Rear Hub Carrier - Rebuild

Having installed the differential and the swing arms, the next step is to build up the rear hubs so they can be mounted to the swing arms. In a previous post, I covered the strip down, cleaning and painting of the rear hubs and their carriers. In this post, the aim is to install the new races and bearings into the bare hub carrier. 

Freshly painted rear hub carrier.

Race Installation

The process of installing the races into the rear hub carrier is the same as that on the front. This being to use an old race with a slit cut into it and then a lump hammer to drift the new races into place. When I began to install the races, it was apparent that they are a slightly tighter fit than those on the front hubs. To aid the installation, I enlisted the help the kitchen oven to heat up and expand the aluminum casting. As I had never done this before, I was worried about applying excessive heat and warping the aluminum parts. I therefore gradually increased the oven temperature in stages starting at 80 degC and testing fitting the races after 30 mins in the oven. I finally ended up setting the oven to 120 degC. Of course with numerical simulation tools like COMSOL Multiphysics (the company which I currently work for), I could have predicted the expansion with a numerical model far more quickly. However, that sounded too much like work and so I chose instead to pick up the hammer and do the physical experiment!

Rear hub carrier in the kitchen oven. Such an odd sight!

With the little extra room, the outboard race easily drifted in. One thing to note, due to the considerable depth at which the outboard race sits, I had to use a pair of old races to drift the new race in. This is shown below, where three races are shown; the new race (barely visible), an upside down old race with a slot cut into it, and another old race sitting on top. It was here where the cut out in the old race really became useful.

Selection of old races being used to drift the new outboard race into place.

As before, when the tone of the impacts change the new race is home. Leaving you with this lovely view.

New outboard race installed.

The inboard race however proved a lot more difficult to install. This is mainly due not being able to impart much force onto the race due to the high sides of the carrier itself. Luckily, I was able to use the top of the hammer to gently drift the race in, with little taps. As a result, this race took almost as much time to install as all of the front races combined. Still, I got the job done in the end and that’s what counts. 

Installing inboard race.

Bearing installation

Now with the new races installed, their respective bearings can be greased up and installed. As with the front bearings, I used plently of grease and made sure to spin the outer casing with respect to the inner casing to work grease into the bearing. 

The final assemly of these bearings into the hub harrier also requires two new grease seals and a pair of spacers, one large and one small, from the donor car (top right in the image below). The order of the parts, from inboard to outbard is as follows: grease seal, bearing, small spacer, a larger spacer (tapped section facing inboard), bearing and finally grease seal. 

Bearing and seals.

To avoid the spacers and bearings falling out as you build up either side of the hub, AK suggests the following method: insert the greased inboard bearing and secure it with its respective seal. Then having turned the hub over insert the small and large spacer in turn. This is then followed by the remaining race and seal. Unlike the front grease seals, both rear grease seals went on without a problem. Just a small tap with a hammer and presto. The rebuilt hub carrier now looks like this.

Seals installed into hub carriers

Rebuilt rear hub carrier. The few marks on the inside of the hub occurred whilst trying to install the new races.

Lower shaft and bearing 

The last part of the rear hub carrier which needs rebuilding are the lower fulcrum bearings. This comprises of two sets of races and bearings connected with a metal tube. These bearings are held in place with an integral grease seal and a large washer/spacer. In a previous post, I have removed all these components, given them a thorough cleaning and inspected them for excessive wear. When I inspected the cleaned parts, they appeared to be in good condition and so decided to reuse them. When reusing bearings, be extra careful to ensure you remember which races belongs to which bearing. Don’t mix races/bearings when re-building the hub as this increases the wear on these parts.

As with all parts to this cobra story, the first step is to layout the require parts. 

Cleaned parts ready for being re-installed.

As I am not replacing these races or bearings, this process is very quick. Slide one of the re-greased bearings onto the fulcrum tube and then pass this through the hub carrier. Then the opposing bearing can be slide onto the other end of the tube, which should now be exposed on the opposing side of the hub carrier. 

Re-greased bearing.

With the bearings in place, there should be a small amount of the fulcrum tube exposed which the spacers/washers can be slid over. Then with this all assembled and placed on its side, a few very gentle taps with a hammer can be applied to ensure the integral seal finds its home. 

Installed bottom bearing.

Final components 

With the hub carrier rebuilt, the final step is normally to install the brake shield and handbrake shoes. However, when I got to this stage I hadn’t ordered these parts yet. I am planning another order with SNG which will include amongst other items the rear brake rotors and pads and the required half shaft spacers/shims. However, before I can order the half shaft shims, I need to have an idea on how many and what size of shims I require to achieve the desired angle. For this, I need to install the hub with its carrier and the half shafts onto the chassis. Therefore, the plan now is to skip past the handbrake assembly and just push the hub shaft through and secure it in place with the ABS ring. I can, with the correct pullers, easily separate these parts again later to easily fit the handbrake mechanism. This is certainly starting to feel like a habit: do the work once, pull it apart and repeat two or three more times. 

With handbrake step omitted, the hub can be slid into the carrier and secured in place with the ABS ring. Some gentle percussive persuasion is required to mate these parts together. 

Assembled hub carrier with hub and ASB ring.

Of course, this entire blog entry is then repeated on the other side, but apart from the inboard race, it’s not such a long task. Before these parts are installed onto the chassis, I have to first assemble the half shafts, and that will be in the next post.