Tech: Rebuilding the Rear Brake Cylinders
|Subject Vehicle: Classic Style Montero/Raider with Rear Drum Brakes|
Gord McFarling shows us how to avoid buying new brake cylinders, by rebuilding the old ones. This fix is relatively easy, and should take about 40 minutes for both sides. If you are not familiar with the workings of a rear drum brake, enlist the help of someone with experience to watch over your shoulder, in case you get stuck.
Dental pick (to pull the seals on the piston)
Two cans of brake cleaner.
|Place a jackstand under the rear axle, block the front wheels, and remove the back wheels|
|If the drum is hard to remove, thread a bolt slowly into the holes on the front of the drum|
|With the drum off, clean the whole assembly with brake cleaner. (Do one at a time, just in case!)|
1. Remove the wheel
2. Pull off the drum and clean the brake assembly and drum with brake cleaner (use one whole can)
|When removing the brake shoes, be careful not to lose the springs|
3. Disassemble the shoe assembly
4. Remove the rubber dust boots from around the brake cylinder
5. Pull the pistons from the cylinder
6. Inspect the interior of the cylinder for burring and corruption
7. Using a clean rag, wipe the brake cylinder being careful not to leave lint in the cylinder
8. Inspect the pistons for burrs and damage
9. Replace the rubber grommet on the pistons being careful to
match the direction in which it is to seat. If they are installed
backwards they will not hold compression and will weep
DOT3 all over the interior of the drum.
|The piston with dust boot in place|
|The reassembled rear brake, as it should look.|
10. Replace the rubber dust boot on the piston. It only goes on in one direction, if it goes on backwards it will not cover the cylinder ends.
11. Reinsert the pistons into the cylinder. Remember to remove the bleeder screw as it releases the compression on the cylinders. The easiest way to do this is to wiggle and push the piston at the same time.
12. Pull the rubber dust boot back on the cylinder. Easiest if you put the back of the boot on first and then do the front.
13. Reassemble the pad assembly (I also cleaned the outer pads again as a precaution to corruption and contamination).
14. Put the drum back on and bleed the brakes. (It is easier to bleed the
brakes with the tire off).