Rebuilding Rear Brake Callipers
The rear callipers on my 1996 Griffth are from a Ford 4x4 Sierra Cosworth earlier cars I understand use a different calliper
During the body off restoration I decided to replace or restore most of the braking components including the rear callipers. Having bought a reconditioned set a few years ago as spares it seemed sensible to use them. After fitting the off side calliper leaked brake fluid quite badly and on inspection I found both the dust and piston seals were damaged it looked very much as if whoever reconditioned them did not know how to insert the seals. There is a good U-Tube video of the process that is worth viewing: Escort Cosworth Brake Caliper Rebuild ** Can We Do It ** allthough it is an Escort Cosworth the callipers are the same. It gives a decent description of the process but misses out a few steps.
In the rebuild kit: Rear Brake Caliper Repair Kits & Pistons For Ford Sierra Cosworth 4x4
There are a couple of seals that he did not replace, one is on the central rod with an external thread and the other is within the piston itself . The O-ring on the central threaded rod is seen below with the steel plate that locates the rod to the base of the calliper, the calliper bottom has a small hole to locate the raised pip on the plate, the Circlip secures the plate in the calliper body. Next the main spring assembly is assembled over the central rod and secured with another circlip as the video shows some means is required to compress the spring assembly to enable the circlip can be fitted. The handbrake assembly with its spring and bolt fits at the back of the calliper and as the handbrake cable turns the shaft, movement is transferred to the central rod via the steel torpedo seen next to the handbrake shaft. Its a rather strange arrangement but seems to work OK. As the piston is threaded onto the central shaft the handbrake action pushes the piston out to apply pressure to the brakes.
During the body off restoration I decided to replace or restore most of the braking components including the rear callipers. Having bought a reconditioned set a few years ago as spares it seemed sensible to use them. After fitting the off side calliper leaked brake fluid quite badly and on inspection I found both the dust and piston seals were damaged it looked very much as if whoever reconditioned them did not know how to insert the seals. There is a good U-Tube video of the process that is worth viewing: Escort Cosworth Brake Caliper Rebuild ** Can We Do It ** allthough it is an Escort Cosworth the callipers are the same. It gives a decent description of the process but misses out a few steps.
In the rebuild kit: Rear Brake Caliper Repair Kits & Pistons For Ford Sierra Cosworth 4x4
There are a couple of seals that he did not replace, one is on the central rod with an external thread and the other is within the piston itself . The O-ring on the central threaded rod is seen below with the steel plate that locates the rod to the base of the calliper, the calliper bottom has a small hole to locate the raised pip on the plate, the Circlip secures the plate in the calliper body. Next the main spring assembly is assembled over the central rod and secured with another circlip as the video shows some means is required to compress the spring assembly to enable the circlip can be fitted. The handbrake assembly with its spring and bolt fits at the back of the calliper and as the handbrake cable turns the shaft, movement is transferred to the central rod via the steel torpedo seen next to the handbrake shaft. Its a rather strange arrangement but seems to work OK. As the piston is threaded onto the central shaft the handbrake action pushes the piston out to apply pressure to the brakes.
Central rod O-ring
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Main Spring assembly
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locating hole for plate
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The Piston is seen below with its various components again secured by another circlip, the seal is shown at the base of the internally threaded core. Sometimes an O-ring can be used instead of this seal. To remove the circlips a special 90 degree tool is required like the one below but make sure that the tips have a diameter of less than 1.5mm otherwise they will not fit the circlips
The Piston
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Piston components
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Seal within the piston
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Special Circlip Pliers
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The most difficult part of the process is without doubt inserting the dust seal on the piston into the calliper body a most instructive U-tube video explains the process very clearly: Replacing Calliper Dust Seals