DIY Roller Throw Out Bearing

Many LBCs of the 1920s to the late 1970s used a carbon faced throw out (or "release") bearing to operate the pressure plates on their clutch systems.

Back in the 1930s-40s, virtually all automobile manufacturers used carbon faced release bearings. Yet, not one uses carbon T/O bearings today. Why? Because Carbon T/O's were not designed to withstand the abuse of modern stop and go driving conditions.

If you live in a rural area, or put mostly highway miles on your LBC, carbon can be quite adequate and last the life of the clutch. But If you subject that same carbon T/O bearing to the rigors of modern, daily city driving, chances are that it will fail before the other clutch components are worn.

This problem lead to aftermarket roller T/O bearings designed to replace the antiquated carbon units. Unfortunately, these are hard to find and are prohibitively over priced. Here is my alternative.

[Ed. Note- Moss Motors sells a roller bearing for MGBs, if you don't want to go the DIY route.]

What you will need:

1. 1992-07 throw out bearing from a Honda civic
2. New or used MGB carbon-faced (stock) throw out bearing
3. A little J.B. Weld (or J.B. Quick)
4. Tin snips, Grinder, Drill, Propane torch, pliers, some light gauge sheet metal
5. 4 stainless steel pop rivets & a Pop rivet gun.

Build Procedure

The first step is to disassemble the Honda throw-out (T/O) bearing.

Image bearing06.jpg missing, sorry

Grind the 4 tabs flush, to open up the throwout bearing assembly.

We will only be using the 3 pieces of the Honda bearing shown below:

Honda throwout bearing pieces: ring spring, roller bearing, bearing housing

You can use your old MGB T/O bearing to build the new hybrid roller bearing, since the carbon "face" is going to be removed anyway. If it's in really bad shape, you can buy a new one for the next step.

Next, remove all the carbon from your original MGB throwout bearing) and insert the Honda ring spring, bearing and bearing housing into the MGB throwout bearing. It should fit snug, and the bearing should have about 1/16" up and down, spring loaded movement.

Place the Honda bearing, ring spring, and retainer into stock MGB bearing housing

Below is a side view of the unit with the Honda bearing installed.

Side view of hybrid Honda MGB roller bearing, verify dimensions

My used MGB T/O bearing housing had been ground out a little bit to much when it failed, so I filled this space with JB Weld. If you're not comfortable doing this, you can buy a new stock/OEM MGB throwout bearing.

Filling in worn area on used throwout bearing housing with JB Weld

The retainer clip was cut and fabricated from light gauge sheet metal. I cut the hole to allow for the bearing to move up and down, then made 4 tabs that I bent around the sides of the MGB T/O housing. After it was cut and bent, I heated the clip (3 times) to red hot and quenched it in motor oil to harden it.

Image to%20bearing%20clip.jpg missing, sorry

Finished hybrid MGB-Honda roller bearing, fabricated retainer cover and rivet location

And that's it. The roller bearing is quiet and it doesn't lower engine RPMs when depressed like some carbon bearings do.

Cheers!