design - Land Rover section

 

My front disc brake conversion using the kit made by Torrel Industries Ltd, 

          Sold through Rocky Mountain Expedition Equipment Ltd.
                             (604 913 7910 ask for Jeremy)

 

Also see my web page  providing a Series Land Rover disc brake conversion overview 
and my web page about converting a Series Land Rover to dual circuit power brakes

 

I choose The Torrel Industries disc brake conversion kit for a couple reasons: First Rocky Mountain Expedition Equipment Ltd is known to me as a company that supplies well tested rugged equipment at reasonable prices.  I felt that any product that they offer will have been well tested and found to be robust; I wanted a kit that allowed me to easily source "consumable" brake components locally, preferably at my nearest chain auto parts store (I was unaware that the rotor required machining); I wanted a complete easy to install kit and I wanted a "value priced" kit considering the value of the American dollar, shipping costs and how shallow my pocket book is.

 

Torrel Industries ltd Series Land Rover front brake conversion kit:

Instruction manual in Acrobat format (1.6 Meg)

Additional information about the conversion from the Manufacturer

Difficulty - Low

Except for one section, the manual is very good.  The project is no more difficult than rebuilding the front brakes and replacing the bearings.  A person well experienced with rebuilding Series Land Rover front brakes and hubs can carry out the conversion in a day.  Less experienced people will need a weekend for the project.   There are no special modifications needed.  Everything is bolt on.

 

Special tools needed

You will need your normal work on Series Land Rover tool kit, including the hub wrench, a tube of your favourite gasket sealant and fresh brake fluid.

Special tools that a Series Land Rover owner might not have are: 10mm socket or wrench for the bleed nipple, 15 mm socket, 11 mm socket, 8 mm hex socket, T60 Torx socket (The torx socket comes as part of the kit).  You will need a torque wrench that will read 150 lb ft of torque and a method of applying that much torque on a couple special  fasteners (rent someone from the local gym?).

 

The project

Box for Series Land Rover disc brake conversion kit as delivered from Rocky Mountain Expedition Equipment Ltd.The disc brake kit came in a sturdy compact wood box that weighs in at over 100 lbs (umph!).   From the beginning  everything seems well designed and user friendly.  Each screw that needs to be removed to open the box is marked with a spot of raspberry paint.

Opening the box the parts are well packed and the small parts are bagged.  The kit comes with everything  you will need for the conversion except for wheel bearings. Series Land Rover  wheel bearings seldom go bad so you are expected to reuse the ones on your vehicle after inspecting them to insure that they are indeed in good condition.  The kit even comes with all new lock tabs, oil seals and a package of Permatex thread locker.  

Throughout the project the one thing that stood out to me is that someone went through a lot of effort to to make the conversion as easy to perform as possible, from the marking of the screws on the shipping container, to the well written manual to the way some components were partially assembled to show how they go together, to the way components were grouped in individual wrapping.

 

Complete Torrel Industries Disc brake conversion kit for Series Land Rover
Contents of the box as unpacked

Backplate for Series Land Rover disk brake conversion

This is the back plate.  It goes where the drum brake back plate is mounted and holds the caliper frame in location.  The two back plates provided in the kit are sided and are stamped "Left" and "Right" to help you mount them correctly.

Hub and rotor for Series Land Rover disk brake conversion Front view of rotor and hub for Series Land Rover

The two pictures above show the hub and rotor preassembled.  Mel chose 11 inch rotors as being that largest that will fit all Series 16 inch wheels.  It is my understanding that kits with larger diameter rotors restrict which 16 inch steel rims will fit without a wheel spacer.

Note: I use Discovery I steel wheels.  I found my wheels to be a very tight press fit onto the hubs. If I were to  do another conversion, I would make a trial fitting between the hub and wheel before mounting the hub  then file down any excess metal if the wheels do not slide on prior to assembling the kit.  One of the hubs was a tighter fit for the wheel than the other, so be sure to check both.

Custom hub casting for  Series Land Rover disc brake conversion

Here is a hub side view.  The disc brake hub is slightly longer than the drum brake hub to place the rotor in the correct position for the calipers. This hub is a custom casting .  The studs are a larger diameter than the standard series wheel studs.

This picture shows the centre section of the rotor.

The rotors are from "sport models" of Chevy Luminas and Chevy Monte Carlos equipped with 286mm brakes.  The centre of the rotor has been cut to a larger diameter and new mounting holes were drilled.

Replacements are available through the kit manufacturer and their dealers.

Rotor machined out to fit Series Land Rover disc brake conversion
Calipers and pads for Series Land Rover disc brake conversion

The two piston caliper and the brake pads.  The pads lock onto the calipers

 

Here is the most confusing part of the assembly

The rubber brake hoses are handed and I found the instructions to identify which is which to be a little difficult to understand.

1. Is the tang mention in the instructions.  This hose goes on the left side of the vehicle.

2. Is the  rounded point mentioned in the instructions (round surface where 2 adjacent hex flats would be).  This hose goes on the right side of the vehicle.

The calipers are marked R & L, but are fitted to the Land Rover opposite the manufacturer's marking.  So the #1 hose is assembled to the caliper marked "R" and goes on the left side of the vehicle.   The #2 hose is assembled to the caliper marked "L" and goes on the right side of the vehicle.

Hoese end differences
Disc brake back plate mounted to Series Land Rover swivel housing

Here is the left side back plate installed.  It fits where the drum brake back plate was and uses the same fixing bolts and lock tabs.  The hole in the top tab is lined up with the rear bolts on the top swivel pin. The hole on the lower tab lines up with the  swivel housing oil fill plug.

Next step is to lock the lock tabs.  Here is a little trick.  If you pre bend the lock tabs just a little, about 2/3rds of the way down their length, they will not interfere with the bolt head and the ends are off the back plate enough to get a tool under them to bend them into place.  They can be a pain to lock if left flat.   The holes are offset on the tabs.  Be sure to mount the tabs so that the locking tabs do not partially cover the centre back plate hole.

Here is the rotor and hub assembly installed with free play adjusted.  The process for mounting the hub and adjusting the bearings is the same as with a drum brake hub.  Series Land Rovers wheel bearings need to  be set a little loose.  The workshop manual explains how to set the play with a dial indicator.  Here is an alternate method that a lot of people use.

Mount the hub and inner hub nut.  Tighten down the inner hub nut to eliminate all free play on the bearings.  Spin the hub and retighten the inner nut to make sure the bearings are seated properly and that there is no free play  Back off the inner hub nut  one and a half flats of the nut.  This will provide the free play needed for the bearings.  Add the lock washer and outer nut per the manual instructions.

Disc brake rotor and hub mouted to Series Land Rover
Disc brake caliper frame mounted to Series Land Rover

Here is the caliper mounting bracket mounted to the back plate  The caliper is held to this bracket by two long slip pins that go through the two corrugated rubber boots at the back of the frame.  The caliper is free to move on the pins.  The pistons press one pad against the rotor, pushing the caliper away from the rotor which engages the pad rigidly mounted to the caliper. The slip pins that mount the caliper to the caliper mounting bracket get torqued to 80 pounds of torque.

You can see a horizontal silver cylindrical object next to the lower  rubber boot on the caliper mounting bracket.  That is one of the two special bolts that mounts the bracket to the frame plate.  This puppy is what requires the 148 pounds of torque.

This is one side finished and ready to mount the wheel. Yes that is the bottom of a power steering box at the top of the picture and no I do not use the stock tab for mounting the brake hose to the frame.  I find that the lower otherwise unused frame mounting tab allows for  greater downwards articulation without stretching the rubber brake hose.

Series Land ROver converted to front disc brakes

 

Going one step farther

The lower caliper mounting bracket securing bolt may interfere with  removing the swivel housing oil fill plug.  If it does the instructions suggest shortening the filler plug so that you can get it off and back on.  Even if there is no interference  with the plug it will be harder to get the plug on and off and to fill the reservoir.  Swivel housings are not handed.  You can switch the housings between both sides of the Land Rover and not affect steering, suspension or anything.  If they are switched, the filler plug ends up facing forward away from the brake caliper.

If you need to remove the swivel assembly to work on axles, differential, replace the swivel seal, work on swivel pins or whatever, you might consider switching the housings to the other axle side.  Of course you will needs to keep the steering arms in their original sides.

Additional information from the manufacturer:

Designing the conversion:
During design of the disc brake system we concluded that the only economically practicable approach would be to adapt a widely available disc brake system to the Series Land Rover in a way that minimized the need for any other changes to the Land Rover. Due to the relatively large size of the Series Land Rover swivel ball housing, space between the swivel ball housing and the inner wheel rim is quite limited. We determined that the AC Delco dual piston floating caliper system used on many GM cars was the best choice because of its low profile. The AC Delco calipers and caliper brackets and brake pads can be used without modification and the (GM designed) rotors can be modified using general purpose machine tools to fit our Land Rover application. Because the design is based on relatively straight forward modifications to widely available rotors we are able to commit to providing customers replacement rotors as long as replacement rotors for GM cars are available.

 

Which master brake cylinder:

Question: The calipers are 2 pot and the 88 master cylinder is designed to push fluid into a single cylinder at each front brake.
Does an 88 master brake cylinder pump enough volume for the disc brakes & get good pedal height on the first try or do you recommend switching to 109 master cylinder?

Reply: During application, the pads in a disc brake system are displaced much less than the shoes on a drum brake system so a smaller volume of brake fluid must be moved by the master cylinder. This is offset to some extent buy the larger cross sectional area of the disc brake caliper pistons as compared to the drum brake cylinders but a disc brake system in good condition will have less pedal travel and the pedal will "feel" firmer than in a drum brake system. Note that "pressure" is as important a design consideration as "volume" in choosing a master cylinder. I recommend upgrading any Land Rover to a dual braking system for the significant additional safety margin the dual system provides. Power boost is helpful (and commonly used) in disc brake systems which do not have the same "positive feedback" characteristics as drum brake systems.

Mel

Also see my web page  providing a Series Land Rover disc brake conversion overview 
and my web page about converting a Series Land Rover to dual circuit power brakes

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