Adjusting the Handbrake

One of the most common DIY mistake must be the handbrake adjustment issue. For many years manufacturers have been obliged to build in self-adjustment to the rear brakes, keeping the friction surfaces close together so that the handbrake itself works throughout the life of the pads or shoes on the rear brakes. This has been a legal requirement for some years.

The same manufacturers of course have to install some way of compensating for 'stretch' of the handbrake cable - and it is too easy for the amateur to believe that the handbrake cable adjuster is the handbrake adjuster. IT IS NOT and must not be used for adjusting the position of the handbrake lever.

If the handbrake lever is too high then the actual brake adjustment has to be checked, and this is shown in the diagram of the rear brake callipers. The actual adjustment for wear on the brake pads is taken up by the group (21). The piston and seals marked as (19) rotate about the shaft (21). As the pads wear the rod is rotated slightly and becomes longer - this compensates for the thinner brake pad by moving the brake piston out. At all times the handbrake lever should be at the right angle when the handbrake is engaged. If it is not then this self-adjustment is not working and must be investigated.

CORROSION

Perhaps the most common cause of the handbrake failing to adjust is corrosion. The brake parts are steel and are submerged in a bath of brake fluid, which is hygroscopic - it absorbs moisture. As time passes the water content in the brake fluid is high enough for rust to commence.  To prevent this the brake fluid should be completely renewed every two years.

If the brake fluid is not changed rust begins and the finer parts, like screw threads, deteriorates. The brake pad wears away and move further away from the brake disk. This requires further and further movement of the handbrake lever to take up the slack. At this stage tightening (shortening) the brake cable only lowers the brake lever - it does not move the pad nearer the disk or take up the slack between the piston and the brake pad. Further wear will quickly negate the adjustment, and in the meantime brake efficiency is much reduced, while ABS will cease to function on the rear wheels because the pistons have too far to travel to make braking effort. The car is now in a dangerous condition.

REPAIR

A complete set of both new rear brake callipers may now be required. If on dismantling there is no corrosion to the bores of the caliper, it may be possible to renew the pistons and seals - but bear in mind that it would be a waste of money to replace pistons and seals into corroded bores - they will quickly cut through and leak.

(19) group:- Caliper Repair kit Finis 6 141 146 about £55 each side.

(21) group:- Parking Brake Repair kit, Finis 6 127 710, £18 approx each side.

 

REPEAT                                                                            

 

So how do you adjust the handbrake? You Don't.

 

 

HANDBRAKE CABLE ADJUSTMENT

 

How do I adjust the handbrake cable? This is relatively easy. NOTE: This operation should only be carried out to compensate for stretch in the cable, or after fitting a new one.

1. Raise the vehicle and release the handbrake.

2. De-adjust the handbrake cable.

1 Remove the locking pin.

2 Slacken the adjuster locknut.

3 Slacken the adjuster until the levers on the callipers have returned to their stops.

3. Paint alignment lines on the lever and caliper assemblies (arrowed above).

4. Tighten the adjuster until the caliper levers move from the alignment lines.

5. Apply the handbrake to equalise the cable.

6. Tighten the adjuster locknut to a minimum of three clicks and a maximum of six clicks.

7. Fit a new adjuster locking pin.

8. Lower the vehicle.

Diagrams by kind permission of Ford (Europe)

EricR