Tightening rear axel nuts

[Richard Dickinson]

I am replacing the rear axel seals in my BT7. I found a good write-up on replacing bearings and seals on the Austin-Healy 100 Restoration web site, but I can't find any torque specks on thightening the nuts. Should they be just firmed up by hand?

 

[Dave Russell]

Assuming that you are talking about the two large retaining nuts, they should be as tight as you can get them. The nut tension is the only thing that keeps the bearing race from trying to move around in the bearing retainer. It is not a tight fit on the axle. If it moves, there will eventually be a loose fit in the retainer/hub which cannot be corrected. 140 ft lbs of torque would not be too much. You will need to use a good fitting special socket to get it this tight.

The hub to splined adapter self locking nuts should be in very good condition & torqued to 55 ft lbs. A little Loctite wouldn't hurt.
D

 

[Richard Dickinson]

Dave- Thanks for the info, this seems to be a critical adjustment, don't know why it was not covered in the service manual.

RD

 

[Dave Russell]

RD,
You didn't ask, but the amount that the bearing spacer ring sticks out of the hub, usually around .004" is also very critical. This dimension is set by the bearing seating depth in the hub & the spacer ring thickness.

Too much projection & the hub to axle flange joint will not seal. Too little projection, & the bearing will try to move around in the hub. The average paper gasket plus O ring will compress to about .004" which allows a perfect fit. This dimension is set by the bearing seating depth in the hub, the bearing thickness, & the spacer ring thickness.

Sometimes if the bearing is the wrong thickness or the hub/carrier is distorted, there will be less than the .004" projection. Too much projection would mean that the bearing is too thick, or not fully seated in the carrier, or the spacer ring it too thick. Spend some time measuring & checking this relationship.

The whole thing is a PIA but well worth getting right the first time.
D

 

[Richard Dickinson]

Thanks again Dave, it seems the Brits always make things more complicated than they need to be. The only rear axel bearings I have ever replaced were on a '72 Ford pickup and all I had to do was press the old bearing off and a new one on and tap in a new seal. I probably would just leave it alone except the car has been siting for 30 years except for being towed from place when I moved several times. While I've got it dissassembled I'm trying to replace all of the seals and gaskets that I can.