I am having problems with my brakes.
My Indy is ready to be dropped on the deck as a rolling chassis. The problem is that I have bought 300mm x 32mm HIgh spec discs and bells. I have seirra cosworth vented rear discs 273mm x 20mm.

I think that the brakes are overkill, although i havent tried them.

I am stuck with using cosworth spacing on the rear discs, but I was wondering if anyone has the following spec and would tell me if its anygood:

Fronts - 283.0MM DIA 24.0MM THICK
Rears - 273.00MM DIA 10.3MM THICK

And what calipers are you using on the front?

If I make the change I will have for sale 4 brand new 300mm x 32mm hi-spec discs and 2 aluminium bells suitable for a sierra. Along with 2 cosworth rear vented discs, and 2 std sierra solid rear discs.

Even your 'new' set up is major over kill in my opinion (and I am an Engineer working for a company that makes and specifies brakes for mass produced cars).

You don't need a ventilated front disk - I'm assuming they are vented if they're 24 or 32mm thick.

At a push the rear caliper with a 10mm thick solid disk is suitable.

The standard Cortina/Sierra/Escort front brakes (with a solid disk) and an 8" or 9" rear drumbrake are more than capable of stopping any car, of upto 900Kgs, at 1g.

If it's just a bling thing - well that's your choice but your spending a lot of unnecessary cash

its not a bling thing, its hobsons choice because the lugs on the rear hub carriers are spaced for cosworth rears. I don't want to take the hub nuts off and replace with std sierra hub carriers (which I don't have anyway)

So with cosworth rears I have to go bigger at the front otherwise I may aswell drive around in reverse

Whilst it may be overkill, how can it be bad thing having even bigger, better brakes?

No you don't, just dial out the rears with an adjustable bias valve. rears on mine are virtually disabled, using wilwoods up front on 10mm solid discs. Stopping is awesome because the cars are so light.

So with cosworth rears I have to go bigger at the front otherwise I may aswell drive around in reverse

All it means is you will lock up quicker, doubt you would stop any faster. I reckon you could lock the fronts even if you used drum brakes, due to the lightweight nature of the cars.




Originally posted by DIY Si
Whilst it may be overkill, how can it be bad thing having even bigger, better brakes?

I have a tiger supercat, with 278mm front vented discs and calipers off a 2.9 24v scorpio cosworth and the 273mm rear vented discs and calipers off a 4x4 sierra cosworth. The front discs are the largest discs that I could find without going the expense of using bells etc, I did however have to make spacers to change the offset on the front caliper. Have a look at my build on http://mintynet.7host.com/supercat.aspx

Ian

Braking force is still dependent on how hard you push the pedal, try it first and worry later. If the brakes lock up easy then either increase the size of the master cylinder or cylinders, or move the pivot point of the cylinder pushrod further away from the pedal pivot. Rear bias can be adjusted using a valve (cheap option) or with a twin cylinder pedal box (more money). As for the front calipers any of the aftermarket alloy calipers look nice, or stick with the Cossy stuff if you want, but anything can be made to work with right master cylinder and bias setup.

It can be a bad thing

Most pad materials work best within a specific temperature range. With big ventilated disks they'll never get hot enough to get upto the pads operating temperature - hence poor decel', poor feel and wooden brakes.

If you fit the Cosworth rear caliper with a solid disk (if you can) then a 240-260mm disc with 57mm bore calipers on the front it will probably work fine.