eurekax

have a 72 vette without a power brake booster, to stop the car I have to put a lot of pressure on the pedal,and if I stomp on the brakes the car just slows to a stop without the wheels locking up,i know something is amiss but don't quite know where to start,any info would be helpful Thanks Alan

mrvette

Typical brakes for my '72, when I bought it in '95 had stainless lined calipers on it already, VERY hard to imagine any of these cars left today without stainless caliper bores lined in the old castings....

several things to check, and replace, the pistons/seals with O rings pistons/seals....the rubber hoses, check the damn run out on the rotors, shim with aluminum foil and flipping the rotor over on the hub to get minimum lateral play, keep the pistons from pumping and injecting either soft pedal OR AIR into the system, which is why a O rings, not the OEM lip seals.....

obviously you need to check that front/brass pressure switch that tells you if you have a front/rear brake failure, and lights a idiot light on the dash......that switch was a leak/failure point on my car.....

So after trying to fix/seal it, it failed again, so I just put in a separate front distribution block and so put the rear brakes to the m/cyl directly....and same with front.....

I have power brakes, but since you don't, I not commenting on that asspect of it.....another story.....

redvetracr

you may have an 1-1/8 power brake master cyl when you should have a 1" for manual brakes

ddawson

redvetracr may be on to something there. I can lock up my stock non PB setup just fine without much effort.

blue427

after checking the m.c. as was suggested I would just change the brake hoses before ripping everything apart.They swell from the inside when they get old and stop the calipers from working properly.

'75

I was going to make a joke to make sure the brake pads aren't inside out, but someone has probably done it in the past.

eurekax

I have just purchased this car its original with 96 K miles on the ODO,looks like it has had the calipers replaced at some time as they are yellow in colour[ don't think they came out in that colour]anyway where is this pressure switch to check and how do I check it I will start with it and see how it goes, no light on dash !!! Thanks for your input. Alan.

doorgunner

I am not a person who replaces parts that I feel are "O.K."........

BUT..........................

If you can get 4 new flexible rubber brake lines that connect the calipers to the steel brake lines, it would be a very good and safe thing to do. Unless those hoses have been replaced by a previous owner, you should get new hoses, since they do not give you any warning when they decide to explode.

(Just the way my 40+ year old "O.K.-looking" engine heater hose did 2 days ago.....with me standing there with the engine running and the hood up-----NOT fun!)

As for the "pressure switch"..........on my '68 with manual brakes....it's a "diverter block/valve assembly" located under the master cylinder with 2 inlets and 2 outlets and 1 electrical connector....I'm not sure if your year-model is set up the same way.

If a brake line ruptures in the front, the diverter automatically bypasses the front brake system so that the master cylinder will not lose all the fluid----if a rear brake fails, the diverter sends the fluid to the front brakes until you can drive to a repair shop.

69Vett

if you want a solid pedal, replace the rubber lines with
Stainless flex lines they do not swell, and will provide a more solid pedal feel.
of course all this brings you into the Brake bleeding world for corvettes,
research Brake bleeding corvettes, before you start.

PeteZO6

Braided stainless hoses will make a world of difference. When the brakes are completely bled, you will have a very firm pedal, and a very secure feeling about the brakes.

Pete

doorgunner

Let us know the condition of the diverter"block".....I had to dis-assemble mine because it was stuck....the internal O-rings were in great shape, but "sludge" had completely jammed the small piston to one end of the block, and the "warning switch" was also seized because od sludge. It works perfectly since I cleaned/re-assembled it........

BUT BLEEDING THE 4 CALIPERS TOOK THE ENTIRE DAY.....this brake system is a MAZE!

eurekax

to everyone who sent in advice thanks very much,i have the car on blocks ,calipers and brake lines are in good condition,calipers work well when pedal is depressed,i suppose all is left is to replace diverter valve,will keep you guys updated,will take a week or two as have to get some other parts as well to Australia Thanks Alan