Workshop Basics

Disassemble, inspect and rebuild your classic’s calipers for £20

We show you how to overhaul your crusty brake calipers.

Many of our classics are fitted with front disc brakes and some have discs at the rear, too. Disc brakes rely on hydraulic calipers squeezing the pads’ friction material onto the discs to provide retardation. Most British classics have Girling or Lockheed calipers of a fixed rather than more modern ‘floating’ design.

Calipers require servicing or rebuilding from time-to-time. Their rubber seals are consumable items and need to be replaced on a periodic basis. Damaged dust boots, infrequent fluid changes and long periods of inactivity can lead to corrosion, accelerated seal wear and seizure. Signs that something’s going badly wrong include pads binding and overheating, uneven pad wear, brake imbalance or – in extreme cases – fluid leakage. If your classic exhibits any of these symptoms, it’s telling you that its calipers are long overdue attention.

If your calipers are in good condition, an overhaul will simply involve fitting a kit of new rubber parts. If they’ve been neglected, however, it’s likely that the pistons will require replacement, too. In extreme cases, the bores may need re-sleeving, which is a specialist process.

The rebuild work is easy to carry out at home and the required parts for common Girling and Lockheed calipers – plus many others – are available at modest prices. Once rebuilt, your calipers will give reliable service for many years, as long as you exercise them regularly and keep on top of fluid changes. Silicone DOT 5 fluid will make them last almost indefinitely.

The calipers shown are Austin Princess ‘four-pot’ items, which are a popular upgrade for other classics. Most Girling and Lockheed calipers are of a simpler ‘two-pot’ design, with just one piston on each side.

Before you start If the calipers are fitted to your car, use its hydraulic system to carefully extend the pistons before disconnecting the flexible hoses. Stop them popping out completely by placing a piece of wood between them or restraining them with G-clamps. You will need Brake cleaner, compressed air and/or grease gun, penetrating oil. Replace pads Always renew the brake pads when overhauling the calipers – and always replace or rebuild braking components in axle sets. Finishing off Tighten the caliper bolts to the torque specified in your manual. Renew locking washers or thread lock. Finish by bleeding the brakes. Replace DOT 4 fluid every two years.