Wedge braking or lack of it......

[350matt]

Chaps
I was wondering the other dauy why is it the wedge brakes leave a certain something to be desired - stopping mainly.
The basic hardware is fairly respectable 238mm vented Ø discs, servo assisted ,large opposed piston solid calipers. I've fitted better pad material, braided hoses and ducting for the rear inboard discs and fitted a brace for the master cylinder as the pedal bulkhead can move alarmingly.

yet still in hard braking it feels like I'm having to kick the pedal through the bulkhead to get it to stop.

I know the later wedges had 4 pot calipers but I've driven these and they're not much of an improvement, I think the basic problem is a lack of pedal or hydraulic leverage has anyone tried a smaller bore master or experimented with the pedal geometry?

Matt

[speedy_thrills]

350matt said:

has anyone tried a smaller bore master or experimented with the pedal geometry?

You could make changes to the pedal geometry and cylinder size but both would have a negative effect on pedal travel required. Similarly you could exchange caliper.

Have you thought about trying to modify your servo system to increase the vacuum assist? Alternatively you could salvage a vacuum pump from a diesel car and use that instead of tapping the intake.

[steve_D]

An Ultima has 320mm discs, 4 pot AP racing calipers and no servo.
Stops from 100mph in 3.5 seconds and a distance of 97.41 meters.

I think you need to upgrade.

AP do kits for most cars and will advise if anything other than the disc/caliper needs to change.

Steve

[denisb]

I am pretty sure most wedge TVR's had Ford brakes.

A trip to a decent Ford breakers would soon come up with a number of bigger options for next to no money.

My kit car used Ford Sierra brakes. The easiest upgrade was to go to Cosworth discs and a spaced out caliper, which helped a lot.

I then upgraded to Hi-spec and instantly wish I had paid the extra couple of hundred for AP. The Hi-spec stuff is cheap and works but isn't as nicely engineered as AP.

How much does your car weigh?

[tvr_nut]

I fitted a set of grooved front discs to my old 350i, and found the braking power greatly improved (i.e. could actually lock the wheels on a dry road if I really tried, previously an impossibility). Also used fast road pads front and rear.

Did not upgrade rear brakes, as too hard to get at to remove caliper/discs, and anyway I kept boiling the fluid at trackdays with normal discs (and assumed better braking at rear would result in more heat, and even more fluid problems.

I got the grooved discs from Richard Thorpe (RT Racing, though it was called Wedge Automotive back then!) - were not much more expensive than the standard vented disc either.

[lukeb]

What's the standard braking system based on with wedges? Pov spec Sierras did use a 240mm vented disc, but never a two pot caliper. They were all (except the 2wd Cos) a sliding single pot AFAIK.

[FrenchTVR]

I run 17's on my Wedge and upgraded to 330mm AP's with 4 pot calipers and Ferodo fast road pads. Also changed the master cylinder ot one from a Ford Mondeo(I think) which reduced the pedal travel a bit.

Now stops on a sixpence and was totally fade free during 200 hard miles around Spa earlier in the year. Wasn't cheap at about £1300 all in but well worth it in my opinion.

The originals were based on Ford Granada mark 2, with the SE's etc using the vented discs and slightly larger calipers from the estate.

Later 400SE and 420s etc went to a four pot caliper, some of them AP.