Front Discs and Pads - A Pictorial Guide

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[url=https://imoc.co.uk/app.php/kb/viewarticle?a=137&sid=fad20d162ef2fbda5dca1027b64889f2]Knowledge Base - Front Discs and Pads - A Pictorial Guide[/url]

I'm just expanding on Speedys article a bit. I like to see photos to help me envisage a job. Hopefully after reading this you will be able to attack your own front brakes. After doing this once, you'll wonder why you ever paid money to have it done, Honest! Using this method should not involve bleeding the brakes. I went from well worn dics and part worn pads to new everything without overtopping the Brake fluid reservoir. However, I am planning a complete bleed in immediate future!

You will need:
- A 12 mm socket for the caliper bolts
- A 17 mm socket for the carrier (torque plate) bolts
- A 21mm socket or the wheel brake for the wheelnuts
- Ratchet for above sockets
- Breaker bar for above sockets
- Jack and axle stands for safety

It is nice to have:
- Something to support the caliper (I used an axle stand)
- Caliper wind-back tool (rear brakes only) or G-clamp
- Some lithium grease for the pins (optional)
- Some copper grease for the hub face, disc bell and Pad shims (optional but highly recommended)

Here are all the tools I used:
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Before you lift the car, loosen the wheel nuts half a turn. He's me all ready to go:
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Remove the caliper bolts. These are the long 12mm bolt that runs through the caliper onto the carrier: You can see them part undone here:
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Remove the caliper from the carrier and pads. It slides off outwards with a bit of a wiggle. It's important to support it with something other than the brake lines. I used a second axle stand and some cable ties:
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(Warning! From this point on DO NOT press your brake pedal. You run the risk of firing the piston out of the caliper and having to re-build it.)

Undo the two 17mm bolts that hold the carrier onto the hub knuckle:
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And finally remove the brake disc if you are replacing it. Mine slid straight off. If yours doesn't, you can give it a thwack with a rubber mallet or if you can find the right bolts there are two bolt holes so you can push the disc away from the face of the hub. It's a good idea to clean up the hub face and give it a bit of Copper grease to make removing the new disc easier. It can also lessen the chances of disc vibration if the hub face is clean.
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You can now dismantle and re-build your carrier with new pads. The parts that come off it should look like this:
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Parts:
Carrier (Torque plate)
2 12mm Caliper bolts (the shorter one is the bottom one)
2 17mm Carrier bolts
2 Springs
4 Shims (I only have 3 :|)
4 Pad clips (may be bonded to the carrier like mine!)
2 pad wear indicators (mine have gone AWOL with the missing shims)

For reference, here is the Page showing the order the parts fit in the BGB:
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Rebuild your calipers as they came apart. I found it easiest to put the shims in place on the back of the pads first, then place the pads into the carrier before re-fitting the springs. A layer of Copper grease between each shim and the pad will do wonders for stopping your brakes squeeling. WARNING! Do not get grease of any kind onto the pad face!
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Now we need to retract the piston on the caliper. This is the way to do it without opening your bleed valves!

First, take the lid off of the brake fluid reservoir. If it's near min level then you won't have a problem. If it's closer to full then put some absorbant cloth around the neck as you don't want brake fluid all over your frunk.
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Now use a G-Clamp and a block of wood to push the piston back into the caliper. Go slowly and keep an eye on the level of your Brake fluid reservoir. Because I was ftting new pads and discs, I needed the piston fully retracted.
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Now close your Brake fluid reservoir cap!

Clean the the new brake disc with brake cleaner to throughly de-grease it, and then place it onto the hub:
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Fit the carrier bracket, complete with pads, back on to the hub knuckle using the 17mm bolts.
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Torque the 17mm bolts to 65lb/ft or 88N/m.

Now, Slide the caliper back over the Pads. You will probably need to hold the pads together to do this, and it would be nice to have someone hold the disc flat to the hub at the same time. Alternatively you could use a wheel nut.
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This picture shows the Caliper fitted and ready to be bolted back into place. Torque the 12mm caliper bolts to 18lb/ft or 25N/m.

Now you can refit your wheel and embark on the other side!

On your first drive:
Start the engine.
Pump the brake pedal. It may well go straight to the floor a few times as you push the pistons back out to meet the pads. Keep pumping it until it is firm.
Wait a moment and give it another prod just to be sure!
If it stays soggy then you either need to bleed your brakes, which shouldn't be necessary with the method above, or you may have damaged a piston seal or brake line. Stop the engine and check for brake fluid leaks. Prepare for head/wall interface.

Now, gently move the car from a standstill and perform a low speed brake test. That is, a gradual stop with minimal brake pressure. After a couple of these, perform a moderate speed brake test with firmer pressure.
These tests should be done on straight level road with no other road users in sight!

Once you're confident that your brakes are working 100% follow the pad manufacturers guidance for bedding in.