Brake master cylinder brace

DBM58 · Post by **DBM58** » Wed May 25, 2005 8:08 am

I read somewhere that there the action of braking is improved by the fitting of a brace to prevent the movement of the brake master cylinder that happens when breaking - perhaps the reasoning is that the length of some hoses increase (stretch) , thereby increasing their internal volume and consequently increasing the pedal travel required - or not. After procrastinating for months, a quick look under zorruno's bonnet (not for the faint-hearted) I was inspired to make my own brace. Anyway, another company that I work with fabricates products from sheetmetal, and I was able to scavenge from their scrap bin some pieces of 3mm galvanised steel - the same thickness as the shock-tower brace brackets. I used the same bracket as a template - which I can supply to anyone who would like to make their own. A junior hacksaw and lots of elbow grease was all that it took to cut away all the excess metal, and a coarse half-round file was enough to clean up all of the edges. I took Gazza's s!
uggestion and welded a triangle-shaped gussett piece at the base of the right-angled fold to absolutely remove any chance of the brace bending - better to over-engineer than have to fix later.

Does it make any difference?

I actually think it does, but then, after all that effort, maybe I am imagining something that I want to be true.

Anyway, in the end, I ended up with two braces, the first was bent in the wrong place and it was not until I had re-made it that I found that it could be re-folded. I will bring the second one to the Tarseal Gymkhana that the Northern Region is hosting on Sunday 29 May, along with tools to fit it (less than five minutes), if anyone would like to try it to see if it makes a difference to the brake performance in their car - in general, not specifically for the gymkhana.

I can also provide pictures of the brace for anyone with an iterest.

Regards

David Moughtin

garry · Post by **garry** » Wed May 25, 2005 11:09 am

Hi David,

These braces work by stifening the firewall so it moves less while you are
pushing against it, some cars are prone to cracking around the master
cylinder if an aftermarket brace is not fitted ...most recently i have seen
this on a gt4 celica ...not a nice job to have to fix if it happens to you.

Garry

Bob Anderson · Post by **Bob Anderson** » Wed May 25, 2005 11:15 am

The simple brace I devised is a bolt threaded into the after market tower
brace. The bolt extends to butt against the end of the master cylinder.
Locknuts on the bolt makes it very strong. I rebuilt complete brake system
with EBC green stuff's at the same time as I installed my bolt brace. Brakes
are excellent now. Crap before.

Dr Bob

poison · Post by **poison** » Tue Jun 07, 2005 7:18 pm

David M and I recently conspired to make a couple of brake master cylinder
braces (Conspired - v. Meaning we talked about it, I made one then David make
a shonky copy

and even worse chipped the paint on mine in the process...

Anyway the moral of the story is, don't let him touch anything valuable.

It involves a piece of (at least 3mm) steel with a semi-circle cut out (the
hard part) mounted onto the top of the front shock bolts. Part of it is bent
up (with a gusset welded in place as it takes a lot of force) to sit in front
of the master cylinder, this in turn has a bolt through it to lock against the
master cylinder.

Without the brace when the brake is pressed hard the firewall mounting flexes
slightly and the master cylinder can move 2 to 3 mm. Given the length of the
brake pedal, this equates to quite a lot of movement in the brake pedal
itself. Once the brace was in place and a slight bit of pretension put onto
the bolt the result was quite impressive, the brake pedal went from soft and
squishy to rock hard. So if you have the time and inclination a good
worthwhile little project. Or David and I can make you one for $2584.63
(cash), we're good like that!

I'll send a pic to zorruno and see if he will post it for all to see.

Gazza
"PO1SON"