I'm converting from manual brakes to power using a kit from Zip Corvettef for a 1968 C3 Vette. Have several problems with installation as follows.
1, When installing the new booster using the lower hole on the pedal as suggested in the instructions, the brake pedal is position about 3 inches below where the original brake pedal was on the 68 Corvette? Thinks they may have sent me the wrong booster not the correct one. but the is no part number on the booster as received, Wondering if upper hole on pedal should be used instead of lower one.
2. I also installed a new proportioning valve but I need Bleeder tool to thread into the proportioning valve but can't find the tool with the right thread. I need that to to lock the proportioning from moving during bleeding of brakes. I've ordered the orange version but not sure if has correct threads either.
3. Have a very difficult time reaching the old but good brake light switch for the 68 C3 What is best way to get to the mounting bracket to adjust for new lower position of pedal? Is a different bracket needed? Note the brake light swithch is the lever type only used on the 68 Corvette
Lot of questions but absolutely no help from Zip Corvette who provided the conversion kit. No tech assistance at all on products they sell.
Appreciate help on any of the questions above
GR

 

unless you have J56 there is no proportioning valve. do you have the AIM? that will outline what needs to be changed and what parts are really needed. what is the reason you thought you needed power brakes?

 

the 68 C3 had a proportioning valve but the existing one was stuck cutting off braking to the front brakes. Now my problem is getting a bleeder tool that has the right threads.to fit into and lock the valve when bleeding the brakes. The fact hat the front brakes were not functioning lead me to go to the conversion to power brakes. If I'd known that I won't have gone to the conversion. Too late now as power brake conversion is almost in. GR

 

What is a 156 and yes I have the AIM which shows it

 

J56 is Heavy Duty Breaks.

 

only J65 cars had a prop valve

 

68s had the proporting valve. You dont need to touch it to bleed your brakes. Do a bench bleed, then install the master, make sure the pushrod gap is correct and the pushrod type is correct if you mix and match boosters and masters, fill it put the lid on, take off the bleed tubes that went to the reservoir and attach the brake lines one at a time. Rags underneath to catch ant drips. Then slowly push the fuid to the calipers with the brake pedal, keep filling the master as needed every 3 to 5 pumps. Once the fluid gets to the back, Get a power bleeder and force out the bubbles. Furthest to the closest caliper, inside then outside in the rear.
Ive never ever have touched my proporting valve in a brake bleed including when i replaced all my lines.

 

don't confuse the low-pressure switch with a prop valve

 

Sometimes the little double-ended piston in the center needs new o-rings.

My DIRECTIONAL/LOW PRESSURE SWITCH VALVE WAS CLOGGED WITH GUNK WHHEN i DISSASEMBLED IT...PIC SHOWS IT WIPED OFF A LITTLE.

Name: 101_1372_zpscff2c126.jpg
Views: 737
Size: 78.2 KB