The Midget clutch is a hydraulically operated single dry plate system on both the 1275cc and 1500cc, but the mechanical and hydraulic components differ entirely between the two engines. The driven plate, clutch cover, release bearing, release mechanism, slave cylinder, and hydraulic pipework are all specific to the engine fitted, and no parts are interchangeable between the A-Series and Triumph applications.
1275cc Clutch Assembly
The 1275cc clutch consists of a driven plate, a diaphragm-spring clutch cover, and a release bearing. The release bearing is carried on a clip arrangement and is pushed forward by the release arm when the clutch pedal is depressed. The release arm pivots on a bush and is operated by a push rod from the slave cylinder. The slave cylinder is mounted on the gearbox bell housing and is connected to the master cylinder by a hydraulic pipe routed through the bulkhead and along the footwell, with a flexible hose section between the rigid pipe and the slave cylinder.
Master Cylinder and Bleeding
The clutch master cylinder is mounted in the pedal box alongside (but separate from) the brake master cylinder. The hydraulic fluid reservoir may be integral to the master cylinder or remotely mounted, depending on production date. When bleeding the clutch hydraulic system, a pressure or vacuum bleeding tool is strongly recommended, as the system is notoriously difficult to bleed by conventional pedal pumping alone, the routing of the hydraulic line and the natural air trap at the slave cylinder make air difficult to expel through pedal action. Priming the master cylinder with fluid before installation does not always resolve the issue; a pressure bleeder provides the most reliable results.
1275cc Clutch Troubleshooting
Poor clutch disengagement on the 1275cc can be caused by several factors beyond worn hydraulic seals: elongated clevis pin holes in the push rod forks, worn clevis pins, a bent release arm, or a weakened flexible hose that expands under pressure rather than transmitting full hydraulic force to the slave cylinder. All of these mechanical wear points should be inspected if disengagement problems persist after renewing the master and slave cylinders.
1500 Clutch Assembly
The 1500 clutch uses a different driven plate, cover, and release bearing from the 1275cc. The release mechanism employs a sleeve, tolerance ring, and pin arrangement rather than the bush-and-bolt pivot of the 1275cc release arm. The slave cylinder mounts differently, bolting to a housing on the gearbox with a single bolt and nyloc nut. The push rod and clevis pin arrangements also differ from the A-Series setup.
1500 Clutch Hydraulics
The clutch hydraulic pipe on the 1500 runs directly from the master cylinder to the slave cylinder, without a flexible hose section in the main run. Two pipe specifications were used: an earlier type for non-dual-circuit brake cars with a 3/16-inch bore, and a later type for dual-circuit brake cars with a 1/4-inch bore. The chassis number and brake specification must be confirmed before ordering replacement pipework.
Complete Clutch Kits
Complete clutch kits containing the driven plate, clutch cover, release bearing, and (where applicable) the spigot bush provide everything needed for a clutch renewal in a single ordered package. Kits are available for the 1098cc, 1275cc, and 1500cc, each containing the correct specification components for that engine. Renewing the clutch as a complete set is strongly recommended over piecemeal replacement, the cost difference is small, and the labour involved in accessing the clutch is substantial enough that returning to fit a missed component shortly afterward is not economical.
Release Arm Kits and Alignment Tools
Release arm kits containing the arm, pivot bush, bolt, and associated hardware are available for the 1275cc, where the release arm pivot bush is a known wear item. A clutch alignment tool is essential when fitting the driven plate, ensuring the splined centre is concentric with the spigot bush so that the gearbox input shaft can re-engage cleanly during refitting. The alignment tools are specific to each engine, the 1275cc and 1500cc tools differ in diameter to match their respective spigot bushes and input shaft splines.