Stalling after driving long distance???
Thread Starter
Advanced
Joined: Nov 2018
Posts: 71
Likes: 0
From: Texas
Stalling after driving long distance???
So I usually just drive my 89’ Corvette around town but today I decided to drive it to a town an hour away. My brakes are usually pretty stiff but all of a sudden while driving they got spongy. I had to practically hold the pedal to the floor to brake (brake fluid is full, no leaks) . Then I hit rush hour traffic after driving for 45 minutes. When I came to a stop the car died and the brakes locked up, I couldn’t press the pedal down at all. I put it in park, and it turned back on (I had to press the pedal down to get the engine going again) I drove further down the expressway with no problem. But once I got off and hit that first stop light, brakes locked up/died. It turned on again same as last time. I got to a neighborhood, and came to complete stops at the stop signs, no problem... it stayed running. What the heck is going on???
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
It sounds like a brake booster problem. Make sure there's no vacuum leaks. I would change booster make sure brakes operate correctly. Then evaluate stalling if it continues. Booster may solve both.
Race Director
Joined: Jul 2000
Posts: 16,500
Likes: 2,384
From: Out Where the Buses Don't Run, Eglin AFB/ Niceville FL
2025 C8 Z06/7/E-Ray of the Year Finalist - Unmodified
2022 Corvette of the Year Finalist -- Modified
2021 C6 of the Year Winner - Modified
2020 C7 of the Year Finalist -- Modified
2020 C6 of the Year Finalist - Modified
My 89 had the same brake symptoms when the booster failed. Easy swap if you're handy with a wrench. I did not have the stalling issue but it is possible the loss of vacuum is causing it.
Last edited by Tally Ho; Dec 8, 2018 at 02:24 PM.
Thread Starter
Advanced
Joined: Nov 2018
Posts: 71
Likes: 0
From: Texas
I did several brake booster tests, and it passed all of them. One mechanic told me it could be bad seals on the master cylinder. Whenever I drive short distances and the brake fluid is still cold it’s thicker so it’s able to block up the bad seal, but once it gets up to operating temp the brake fluid is hotter/thinner it is more easily able to get passed the bad seals causing that spongy Brake feeling. Then once the car cools down the brakes feel normal again. And there is also a wet spot, I’m guessing brake fluid dripping down on a part of the car right below the master cylinder. Brake fluid isn’t low, but I also only had that spongy brake feeling for about 10 minutes.
Drifting
Joined: Feb 2006
Posts: 1,423
Likes: 96
From: Magnolia Tx
I did several brake booster tests, and it passed all of them. One mechanic told me it could be bad seals on the master cylinder. Whenever I drive short distances and the brake fluid is still cold it’s thicker so it’s able to block up the bad seal, but once it gets up to operating temp the brake fluid is hotter/thinner it is more easily able to get passed the bad seals causing that spongy Brake feeling. Then once the car cools down the brakes feel normal again. And there is also a wet spot, I’m guessing brake fluid dripping down on a part of the car right below the master cylinder. Brake fluid isn’t low, but I also only had that spongy brake feeling for about 10 minutes.
Thread Starter
Advanced
Joined: Nov 2018
Posts: 71
Likes: 0
From: Texas
What would cause it to only happen during long distance drives though? It’s the second time the car has stalled going long distance. But around town it’s fine. And it passed all the brake booster tests.
Drifting
Joined: Feb 2006
Posts: 1,423
Likes: 96
From: Magnolia Tx
A spongy pedal and a fluid drip aren't symptoms of a brake booster so it sounds like you need a master cylinder. How did you test your booster? They are a pretty common failure point on older C4s. I have 2 bad ones on my work bench and none on my car at the moment.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Thread Starter
Advanced
Joined: Nov 2018
Posts: 71
Likes: 0
From: Texas