who is running 4wheel manual disc brakes

Like the title asks,

ON your race car, who has 4 wheel manual disc brakes.

How well do they work and what are the parts, or kit you used?

my A body disc brakes (73 dart front), inline tube dana 60 rear disc conversion DR.diff master cylinder around 1" bore, and wilwood proporting valve. My brakes are flat out bad. They do work, but not well, I could never lock of the tires. NO MATTER HOW HARD I PRESS!

They bleed fine, both front and back, but when bleeding the back the brake pedal will not drop all the way to floor, like when bleeding the fronts.

Not sure what my problem is, I am not bove just replacing parts till it works.

On my sons duster, we have stock 73 up discs. THe rear had an 8.8 rear with factory disc brakes. We used a 15/16 alum master, stock distribution block. car stops great , Maybe something that helped, we ran all steel braid instead of factory rubber lines. If you are using the factory rubber hose up front, that may be a problem....

Thanks, but I have steel braded at all 4 corners as well.

Im thinking it may be in my proportioning valve. I have a generic GM 4 wheel disc brake proportining valve I may install to see what happens.

Wilwood front, SVO rear. Dr. Diff supplied the master cylinder and rear brakes. Proportioning valve to bias rear (pro street car). I used the 1st turn out at the track (10.15 @133). Stopped fine, but smoked the front pads. I'll call this one a driver error on a new set up that has a lot more MPH than the old set up. Car will go 9's and I will be using the second turn out (parachute if/when I use the nitrous).

P4020004 by Greg Ault, on Flickr

IMG_2203 by Greg Ault, on Flickr

Willwoods on all 4 for me. Stops great now I have the correct master cylinder (7/8" Bore ?) 145+ @ 4000lb + best. If I really stood on them I reckon I could make the first turn.

Throw the factory prop valve out.....If its a big tire car with 4-wheel disk, all is good with a 50/50 split. My cars stop awesome with Willwoods on all four.

My Dart is a street/strip deal that runs 10.0's. I started with 73 disk on the front and Wilwoods on the rear, factory non power 7/8" (I think) mc through a 73 proportioning valve. The car stopped great, it was like the car sat down when the brakes were applied. Hemi Fred made me a good deal on a set of Strange fronts so I added them, the mc was leaking so I bought a 1 1/16" aluminum mc to replace it. The car would hardly stop and the pedal was hard as a rock. I installed an adjustable proportioning valve, had it in the front and rear, no help. I them bought a 15/16" mc from Dr Diff. Better but still not what I wanted, in the end I gutted the factory proportioning valve and just running the rear brakes through it. The fronts are on a T with the line directly from the mc.

The car stops fine, just not as good as the original set up. If I ever need to replace the mc I will use a 7/8" bore.

I have Wilwood 4 wheel discs on mine, with an adjustable proportioning valve. . Stops great. I also have a used front Wilwood brake setup for sale, hubs, rotors, calipers, caliper mounting bracket, Needs 1 hub, hub is cracked. . But it is for a Mustang II/Pinto spindle setup.

my 68 Barracuda weighs 3550 with me in and runs 10.40s. I have Willwood disc brakes all around with a dr diff master and no prop valve. The car stops great, I occasionally race on a track with a very short shutdown and I don't sweat it one bit. They work fine in the street as well, I have vented discs in front and drilled non vented in the rear.

I have Strange 4 piston calipers, front & rear, with Strange alum hubs on front. Stock spindles, Dana 60 out back. 1-1/32" bore (I think) master cylinder (cast iron Wagner from a pick up), adjustable proportioning valve, braided steel line at the corners. Car is 3250 lbs w/driver. I run mostly 1/4 mile, 128 mph. The only problem I've had is a caliper bolt backed out. Safety wire took care of that. With big rear tires & narrow tires up front, 50/50 is very close to correct. Sorry, no pictures.

Brian

Try a smaller diameter master cylinder first to help it stop better, 7/8 or smaller
My S/P car has dual Wilwood calipers on the rear with the same size single Wilwoods on the front, dual 7/8 Wilwood master cylinders with a balance bar, stops fine at 150+ MPH weighing 2850 Lb. with me in it, stops fine on a short 1/8 mile track at 125.+ MPH.
I took the parachute off do to it not running above 150.+ MPH in the 1/4 mile so it would fit in my enclosed 24 Ft .race trailer better with more room in front of the car
Keep the hoses as short as possible also

go from rear caliper towards mcyl . with someone holding a little pressure on brake pedal. crack /then shut, bleeder and each line fitting one after the other till pedal goes to floor . that will show where potential restriction/blockage is .
i have SSBC front brakes , metric rear GM calipers and a 1 1/32(?) master , works fine street and strip .

Tex

[quote=8urvette]Like the title asks,



They bleed fine, both front and back, but when bleeding the back the brake pedal will not drop all the way to floor, like when bleeding the fronts. /quote]
That tells me that the back brakes are working good, their stopping the pedal like they should when they doing all the stopping
I've had the back part on a dual master cylinder go bad due to heat from the Hooker fenderwell headers getting to it after years of use. It ended up having a soft pedal on the rear part for the stock A body front brakes, it didn't stop worth a hoot either above 30 MPH using the stock A body rear drum brakes
I replaced it as I couldn't find a rebuild kit for it in SO CA based off of the Mopar casting number on it

64 Belvedere 3335lb using 4 wheel Will Woods. Runs 145-150. Stops great. Sons 62 Savoy has FMJ factory style front disc , Ford Explorer rear disc. 3750 stops from 135-140 very nice.
Doug

Wilwood front/rear no prop valve @ 3400. Great on the street as well as 148 mph at the track.

Same Wildwood on all four. 7-8 bore mc. The only thing I need is a proportioning valve to add brake force to the rear. Locks up the front too easy. 3015 lbs, 154 mph no problem.

A prop valve reduces the force to the rears so that won't work for you. You could put a prop valve on the front to kill some of the front pressure but that typically isn't a good idea. Increasing the rear brake force might be a better bet. Use a bigger caliper piston on the rear or a bigger rotor in the rear or maybe even both.

Ka-Blue-E has 4 wheel wilwoods, strange mc, 2 residential valves and a wilwood adjustable proportion valve. Stops great from 160 mph .

When I went 4 wheel Wilwood manual disks on 71 Dart Swinger, I installed the Wilwood proportioning valve. May be wrong, but was of the impression what some are referring to as the stock "proportioning valve" is actually a "distribution block" - equal fluid in all directions.