Strange Brake Problem 78 corvette.
Thread Starter
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
Strange Brake Problem 78 corvette.
1978 corvette wilwood calipers Carbotech XP10 brake pads.
Normal street driving brake are nice and firm and very little travel to start stopping.
Hard acceleration in 2nd gear 1500-5500 let the egine cost to 4500 RPM I need much much brake travel to get the brakes to start stopping
Hard acceleration in 3rd to 4500 brakes need more brake travel to start stopping. Coasting the highway @ 2000 RPM brake are firm and take very little travel to start stopping.
Seems this has something to do with the change in vacuum in the engine effecting the vacuum booster.
Any thoughts ?
Normal street driving brake are nice and firm and very little travel to start stopping.
Hard acceleration in 2nd gear 1500-5500 let the egine cost to 4500 RPM I need much much brake travel to get the brakes to start stopping
Hard acceleration in 3rd to 4500 brakes need more brake travel to start stopping. Coasting the highway @ 2000 RPM brake are firm and take very little travel to start stopping.
Seems this has something to do with the change in vacuum in the engine effecting the vacuum booster.
Any thoughts ?
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,597
Likes: 7,046
From: New Or-leens Loo-z-anna
From what I've read boosters need a certain amount to operate correctly.
Can you attach a temporary long vacuum hose to the port that supplies vacuum to the booster, then place the gauge in the cabin where it can be easily seen?
This will let you know how much the vacuum varies under different conditions.
Also.....have you changed to larger rims and tires lately.....larger wheels require much more effort to slow down at higher speeds....(as I learned on my Harley Davidson when I upgraded to a 30% larger/wider rear tire).
Can you attach a temporary long vacuum hose to the port that supplies vacuum to the booster, then place the gauge in the cabin where it can be easily seen?
This will let you know how much the vacuum varies under different conditions.
Also.....have you changed to larger rims and tires lately.....larger wheels require much more effort to slow down at higher speeds....(as I learned on my Harley Davidson when I upgraded to a 30% larger/wider rear tire).
Race Director
Joined: May 2006
Posts: 18,734
Likes: 2,582
replace the valve in the link below and make sure the hose connected to it isn't aged and leaking
https://willcoxcorvette.com/corvette...er-valve-64-82
https://willcoxcorvette.com/corvette...er-valve-64-82
