Rear Brake overhaul
Posted: Sun Apr 08, 2018 10:38 am
Lets get the basics out of the way first; Brakes are important. If you're not confident changing stuff, get a proffessional to do it.
On the flip side, I'd sooner do things like brakes myself as I want to know their done right - Proffesional mechanics are always hard to find in the uk.
What I'd recommend: (do it once, do it right)
Reconditioned calipers
Brake pads
Brake discs
Handbrake cables.
Tools you're going to need:
7mm Allen key to remove caliper sliders - 7mm is NOT a common size (which is why it was used).
4mm Allen key to adjust handbrake.
14mm Sockets for caliper carrier bolts - I recommend 6 point sockets, as they've less chance of rounding.
10 mm socket for exhaust heatsheild, type 2 pozidrive screwdriver.
Type 3 pozidrive screwdriver (BIG bit)
You may need an impact driver and BFH
Jack, axle stands, copper grease,brake fluid, WD40 patience and a choice of good swear words.
So, to begin, jack and support the rear of the car, remove the roadwheels and you'll find something like this.
Have a good look around to see exactly what you're dealing with. Its a good time to start spraying your penetrating oil on stuff.
If you're changing discs, Undo the retaining screw in the middle of the disc - It shouldn't be super tight, but you don't know who's been there before you.
If you're not swapping the caliper out, you'll need to reset the parking brake mechanism.
Remove the cover from the adjuster and then using a large screwdriver between the outer pad and brake carrier, apply gentle, but constant pressure, whilst turning the brake adjuster anti-clockwise with 4mm allen key until no more resistance is felt.
Next pop off the plastic caps on the sliders and undo using a 7mm allen key. If these are tight, you can use a ring spanner over the end of the allen key to give you leverage.
After removing the spring clip, you should now be able to wiggle the caliper free.
If we're changing discs, we need the caliper carrier off too - 14mm bolts and likely to be swearing induced tight.
With the carrier off, the disc will come off easily.
Clean everything up thoroughly. New discs come with a protection coating that needs cleaning off.
The carriers should be wire brushed, with particular attention paid to where the pads seat.
All bolts should be wire brushed of rust.
If your swapping the caliper, Pop the handbrake cable off and clamp the brake hose. If you've not got a proper brake hose clamp, a pair of mole grips clamping a piece of cloth will suffice.
Compare the new and old calipers (yes, they're handed) and thread the caliper onto the hose fitted.
Everything is now the reversal of removal, but with the following observations.
If it was tight coming off, grease it. The carrier bolts have locking washers machined in the head, so a blob of copper slip on the end of the bolt will make the job a lot easier next time.
The sliders should be coated with red rubber grease; You can pick up small tubes (enough to do the job) for pence from eBay, or be like me, and have a whopping great big tub of it that will last me forever for a couple of pounds more.
The carriers should get a smear of copper grease, as should the pad edges where they sit on the carriers. I also like to but a blob of copper grease in the spring retainers.
If we've swapped the caliper, it's going to need bleeding.
then we need to adjust the handbrake:
The handbrake cable adjuster is actually only there to account for cable stretch - NOT pad wear. Once the cable is 'stretched in' it actually wont stretch that much more in it's lifetime.
If you use the central adjust to "improve" the handbrake, you may end up with the handbrake lever arms at the caliper at an angle which is past the point of mechanical advantage.
So....
Let off the handbrake cables at the adjuster underneath the middle of the car so that both caliper levers are OFF against their stops. I tend to wind the adjuster right to the end of the stop, just to be sure.
Now, Jump on the brake pedal until its rock hard. Then jump on it some more. Then, just to be certain, jump on it again. What your making sure, is that the brake pads are shoved as close as possible to the discs. You then need to remove the 'bungs' on the backs of both calipers. Once the bungs are removed you will find a 4mm allen key to adjust the calipers. To do this you need to wind the adjuster clockwise until it locks the brake on. Then back it off until you can just turn the disc, then back off another quarter of a turn - this will allow for expansion when hot.
Once you have done this adjustment pump the brake pedal half a dozen times then see what handbrake lever travel you have. if this is too much you will need to adjust the previously slackened cable adjustment. I aim for 5 to 6 notches fully locked on. You don't want the lever to be able to reach the end of it's travel (this is a reason to fail an MOT - "no reserve travel") but equally, if it comes up 2 notches, your cables are probably already pulling the handbrake levers on, giving you binding rear brakes (another MOT failure).
On the flip side, I'd sooner do things like brakes myself as I want to know their done right - Proffesional mechanics are always hard to find in the uk.
What I'd recommend: (do it once, do it right)
Reconditioned calipers
Brake pads
Brake discs
Handbrake cables.
Tools you're going to need:
7mm Allen key to remove caliper sliders - 7mm is NOT a common size (which is why it was used).
4mm Allen key to adjust handbrake.
14mm Sockets for caliper carrier bolts - I recommend 6 point sockets, as they've less chance of rounding.
10 mm socket for exhaust heatsheild, type 2 pozidrive screwdriver.
Type 3 pozidrive screwdriver (BIG bit)
You may need an impact driver and BFH
Jack, axle stands, copper grease,brake fluid, WD40 patience and a choice of good swear words.
So, to begin, jack and support the rear of the car, remove the roadwheels and you'll find something like this.
Have a good look around to see exactly what you're dealing with. Its a good time to start spraying your penetrating oil on stuff.
If you're changing discs, Undo the retaining screw in the middle of the disc - It shouldn't be super tight, but you don't know who's been there before you.
If you're not swapping the caliper out, you'll need to reset the parking brake mechanism.
Remove the cover from the adjuster and then using a large screwdriver between the outer pad and brake carrier, apply gentle, but constant pressure, whilst turning the brake adjuster anti-clockwise with 4mm allen key until no more resistance is felt.
Next pop off the plastic caps on the sliders and undo using a 7mm allen key. If these are tight, you can use a ring spanner over the end of the allen key to give you leverage.
After removing the spring clip, you should now be able to wiggle the caliper free.
If we're changing discs, we need the caliper carrier off too - 14mm bolts and likely to be swearing induced tight.
With the carrier off, the disc will come off easily.
Clean everything up thoroughly. New discs come with a protection coating that needs cleaning off.
The carriers should be wire brushed, with particular attention paid to where the pads seat.
All bolts should be wire brushed of rust.
If your swapping the caliper, Pop the handbrake cable off and clamp the brake hose. If you've not got a proper brake hose clamp, a pair of mole grips clamping a piece of cloth will suffice.
Compare the new and old calipers (yes, they're handed) and thread the caliper onto the hose fitted.
Everything is now the reversal of removal, but with the following observations.
If it was tight coming off, grease it. The carrier bolts have locking washers machined in the head, so a blob of copper slip on the end of the bolt will make the job a lot easier next time.
The sliders should be coated with red rubber grease; You can pick up small tubes (enough to do the job) for pence from eBay, or be like me, and have a whopping great big tub of it that will last me forever for a couple of pounds more.
The carriers should get a smear of copper grease, as should the pad edges where they sit on the carriers. I also like to but a blob of copper grease in the spring retainers.
If we've swapped the caliper, it's going to need bleeding.
then we need to adjust the handbrake:
The handbrake cable adjuster is actually only there to account for cable stretch - NOT pad wear. Once the cable is 'stretched in' it actually wont stretch that much more in it's lifetime.
If you use the central adjust to "improve" the handbrake, you may end up with the handbrake lever arms at the caliper at an angle which is past the point of mechanical advantage.
So....
Let off the handbrake cables at the adjuster underneath the middle of the car so that both caliper levers are OFF against their stops. I tend to wind the adjuster right to the end of the stop, just to be sure.
Now, Jump on the brake pedal until its rock hard. Then jump on it some more. Then, just to be certain, jump on it again. What your making sure, is that the brake pads are shoved as close as possible to the discs. You then need to remove the 'bungs' on the backs of both calipers. Once the bungs are removed you will find a 4mm allen key to adjust the calipers. To do this you need to wind the adjuster clockwise until it locks the brake on. Then back it off until you can just turn the disc, then back off another quarter of a turn - this will allow for expansion when hot.
Once you have done this adjustment pump the brake pedal half a dozen times then see what handbrake lever travel you have. if this is too much you will need to adjust the previously slackened cable adjustment. I aim for 5 to 6 notches fully locked on. You don't want the lever to be able to reach the end of it's travel (this is a reason to fail an MOT - "no reserve travel") but equally, if it comes up 2 notches, your cables are probably already pulling the handbrake levers on, giving you binding rear brakes (another MOT failure).