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 your disk have 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 socket for calliper bolts
- Axle stand (extra to any used for supporting the car)
- 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.
- 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 calliper bolts
There are two big star drive bolts holding the calliper 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 on reducing the chances of the star drive slipping or pushing the car towards or backwards.
Once the bolts were out I used some wire to hang the calliper so as not to strain the hose.
If you are only changing pads then you can skip to here.
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 bolt.
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.
Add the sliders and a little grease, then fit the pads.
Refit the wheel and test they work!