Help, 1979 c3 corvette brakes

[blown69nova]

My brother just swapped in some new 6 piston front and, 4 piston rear Wilwood brakes, now he can't get a pedal! It has a "stock" Napa m2300 master cylinder, 1-1/8 bore. He even replaced the master with a new one. He even used a air powered bleeder. Wilwood says it's supposed to work with the stock master.
Any thoughts?

[blown69nova]

Anyone have experience with Wilwood d8-6 and d8-4 calipers? from what I've read, we may have to remove and rotate to vertical.

[Skip Fix]

I've had even a new Vette MC be bad. I've also bench bled one a lot and thought I got all the air out and then had more in it that needed bleeding. Put plugs in the MC instead of the brake lines and see if it has pedal. It should hydraulic lock it with very little pedal movement.

As long as caliper bleeders are on the very top they should bleed. I know my Wilwood Dynalites have 4 bleeders, so two on top that I bled so air was not hiding on one side-not sure if that are similar.

[Gil]

hi,

My pedal feel was spongy & can't lock brakes after bleeding the calipers, I don't have the same setup & not sure if it's your problem but seems the same symptoms :

Here's what I did with my brand new C3 1" bore MC to bench bleed :

BRAKE MASTER CYLINDER BENCH BLEEDING INSTRUCTIONS
1. Secure the master cylinder in a vise by firmly clamping the mounting flange on the casting.
DO NOT CLAMP THE BORE AREA OF THE CYLINDER! DISTORTION OF THE BORE CASTING WILL OCCUR!
2. If the outlet ports have non-threaded protective caps installed, replace with the provided threaded solid bleeder plugs. Tighten bleeder plugs by hand to seat.
Note: The plugs must be tightened enough to keep air from entering the master cylinder through the ports, but over tightening will result in stripping the plastic threads and rendering them useless.
3. Fill the reservoir with the appropriate brake fluid.
4. Using a blunt instrument or wooden dowel to avoid piston damage, slowly depress the piston into the bore using no more than 1 inch stroke. Do not bottom out piston.
5. Slowly release the piston to rest position. Wait 15 seconds to avoid fluid aeration.
6. Repeat steps 4 and 5 until air bubbles cease to appear in both reservoir chambers and the piston cannot be depressed any more than 1/8 inch.
7. The unit is finished with the bench bleeding process. Ensure reservoir lid is secure and release the master cylinder from the vice. Proceed to installation instructions.
TECH TIP: Gently tapping the casting (not the reservoir) with a plastic screwdriver handle or a wooden dowel will encourage the air bubbles to escape from the bore during the bleeding process.

Took me 1h45 to stroke all bubbles out from the MC, "litle" PITA but MUST be done properly if you want good pedal, so...


And yes, vertical bleed the calipers & the on top screw! One of my rear is upside down & won't bleed the bleeder screw down.

Hope you'll find & cure the problem
Gil

[blown69nova]

Thanks for the replies!
He rotated the calipers to vertical and bled, working perfectly now.
Thanks, Steve

[Aficionado]

Glad to hear the problem is solved. I had the same setup on my '72 Vette when it was on a stock chassis. I changed the MC to a Wilwood at the same time, and bled both MC (bench bleed prior to install) and calipers according to their instructions, and did not have any trouble.

Sucker would stop, too....

[blown69nova]

He's super happy with it now! He went from factory brakes/replacement pads, to this setup, along with the braided hoses and BP-10 pads.