Carrying out a Rear Brake Shoe & Rear Axle Seal Replacement on an MG Midget

Today’s job is an MG Midget rear brake shoe replacement, including bleeding the braking system and replacing the rear axle seals.

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MG Midget Rear Brake Shoe Replacement

MG Midget Rear Brake Shoe and Axle Seal Replacement

In classic car repairs, few things are as crucial as ensuring the vehicle’s braking system operates flawlessly.

Recently, a 1979 MG Midget arrived at our workshop concerning braking issues. Upon thorough diagnosis, we uncovered a dual challenge: leaking rear brake wheel cylinders and compromised rear half-shaft seals. Moreover, this compromised the car’s braking performance and risked further damage if left unattended.

In response, we embarked on a meticulous repair journey. This article chronicles our step-by-step process in addressing these issues, divided into two key sections: the MG Midget rear brake shoe and wheel cylinder replacement and the replacement of the rear half-shaft seals and gaskets.

Join us as we delve into the intricate world of classic car repairs, showcasing the expertise and dedication required to preserve these automotive icons for generations.

Please note that this is not a step-by-step description of performing an MG Midget brake shoe replacement. We have condensed parts of the procedures to make this article shorter.

MG Midget Rear Brake Shoe Replacement
MG Midget Rear Brake Shoe Replacement

A Brief History of the MG Midget

The MG Midget is a classic British sports car with a rich history dating back to the late 1920s. Here’s a brief overview:

Early Years (1920s-1930s):

The MG Midget traces its roots back to the introduction of the MG M-Type Midget in 1929. It was a small, affordable sports car that became popular among enthusiasts for its performance and agility.

Post-War Revival (1940s-1950s):

After World War II, MG resumed production of the Midget by introducing the MG TC in 1945. The TC and its successors, the TD and TF models, continued the tradition of compact, lightweight sports cars that offered an exhilarating driving experience.

The Sprite Era (1958-1979):

In 1958, MG introduced the iconic MG Midget AH Sprite, a joint venture with Austin-Healey. The Sprite and its badge-engineered counterpart, the MG Midget, became immensely popular due to its affordability, nimble handling, and timeless design. Over the years, the Sprite/Midget underwent several updates and iterations, including the MkII, MkIII, and MkIV models.

Later Years and Legacy (1980s-present):

Production of the MG Midget officially ended in 1979, marking the conclusion of an era for this beloved sports car. However, its legacy lives on through countless enthusiasts and collectors who continue to cherish and preserve these iconic vehicles. Furthermore, the MG Midget remains a symbol of British motoring heritage and a testament to the enduring appeal of compact, fun-to-drive sports cars.

Throughout its history, the MG Midget has left an indelible mark on the automotive world, captivating generations of drivers with its blend of performance, style, and character.

MG Midget Rear Brake Shoe Replacement

Replacing the rear brake shoes on an MG Midget is a crucial maintenance task ensuring your vehicle’s safety and performance. In fact, the rear brakes play a significant role in slowing down and stopping the car, making it essential to keep them in optimal condition.

Why Rear Brakes Matter

While often overshadowed by the front brakes, the rear brakes are equally crucial for maintaining vehicle control and stability during braking. Consequently neglecting rear brake maintenance can lead to uneven braking, reduced stopping power, and safety hazards.

Signs That Rear Brake Shoes Need Replacement

Common indicators that your MG Midget’s rear brake shoes require replacement include squealing or grinding noises when braking, reduced brake responsiveness, uneven braking, and visible wear on the brake shoes.

Removal of the Old Parts

Click or tap the image to enlarge and view in full size!

Here, we are removing the rear road wheel from the MG Midget.
Here, we are removing the rear road wheel from the MG Midget.
After removing the two securing screws, we begin to remove the brake drum.
After removing the two securing screws, we begin to remove the brake drum.
In this image, you can see the rear brake drum just before removal.
In this image, you can see the rear brake drum just before removal.
The rear brake drum is heavily contaminated with axle oil and brake fluid.
The rear brake drum is heavily contaminated with axle oil and brake fluid.
The half-shaft seal and wheel cylinder leak badly contaminated the brake shoes.
The half-shaft seal and wheel cylinder leak badly contaminated the brake shoes.
This is the right-hand wheel cylinder, which is leaking from the bottom of the seals.
This is the right-hand wheel cylinder, which is leaking from the bottom of the seals.
We begin removing the old brake shoes by unclipping the top and bottom retaining springs.
We begin removing the old brake shoes by unclipping the top and bottom retaining springs.
In this image, you can see us removing the retaining springs to allow for the removal of the brake shoes.
In this image, you can see us removing the retaining springs to allow for the removal of the brake shoes.
With the retaining springs removed, we can now remove the brake shoes.
With the retaining springs removed, we can now remove the brake shoes.
Here, we detach the trailing brake shoe from the hand brake mechanism.
Here, we detach the trailing brake shoe from the hand brake mechanism.
In this image, we have removed both the brake shoes and moved on to removing the wheel cylinder.
In this image, we have removed both the brake shoes and moved on to removing the wheel cylinder.
The next step is to remove the wheel cylinder by unscrewing the brake pipe union.
The next step is to remove the wheel cylinder by unscrewing the brake pipe union.
With the removal of the securing clip and brake pipe union, the cylinder can be removed.
With the removal of the securing clip and brake pipe union, the cylinder can be removed.
With the brake shoes and wheel cylinder removed, It was time for a thorough cleaning with brake cleaner.
With the brake shoes and wheel cylinder removed, It was time for a thorough cleaning with brake cleaner.
This image shows the brake drum back plate, and half-shaft flange thoroughly cleaned and ready for the next step.
This image shows the brake drum back plate, and half-shaft flange thoroughly cleaned and ready for the next step.

Fitting the New Parts

Fitting the new rear brake shoes, retaining springs, and wheel cylinders is the reverse of the removal procedure, with some notable essential caveats.

We used brake cleaner to thoroughly clean the brake drums, hardware, and surrounding components. And we removed any dirt, debris, or brake dust buildup that could affect braking performance.

We carefully reassembled the brake hardware, springs, and adjusters according to the manufacturer’s specifications.

Also, we ensured all components were securely in place before proceeding with the reattachment of the brake drums.

Click or tap the image to enlarge and view in full size!

This image shows the cleaned backplate and hub assembly ready to fit the new parts.
This image shows the cleaned backplate and hub assembly ready to fit the new parts.
One of the old brake wheel cylinders (Right-Hand Side) with the dust covers folded out.
One of the old brake wheel cylinders (Right-Hand Side) with the dust covers folded out.
The left-hand side brake shoes and retaining springs which will soon be replaced.
The left-hand side brake shoes and retaining springs which will soon be replaced.
New MG Midget brake shoes, springs, drum inspection hole plug, wheel cylinder and securing clip.
New MG Midget brake shoes, springs, drum inspection hole plug, wheel cylinder and securing clip.
This image shows the old brake drum with the old inspection plug still attached.
This image shows the old brake drum with the old inspection plug still attached.
The new bleed nipple is removed to aid the installation of the securing clip.
The new bleed nipple is removed to aid the installation of the securing clip.
The brake wheel cylinder is then installed, and the brake pipe union is screwed in.
The brake wheel cylinder is then installed, and the brake pipe union is screwed in.
In this image, you can see the new brake wheel cylinder securing clip.
In this image, you can see the new brake wheel cylinder securing clip.
In this image, you can see the wheel cylinder securing clip about to be installed.
In this image, you can see the wheel cylinder securing clip about to be installed.
This view of the brake drum backplate shows the wheel cylinder securing clip fully installed.
This view of the brake drum backplate shows the wheel cylinder securing clip fully installed.
At this stage, we fully tighten the copper brake pipe union.
At this stage, we fully tighten the copper brake pipe union.
We now begin the installation of the brake shoes and retaining springs.
We now begin the installation of the brake shoes and retaining springs.
In this image, the mechanic fits the top retaining spring to the brake shoes.
In this image, the mechanic fits the top retaining spring to the brake shoes.
The brake shoes and retaining springs are installed in this image, and the handbrake is reattached.
The brake shoes and retaining springs are installed in this image, and the handbrake is reattached.
Once satisfied with the brake shoe fitment, we reattach the brake drum.
Once satisfied with the brake shoe fitment, we reattach the brake drum.
The next step in the process is to reattach the two brake drum securing screws.
The next step in the process is to reattach the two brake drum securing screws.
With the brake drum securing screws firmly attached, we installed the inspection hole plug.
With the brake drum securing screws firmly attached, we installed the inspection hole plug.
Finally, we give the brake drum face a coating of copper grease to prevent seizing before we reattach the road wheel.
Finally, we give the brake drum face a coating of copper grease to prevent seizing before we reattach the road wheel.

MG Midget Rear Half-Shaft Axle Seal Replacement

After removing the left-hand rear brake drum, we noticed a leak from the rear axle-half-shaft flange. Consequently, the oil leak contaminated the rear brake shoes, necessitating the replacement of the shoes.

We also noticed that the left-hand rear brake wheel cylinder had developed a small leak, but nowhere near as bad as the right-hand side.

Additionally, it was recommended to the client to replace the right-hand side half-shaft seal and gasket as a preventative measure. Furthermore, doing this now reduces further costs as we already have both rear brake drums removed.

In the images below, you can see us removing the axle half-shaft flange securing screw and carefully removing the shaft from the axle tube.

Notably, great care must be taken when removing the shaft from the axle tube to avoid damaging the shaft or the outer bearing.

With this in mind, the old gasket was removed from the half-shaft flange’s mating surface and thoroughly cleaned with a wire wheel brush on the bench grinder.

Finally, a new rubber O-ring seal was fitted to the axle tube flange side after the mating surface was thoroughly cleaned with a wire brush and sprayed with brake cleaner.

Removal of the Half-Shafts, Gaskets and Seals

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Here we can see the axle oil leaking from the axle half-shaft flange
Removing the securing screw on the half-shaft flange with a screwdriver
Removing the securing screw on the half-shaft flange with a screwdriver
Carefully removing the half-shaft from the rear axle tube
Carefully removing the half-shaft from the rear axle tube
This image is a close-up of us withdrawing the half-shaft from the hub & axle tube.
This image is a close-up of us withdrawing the half-shaft from the hub & axle tube.
In this image, you can see the remnants of the old gasket on the half-shaft flange.
In this image, you can see the remnants of the old gasket on the half-shaft flange.
Here we are carefully removing the old gasket from the half-shaft flange.
Here we are carefully removing the old gasket from the half-shaft flange.
We have removed all remnants of the old gasket from the half-shaft flange.
We have removed all remnants of the old gasket from the half-shaft flange.
The O-Ring seal was then removed from the hub on the rear axle.
The O-Ring seal was then removed from the hub on the rear axle.
The hub mating surface was then thoroughly cleaned with the aid of a wire brush.
The hub mating surface was then thoroughly cleaned with the aid of a wire brush.
And now it is time to clean the rear axle hub with a generous amount of brake cleaner.
And now it is time to clean the rear axle hub with a generous amount of brake cleaner.
Any gasket remnants are removed from the half-shaft flange with the aid of a wire wheel brush.
Any gasket remnants are removed from the half-shaft flange with the aid of a wire wheel brush.
Here you can see the half-shaft flange after gasket removal and cleaning.
Here you can see the half-shaft flange after gasket removal and cleaning.

Installing the Half-Shafts

With the half-shaft cleaned, we fitted a new gasket and carefully re-installed the shaft into the axle tube, ensuring the splines engaged correctly. This can be a fiddly process; however, taking the time to gently turn the shaft side to side as it is pushed in usually helps it sit properly.

Once we were happy the shaft had engaged in the rear differential, we installed the new securing screw into the flange. Typically, the securing screw on its own will not fully seat the half-shaft, so we use a little ingenuity to press it in thoroughly.

You can see from the last image below that we have fitted all the wheel nuts on their respective studs. We then gently tighten the nuts, which presses the flange surfaces uniformly together, allowing the flexible sealing paste to seal correctly.

Next, the flange securing screw is re-tightened and torqued to the correct specification.

After replacing seals and gaskets on both sides, we checked and topped up the rear axle oil to the correct level and checked for leaks.

Replacing the rear half-shaft seals and gaskets was carried out after we removed the old brake shoes and wheel cylinder but before we installed the new brake shoes.

Important Notes:

    • Always thoroughly clean both mating surfaces before installing the new gasket and O-ring seal.
    • Care must always be taken when removing and re-inserting the half-shafts into the axle to avoid damage.

Click or tap the image to enlarge and view in full size!

In this image, you can see us fitting the new o-ring seal to the rear axle hub.
In this image, you can see us fitting the new o-ring seal to the rear axle hub.
Here, you can see the new o-ring seal fitted into its locating groove on the hub.
Here, you can see the new o-ring seal fitted into its locating groove on the hub.
The half-shaft is installed in the axle tube with a new flange gasket fitted and sealing paste applied.
The half-shaft is installed in the axle tube with a new flange gasket fitted and sealing paste applied.
In this image, you can see that we have fitted the flange securing screw.
In this image, you can see that we have fitted the flange securing screw.
With some hex nuts acting as spacers, the wheel nuts press the half-shaft home.
With some hex nuts acting as spacers, the wheel nuts press the half-shaft home.

Bleeding the Brakes and Finishing Up

Now that we have completed the MG Midget brake shoe replacement and tackled the half-shaft seal leak, it is time to bleed the brakes.

Bleeding the rear brakes is a critical step in the overhaul process, ensuring the removal of air bubbles or contaminants from the brake fluid system.

This procedure is necessary when replacing rear brake cylinders, as air can enter the system during component removal and installation.

Moreover, bleeding the rear brakes is crucial in maintaining proper brake function and safety.

After we bled the brakes, the MG Midget was taken for a test drive to help bed in the rear brake shoes and to ensure the braking system was operating at peak performance. 

Click or tap the image to enlarge and view in full size!

Before the brake bleeding process, we ensure the fluid reservoir is topped up.
Before the brake bleeding process, we ensure the fluid reservoir is topped up.
The mechanic now adjusts the brake shoes to a point where the drum lightly drags on the shoes.
The mechanic now adjusts the brake shoes to a point where the drum lightly drags on the shoes.
In this image, you can see the left-hand rear brake bleed nipple with the dust cap removed.
In this image, you can see the left-hand rear brake bleed nipple with the dust cap removed.
We then begin bleeding the rear brakes to remove air from the hydraulic system.
We then begin bleeding the rear brakes to remove air from the hydraulic system.
With the brake bleeding hose and reservoir attached, we continue to bleed air from the system.
With the brake bleeding hose and reservoir attached, we continue to bleed air from the system.
In this image, you can see the air in the tube bleeding from the hydraulic system.
In this image, you can see the air in the tube bleeding from the hydraulic system.
With all the air purged from the rear brake hydraulic system, we reattach the road wheels.
With all the air purged from the rear brake hydraulic system, we reattach the road wheels.
The final job on the ramp is to tighten and torque the road wheel nuts to factory specifications.
The final job on the ramp is to tighten and torque the road wheel nuts to factory specifications.

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