I have two projects that need brake caliper updating. Charger doesn’t even have brake calipers yet as it came with drum brakes. My BTCC replica Vectra has puny disc brakes and a lot bigger will be needed in the future. The brakes were already at their limit when I was driving the car on track with very slippery 14 year old tires. The Charger is progressing slowly so I’m just collecting parts and doing more to get the Vectra move faster.
I bought huge Brembo brake calipers from a Citroën C8 with a V6 engine. They use 310x32 mm brake discs with a very large 4 piston calipers. The calipers are radial mounted so the adapter are quite easy to make. The same caliper has been used in various purposes so race spec brake pads are available. Mine don’t look as nice as the one in the picture.
I would like to use a disc size that come from some production vehicle. If I later want to change to use rotors with separate bells I can build ones that use same dimensions.
I have now switched my plans. I want to get a bit larger diameter discs even though the thickness might drop. I decided to get calipers from a Alfa Romeo 159/Brera with large engines. They are quite similar with the earlier purchases and they even use the same pad size. They are designed to use 330x28 mm brake discs and these discs will fit directly over Vectra’s hubs and they have the same bolt pattern and the center hole.
The main differences in these calipers are that they use unequal sized pistons and monobloc design. The piston areas with the Vectra’s original calipers and with the two Brembo calipers are nearly equal. So there no need to switch the master cylinder (the rear brake line has already a bias regulator).
So I purchased a set that has 159 Brembo calipers and also rear calipers that have hand brake function using the disc. Vectra uses a separate drum for the hand brake. Upgrading the rear brakes isn’t very essential at this point but maybe in some later phase I will upgrade them too.
While I was waiting the calipers to be delivered I noticed that I had misread the sizing tables and the rear caliper were for solid discs and not for the slightly thicker ventilated ones.
When the package arrived I noticed that I had made another mistake. The front calipers were also the wrong ones. For some reason Alfa Romeo had offered Brembo calipers in one certain model that did use 4 piston monobloc calipers but with smaller brake discs (shared with the low spec models). So they are suitable for 305x28 mm brake discs and not the big ones that I’m going to use. I had missed this weird option.
So now I have one useless set of semi large calipers. The front ones look like these:
The big brother looks like this (the external brake line and the location of bleeding screws should have been good ways to spot my mistake):