Bought my car in August and I haven't been able to get the brakes right. The pedal basically goes straight to the firewall and the brakes barely stop the car at idle. Bleed everything many times and also threw the parts cannon at it, multiple master cylinders, new lines, rebuilt calipers, and 3 boosters. Anyone have some ideas?

Only thing I could find that was weird was with the booster adjusted all the way out it comes out 1 1/8in. When I measure the master cylinder travel it's 1 3/4in. But I've been through many different setups and haven't gotten anywhere yet.

1984 Corvette

-Thanks, Phil

 

Well you definitely should stop throwing parts at it. Especially if you're replacing the same parts repeatedly.

You've likely got a pile of perfectly good brake parts laying around now.

Do you have one of those brake booster adjustment tools? You'll need one of thse to get it right, if it's out of adjustment.

Others can correct me if I'm wrong here, but I think a brake booster adjustment is only gonna be right after all of the air is purged from the system and you have known good fluid.

You said you've bled them multiple times, but that doesn't matter if the ABS system is gummed up. Given its an '84, and it's only new to you recently, that's something to look at.

Also, did you flush the brake system or just bleed the brakes. You really should flush the entire system. I'm assuming that you did if you replaced all of the brake lines, as you said.

You also said that you replaced lines, but didn't mention anything about hoses. Did you replace those, too? Because they collapse. And they might even still be original to the car anyway.

Maybe find some gravel and try to work the abs system, unless you don't have any brakes at all. Don't chance driving like that.

All you need is a rolling idle, working the brakes on the gravel a few times.

I had the same problem last year of my pedal going to the floor and it caused a few scary situations which totally caught me off guard and had to make it home on just the e-brake alone.

All I did was flush the fluid, bleed them a few times, work the ABs and checked booster adjustment.

They've been fine ever since.

 

No abs in '84. You still have air in the system.

 

Phil

Did you check you Vacuum system . . ???
FYI . the 1984 (I have one) has many challenges with the vacuum system due to the CF .

Bill

 

Hm. I did not know that.

 

nor 85

bench bleed the master

 

Been a few weeks but it's nice and warm again. I've bled the brakes fully again, and I have no air in the system but the brakes still barely stop the car at idle. The master has been bled multiple times, and the hoses were replaced a while ago. The brakes still don't pump up, it gets slightly stiffer but nothing like my Fiero. Could there be trapped air bubbles somewhere?

Thanks for the help
-Phil

 

I second bench bleeding the master. Also, tap on each caliper as you're bleeding it to dislodge any air bubbles that may be sticking inside the rough casting.