Tuesday, January 2, 2007

Power Brake Upgrade for pre-1968 Series II and Early IIA Land Rovers



This 1964 Land Rover 109 Regular came from the factory with single-circuit, non-power drum brakes. This system is notorious for retaining air, resulting in poor brake action. When these vehicles were new, the brakes worked fine. But over the years it seems people have assumed that the system never worked right. Not the whole truth, but in fact, it has some design flaws that make bleeding the system very difficult. I have spoken to longtime Land Rover mechanics who remember that even when new, the system was problematic for professionals to bleed. You will see why in a moment. The following details an upgrade to the later model power assisted brake system, which will solve all the problems inherent in the original setup.

To accomplish this conversion, you'll need new brake pipes, new clutch and brake master cylinders, a brake servo, a late Series IIA or Series III pedal and tower, new brake pedal return springs, and some vacuum fittings. I won't go into part numbers here, since various suppliers have their own part numbering systems. You can do some research and source all this stuff easily.

DISCLAIMER:This conversion requires a basic understanding of mechanical principles and some skill to perform properly. Your brakes are a vital safety system in your vehicle and you should not attempt the following operations without careful planning and postconversion testing. YOU are responsible for the safe operation of your Land Rover. If you have any doubts, go to a professional.




In the above shot you can see the angle of the bulkhead where the pedal boxes mount up. The compression barrel master cylinder in the single circuit system sits at the same angle, keeping air bubbles trapped in the rear of the bore. The output port is lower than the rear of the bore. The other problem is that the 109 has two wheel cylinders on each front wheel, but the bleed screw is at the bottom, so the top cylinder can trap air, too.



Here is the early style pedal box. You can see the compression barrel master cylinder mounted in the box.




The later pedal box eliminates the angle, keeping the master cylinder level. The later master also has a larger capacity bore and a fluid reservoir independent of the clutch master cylinder. It is a snap to bleed.



The rectangular hole in the bulkhead need to be enlarged for the new pedal box. The new box is longer and requires two retrun springs, so the hole must also be wider to keep the springs from fouling on the edge of the hole. I used a jigsaw to cut the hole.



The edges are not arrow straight, since I had no desire to pull the steering box, which makes for tight cutting quarters. Anyway, the hole was cut big enough to work and in the end you won't see the edges.



The bulkhead has a bracket for a stiffening rod, but this bracket is in the way of the new pedal box. It had to go. You also will need to trim the fender bolt bracket where it angles down on the inside of the bulkhead (the third bolt hole is deleted to clear the pedal box).



A three-inch grinding wheel did the job quick.



Here's the bracket removed. Into the trash bin it goes.



After filing sharp edges of the new cut, spraying a coat of cold galvanizing primer and a couple topcoats of Marine Blue, the pedal box assemblies were mounted up to the bulkhead. You can see how the master cylinder is level and the masters have independent fluid reservoirs. The old system relied on a single steel can reservoir that is prone to vibration, leaks, and peeling paint that will promote rust in the footwells. But note also that you will now need to cut an access panel in the top surface of your fender to check and fill your clutch master cylinder fluid reservoir. (I don't have a good pic of this right now- honestly, it's because I made the cut and then taped the cut out panel in place with aluminum tape due to time constraints. When I get a chance I'll install a piano hinge with a couple pop rivets.)



This is the original brass manifold junction on the front right frame rail. The later brake system used a five-way junction which is no longer available. That manifold was the key to making the brakes failsafe, since the rear and front circuits could be isolated to prevent fluid loss in the event of a brake pipe rupture. However, you can retain the original junction by running the front lines to the proper connection, the rear downpipe directly to the rear feeder line, and capping the remaining port with a spare brake light switch. No need to use the later brake light switch for the power brake system (mounted on the pedal box), since the original switch will still be functional.



The next task is to make a vacuum fitting for the brake servo. The new power assist brakes will take suction off the intake manifold and use it to decrease your effort when the brake pedal is applied. This shot shows the tapped hole for the vacuum fitting. This engine is not original to the truck, so if your truck doesn't have this later manifold you will need to tap a hole or find a later manifold. This is a 3/8 pipe thread tap.



Here's the double male fitting that goes into the manifold. I found this in the plumbing section of the hardware store.



You will also need a female sleeve to mate to the male fitting and a piece of copper pipe about 4 inches long. Bend the pipe at a 90 degree angle and put a double flare on the end so it seals to the fitting on the manifold. You can rent a flare tool at any auto parts store. (As an aside, double flares can take practice to form perfectly, but copper is a good metal to start with because it is so soft. Maybe get yourself some extra length in case you screw it up the first try).



Here's the double flare. Ready to go.



Once you are done fitting the brass and copper, just run some automotive fuel/vacuum line from the copper pipe to the barb on the booster. Make sure all your brake pipes are routed well and clamped to the bulkhead and frame at least every 18 inches. Vibration will otherwise cause stress cracks to form and you have a brake failure.



Finally, cut your fender top to accomodate the new brake booster and cylinder. I did some quick measurements, pencilled in the cut line, then hit it with a Sharpie marker and made the cut with a jigsaw. This cut is not perfectly matched to the later fender but it's close. Before you install the fender, bleed the system. I use a power bleeder which is just a pressurized bottle containing brake fluid that puts 15 psi into the system and all you need to do is open your bleed screws. Don't forget to back off the snail cams at all wheels for maximum flow, then adjust brakes per the factory manuals. The systems should bleed easily. With the engine off, your pedal will be firm when pushed. With the engine on, the booster will do its job and give an easier pedal push due to the vacuum assist.


This conversion is simple, requires only a few special tools, and will give your early 109 far better braking and most importantly, ease of service.