LT1 rear brakes on a LS1 F-Body (yes I searched)
07-22-2010, 06:33 PM
#1
LT1 rear brakes on a LS1 F-Body (yes I searched) I’ve installed the rear brakes from my long gone ‘94 Formula onto my ‘99 Trans Am. I did this to clear some 15 inch drag rims I have.
To do the job, I did the following:
-Swapped the backing plates-they’re completely different;
-Swapped the hose/line mounting bracketry-they’re also completely different;
-New (from GM) parking brake cables to the center of the car-from there forward it’s the same;
-New hoses (yes, I did all three);
-New pads and rotors.
The car stops fine BUT I’m noticing when I step on the brake pedal, in the first instant they grab then ease up and grab again as the pedal moves downwards. Yes-the system is very well and correctly bled. I’m also noticing more pedal travel than prior to the swap.
The LT1 calipers have the integral parking brake mechanism within the piston. To prevent drag, there’s springs to pull the piston back, much like a drum brake setup. To compensate for this in a drum brake system, there is a residual valve in the master cylinder to always keep a few PSI to the shoes. This reduces the shoe travel distance to the drum.
Here’s the question (finally!): The master cylinders are different from LT1 style to LS1 style brakes. Does the LT1 style master cylinder have a residual pressure valve? When swapping from LS1 to LT1 style rear brakes (as I’ve seen a few here have done), should the LT1 style master cylinder also be used? The brake booster is the same for all 93-02 F-Bodies so either master cylinder will bolt up.
To do the job, I did the following:
-Swapped the backing plates-they’re completely different;
-Swapped the hose/line mounting bracketry-they’re also completely different;
-New (from GM) parking brake cables to the center of the car-from there forward it’s the same;
-New hoses (yes, I did all three);
-New pads and rotors.
The car stops fine BUT I’m noticing when I step on the brake pedal, in the first instant they grab then ease up and grab again as the pedal moves downwards. Yes-the system is very well and correctly bled. I’m also noticing more pedal travel than prior to the swap.
The LT1 calipers have the integral parking brake mechanism within the piston. To prevent drag, there’s springs to pull the piston back, much like a drum brake setup. To compensate for this in a drum brake system, there is a residual valve in the master cylinder to always keep a few PSI to the shoes. This reduces the shoe travel distance to the drum.
Here’s the question (finally!): The master cylinders are different from LT1 style to LS1 style brakes. Does the LT1 style master cylinder have a residual pressure valve? When swapping from LS1 to LT1 style rear brakes (as I’ve seen a few here have done), should the LT1 style master cylinder also be used? The brake booster is the same for all 93-02 F-Bodies so either master cylinder will bolt up.
Last edited by Paul Bell; 07-22-2010 at 08:34 PM.
