View Full Version : Rear hub reassembly (Rotoflex)

07-22-2006, 06:49 PM
I am rebuilding the right rear hub on my 72 GT6 - new bearings and seals. My problem involves reassembling the hub to the drive shaft. Apparently, the PO ran into the same problem because was not driven onto the drive shaft fully, allowing too much play in the bearings, which is the problem I set out to fix.

The hub has internal splines and fits onto the splines on the drive shaft. It is a very tight fit. I was not able to get the hub fully onto the shaft using the hub nut and a 24" breaker bar. I stopped when I became concerned that I would strip the threads on the axle shaft. The instructions in the Bentley manual are to use a "slave" nut, which means, I guess, that you probably ruin it in the process.

Has anyone encountered this particular problem and if so, how did you handle it?

07-25-2006, 06:03 PM
I guess Triumph rear hub bearings never fail - no one offered any advice on my problem. So I embarked on my own solution. Should anyone try to rebuild a rear humb, perhaps they can benefit from my experience with this one.

First, my comments apply only to Rotoflex-equipped cars. The problem, as it turned out, was that the two halves of the hub could not be made to come together by tightening the axle nut. The solution was to remove the inner axle shaft by unbolting it from the Rotoflex coupling. This allows the hub assembly to be placed in a press. It took 5 tons of pressure to bring the two halves of the hub together. It is necessary to do this so that the inside and outside bearngs are the rignt distance from each other. The hub must have end play of .0005" to .0025", i.e., just slightly loose. This distance is set by one or more shims that fit between the two halves of the hub. The illustrations and explanations in the Bentley manual (pages 3-125 through 3-127) are clear, but the method of final assembly suggested isn't workable.

By using a press, you avoid risking damage to the axle shaft threads.

I did not have any shims other than the one that came with the axle. Fortunately, my guess that the manufacdturing tolerances on the new bearings would be very close to the original bearings was right and I did not have to fiddle with machining shims.

Getting the assembled axle and upright back on the car is a perfect PIA. The repair made a huge difference in the handling of the car. I sure hope I never have to do it again.

07-25-2006, 09:04 PM
Rogers, Nice job, sorry I haven't been on the board lately or I could have told you about the press and sent you a picture of the bar, with specs, that is used to put the spring back on. If you end up doing the other side, I will get it to you. I would send the bar but it weights a good bit. Wayne

07-28-2006, 05:51 PM
I just did mine and had a heck of a time figuring out exactly what you did.....a press is what I used.
I have been on the road for a month and haven't been logged in for a while or I would have gladly told you that as well!
Too bad, I have been waiting to contribute something I have learned on my ongoing GT6 rebuild for a long time, and just missed the chance!!
I do better next time.