Saturday 20 August 2022

Brakes - Part 2 - Front

I'm planning to run 16" rims on Project Snake so I went with the smaller option of the AK Big Brake Upgrade kits which is suitable for 15"-17" rims.  The kit includes two vented front discs (335mm diameter by 32mm thick), two bells for the front discs (discs and bells came pre-assembled), two 6-pot calipers for the front, and two 4-pot calipers for the rear. The kit uses the standard Jaguar rear discs.  I also elected to upgrade the brake pads supplied with the kit from EBC Green Stuff pads to Ferodo pads.

The front calipers are not a massive difference in size from the original Jag twin-pot items, althoigh they are a lot slimmer and in fact, the brake pads are practically the same size as the Jag originals.  However, with three pistons per side, the braking pressure will be more evenly applied to the pads (and to both pads) providing superior stopping power.  The other massive difference is in weight.  The original cast iron calipers weigh in at a hefty 5.2kg.  The AK items, being billet, are a svelt 1.9kg, which provides a huge benefit through the reduction in the unsprung mass of the car leading to better handling on the far-from-smooth UK roads!

Gratuitous Brake Porn...

Looks far more attractive than the original...

...with 3.3kg of added lightness and 6 pistons of (stopping) power!

New pads (bottom) are similar in size to the originals (top)

Original front disc dwarfed by new shiny monster disc!

The kit comes with some new brackets and bolts to fix onto the front uprights onto which the calipers are attached.  I fitted these and torqued up the mounting bolts to 100Nm/74ft-lb.  The new discs were placed over the studs on the front hubs and secured with a new retaining screw (P/N SF605047 from British Parts UK).

New caliper mounting block and bolts...

...installed onto front upright

Before installing the calipers, the brake pads need to be installed (technically this can be done later as the pads install from the outer side of the caliper).  This required removing two threaded pins, allowing the pads to be slid into place.  The pins and spring clip were then reinstalled, the caliper placed over the front disc and then secured to the mounting block with two Allen-headed bolts.

It is recommended that a smear of copper grease is applied to the rear of the brake pads to prevent brake squeal.  This is something I have made a note to do later.  I have not removed the protective coating from the brake discs yet as I don't want them to start flash rusting while I finish off the rest of the car.  So the calipers will need to come off again at some point.  For that reason, I also haven't torqued up the caliper mounting bolts to their final spec - 60Nm (44lb-ft).

Starting to look more like a proper car!!







 

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