Replace slave cylinder
Ok, the job is fairly simple if you follow the, safety first, Rule 1.
Do not breath in any material that is contained within the brake drum assembly.
Loosen wheel nuts on the wheel or wheels on which you wish to change the slaves. Chock the front wheels to immobilize the car(don't attempt to do this fix on slopping ground, Rule 1), let the hand brake off and disengage the gears. Jack the wheel or wheels off the ground and place jack stands(you can use other means of support, but I mean substantial support, bare in mind the weight involved and possibility of minor movement, Rule 1) under one or both ends of the axle. Remove the wheel or wheels.
Remove the brake fluid hose from the slave at the rear of the brake unit. Crimp the rubber hose to avoid excess fluid lose or you will drain the brake system and it is a pain to fix, not hard, but just a huge pain in the proverbial.
Look at your brake drum, some have small flush retainer screws which hold the brake drum to the axle end, if so remove them. Look at the back of the brake backing plate, there will be a rubber grommet that allows access to the brake adjuster, remove it. There is a special brake adjuster you can buy for a few $s, but a screw driver with a wide blade will suffice. Adjust the brake shoes off turning the star shaped adjustment wheel, if you turn the adjuster the wrong way it will lock the drum up, just reverse the direction of adjustment the right way to off, a couple of full turns is sufficient. Remove the brake drum, now more times than not they don't fall off easily because of corrosion and crud build up. If so, give the drum some gentle taps(I do mean gentle, this is a cast item and will shatter if it is hit too hard. You will be buying a new one if you break it) with a hammer to loosen and remove. Wipe clean and inspect the brake drum for wear and scoring, if it is too great you may have to have it replaced or honed. Check brake shoes for wear that sufficient material is still left. If they are down might be an idea to replace them, that is if you don't want to repeat most of this again later :-). Do not allow any oil or grease to contact the inner drum contact area. There are specialized brake component cleaners for sale.
Now you can see the business side to the brake assembly. You will see the brake adjuster, slave, 2 shoes, 2 springs(1 top and 1 bottom), 2 or 4 retainer pins and the hand break cable and arm. Take special attention of how the the springs are mounted, better still, take photos. Disengage the hand brake cable from the control arm and pull cable with the associated grommet out of the brake system, one less thing in the way. Remove the top and bottom springs, these are nasty powerful springs, refer Rule 1, pointy nosed pliers or multi-grips should suffice. Your adjuster can now be removed. Only thing holding in the shoes now is the retainer pins, put your finger on the pin at the back of the brake backing plate, with pliers, push and turn the lock washer on the inside 1/4 turn and it will all come apart. Take note of the disassembly of these components, they go back in the exact same way they come apart. The shoes will fall out. Now all you have left is the offending slave, remove the 2 bolts holding it in place and replace with the new item. Reassemble in the reverse order, make sure everything is clean, oil and grease free. You can use a good screw driver to put the springs back in, again refer Rule 1.
If you replace the shoes, you may have to wind the adjuster in some more to get the drum back on.
Nearly there, all that remains is to bleed the brake fluid line, slave and adjust the brake shoes.
Make sure you have sufficient brake fluid on hand and in the master cylinder. The level will drop in the master, so keep an eye on it and maintain a good level in the master. I, myself prefer to gravity bleed brakes, but that is me, it takes time, but you can bleed them quicker with the help of another person. Have person slowly pump brake peddle till they have pressure, undo bleed nipple, peddle will drop to the floor, hold on floor till you tighten bleed nipple. Repeat until you have fluid free of air, remember the MASTER. Brake peddle should have constant pressure and not feel spongy or slowly go to the floor. If it does, check for leaks or it is possible to still have air in the line. Bleed until you have a firm peddle. If the peddle is good, then all that is left is to adjust the shoes. Adjust until drum locks, push brake peddle, wind back adjuster until drum runs free.
All done, you will notice the peddle has increased after the shoes are adjusted, all good. Put the wheels on, drop to the ground, final tighten on the wheel nuts. engage gear, put hand brake on, remove chocks.
I can't stress how important it is to get the brakes right. A car without good brakes is only a missile looking to kill you or someone else. If in doubt, ask someone. Rule 1 always.
Feb 10, 2014 |
1994 Nissan Pickup