Checking and replacing brake pads and disks is useful skill to have if you enjoy car maintenance, even if you decide not to do the replacement yourself it's handy to be able to spot an issue before it has an impact on your ability to stop.
Checking the brakes
If your turn your wheels to full lock you should be able to get a fairly good view of the inside of one of your wheels. The things you are looking for are excessive wear to the pads and pitting to the disks.
Bit subjective but most pads start out at >10mm thick so if you look to have less than 5 mm of pad then it's worth thinking about how long it's been since they were replaced.
Surface pitting is little rusty spots bellow the surface of your disks. If a disk has a full circle of rust where the pads should be making contact then there is no question about replacement time, your braking is being affected. If not then the AA website says this:
"This used to be a reason for MOT test failure but data available following the introduction of the computerised MOT showed that too many cars were failing the test on 'brake discs pitted' even though this was not sufficient to weaken the disc."
This is means there's no standard amount of pitting for an MOT pass or fail.
- Means to lift car
- 17mm socket to remove the wheels
- Star (or 'T') socket for caliper bolts
- For my car it was a T55 similar to this : Amazon link
- Axle stand (extra to any used for supporting the car)
- I use some like these : Amazon link You can get them much cheaper, for me it's the kind of thing I'm likely to buy only once in a lifetime... :)
There are a couple of differences in the C3s with things like the breaks being either Bosch or Lucas, so that even with your registration you are guaranteed to get the correct parts from a spare shop. I try and take some photos and ask to look at both types, most of the time you can spot which you have. I do try and keep the box with the part number but these jobs are done so rarely it's often lost by the time I need it again. This is for the Bosch version but the method will be similar for the Lucas set up.
- New disks
- New pads
- New brake fluid
Step 1: Before We Begin...
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 and YouTube on how to do this safely. Five minutes watching how others do it successfully you save you a lot of hassle. I made a few of my own notes here: C3 drum brake replacement
- Prepare your work area
- Sort out tools
- Double check the car is chocked and hand brake is on
- I often loosen the wheel bolts while it's on the ground to make life easier
- Lift car
- Remove the wheel - 17mm socket
Step 2: Remove Old Pads
With the wheel off you can undo the two 13mm bolts, loosen the caliper and remove the old pads.
The old pad and a new one.
Step 3: Remove the Caliper
Two caliper bolts
There are two big star ('T') drive bolts holding the caliper on. Mine were rusty and may have had lock tight or something. The second picture shows the ratchet on an axle stand, this allowed me to put a lot of downward force while reducing the chances of the star drive slipping out of the bolt, or pushing the car forwards or backwards.
Once the bolts were out I used some wire to hang the caliper so as not to strain the hose. Hoses are fairly study but I wouldn't ever let them take any of the caliper weight.
If you are only changing pads then you can skip to step 5.
Step 4: Remove the Old Disk
The disk will be attached with a short posi-drive screw. WD40 and an encouraging tap with a hammer may help free it.
Step 5: Add the New Disk and Pads
Your new disk may have a protective grease coating so a wipe with a petrol rag will clean it up.
Now it's the reverse of the disassembly:
Drop the disk onto the hub and secure with the posi-drive machine screw.
Refit the caliper and the securing bolts.
I practice fitting the metal sliders on the caliper before refitting, they are often a slightly different shape and you need the correct orientation. You my need to compress the piston to open up enough space for your thicker pads and disk. I used a large pair pf pump pliers and very carefully squeezed the piston, you don't want to damage anything or get brake fluid overflowing from the reservoir - a rag around the reservoir cap might save a bit of mess.
Add the sliders and a little grease, then fit the pads.
Refit the wheel and test they work!