QUESTION - I have just replaced
the brakes on my 109 and now I can not get the brakes to work on
the first pump. Also not all the shoes adjust properly.
ANSWER - Don't feel alone
about this. Even a lot of factory trained service technicians
got it wrong. In October 1970 Land Rover issued a confidential
technical service bulletin (No. 1-F-9) (pdf) to explain the correct assembly
to their own service techs. The infomation provided
below more comprehensivly covers the content of that bulletin. To make things even more confusing around 2017 or so both Mintex and Ferodo have been supplying 109 rear brake shoes that are of a different configuration than what the NLA shoes the Land Rover factory sourced.
While
rear 109 brake shoes may look the same at a glance there is a
leading shoe and a trailing shoe. One of the differences between
the shoes is where the adjustment peg is located.
Leading and trailing brake shoes side
by side showing brake adjusting pegs in different locations.
If the shoes are mounted incorrectly they can not be adjusted correctly
Genuine Land Rover and older aftermarket 109 rear brake shoes:
Both shoes are mounted so that the
tapered end is adjacent to the wheel cylinder. The leading shoe,
which goes towards the front of the car, has the lining fitted
so that the distance from the wheel cylinder to the shoe lining
is greater than for the trailing shoe.
Newer aftermarket 109 rear brake shoes:
New aftermarket 109 rear brake shoes
The front and rear adjusting cams are fitted in different positions
on the back plate (they are not symmetrical about the centerline).
The front cam works on the underside of the peg on the shoe ( in
the 3 o'clock to 6 o'clock quadrant ) whereas , the rear cam works
on the top of the peg ( i.e. the 9 o clock to 12 o clock quadrant
).
If the shoes are fitted the wrong way around, or with two leading
shoes on one side and two trailing shoes on the other, the brakes
can not be adjusted properly and you will not achieve proper brake
pedal height. If you have these problems after installing new shoes,
pull the rear drums to make sure that the shoes are mounted properly.
If you have removed the rear brake back plates or suspect that
someone else has you will need to measure the plates to make sure
that they are not on the wrong side. According to land Rover technical
bulletin 1-F-9 the centre of the front snail cam is 4.5 inches
from the centre of the hole in which the wheel cylinder fits. The
center of the rear snail cam is 4.25 inches from
the centre of the wheel cylinder hole.
IMPORTANT TIP: Use anti seize
on the threads of the flat head screws that hold the drum to the
hub. Otherwise they tend
to rust in place and often need to be drilled out.
If you are here because you Forgot how everything goes together:
The tapered end of both shoes go to the top by the wheel cylinder.
Both springs mount on the back plate side of the brake shoes.
The spring that is two short coils with a long straight section
in-between mounts near the top of the shoes. The single coil spring
mounts near the bottom.
This picture shows the locations of the rear brake springs. The yellow lines show which holes the springs go through.
I had to hub off to change the inner hub seal while I was renewing the brake system. Usually you assemble the springs on the shoes between the hub
and back plate, mount one shoe in its slots, mount the lower end of the second shoe in its slot and pry the top of the second shoe into place.
You can use a hammer to tap the shoes up or down to center them around the stub axle before applying the drum.
Be sure the snail cam is all the way adjusted in before applying the drum.
Each spring goes in the same mirrored hole on each shoe. There
is only one combination that will fit properly. It will be obvious
if you try to assemble the springs in the wrong holes.
New Mintex rear shoes average 0.3 inches thick, lining plus back
plate. Back plate is 0.1 inches thick. This should allow
you to mic rear brake shoes and estimate the amount of wear on
the lining.
If you forgot where the rear springs mount I suppose you should
also see a picture of the front spring location:
The front shoes are identical. The spring mounts
through the same hole on each shoe. Spring mounts on back
side of shoe. Fit spring to shoe, offer up spring and shoe
to spring peg on back plate, set tapered end of shoe to brake
piston slot then lever blunt end of shoe into slot at base of the
other wheel cylinder. Adjust brake adjustors all the way in, tap
shoes to be centred top to bottom against back plate then offer
up drum. Don't forget the anti sieze on the flat head screws that
hold the drum to the hub!
Six cylinder front brakes. Also used on the One Ton and the Stage 1 109s
photo by Keith Shukait
I don't know where else put put this info yet so
it is here for now:
Brake configurations for different models
SII, SIIa 109
Front= 11" double leading shoe, w/two wheel cylinders
Back= 11" single leading shoe, single wheel cyl, same cylinder
that is used up
front on all 88's up until 1980.
88's up until 1980
10" drums w/snigle leading ahoe set up, front wheel cylinders
same as rear
wheel cylinders on a 109. rear wheel cylinder is smaller (1")
88's after (june?) 1980
Front= 11" drums w/ double leading shoe set up, as standard
on previous 109s
Rear= 10" single leading set up as was previously standard
on all 88's
The dual master cylinder and I believe the servos as well were
not standard in
the UK until quite some time after they were introduced over here
in NA.
Also I should state that the 109's were mostly 11x2" drums
except for six cylinder versions and the SIII
Stage One 109 V8s which came with 11x3" drums.
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