be any adjustment for centering the diff but in one book that I read, it looks like there might be some possible misalignment potential if the Quaife flange boltup to the crown wheel is not accurately centered before torquing down the bolts (Part #RB-20).

Sorry if this is confusing but ask away with your questions or solutions. Whatever, this will not be going back into the car anytime soon

Quaife LSD

RB-20 Bolts

Bottom Oils Seal Fit

Top Oil Seal Gap - 0.065" +/-

[rgh0]

My guess is the most likely cause is a machining error on the aluminium diff housing. Careful measurement should reveal what's wrong

cheers
Rohan

[promotor]

How does the driveshaft into the oil seal look if you fit the an old Lotus casing, presuming you have access to one?

On the new casing, it might show something meaningful if you measure from the casing flange mounting face to the bottom of either oil seal bore with the seals removed.