Choosing a Braking Setup

Time to choose a braking setup. I've been toying with the various options of what braking setup to use on the Avon, the only reasons I have for not going completely standard are 1) Cost. To recondition the standard cortina components can cost nearly as much as some aftermarket conversions. 2) After seeing the Avon on the Ultimate kit car DVD, the only complaint the racing driver had with the car was that it ran out of brakes! As I will be using this car a lot on track, I didn't want the same thing happening.

Standard Setup

The standard setup for the Avon is to use the original cortina front discs and calipers. These are 245mm solid discs. The rear stopping is provided by Sierra 8 or 9 inch drums. The cost of reconditioning the fronts is about £75 per caliper + £25 for new discs and £10 for pads. Totalling £185 The rears are much cheaper coming in at about £100 for new back plates, cylinders, drums and shoes.
Although more than enough to stop the car on a day to day basis I wanted something that was going to be more durable on track. Also lets not forget that the Cortina caliper is getting on a bit now, parts may become increasingly hard to find so it makes sense to minimize the dependence on older kit, from a consumables point of view.

New Front Calipers

I came across the rally design site after a post on the Cam7 forum, although the name suggests rally parts they have a large kit car selection at some great prices. They offer numerous kits for all makes of kit car. They are also a stockist for the leading US brake manufacturer Wilwood.

I opted for the following brake kit [BK1P] as listed on Rally Design.
The kit consists of :

• x2 Wilwood Powerlite Calipers
• x2 Solid (plain or grooved - I am going for grooved) disc
• x2 mounting brackets
• x4 pads
• Mounting bolts

All for the princely sum of £200. When I get nearer to the time of fitting the brakes I will order them and post up some pictures.

Rear Setup

Discs or Drums? Well its clear cut. Discs! Except that I can't afford them, so drums! My donor pack comes with 9 inch Sierra drums. I have to say that I really would prefer a disc brake setup as it is far more modern, easy to work on etc. However the drum setup is cheaper and easy to fit. The Avon can accept a rear disc setup but it requires modifying of the rear hubs. The drums just bolt straight on.

Whilst I was deliberating this, I spoke to a couple of people who race Seven cars, one of them had switched back to drums from discs as they preferred the feel of it.

As with all cars, most of braking force is dispensed by the front but given the weight of these cars, the rear brakes do little more than keep the car in a straight line under braking. So ultimately I don't think it really matters what you use. Switching over to discs at a later date might make a nice mini project once the car has been completed and passed its SVA.

I decided to keep my drum arrangement, just fit new shoes, drums and cylinders. The back plates will be shot blasted and refurbished to as good as new.

Tiger Rear Handbrake

Tiger have a pretty simpe but effective handbrake system. I will show some pics when I put mine in place. Essentially it comprises of two cut down sierra cables feeding into the drums, attaching to a balance bar, behind the brake lever. The standard sierra handbrake then mounts above the drive tunnel and connects via a single cable to the centre of the bar. This is used on all Tiger models.

Master Cylinder Setup

Deciding on the master cylinder setup took me to quite a few experts, as I have to confess I know nothing about braking systems, i've never really trusted myself to do my own brake work, after all they do keep you from getting front row seats at the scene of the accident!

The general consensus from the forums and experts I spoke to was, if I was going to use a twin master cylinder system, the front master cylinder should have a bore of 0.625. Opinion was divided on the rears between a 0.7 and 0.75 bore cylinder. I finally decided on a 0.7 cylinder as this would apparently give me a firmer pedal, something I have longed for, ever since fitting large brakes to my road car and feeling the sponginess in the pedals after, I really wanted to get that racing feel back!

Pedals

I'm going to cover the selection of pedals and arrangements in another post. Suffice it to say, floor mounted is the way to go, the Sierra standard pedals are not comfortable for me, I tested them in a Tiger Cat and a Robin Hood and I think they feel horrible.

Bias Bar

I am very keen on having an adjustable bias bar, especially for track day use or if I decide to go racing, as this allows rapid change of the brakes setup. Even better would be a remote adjustable bias bar, allowing the bias to be changed whilst the car is in motion.

SVA

Whilst all this sounds lovely Mr SVA will have a few things to say before he passes my car. The first rule is that the rear brakes must NOT lock before the fronts in the braking test. Secondly, the bias cannot be adjustable. This requires a bit of a hack. The bias bar must be locked off so that it cannot move. This means drilling a hole through the retaining nut, the bar itself and then securing with a roll pin.

Fortunately I have a good friend who is an MOT tester, hopefully I will be able to set the brakes up properly on the brake tester machine before the SVA and locking off the bias bar.