Replacing Rear Brake Shoes and Brake Cylinder on an '06 Citroen C3
Intro: Replacing Rear Brake Shoes and Brake Cylinder on an '06 Citroen C3
- Worn rear brake shoes may not have an immediately noticeable effect on braking but may make your handbrake poor.
- If you have excessive movement on the hand brake to engage it may only mean the auto adjuster is a bit dusty and stuck.
- If the handbrake sticks after being sat for a couple of days it may be an indicator that you have a weep on a cylinder.
Popping the drums off can be an easy job if they are removed regularly, however if not the combined effect of wear to the inside of the drum and corrosion to the outside edge will cause a lip to form making the removal very difficult.
CAUTION: This will involve jacking your car up off the ground so that the wheel can be removed. If you've not done this before grab someone who has! Also many videos can be found on Google on how to do this safely.
Tools:
- 17mm socket - wheel nuts
- 32mm socket - Hub nut
- Flat head screw driver
- Center punch
- Hammer
- Sandpaper
And optional but handy to have:
- Hub puller
- Brake bleeding kit
- Brake pipe spanner
Materials:
- New rear brake shoes
- Fitting kit (new springs, hub nut etc.)
- Copper grease
- Brake cylinder
- Brake fluid
It is also worth knowing, there is a Lucas and a Bosch version of the brakes on the C3, and the shoes are not cross compatible. I don't know of a way to find which you have before removing the drum. These notes are for the Bosch version.
STEP 1: Remove Rear Wheel
Find a level place you can work on the car safely, I loosen the wheel bolt with a 17mm socket and bar before jacking the car as they can sometimes be a bit stiff (especially if done by a garage with a pneumatic wrench) and you may need to push on it a bit.
Follow all car jacking precautions including:
- Chock the front wheels with four bricks
One in front and one behind each wheel will reduce the potential for movement.
- Leave the car in gear
As we want the drums off we can't leave the handbrake on but we can significantly reduce movement on the front wheels by leaving it in gear.
- Extra support
Once jacked up I put a couple of axle stands under something solid and lower the car onto them giving more support.
Once the wheel is up remove the bolts, then the wheel. Use a piece of chalk to mark the drum with the orientation of the wheel valve if the wheel balancing was done on the car.
STEP 2: Remove the Drum
Removing the drum
Use a flat screwdriver to pop the cover cap off the hub nut.
Use the center punch and hammer to "unding" the hub nut.
Use the 32mm socket to undo the nut.
On some cars one side is a left handed thread (not this C3 though), these will be reasonably tight but not impossible so if you have problems with the passenger side try the other direction. If you are having problems undoing the hub nut then this youtube video from TK42138 could well be of use.
The handbrake should be off and can be loosened a little from an adjuster by the handbrake lever.
On a car which has had the drum removed regularly or a new car, this should be reasonably easy and the drum will slide off. Sometimes the use of a soft (leather or nylon) mallet will help jiggle shoes to the center to help. Often the wear to the inside of the drum and corrosion to the outside edge will cause a lip to form making the removal very difficult.
Note of caution:
Brake shoes shouldn't contain asbestos any more but it would still be best to avoid breathing the dust. Also if a cylinder has leaked the inside will have brake fluid residue which can be an irritant to some.
Use a hub puller if necessary;
It is theoretically possible to un-ratchet the auto adjuster and make the most stubborn of drums slide off. You would need to use a thin flat screw driver stuck though a wheel bolt hole to lift the ratchet and at the same time use some sort of tiny hook to unwind the auto-adjust bolt, this is akin to lock picking and I had no luck.
Use the wheel bolts to secure the puller to the drum and slowly wind in the center bolt. I'm not sure if it had any more then a psychological benefit but I was alternating a little turn on the pushing bolt and a turn of the drum hoping to encourage the shoes over the lip edge. For me this took some time because I was worried about damaging the bearings (which are fastened inside the drum).
STEP 3: Removing the Brake Shoes
With the drum off you can remove the shoes, it's also worth checking for signs of brake cylinder leakage. I couldn't tell at the time but my photos are rather blurry, the first shows a dry dusty non-leaking shoe assembly, the second a gummy leaky cylinder. As brake fluid strips paint it was clear I had one side leaking, probably for a while.
The order you remove the springs is only critical in the sense that you need to be able to reassemble them later. It may be useful to take a couple of photos in case it goes wrong and all pops undone.
I removed the bottom spring first by pushing with a small flat-head screwdriver then removed the two retaining pegs. Grab the 'plate' on the peg with some pliers, push against the spring and turn 90 degrees, it may help to have a hand around the back on the peg head to stop it turning. Now it will be possible to remove the shoes and auto-adjuster intact to help reassemble them onto the new shoes, by lifting the bottom edge of the shoes off the plate and wiggling the top edge off the cylinder.
STEP 4: Replacing a Cylinder
If it needs replacing, the cylinder (for the Bosch brakes) fits either side so for the sake of £15 it may be easier to have one in rather than reassemble the old brakes so you can drive to a shop.
The cylinder is held on with a single nut (10mm). The photo is of the back of the brake plate, an angle you can't get your head into easily unless you have a proper car lift. Have plenty of absorbent rags around to catch the brake fluid. Use a brake pipe spanner to undo the pipe and the cylinder will wiggle out. Put in the new one, connect the brake pipe and replace the bolt. The shoes and drum need to be on before bleeding the system. You will need to squash the pistons in and I didn't want to force air into the system so I loosened the bleed nut while I did it.
STEP 5: Reassembly
Taking note of which spring is which and the orientation, remove the auto-adjuster and clean. Remove any grit from the adjuster thread and wind it in a few turns. I use a little WD40 on the adjuster and the handbrake lever to keep things moving (but not too much to avoid it becoming a goo with shoe dust).
I also put a little blob of copper grease onto the back plate where the edges of the shoes rub, this should reduce the rate of corrosion here, keeping some movement to the shoes.
The shoe assembly is held on with spring loaded pegs, these can sometimes be a bit difficult with new strong springs. I find a foot can hold the assembly in place, one hand around the back to stop the peg turning with the other pushing and turning the front using pliers.
Replace the drum
Once the shoes are on I give them a little roughing with some sand paper to remove any finger prints, also sand out any imperfections to the inside of the drum and any sign of a lip to the front edge. If the drum is excessively worn, pitted or grooved it would be worth replacing. The drum should spin freely but you may hear a little rub from the new (and thus bigger) shoes. If the shoes are nowhere near the drum it would be quicker to remove the drum and wind the adjuster by hand.
Replace the hub nut and bleed if necessary
With the drum on replace the washer and hub nut (there should be a new one in the fitting kit). Now would be the time I would bleed the brakes if you've replaced the cylinder (see bleeding below). Once tight the hub nut is secured by bending it into the stub axle groove with a center punch. Replace the covering cap and put the wheel back on, lower the car and tighten the wheel bolts. If this is the last side don't forget to re-tighten the adjuster on the hand brake lever so the cable has just a little tension. Also check the movement of the handbrake if it moves a long way press the brake pedal hard many times to wind the auto adjuster a bit tighter.
Before you drive off, check the brake fluid level and that the hand brake can hold the car.
Bleeding the brakes
If you've replaced the cylinder you'll need to bleed the brakes. I'd recommend a bleeding kit but it can be done with jar and some thin hose. An assistant will be of use but a brick could work. Put a spanner on the bleed nut and a hose over the nipple. Press and hold the brake peddle with the bleed nut cracked open. Close the nut then release the peddle. Repeat until only fluid with no bubbles is being forced through the pipe, you want no air in the system.
Note of caution:
The odds are all is well with your brakes and your new shoes are fine, however I tend to do mine just before an MOT as they test all the brakes on a rolling road, I haven't yet made an error but I'd like to know if I had.
Thank you for reading, hope these notes are of use.
3 Comments
l12g 2 years ago
Your photos are just right to show some of the more difficult operations. however, I can add a couple of tips (a video would make the following text shorter):
1. The threads of the handbrake adjusters are handed. Easy to remember - left hand thread on the left side of the car, and right hand thread on the right hand side - your photos show this but you do not mention it.
2. To loosen the handbrake adjuster mechanism the toothed adjuster wheel must be moved down when viewed through the wheel bolt hole. The system works like a pawl and ratchet. The ratchet is the toothed wheel and the pawl is just visible behind the bottom of the toothed wheel. The pawl has to be pushed out of the way at the same time as rotating the toothed wheel. This can be done with a thin blade (the width of a smallish screwdriver) with a right angle bend of about 1 - 2 mm / 0.1inch. Engage the toothed wheel at the bottom and push gently until resistance is felt. The trick is to keep the blade engaged against the toothed wheel while pushing the pawl out of the way. Once the blade has come between the toothed wheel and the pawl, insert another screwdriver and proceed to turn the toothed wheel down. This is a long process if the brakes are worn as a lot of slack needs to be wound back. Keep going until the toothed wheel does not spin any more. There should be no need for force.
3. If everything else fails and only as a last resort there is another trick _BUT_ this means that the drum MUST BE REMOVED. You will not be able to drive to a garage for help because the mechanism will become loose or even broken if not done carefully, and WILL RENDER THE CAR UNSAFE UNTIL THE REPAIR IS COMPLETE. Align the top of a bolt hole just above the handbrake adjuster. Ask a someone to press the foot brake in order to expand the shoes. This will take pressure off the handbrake adjuster and allow the next operation ... Use a flat blade screwdriver inserted above the adjuster and push the adjuster down.
DO NOT USE EXCESSIVE FORCE as this will damage the adjuster. It should pop off the mounting point on the leading shoe (towards front of car). This will release the brakes from the drum once the foot brake is released.
4. Removing the brake drum: Many videos show the use of a drum puller - that can be rented, or levers in complicated arrangements. However, try this. First wind the axle nut back onto the axle for at least 3 turns, to prevent the drum from being accidentally removed completely. Remember there is a perfect lever that allows pulling off the drum evenly. It is big enough to provide sufficient purchase to wiggle the drum loose ... remount the wheel on the drum. It makes it so much easier to loosen everything. Once sufficiently loose remove the wheel to avoid possible damage to the bearings and bearing faces in the drum while removing the drum. Finally remove the wheel nut and the drum as in the article.
joshabgvghn 10 years ago
cbm104 8 years ago
Thanks! I've found I make use of my phone camera with things like this :)