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Upgrading brakes - ideas needed
Shamrock GS - 5/5/08 at 09:39 PM

I have standard sierra discs up front and capri drums at the back, no servo fitted.

Looking for ideas to upgrade to give a bit more bite without costing a mint or needing major engineering works.

What are my options? (No space for the Ford servo)

Cheers

Gary


phoenix70 - 5/5/08 at 10:08 PM

First question I would have to ask, is why bother, the standard Sierra brakes have more than enough stopping power for a seven

Cheers

Scott


mookaloid - 5/5/08 at 10:08 PM

Some grippier pads at the front? Try mintex 1144 's

Cheers

Mark


Paul TigerB6 - 5/5/08 at 10:22 PM

when was the fluid last changed?? Fresh fluid and maybe a set of decent pads as ^^^ might be as far as you need to go as the brake calipers were good enough to stop a car of double the weight.


nick205 - 5/5/08 at 10:48 PM

IMHO the fact that the brake components were designed to stop twice the weight is a bit misleading, particularly when used without the servo.

For starters, the vented discs mean it's harder to get up to temperature with so much less weight.

Also, with or without the servo, each builder can have very different pedal leverage ratio and travel set-ups which can greatly affect the actual feel of the brakes. You have to push a LOT harder than you do in a modern tin top.

What pedal leverage ratio do you have?

What bore master cylinder do you have?


Bluemoon - 6/5/08 at 08:44 AM

Tend to agree with Nick, if it's the standard setup and you have a 5:1 peddle ratio, should stop as well as the sierra (assuming servo added 50%, car weight is half the sierra). But by argument of heat in the breaks, you should be using cheap sold disks at the fount rather than exotic and expensive vented/drilled disks (I would think this is only need on track/racing for a 7??)...

Still not had mine on the road, so what do i know

Dan


simes43 - 6/5/08 at 08:45 AM

Fit a bias bar, go to an MOT bay and have the bias set between 60 to 70 % front and 30 to 40 rear.

Or fit softer tyres.


rj - 6/5/08 at 12:08 PM

I would try different pads , or alter the pedal ratio, you will feel a massive difference by redrilling the pedal / clevis hole and moving the clevis nearer to the pedal pivot, but that is assuming that the current pedal movement is short, quite ok to trade a longer pedal movement for a bit more leverage


britishtrident - 6/5/08 at 03:19 PM

As Bluemoon and nick 205 spotted its is a pedal leverage and lack of servo problem.
The standard Ford master cylinder from a car with servo is 0.81" this is too big for a car without a servo and less pedal leveage.

Easy way to fix it is fit a different master cylinder -- the one required is the 0.7" dia dual circuit master cylinder used on some late Triumph GT6 & Spitfire 1500 models and many Lotus models.

Westfield supplied these as part of their kits
see
http://tinyurl.com/5r2eu2

Brakes int part number is BMC4634 (ignore illustraion on brakes int site it is wrong)

This mod alone will give a 25% reduction in pedal effort.



[Edited on 6/5/08 by britishtrident]


Mark Allanson - 6/5/08 at 07:05 PM

Have you got standard brake flexies or braided ones - the difference is VERY apparent


Shamrock GS - 7/5/08 at 06:33 PM

Interesting responses.

The problem may well be down th 'feel'. I just dont have a lot of confidence if I need to stop quickly. System was completely renewed last year with new fluid. Solid discs up front and rubbed flexis. Will have a look at the pedal box and see if a change of leverage is possible.

Thanks all

Gary


britishtrident - 8/5/08 at 07:08 AM

quote:
Originally posted by Shamrock GS
Interesting responses.

The problem may well be down th 'feel'. I just dont have a lot of confidence if I need to stop quickly. System was completely renewed last year with new fluid. Solid discs up front and rubbed flexis. Will have a look at the pedal box and see if a change of leverage is possible.

Thanks all

Gary



Can be difficult to change the leverage -- lack of available space in the foot well, if I was building a chassis again I would go 1" taller for this reason alone.