Rear Hub Rebuilding - TR6

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I like a challenge - and hearing almost all Triumph mechanics say that rebuilding hubs is something better left to qualified shops was a challenge I couldn't refuse. Sort of an ego thing - plus I wanted to see what the rebuilders do that requires $200 of labor costs!!! Besides after repairing and repainting the frame, I started detailing all of the other parts. I painted the upgraded rear shocks with POR-15 and powdercoated the differential, brake drums, axles, trailing arms and suspension springs. I wanted to powdercoat the rear hubs but if I bought rebuilt hubs then I would have to paint them. That settled it - I will rebuild the rear hubs.

Cost savings may or may not be a reason to attempt a rear hub rebuild. The Roadster Factory sells a rebuilt rear hub for $299 which includes new bearings, universal joint, wheels studs, and a fresh coat of paint. The costs (prices may have changed) per hub for the individual rebuild parts are :

$45.95 - Bearing Kit
$18.95 - Universal Joint
$11.80 - Wheel Studs
$76.70 - Total

You will save $222.30 per hub if you rebuild it yourself BUT if you bend or damage the hub flange then you will need to spend an additional:

$193 - Hub Flange (Victoria British) I had to buy one - read on

and if you accidently reduce the bearing end float to below 0.002 inch

$2.95 - Extra Spacer

This project requires special tools which you may have to buy, borrow, or make. The Haynes and Bentley manuals list three special tools numbered S.109A (hub puller), S.318 (holder), and S.4221A16 (bearing puller) as well as a torque wrench and a dial indicator gauge. Tool S.4221A16 can be replaced by a large three leg puller and I didn't use tool S.318. Other required tools are bearing drivers and a moderately thin 2 1/8" wrench. You may need a high-speed rotary tool with a cut-off wheel to cut the bearing races (I did).

Most projects I have undertaken are usually straightforward having only one or two difficult steps. This project was different. There were one or two simple steps but the rest of the project was somewhat of a pain in the A$$. Conceptually this isn't a difficult project as there are very few parts and only one step requires a specific measurement (setting the bearing float). This project was difficult because parts did not easily separate - even when I used the special tools. But once everything was disassembled and cleaned, the reassembly process was straightforward.

After looking at the shop manual/catalog diagram and reading the shop manuals procedures, I didn't anticipate any problems after removing the hub flange. A standard rebuild of the hubs only requires two bearings, two grease seals, a collapsible spacer, and a Nylock nut.

The stub shaft is tapered and mates with a similar taper in the hub flange. This is similar to how the front stub axle fits into the vertical link, however you cannot separate the stub shaft from the hub flange as you would the front stub axle from the vertical link. The idea that the stub shaft and hub flange would easily separate is incorrect. Because of the angle of the taper, the flange and hub are extremely difficult to disassemble and easy to damage if improperly attempted. This is why the special hub pulling tool is required. Most machine shops will try to convince you that they can put the hub assembly in a press, support the flange by its edges, and press the stub shaft out. Chances are very good that they will bend or warp the flange before the stub shaft is pressed out.

OOPS!! - Hub flanges can be damaged even when using a hub puller. If you look at my "build a hub puller" page, you may notice that I wrote "It Works". On that particular hub it worked too well - the flange broke off just above the outer bearing race - (this demonstrates how much pressure is applied by the screw). The break was so clean that I didn't notice it at first. I couldn't get the stub axle out of the bearing housing because the bearing, stub axle, and remaining flange piece kept everything in place. It was then I realized what happened, part of the flange was so tightly bound to the axle that the flange broke instead of separating from the axle. The picture below shows a brand new flange on the left and the broken flange on the right. Using the new flange as a guide, the yellow arrow points to the portion that broke off and remained in the bearing housing. It is difficult to see in the photo below but the break is so clean (flat) that I didn't notice it at first. I wanted to salvage the stub axle and housing so I took the hub to a machine shop and had them press the axle out of bearing housing. Since the flange was already removed, they were able to support the bearing housing by its mounting tabs and use heat and their largest press to remove the axle (I think it was a 90 ton press - this machine shop does work for local shipyards and was recommended by another hobbyist). They charged me about $35 - I thought it was a bargain. I bought a brand new flange from Vicky-Brit and continued with the rebuilding process. The other hub flange came off without any problems.

After I removed the flange disassembling the rest of the hub was straightforward. The only exception was the inner cone of the inner hub bearing which I had a hard time removing. None of my standard bearing removal tools could remove the inner cone/race because it was tightly bound to the stub shaft. I used a rotary cutting tool to cut the inner cone/race. After removing the race, I cleaned all of the parts, inspected for wear and tear, and powdercoated the hub. The image below shows all of the parts ready for reassembly.

Reassembly was proceeding smoothly until I reached step 14 in the Haynes manual which states "Replace the stone guard bearing spacer, the inner cone of the inner hub bearing and a new collapsible spacer onto the stub shaft and fit the rectangular key into the stub shaft." The inner cone of the inner hub bearing would just start onto the stub shaft before it would bind. Trying to lightly drive the bearing using a piece of appropriately sized pipe was unsuccessful. I thought it would require too much force to seat the bearing. Concerned that I could damage the bearing if I tried to drive it on, I removed the bearing and all of the other parts from the stub shaft. I polished the stub shaft with emery cloth, washed and dried the shaft, and test fitted the bearing. I repeated this process until just a slight amount of driving with the pipe would fully seat the bearing onto the stub shaft. I suspect that the bearing should slip onto the shaft without any driving at all but the manual was not clear. I opted to leave just a very slight friction fit. By very slight I mean that the bearing race should not be so tight that an extraordinary amount of force would be required to move it. Step 18 of the Haynes manual reads "It will now be necessary to reset the bearing end float . . . ". Of the two bearings in the hub, the inner hub bearing is the only which moves when the bearing end float is set. If it is too tight and cannot slide on the shaft then it may be very difficult to properly set the bearing end float. Both stub axles had to be polished to properly fit the bearings.

This photo shows the bearing installed on the stub shaft. I have already packed the bearing with grease and have coated the shaft in preparation for installing the bearing housing. You can see how long the shaft is and why I didn't want to drive the bearing if the fit was too tight. Sorry for the fuzziness of the picture - the photos look fine when I review them using the little screen on the back of the camera but are poor quality when viewed on a regular sized monitor. Time for a new camera or I have to increase the distance from the camera to object.

I used a brass drift to remove the bearing races. The bearing housing was put in a parts washer to remove all of the grease and powdercoated using smoke chrome. Using the brass drift, I installed the new bearing races and put grease in the bearing housing according to the Haynes manual.

A low cost bearing driver! After removing the old bearing from the flange, I removed the bearing cage and bearings leaving just the inner race. When turned upside down, it fits inside the cage of the new bearing and allows you to drive the new bearing on without any damage.

Basic reassembly of the rear hub is easy if you follow the steps in the shop manuals. The final step in the reassembly process is to reset the bearing end float. First tighten the adjustment nut (yellow arrow in the photo) to the stoneguard until it is finger tight. Attach a dial indicator gauge onto the hub flange with the stylus touching the bearing housing flange. Firmly pull the bearing housing as far as possible downwards away from the dial indicator gauge. Use a rocking motion to ensure correct contact of the bearing parts and set the dial to zero. Push the bearing housing towards the dial indicator gauge once more using a rocking motion to ensure correct contact of the bearing parts and this time note the reading on the dial. Slowly tighten the large nut one flat at a time. At each flat repeat the previous operations until an end float reading of between 0.004 - 0.002 inch is obtained and lock the adjustment nut with the nut and tab washer.

I believe you need a 2 1/8" wrench to turn the adjustment nut. You need a fairly thin wrench because there is very little space between the adustment nut and the stub shaft shoulder. I tried using adjustable wrenches but they were too thick to fit into the space. I tried a plumber's wrench but it was too weak and broke before the nut turned. I didn't have a fixed wrench of the proper size and didn't want to try to find one at the tool shops. I decided to make a wrench. This is a picture of the tool I built to set the bearing end float. It is a crude looking tool but worked just fine. I built the wrench using a 3/4" pipe which was 18" in length and some 1/4" thick pieces of sheet steel. I bought some 2" wide by 1/4" thick steel and cut three pieces about 6" long. I welded these together to form the jaws of the wrench and welded some 3/4" pipe to provide a handle about 18" long. Initially the jaws were not wide enough to slip over the nut so I used a hand held grinder and a metal file on the inside of the jaws until the wrench just slipped over the nut.

** You may notice two small pieces of pipe welded to the tool. I wasn't sure if the tool would spread when the load was increased so I welded these pieces of pipe onto the tool. The idea was to put a bolt through the pieces and secure it with a nut to prevent the tool from spreading. This was unnecessary as the tool never even came close to spreading or bending. If you build one of these I recommend making the handle 18" or longer. I was surprised by how much effort was required to turn the adjustment nut - and my handle was 18" long.

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