Before I delve into this topic I’d just say that if you are in anyway uncertain about the operation and maintenance of your brake system (on any vehicle) take it to a professional. The following is by no means an in-depth guide on Series Land Rover brake system overhaul / maintenance and should not be take as such. My working knowledge of this topic comes from the one source of information you should be using…. Land Rover Series II & IIa Repair and Operations Manual. Part number AKM8159
Now that’s out of the way, lets begin…
There are two types of brake master cylinder for the Series Land Rover. The Centre Valve (CV) type and (Compression Barrel) CB type. The workshop manual states that the CV model is “normally” fitted to 88” models and CB to the 109”.
During the rebuild, I had decided to fit the CB type. I (wrongly) assumed given its larger physical dimensions that it would offer additional braking. It doesn’t.
In the 3000km LGL has been road legal, I’ve alway thought the brakes could be better. There’s only so far you can go with a non servo drum brake system but the set up I had, certainly had room for improvement.
The CB brake master cylinder had the tendency to trap air under the seal at the cap end. This air gap should be filled with brake fluid. The workshop covers this topic and advises that the correct Castrol-Girling pressuring filling equipment be used.
I obviously don’t have such a thing but the local classic car garage did and they bled the system for me. Even then, it still felt spongy. Despite this I could stop when required and as I don’t hoon around the country side as if I’m in a Subaru, it was never a problem.
The CV master cylinder is identical to that used for the clutch and when I installed that, it bled first time and I haven’t had to touch it since.
Somewhere along the line, I’d ordered a new CV brake master cylinder and as I’d already drained the brake fluid out of the system to fit the rear differential guard, it made sense to swap the brake master cylinder over.
Removing the CB brake master cylinder
BUT… as I move the correct page of the workshop manual… to remove the CB master cylinder, the brake tower needs o be removed from the vehicle as the cylinder is too long to clear the bulkhead. This was very quick to do and took only a few minutes… sorry no photos.
Fitting the CV master cylinder:
Bleeding the brake system:
Bleeding brakes manually requires two people. One to pump the brake pedal, one to loosen and tighten the bleed screw on each wheel cylinder. It can be a long process. The Eezibleed makes the operation a single handed one.
Air is bled from the system at each of the 4 wheel cylinders. These are the components that do the actual braking. When you push the brake pedal, the wheel cylinder expands and forces the brake pads against the inside of the brake drum. The friction thus slows the vehicle down.
To ensure no air gets trapped in the wheel cylinders, the snail cam is backed off to ensure the pistons on the cylinders are pushed right back inside.. i.e. the brake pads are the furthest away from the inside of the drum as possible.
The snail cam is used to adjust the brakes from time to time as the friction material wears down.
To bleed the system correctly the manual states you must start at the wheel cylinder furthest away from the master cylinder and work you way around the vehicle to the wheel cylinder closest to the master. The distance refers the length of pipe runs, not the physical distance. For LGL it’s; drivers side rear, passenger side rear, drives side front, passenger side front.
To ensure all the air was out of the system, I cycled around all wheel cylinders 4 times.
Once that was done and I was confident there was no more air in the system, the brake pads were adjusted using the snail cams. This is why I had all 4 corners up on axle stands. It’s important you can spin the wheel to feel when the brake pad touches the brake drum. When you hear the pads touch, back the cam off so the wheel spins freely.
Job done and the brakes feel a lot firmer than before.