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Converting a Series Land Rover to front wheel disc brakes
An overview
Land Rover 109 drum brakes are adequate for stopping in the forward
direction. With two leading shoes they provide a lot more
forward braking power than conventional drum brake arrangements
with a leading and a trailing shoe. However this extra stopping
ability in the forward direction comes at the cost of stopping
ability in the rearwards direction. This can become a real
safety problem when a 109 Land Rover comes to a halt nose up on
a steep slope. It is very difficult to hold a 109 Land Rover
stationary in such a situation or to halt the Land Rover's movement
backing down a steep slope.
Drum brakes do not function well right after a water crossing
when the shoes are wet. My reasons for switching from front
drum brakes to front disc brakes are to achieve good braking in
both directions and to have good braking right after water
crossings. Note that vehicle manufacturers use more powerful
power brake boosters for disc brakes than Land Rover used for
the Series. You
should not expect increased braking with the same pedal pressure
when converting from drum to disk using the same master cylinder
and vacuum booster. If you are just looking for increased
braking for the same pedal pressure look first at more powerful
brake power boosters.
Disc brake conversion kits consists of some kind of bracket to
hold the calipers in place, a special hub casting that holds the
rotor in the correct location for the calipers plus disc brake
components manufactured for a different vehicle. With
one exception, the custom caliper mounting bracket bolts into place
where the drum brake back plate is mounted. They all uses
stock Series Land Rover bearings and seals.
The size of the caliper assembly determines which wheels will
fit after a front disc brake conversion. Some conversions
will require a spacer to be used with certain wheels. Be
sure to ask if your wheels will fit when purchasing a kit. I
don't think that the old 15inch Series rims will fit on any of
the kits.
Series Land Rover front disc brake conversion kits
There are 5 disc brake conversion kits for Series Land Rovers
that I am aware of:
Bearmarch kit - These
are out of production but you may occasionally find someone
selling an old set on ebay or a boot sale. The Bearmarch
disc brake kit was an imitation of the early Santana Girling
system and was made in Iran. The quality of the imitation
Girling Santana brakes is reported to be low.
Heystee Automotive Components conversion
kit - Formally T.I.
Console, Front and rear disc brake kits are available.
The kits are based upon the disc brakes that come on the
Spanish built Santana PS10 (Iveco Massif). The
PS10 is basically a Land Rover clone so is in the same weight
range as a Series LR. The brake calipers are made by Girling. The
front disc brakes are a 2 piston vented system. The
rear system has the same wheel hubs but slightly thinner discs
(non ventilated) and smaller calipers. This is also a straight
fit without modifications just like the front ventilated system.
A
custom back plate is bolted onto the swivel housing in place
of the drum brake back plate and the PS10
Girling brakes bolt to the plate. There
are no grinding or modifications of existing components
required. Wheel spacers are required to fit the Series wheel
though
As the Santana (Massif) is not available in North America,
North American's would need to source replacement parts directly
from Heystee
Automotive Components or an IVECO dealer. Santana
has been taken over by IVECO and the Santana
PS10 has been renamed the " IVECO Massif". Americans
can usually have pads & rotors shipped by air to them from
Europe in less than a week. Alternatively, if quick repairs
are important, one can keep a backup set of pads and rotors on
the shelf.
 
Timm Cooper conversion kit - As
of 2007 Timm's conversion is back in production. There
has been a casting run made. The
kit is sold as a complete kit through Rovers North or you can
just buy the special castings from Timm and make your best deal
on the rest of the parts. This
kit is based on a custom swivel housing and hub. Land Rover
disc brake components are used that can be sourced through any
Land Rover parts dealer. These are 11-3/4 inch dia rotors
with 4 piston calipers. Timm Cooper does not have
an email address nor a web site.
 
Torrel Industries conversion kit
- Sold as a complete kit through Rocky
Mountain Expedition Equipment Ltd. This 11
inch vented brake kit was engineered by Mel Brown and
uses common (North America) AC Delco dual piston calipers,
pads and rubber hoses. This is a 2 piston system
that works with Series master cylinders They suggest
that the Series III dual circuit power brake system be
used. The back plate that mounts to the swivel
housing and the hub are custom parts. The rotor
is a GM rotor that has the centre machined to a larger
diameter. Other than those 3 parts, everything
else is standard off the shelf GM brake parts or Land
Rover hub parts. These components were used on
some models of the Chevy Lumina, Monte Carlo, Pontiac
Grand Prix, Oldsmobile Cutlass Supreme and Buick Regal. They
recommend telling your part dealer that you need parts
for a 2001 Chevy Lumina.
A step by step
description of a my front disc brake conversion using the Torrel
Industries conversion kit |
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Zeus conversion kit - I saw
one kit installed on a 109 a few years back but know nothing
about the kit. It is
a 4 piston vented system for both front and rear brakes that
requires no special modifications.
The kit is featured on their web
site. They will not ship to an U.S.A. addresses.
The brake system
I strongly recommend making sure that your brake system is in
top condition when installing a disc brake conversion. Land
Rover recommends replacing all rubber in a Series Land Rover brake
system every 2 years. If you have not done it, this
is the time to flush the brake tubes, replace all the rubber
hoses and the rear cylinder rubber. If you have been contemplating switching
from DOT4 brake fluid to DOT5 silicon brake fluid the time to do
it is when you flush the steel tubes and replace all the rubber.
This is also when you want to inspect the steel brake lines for
rust spots and replace if found. All
the manufactures of Series Land Rover disc brake conversion kits
suggest that you convert to a power brake system. I
have a web page describing how
I converted my Series Land Rover brake system to dual circuit power
brakes.
Master Brake cylinders
This advice comes from Paul Heystee of Heystee
Automotive Components. Paul recommends using using a Defender
master brake cylinder with a disc brake conversion. The 1993
D110 master brake cylinder available in North America would
be a good choice for a Series Land Rover that has front disc brakes
and rear drum brakes. Here is what Paul has to say:
"The reason for changing to an early
Defender master cylinder is because these designed specially for
discs/drums set-up. Master cylinders designed for drum brakes have
a so called "remainder
pressure" that keeps the shoes close to the drums. Using this
type of MC with a disc/drum or disc/disc set-up will push the pistons
constant to the disc wearing out the pads quickly ("in no
time").
Also the disc brake set-up requires less volume to work but this
is not an issue because the LR pedal has already a long travel
and a short travel is welcome. The tandem set-up will allow to
keep pushing fluid to the rear although the front is saturated."
"The small valve that is fitted to many Series IIIs was a safety
device and caused more problems and actual safety. I remember trying
to bleed the system for 2 days due to this valve (!)
I recommend to separate the front and rear directly form
the MC and if required you can put a G-valve in the rear line
to limit the pressure on the rear drums when going down a hill or
when decelerating form high speeds. Due to a small mass inside this
valve which activates when it's moved under G force, hence the name.
It is found on many 110 Defenders."
"The Santana PS10 has a load depending valve which is
better when the load variations are big and especially when it's
fitted with parabolic springs (more movement compared to the
rigid multi leaf springs). However, the coil springs form the
Defender make more movement then still they had this G-valve.
It's my favourite also because it is not connected to the axle
which is prone to break off in heavy conditions."
Power brake servo
Most people use the standard Series III Land Rover power brake
servo with the Series III pedal tower when converting to power
brakes. The Series III Land Rover Servo has a 6 inch diaphragm
and works well with a disc brake conversion. Heystee
Automotive Components offers a slightly larger power brake
servo (8 inch diameter diaphragm) that fits the Series III brake
tower without modification and fits in an engine bay factory
equipped with power brakes without modification.
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