skhan

So I have been struggling with my '75 brake system for a bit. First I thought it was only the bleeding problems, so I did that, while doing that, I found a leak in brake-line. I fixed that. Brakes were still not really stopping the car well. Brakes are not powered by the way, no brake booster.

Next I took off front brake pads, they looked like they were worn funny. Got new brake pads for front axle, while changing brake pads, I found out one of the brake caliper was leaking. Sooo went ahead and replaced that too. Brakes got better but no were close to their full potential.

Rear brake pad seemed fine, but i was like why not. So I ended up changing the rear brake pads as well, found rust and gunk and leaks in the rear calipers too. Replaced them both. put new brake pads.

Bleed the who system. Brakes are still crappy. I am not sure what else I can try. I have checked all calipers for leaks all lines for leaks. Calipers are new, brake pads are new. System is bled, with no bubbles.

The car does stop, but its a slower stop then it should be able to stop. If I stomp the brake peddle, it should lock the wheels. Currently, it does not . Any help will be appreciated.

maj75

Strokemyaxe

jsbwac

cagotzmann

So what brake pads did you select. Most OEM replacements that are metallic based last long, but don't stop with any kind of G forces. The best pads for stopping power for my C3 has been the Raybestos ST47 Pads.

Tried many brands from OEM Metalic's , organic , Hawk, Wilwood , Carbotech , Raybestos etc. Carbotech have also been a good. Also my BF Radial TA's could lock with any Pad, My Michelin Sport Sports required Hawk, Wilwood, Carbotech, Raybestos, to lock the tires. The nitto NT01's required Carbotech & Raybestos to lock the tires. But if you cannot lock tires like GF Radial TA's then you have air in the system trapped somewhere. Most common area's are.

So did you bleed the Master Cylinder while on the car ?
How did you bleed the calipers ? Is the pedal nice and firm (manual brakes)

bashcraft

It's possible that you have a master cylinder for power brakes instead of manual brakes. A manual brake master cylinder has a 1" piston and a power brake master has a 1-1/8" piston which will require much more pedal force to achieve the same fluid pressure.

terrys6t8roadster

Is the brake pedal mushy, low, requiring numerous pumps to get pedal pressure, hard with no stopping? Glazed rotors from having brake fluid on them will cause good pedal and hard to stop condition. Any pulling under hard braking? T

Rodnok1

Very possible or brake rod in wrong hole in brake pedal if it has two on your year, I fought that issue before on other vehicles.

69Vett

a corvette is very difficult to bled completely, I thought I did mine right 4-5 times.
until finally got them completely bleed.
my very last trick, was tapping calipers with rubber hammer, during bleed process.
this dislodges the air bubbles clinging to the inside of the calipers.
good luck

kansas123

Not sure I read that you replaced the brake hoses, could be the rubber is now weakened and or collapsed, causing poor brake performance.

skhan

How would I test that?
Bleed the master cylinder? is it possible to bleed the master cylinder while on the car.

skhan

1. The car does not lock the wheels. if the brake are fully engaged, the wheels should lock. Plus the car stops too slow.
2. Pads were worn slanted, not equally.
3. Bled the break by pumping the peddle and opening and closing the bleeder valve.
4. I used dot 3 and 4. I am not sure what it was before. Didnt think it needs anything special.

skhan

I am using Hawk performance pads.
I did not bleed the master cylinder, didnt know I need to.
Bled the calipers by pumping the brake and opening and closing of valve technique. the pedle is nice and firm.

skhan

How do I tell if this is the case?What do I need to measure? Or are there any indications on the cylinder like tag or writing which will tell me this?

skhan

mmm. So I need to look at the Pedal? Could you explain this a bit more please.

skhan

I did not change the rubber hoses. They seem to have been put on by the previous owner. They look like in good conditions. Clean and solid.
Not sure if that is the issue. How could I test that?

Fredtoo

Some race pads need heat in them to work right.
How fast are you going when you do the panic stop?

bashcraft

You'll need to remove the master cylinder and measure the bore diameter from the back.

skhan

I have tried them up to 45mph.

Fredtoo

How many miles on the pads?
They do take some time to bed in, especially on used rotors.

And

Do you have one of those IR heat guns? It is a good tool to see all your calipers are working (getting hot)

After you are sure the pads are bedded, try a few stops from highway speed. That should get the brakes up to operating temperature.
If it makes a big difference, you may need a pad that works at lower temps.
I put some Raybestos pads in my car, and they made a big improvement over the 20 year old brand X pads that were in there.
RAYBESTOS SP8XP Street Performance; Metallic (from Rock Auto)