Maintain Drum Brakes

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17 October 2023
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Drum brakes can function fully if you keep an eye on them : credit: © Jake Shoolheifer
Jake offers advice, tips and tricks while inspecting and replacing brakes and hub seals on his Series I-based Minerva

Need to know

Time: 2 hours
Difficulty: 2 out of 5 
Models: SWB Series vehicles and some early coil-sprung models.
Tools: Wheel brace or correctly sized socket, large screwdriver, dead blow hammer, brake cleaner, copper grease, hub nut socket, chisel, punch, spring puller, ratchet and spanner set.
Work safely: 
• Make sure to lift the vehicle up on even, firm ground and secure with axle stands before working underneath with wheels removed.
• When removing brake drums, wear a breathing mask and avoid agitating any dust within the brake drums; dampen with water or brake cleaner if in doubt.

 

Whether it’s pulling the steering to one side, a pulsing brake pedal or just not stopping at all, Series Land Rover drum brakes are another quirk of the marque to have earned themselves a reputation. Typically though, they just need a little attention to return them to a fully functional condition so you can get the most out of your braking system.

If you know what to look for, it’s fairly easy to diagnose issues with your brakes and, sometimes, it’s not directly a problem with the brakes, but instead something else causing adverse side-effects. The first and best place to start is with a visual examination of all brake lines and the master cylinder. It is definitely advisable (given the MoT is no longer compulsory for most Series vehicles) to inspect your vehicle or have a garage inspect it regularly. Look out for signs of brake fluid leaking or weeping, typically around the joints into unions and between pipes, but also around the master cylinder seal and into the back of the wheel cylinders.

In this instance, I will be showing a service of the brakes on my 1953 Land Rover Minerva TT. This is an 80in model and is therefore fitted with the early, larger, 1/4-inch brake pipes and 7/16 UNF brake fittings. Apart from a few very small insignificant changes, these brakes were retained throughout the production of all short wheelbase model Series Land Rovers, and into early coil-sprung production on the back axle.

When I bought this Minerva, the brakes were pretty good and had been serviced within the last few years. Despite this, after a little use it became apparent that during braking the vehicle wanted to steer to the right quite hard, but it was okay under light braking. Visually, everything seemed okay on the braking system, and no leaks new or old were apparent. But the first thing I picked up on was that the wheel cylinders had been installed the wrong way round, side to side on the front axle.

This can mean that the hoses rub the rims and wear through. Next thing I noticed was damp oil staining coming out around the stud and hub holes in the face of the brake drum on the left-hand hub, confirming my suspicions of oil contamination. Given the brakes’ performance at low speed, I felt that they were adjusted up evenly side to side and, given the receipts for the parts installed by the previous owner, I was confident this newer issue was caused by oil contamination on the brake shoes.

A close inspection and rebuild of the brakes and hub was needed.

Work safely: With the vehicle lifted up and secured on axle stands, I removed the wheels and drums to inspect the brakes. Fortunately, having been looked at within the last few years, the drums came off easily. The old brake linings contained asbestos, so it’s recommended to wear a breathing mask if you’re unsure about these components, as asbestos dust is very dangerous if inhaled.

Leak evidence: With the left-hand brake drum removed, there was clearly oil contamination in the drum and shoes. The oil was very thin and clean so it was certainly a very recent issue.

Check the land: Oil in the brakes is usually caused by a leaking hub oil seal. Sometimes (as in this case) the seal land also needs replacing, as the seal and dirt wears a groove into the land surface so that even with a replaced oil seal, oil can still leak past it.

Check the land: Oil in the brakes is usually caused by a leaking hub oil seal. Sometimes (as in this case) the seal land also needs replacing, as the seal and dirt wears a groove into the land surface so that even with a replaced oil seal, oil can still leak past it.

Techniques: Before refitting the hub, I used a chisel to remove the deeply grooved seal land making sure not to damage the stub axle, and then re-installed a seal land using a hammer and a piece of pipe that fits over the stub axle to evenly push the land onto the stub axle. Note some reproduction stub axles have an integral seal land, so check this before attempting to remove.

Shoe choice: With the hub refitted, I moved my attention back to the brakes themselves. I chose to fit Mintex shoes to the front axle. In my opinion these are one of the better brake shoes, but can be hard to bed-in properly. Woven shoes (from CKD shop and others) have brilliant stopping power and bite, but are pricey and have their downsides on heavy or modified vehicles. Shoes from LOF clutches are also a brilliant alternative; they bed-in more easily but can have a little less bite than well bedded-in Mintex shoes.

Apply sparingly: Applying copper grease to the area of the shoe that sits in the wheel cylinder and on the bottom post helps lower the chance of squealing and stops any chance of corrosion build-up in these areas.

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Spring trick: It’s fiddly to apply the brake shoe springs, but using a spring hook like the one shown can really help. I fitted the leading shoe with the red brake spring first, making sure it was behind the adjuster cam before then installing the lower black brake spring with the trailing shoe.

Worth having: An important improvement over standard is the installation of brake shoe retainers. Not all vehicles were fitted with these but it is a major improvement over not having them. They bolt onto the trailing shoe (rearmost of the two) and prevent it from being flicked up under braking, which can cause the brake to stay locked up after the pedal is released and tries to fight the wheel cylinder being pushed outwards.

Drum location: Everything in place and correct. Next I could fit the brake drums. I decided to replace my original front drums with a pair of remanufactured drums by LOF Clutches. These are built to be very high tolerance and have the important three locating screws, unlike some other aftermarket drums – Land Rover brake drums are not stud- or
hub-centric and are held central by three countersunk screws, which are very much critical components.

Preparation: It is important to degrease the braking surface of the shoes and drums before installing the drums, so I used a rag and brake cleaner to wipe both surfaces. I then applied a tiny amount of copper grease to the hub-side face of the drum to help with later removal.

Screw check: The drum screws fitted to the vehicle stood proud of the drum surface, meaning the wheel was held off from the surface of the drum. This is not great and can cause balancing issues with the wheels when on the car, so I found screws that sat deeper into the recess of the brake drum.

Adjusting: With everything finished, but with the wheels still off, I set the adjuster nut on the rear of the brake backplate. This requires rotating the bolt head forwards towards the front of the car, until you can’t turn the drum by hand, and then backing it off slightly, or by one click.

Test first: As mentioned previously, bedding-in Mintex shoes can be a little difficult. I try to do plenty of test braking before going out on the road to make sure everything is correct and to see how predictable the braking is.

Private track: Being gentle on the brakes for the first few stops can cause them to very quickly glaze and then it’s hard to get them to bite again. Where it is safe and legal to do so, a few very hard stops in second gear combined with driving whilst keeping some pressure on the brakes, tends to help get them pretty broken-in before trying some stops from higher speeds.

I like a helper to use the slow-motion function on my phone when testing brakes. This can show when the wheels are locking up, and if the fronts are locking up before or after the rears. Our car park track is mostly gravel and dirt so although it won’t give a fully real world example, it is brilliant for getting an idea of any areas for improvement and adjustment. Don’t do this on public roads, and be safe.

 

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