Rear wheel bearing fit

[benymazz]

All,

Going to do rear wheel bearing replacement while my Elan is up on stands for engine replacement. One side was starting to give the telltale rumble during cornering so there's no point in taking it to the brink of failure. I'm going to do both sides as good PM. I've never done this job before but I have read the appropriate literature (forums, Buckland's book, the Lotus manual) and done just about every other job that can be done on the rear end. The only thing that isn't clear to me is that there is some mention of "excessive slop" between the bearing and the alloy casting, implying that there is an amount of slop that non-excessive and thus acceptable. This doesn't seem quite right to me but I figured it was important to ask for a clarification and dimensions if possible: should the bearing be an interference fit in the housing, and if so, by approximately how much?

FYI - I do have the appropriate tools for the job. I have a puller that is specially made for the bolt-on hubs that pulls evenly on the hub so as to not distort it. I also have a shop with a press that I can take the housing to for bearing removal and re-installation.

Thanks,
Ben

[CBUEB1771]

The inner and outer bearings have a light to moderate interference fit in the hub carrier. I don't have a dimension but it is likely of the order of five ten thousandths of an inch. The common practice is to heat the hub carrier a bit to minimize the possibility of the outer races picking up any aluminum on the way in or out. Without interference, the outer races are very likely to spin in the hub carrier.

[Mike Ostrov]

Hi, Ben. Having done 9 upright bearing replacements, both issue 16 and 18, happy to talk you through my process. Just give a ring: Mike Ostrov 510-232-7764 Richmond, CA near Berkeley and 15 minutes from Fantasy Junction.

[CBUEB1771]

I finally had a chance to measure a set of new bearings and a pair of new rear hub carriers from TTR. My skills with telescoping gauges are suspect but it looks like the diametral interference between the bearings and the hubs carrier bores is between 0.002" and 0.003". I have heard of plastic deformation of the hub carrier bores over time but I can't believe that some degree of interference fit is not needed.

[nmauduit]

interference fit for small diameters like a hub is typically in the order of 1/1000 to 2/1000 of diameter (i.e. 2 to 4 thou for a 2 inch bearing), so that sounds right.