Brake servos advice

[Paul Bristo]

Hi guys, what are the prevailing thoughts on brake servos ?

I'm aiming for a final car weight of only around 700kg and i'd decided that i wouldn't need any, but now i'm starting to second guess myself.

what have others done ? and if using a remote servo approach what is your setup ?

I plan to fit this braking system;
front calipers: wilwood midilite 1.75" bore 4 pot
rear calipers: wilwood midilite 1.38" bore 4 pot
Master cylinder for front brakes 0.7 size
Master cylinder for rear brakes 0.7 size
brake pedal ratio approx 5:1

 

[Neil]

Hi guys, what are the prevailing thoughts on brake servos ?

I'm aiming for a final car weight of only around 700kg and i'd decided that i wouldn't need any, but now i'm starting to second guess myself.

what have others done ? and if using a remote servo approach what is your setup ?

I plan to fit this braking system;
front calipers: wilwood midilite 1.75" bore 4 pot
rear calipers: wilwood midilite 1.38" bore 4 pot
Master cylinder for front brakes 0.7 size
Master cylinder for rear brakes 0.7 size
brake pedal ratio approx 5:1

Avoid the brake servo; you should not need one.

 

[Paul W]

You won't need any - removed them on my car years ago and lots of track time and weighs far more than yours.

 

[Neil]

Your choice of brake pads will make a big difference in in your car's stopping power. Generally pads with "FF" rating will offer the highest coefficient of friction. One "F" is the cold rating and the second "F" is the hot rating. Each type of pad has different characteristics and you may want to experiment to see which is most suitable for your application.

 

[Dr. Bob Woods]

With a serious cam, my car doesn’t generate enough vacuum to activate the servo. I get the same amount of braking with the vacuum line connected or disconnected. The original pads in my Tornado GT40 wouldn’t lock the tires. My solution was to change the pads. Now it has normal brakes but I get more dust.

 

[Fred W Ballinger]

I think you will need more effort at the front to balance the brake front to rear ratio by using a smaller cylinder on the front circuit

 

[JP Verweij]

Jaguar XJS big four pots up front,
Jaguar XJS big two pots on the rear,
Bias pedalbox.
Two brake servo's, Hella UP28 vacuumpump (25inhg) activated by the brakeswitch.

 

[Neil]

This comment doesn't address brake servos per se but It concerns something that can happen to a brake system.

In the late Sixties I was driving my Ferrari 250 GTE on the street in Charlottesville, VA. Traffic stopped ahead and I pushed on my brake pedal... there was a loud "BANG" and NO BRAKES AT ALL! Fortunately I was able to reach the parking brake handle and stopped in time. Using the handbrake, I carefully drove back to my apartment and then inspected the brake system. I found that the hydraulic pressure had blown the guts out of the stop light switch! When that blew it made that loud "bang"; it sounded like a gunshot. That episode was an unlikely event but it did happen.

 

[Paul Bristo]

Thanks guys, puts my mind at ease !

 

[Scott Calabro]

A pedal mounted switch for the brake lights could be used avoiding any hydraulic issues.