C3LT1

I bought my 1st C3 last week and drove it 3 times since. Today I started the drive it and the brakes gave out on suddenly( luckily right before I hit highway). The car use to be belong to my father in law and he changed the brake master cylinder, metal brake lines, calipers and rotors last year.

Any suggestion on what could make the brake system loose all pressure?

TimAT

How long has I set? Could be it just needs to have the brakes bled again.

C3LT1

My father in law had it sitting for about 8 months. But I drove it a few times last week and earlier this week. Ill bleed it over the weekend and hopefully that solves the problem.

tokim

Is there brake fluid in the master cylinder? If not look at all corners for leaks.

C3LT1

Yes the master cylinder was full.

tokim

Without a loss of brake fluid, and assuming pedal goes to floor, I would be looking at the master cylinder, or power brake booster (if of course it has power brakes).

C3LT1

yes the pedal goes to the floor. I will order a new brake booster and master cylinder to play it safe.

I saw a booster filter online. if vacuum line that filter is off or loose, could that also be a reason for no brake pressure?

thank you

Rodnok1

Loss of power assist just makes brakes harder to push, it's a unique feeling if you've never experienced before.
If you were able to stop the car just with hard pedal could point to booster or vacuum issue with it. If pedal went to floor easily there is a leak or master went bad.
Bleeding isn't going to fix it as air doesn't "appear" without a leak. You need to do a detailed inspection before just throwing parts at it.

540 vette

make sure it's the booster before you change it. You don't want to do that job for nothing. Start with the master.

Dean_Fuller

Is the brake system from the 79 or the 94? What all was reused from the 94 model ?
Is the motor modified from stock? Make sure if it is that it makes enough vacuum to work the 79 system brakes. You may have to go to a different system.

Mr D.

Be smart and don't start throwing parts at it. Troubleshoot/inspect the system to know what you really need, any local parts store will carry any part you need.

FYI, a power brake booster will not cause loss of braking that is a function of the master cylinder and calipers.

MelWff

What thread are you reading that mentions a 94 ? I assumed the OP, C3LT1, has a 70 to 72 LT1.

C3LT1

I do have a 94 LT1. He probably saw it on another thread. I have to confirm if they swapped over the brake system also.

Dean_Fuller

I assumed the same thing but it looks like the OP has a 1979 with running gear from a 1994 LT1....NOT a early solid lifter LT1. BIG difference.

MelWff

thanks for the clarification, important to know the year and all modifications if the correct answers are expected.

C3LT1

After doing full inspection I found that this pin was laying on the floor by brakes and what looks like spot where pin goes is empty. Hopefully that's it

Scottd

Yeah................................

BTW.....welcome to the club. They ALL need their brakes, calipers and seals replaced at some point. Its just how these particular cars age.

C3LT1

The prior owner replaced all those parts about 8 months ago.

I replace that pin with a better one and now brakes working again.

Thanks to everyone for the help. I am glad I found this forum!

TimAT

Where did the retaining clip go? Without that pin, you lose a LOT of pedal travel- And looking at the end of that pin, I think looking for a new one would be a good thing. And more than likely, the brake lights are on all the time.