While I have the hubs and calipers off of the car, I’m replacing the brake disks. The old ones are a bit worn but still OK. When I bought the car, it came with literally 3 complete set of brand new pads! With a car that does as few miles as this… that is essentially a life-time supply. No excuse for new brake pads all round then.
New, OEM Magnetti Marelli brake pads
The first step is to drive out one of the two retaining pins from the caliper with some sort of drift. They can only come out one way which is obvious from the shape.
Removing the first caliper pin
Next remove the retaining spring and the second pin. Then the brake pads can be removed with a pair of pliers. Assuming your brakes are well adjusted, the old pads should come out easily. Grab one of the tabs and pull straight out.
Removing the second caliper pin
Grab one of the tabs and pull the pad straight out
Now you can pop the new pads in but first you will need to carefully push the pistons in a little to make some additional space for the new, thicker pads. If your caliper is off the car look out for escaping brake fluid from the brake line when you push the caliper back. It will squirt out! If the caliper is on the car, then the fluid displaced will simply go into the reservoir. Be careful not to scratch the piston or damage the seal.
Piston pushed back ready for a new pad
At this point you may notice that there appears to be part of the piston edge missing. It’s at about ‘2 o’clock’ on the piston visible above. This is normal as part of the edge is cut away to allow for measurement and adjustment for the caliper piston angle. This does not have to be adjusted when just changing pads and will remain at the optimal 20 degrees to adjust the pressure applied to the leading and trailing edge of the pad.
With new pads in place, check that there is an equal distance between the disk and each pad. There should be if your old pads were set correctly and wore evenly. If the brake disk is not centered between the new pads you will get sub-optimal braking, premature wear and potential damage to the disk. The disk position can be adjusted by shimming the caliper where it attaches to the hub.
Disk/caliper centering shim (no. 3, highlighted)
Finally the pins can be re-inserted, driven home and the spring reattached.
New pads fitted