The front brakes are a Lockheed twin leading shoe arrangement with two wheel cylinders per drum, giving four cylinders across the axle. The 9-inch drum and 1½-inch wide lining specification is common between the TD and TF. Most front brake components are universal across the production run; the only chassis-number-dependent items are the front hub and integral brake drum assemblies (covered under Stub Axles & Hubs) and the wheel-stud thread, which changed from BSF to Unified at chassis 12285.
Wire Wheel Brake Drums
On wire-wheeled cars, the brake drum is a separate component from the splined hub, mounted to the hub by twelve drum-retaining studs and nuts and secured by lock tabs. A rubber inspection plug provides access to the brake adjuster. The wire-wheel drum is common between TD and TF wire-wheeled cars and between left- and right-hand sides. Steel-wheeled cars do not use this separate drum, their front brake drum is integral with the hub assembly, in one of four chassis-number-specific specifications detailed under Stub Axles & Hubs.
Wheel Cylinders
Four front wheel cylinders are used, two per drum, providing the twin leading shoe arrangement that gives the TD and TF their progressive front brake feel. The Lockheed wheel cylinders are universal across all TD and TF specifications. An axle-set repair kit covers all four cylinders and includes springs, expanders, and rubber cups; individual rubber cups are also available separately. The bleed nipples on each cylinder allow air to be purged from the hydraulic circuit during bleeding.
Eight nuts secure the cylinders to the brake backplates.
Banjo Connections
The hydraulic supply enters each front drum through a double banjo connection that distributes fluid between the pair of wheel cylinders on that drum. The banjos themselves are side-specific, separate left-hand and right-hand parts. Each banjo is secured by a banjo bolt and sealed with copper washers (a small washer between banjo and cylinder, and a large washer between bolt head and banjo). The copper washers should be renewed whenever the connections are disturbed, as the soft copper deforms on tightening to make the seal and is unlikely to seal as well a second time.
Brake Shoes, Linings and Springs
Front brake shoes are supplied as an axle set covering both drums in modern asbestos-free friction material. Brake linings are also available separately as an axle set, for owners who wish to reline their existing shoes rather than replace them complete (re-lining requires skill and the correct rivet equipment). Four shoe pull-off springs, one per shoe, return the shoes to their rest position when the brake pedal is released; weak or broken springs cause the shoes to drag on the drum, generating heat and accelerating lining wear.
Brake Shoe Adjusters
Each cylinder position has a Lockheed "Microm" snail-cam adjuster, a mask and an adjusting cam, that takes up lining wear during routine brake adjustment. With four cylinders giving four shoe positions, four adjusters are fitted per axle. Front brake adjustment should be carried out with the drum cool: each adjuster is tightened until the shoe just contacts the drum and the wheel cannot be turned, then backed off the smallest amount that allows the wheel to spin freely without binding. Brake assembly lubricant on the cam contact points and shoe-to-backplate contact points prevents the adjusters from seizing and prevents shoe-end binding on the backplate.
Ordering Considerations
Most front brake components are common between TD and TF: cylinders, repair kits, banjos, shoes, linings, springs, adjusters, and bleed nipples. The wire-wheel brake drum and its mounting hardware are specific to wire-wheeled cars; steel-wheeled cars use the integral hub-and-drum assembly listed under Stub Axles & Hubs (in one of four chassis-specific specifications). Wheel studs and nuts are thread-specific (BSF to chassis 12284, Unified from 12285 through all TFs). Banjos are side-specific (LH or RH).