How To...Fit New Brake Discs & Pads

My thanks go to Rob Trowe and his brother who carried out all the work detailed below on his own XR4x4 and took all photographs within this article. Click on any of the images to see a larger picture.

To start with the wheel nuts are loosened all round the car using a cross brace, before jacking up the car and placing it on axle stands under the cross-member. This is a good solid place for the car to rest, and it saves possible damage to the normal jacking points. Next the rear of the car is jacked up off the diff using ramps with big blocks of wood slid under the trailing arms before lowering the car back down. Now all the wheels can be removed.

The next step is to remove the front calipers and discs. A 17mm socket and short extension is needed to remove 2 bolts behind the disc, these go through the hub and into the caliper. Once the bolts are removed carefully remove the caliper from the disc, some gentle persuasion maybe required, and push the caliper piston in allowing the pads to open up. The caliper should slide off easily and depending how high the car is off the ground use a brick or an upside down bucket to rest the caliper on so as not to strain the brake hose.

However since the hoses were being changed anyway the brake pedal was pumped with the keys out of the ignition about 20 times to release the pressure in the ABS system. Then with a suitable container ready take the hose off the caliper with a 13mm open ended spanner and point the hose into the container and let it drain the brake fluid out.

NOTE : If you get brake fluid on your hands or clothes be very carefully what you touch or brush against, as it will damage your paint work.

The old disc was pulled straight off, however heavy handed persuasion may be required.

The above needs to be repeated for the brake assembly on the other side of the car.

With the calipers off they can stripped down, firstly drain as much fluid as possible and then place the nozzle of an air compressor (if available) into the hole where the hose connects and blow the piston out of the caliper. With this out remove all the seals and clean all the parts. Use something like a wire wheel attached to a drill to clean everything up being careful not to score the surface where the piston slides.

You can use the Lucas caliper repair kit to replace the seals taken out, this can be obtained from Halfords. The kit contains 1 x O-ring seal, 1 x dust cover and 1 x cap for the bleed valve (one of these kits is required for each caliper, so two will be required).

Prior to the caliper being put back together, it needs to be primed with brake fluid before fitting. The O-ring is put into the caliper first, then the dust cover can be slid over the end of the piston about 10mm in, and then push in the rest of the dust cover into the caliper. The piston is then pushed back into place and the dust cover should settle in. The piston may also need some gentle persuasion in the form of a something like piece of wood and a G-clamp. Everything can be put back together, use some copper grease behind the EBC Green Stuff pads and a little on the parts of the pads where it moves along the caliper. The calipers are now ready to go back on.

Now at this point the calipers haven't been put back on but you can proceed to change the hoses for the Goodridge braided items if required. There are a total of 6 hoses in 3 different lengths, long, medium and short. The longest hoses are for the front calipers, the medium length hoses are used to go between the floorpan and the trailing arm and the shortest hoses are for the rear calipers.

With the kit there should also be 16 large copper washers, 4 small copper spring washers and 8 nuts. The small washers are used for the end of the hose which goes into the caliper and the large washers are used for the brackets i.e. you put one large washer on the hose end, push it through the bracket put the other washer on the other side and put the nut on.

The best way to put the front hoses is to put the hose on the caliper first and then put the other end of the hose into the bracket at the bottom of inside wing. The rear caliper can be a bit more tricky, this is due to the fact the nuts on the old hoses will probably be seized and rusted onto the brackets. With a bit of persistence and a pair of mole-grips the nuts will come off eventually. The hoses between the floorpan and the trailing arm swap out quite easily.

With all the hoses changed put the front discs (Black Diamond X-drilled) on with some copper grease on the face of the hub, making sure to keep the copper grease off the surface of the disc. Then make sure the piston is pushed right back on the caliper and slide it onto the disc. Put the two 17mm bolts back in by hand and then tighten up with the ratchet.

Again the above will need to be repeated for the brakes on the other side of the car.

When it comes to bleeding the brakes two people will be required (unless a suitable one person brake bleeding kit is being used). One will be required to operate the brake pedal and another to collect the fluid in a container and check the brake fluid level.

Start at the drivers rear and attach the pipe to the bleed valve and with a 11mm open ended spanner loosen it, top up the reservoir and turn on the ignition and use the ABS motor to bleed the drivers rear caliper by lightly pressing on the pedal. Wait until all dirt and bubbles stop coming out into the container. The bleed valve is then tightened and you can start on the passenger rear in the same way.

Now that the rear has been bled it is time to do the front. The front is bled NOT using the ABS motor but in the normal conventional manner by pumping the brake pedal. The next to be bled is the passenger front and this can be pumped with the key out of the ignition until all bubbles come out. Tighten the bleed valve and then repeat for the drivers side.

It is imperative you keep an eye on the brake reservoir level and ensure it stays above the minimum level. When all the brakes have been successfully bled a total of 2 litres of dot 5 brake fluid will be required.

All the wheels can now be put back on and lowered from the jacks and/or ramps. Ensure all the wheel nuts are tightened correctly with the cross-brace and then the car will be ready to be driven to check the brakes. Recheck the brake fluid level on returning. With the ignition on, after about 30 seconds, the level should be at the max mark. If need be siphon or add brake fluid as required.

The brakes will feel vague until they have time to bed in, this will take about 200-300 miles and heavy braking should be avoided until you have covered this mileage and the brake pedal feels firm.