C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

C3 Brake Question

Thread Tools
 
Search this Thread
 
Old Aug 30, 2011 | 02:09 PM
  #1  
scrappy76's Avatar
scrappy76
Thread Starter
Drifting
10 Year Member
 
Joined: Jan 2011
Posts: 1,853
Likes: 81
From: Hamilton Virginia
Default C3 Brake Question

On my 76 I have been trying to get the brakes working correctly and here is my question ,

If I can press on the pedal easy I have a good stopping power and holding power, but if I press really hard, the pedal will start to stop the car but then go to the floor and barely stop. Even if I pump them up it still does the same thing. Do I still have air in the lines ? or is something else wrong like the master cylinder or the brake booster going bad ?
Reply
Old Aug 30, 2011 | 03:40 PM
  #2  
LB66383's Avatar
LB66383
Drifting
20 Year Member
 
Joined: Dec 2002
Posts: 1,946
Likes: 28
From: Long Beach CA
Default

A couple of questions...

Are you losing any fluid? Is either reservoir going down?

If you're sitting still and press and hold the pedal, does it stay firm, or does the pedal slowly sink to the floor?
Reply
Old Aug 30, 2011 | 09:48 PM
  #3  
scrappy76's Avatar
scrappy76
Thread Starter
Drifting
10 Year Member
 
Joined: Jan 2011
Posts: 1,853
Likes: 81
From: Hamilton Virginia
Default

Originally Posted by LB66383
A couple of questions...

Are you losing any fluid? Is either reservoir going down? Not losing any fluid.
If you're sitting still and press and hold the pedal, does it stay firm, or does the pedal slowly sink to the floor?
If I am sitting still like at a light I can have my foot on the brake and it hold fine, but if I press really hard , it will sink to the floor.
Reply
Old Aug 30, 2011 | 10:09 PM
  #4  
noonie's Avatar
noonie
Race Director
15 Year Member
 
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Default

Rule of thumb.
If you can pump it up quickly and it holds a higher and higher pedal then you have air.
If it sinks while trying to hold a pedal, then you either have an external fluid leak or if none, then an internal master leak. Easy way to check for external leaks is to track the fluid level in the reservoir after many pumps or lots of use.
Reply
Old Aug 31, 2011 | 06:03 AM
  #5  
scrappy76's Avatar
scrappy76
Thread Starter
Drifting
10 Year Member
 
Joined: Jan 2011
Posts: 1,853
Likes: 81
From: Hamilton Virginia
Default

I have no fluid loss at all. If I slow down normal and come to a stop the pedal holds fine. while sitting at a light it holds fine, does not go to the floor at all. its when I am sitting there at a light and if I push real hard, the pedal will sink. If I have to hit the brakes hard and fast, the pedal will hold for a short then sink as I push harder.
Reply
Old Aug 31, 2011 | 06:30 AM
  #6  
MrJlr's Avatar
MrJlr
Race Director
15 Year Member
 
Joined: Feb 2006
Posts: 12,239
Likes: 19
From: Chino CA
Default

I think it needs bleeding.

Reply
Old Aug 31, 2011 | 08:22 AM
  #7  
bobbarry's Avatar
bobbarry
Burning Brakes
15 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2009
Posts: 850
Likes: 36
From: Providence RI
Default

Originally Posted by scrappy76
I have no fluid loss at all. If I slow down normal and come to a stop the pedal holds fine. while sitting at a light it holds fine, does not go to the floor at all. its when I am sitting there at a light and if I push real hard, the pedal will sink. If I have to hit the brakes hard and fast, the pedal will hold for a short then sink as I push harder.
I'd bet donuts to dollars that it's the master-cylinder; what you describe sounds like a seal in the master that holds under moderate pressure, but fails under very high pressure.
Reply
Old Oct 20, 2011 | 07:31 AM
  #8  
scrappy76's Avatar
scrappy76
Thread Starter
Drifting
10 Year Member
 
Joined: Jan 2011
Posts: 1,853
Likes: 81
From: Hamilton Virginia
Default

I am still trying to figure out my problem. I do have some more info to add though. When I do step on the brake fast and hard I hear like air sound under the dash near the pedal and the cars idle sounds like a miss in it till I left off the brake. could there be something wrong with the brake booster? too much vacuum ?
Reply

Get notified of new replies

To C3 Brake Question

Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-1

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-2

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-3

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-4

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-5

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
story-6

2027 Corvette vs The World: Every C8 vs Its Closest Competitor

 Joe Kucinski
story-7

10 Most Common Corvette Problems of the Last 20 Years!

 Joe Kucinski
story-8

5 MOST and 5 LEAST Popular Corvette Model Years in History!

 Joe Kucinski
story-9

2027 Corvette Buyer's Guide: Everything You Need to Know!

 Joe Kucinski




All times are GMT -4. The time now is 12:24 AM.

story-0
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-1
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-2
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-3
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-4
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-5
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-6
2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-24 16:12:42


VIEW MORE
story-7
10 Most Common Corvette Problems of the Last 20 Years!

Slideshow: 10 major Corvette problems from the last 20 years.

By Joe Kucinski | 2026-04-14 16:37:05


VIEW MORE
story-8
5 MOST and 5 LEAST Popular Corvette Model Years in History!

Slideshow: 5 most and least popular Corvette model years.

By Joe Kucinski | 2026-04-08 13:25:01


VIEW MORE
story-9
2027 Corvette Buyer's Guide: Everything You Need to Know!

Slideshow: 2027 Corvette buyer's guide

By Joe Kucinski | 2026-04-17 16:41:08


VIEW MORE