This first picture shows what is included in the Drum Brake Performance Kit and the following
pictures show the individual parts which are available separately.
The price for the performance kit (part # 06-3410) is
One plate (part # 06-3275) is included.
The price for each plate is
Two cams(part # 06-3272) are included.
The price for each cam is
One long pivot pin (part # 06-3274) is included.
The price for each pivot pin is
One short pivot pin (part # 06-3273) is included.
The price for each pivot pin is
Two tab washers (part # 06-0395) are included.These are the same tab washers used to secure the chain
case to the engine.
The price for each tab washer is
Two 1/4 x 28 bolts (part # 14-0101) are included.
The price for each bolt is
The following and write up and schematic are taken from the Norton Service Release No. N74, dated March 1972.
NATURE OF RELEASE: Front drum brake - high performance modification.
MODELS AFFECTED: All Commando.
PARTS AFFECTED: Front brake plate and shoes assembly.
EXPLANATION: To stiffen up the two leading shoe front brake assembly, thereby providing an appreciable improvement in braking figures for high performance purposes, a support plate is introduced. The support plate ties In a precise relationship between both brake cams and pivot pins. The support plate is shown in the illustration, in situ. The parts required to convert an exiting brake are available In kit, Part No. 06-3410, comprising:-
06-3275 Brake support plate, 1 each.
06-3274 Pivot/Torque stop pin,: 1 each.
06-3273 Pivot pin, 1 each
06-3272 Expander cam, 2 each.
14-0101 Set screw, support plate, 2 each.
06-0395 Tab washer, 2 each.
ACTION: To convert an existing brake plate, remove the brake shoes and springs,
the brake expander cams and both pivot pins. To remove the short pivot pin, first support
the brake plate firmly and squarely under a drilling machine and gently remove the riveted
shoulder of the fixed pivot pin. Final detachment of the stop pin may necessitate heating
the brake plate by immersing in boiling water before driving or pressing out. Retain the
chamfered washer. Replace the new pivot pin by pressing into the brake plate pin housing and
supporting the brake plate and new pivot pin firmly and squarely, fit the washer over the pivot
pin, chamfer facing outwards. It is most important to rivet the short pin securely and neatly
in Position in the brake plate. Replace the second new threaded pivot pin and nut and expander
cams. Reassemble the brake shoes and springs then locate the support plate over the brake cams.
Secure the plate with set screws 14-0101 (1/4" UNF) and tab washers 06-0395.
Tighten the set screws then tap the tab washers into the position shown in the illustration.
The brake is now ready to put back into service.
We use a 1/2" drill to remove the riveted short pivot pin. Support the backing plate as described above and remove the rolled over edge of the pin, then press or punch the pin out.
We have a riveting drift (drift Number CD-0003) that we use to rivet the short pin into the backing plate. This drift's first step (see Drifts used in building a Commando for drift nomenclature and dimensions) is just under the I.D. of the pin (pin =.375", drift = .370") and then tapers out to almost the diameter of the pin (pin = .500", drift = .480"). The first step is about .070" long and must be less than the depth of the flange (around .100") to be bent over on the pin. The second step's diameter must be larger than the pin diameter, We used .750" rod.
We use a press to rivet this pin and make sure that we have a base that presses up against the back flange of the pin and not against the end of the pin. If you press against the end of the pin, you run the risk of distorting the end step that fits into the stiffening plate. A deep socket will work for the base.
The riveting drift CD-0003.
Norton Parts ..Wheels, Brakes ..Brakes
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