Brake balance question

gait1969 · 02-26-06, 07:36 AM

This winter I upgraded the GTD brakes to Wilwood superlites 4-pots with all equal size caliper pistons. I also installed a Wilwood pedal assembly with balance bar. I use two .75 MC's Pedal pressure feels good and on the brake testbench I get the correct numbers. On the road the rears seem to lock up to early under havy braking, resulting in slightly braking away from the rear. Even with the balance bar completly set to the front. Therefore I assume I need to change the front M/C. Am I correct that I need to fit a smaller M/C for the front like a 0.70 MC?

Best regards,

Gerard.

Frank Catt · 02-26-06, 11:00 AM

Yes, or conversely, fit a larger one to the rear. Another alternative would be to restrict the vacuum pull on the rear servo ( assuming you are still running servos ) Frank

Tim Kay · 02-26-06, 11:26 AM

Gerard,

I have been running into dead end trying to outfit my Tornado with Wilwood [img]/ubbthreads/images/graemlins/banghead.gif[/img] The local shops here can not help me since I don't have make a model year of car. I am assuming your GTD has similar front spindles from a Granada and similar rear uprights as my Tornado.

Could you possibly post your Wilwood part numbers for rotors, hats and calipers. (Also assuming your running 15" wheels and you upgraded these parts, not just calipers)

Greatly appreciated [img]/ubbthreads/images/graemlins/beerchug.gif[/img]

gait1969 · 02-26-06, 12:16 PM

Frank,

That's what I thought. I got rid of the servo's. Changed the pedals to 7:1 ratio. Pedal feels alright although pretty hard, so a smaller MC for the front will make the pedal a bit softer too.

Tim,
I have the partno's etc. at my office, I will send you them tomorrow. I changed to 17" rims, but they fit in a 15" rim too.

Regards,

Gerard

Gary Gibbs · 02-26-06, 01:44 PM

This brake system calculator might be of some use.

Hemipanter · 03-03-06, 07:33 AM

The brake balance bar should not be used to balance the wrong caliper piston area or master cylinder area size.
The adjusting window is fare to narrow and is only for trac or driving condition adjustments.
Goran Malmberg

Kent · 04-01-06, 03:23 PM

Maybe you could get away with installing a proportioning valve for the rear brakes, then adjusting it off little by little until you get front lockup just before rear lockup.

Though as mentioned, it would only be a band-aid if the problem is with MC sizing.

jdinner · 04-01-06, 11:10 PM

The replica Diablo I made has 13" C-5 corvette front brakes on all four corners. I installed a Wilwood Proportioning valve (adjustable) in the rear brake line and adjusted it on a wet road. I dialed it down until the rear would not lock up in wet conditions. It still stops on a dime with very little pedal pressure.
Here is a video showing some stopping and accelerating from inside the car.
http://stweb.peelschools.org/sssweb/...drivingday.wmv

Cheers
Jim

kent holst · 04-04-06, 03:59 PM

the granada spindels used are from an european made ford not an american by the way