Is this a dumb idea?
Thread Starter
Staging Lane
Joined: Dec 2020
Posts: 88
Likes: 16
Is this a dumb idea? I've recently learnt about the TCC wire on ls1/4l60e. I understand it should have ignition voltage applied to it unless the brake pedal is pressed. This will unlock the torque converter when the pedal is pressed.
I'm having issues with the parking (emergency) brake. It's not holding the car when applied. My question is: can I use the parking brake switch to remove +12V from the TCC wire when the parking brake is engaged ? This should have the effect of unlocking the torque converter and making it easier for the parking brake to stop the car. Does this make sense? Are there any side effects I'm missing here?
Cheers,
Greg
I'm having issues with the parking (emergency) brake. It's not holding the car when applied. My question is: can I use the parking brake switch to remove +12V from the TCC wire when the parking brake is engaged ? This should have the effect of unlocking the torque converter and making it easier for the parking brake to stop the car. Does this make sense? Are there any side effects I'm missing here?
Cheers,
Greg
I doubt it would help very much.
also the parking brake is for parking, it was not designed to stop the car by itself. It also only operates the rear brakes or a separate set of brakes with in the rear brakes. So any attempt to stop the car with only rear brakes isn't gonna be very fast.
if the parking brake keeps the car from rolling off from a stop it is fine. If it still rolls from a dead stop with the pb on it may need servicing.
also the parking brake is for parking, it was not designed to stop the car by itself. It also only operates the rear brakes or a separate set of brakes with in the rear brakes. So any attempt to stop the car with only rear brakes isn't gonna be very fast.
if the parking brake keeps the car from rolling off from a stop it is fine. If it still rolls from a dead stop with the pb on it may need servicing.
Thread Starter
Staging Lane
Joined: Dec 2020
Posts: 88
Likes: 16
A bit more background information may help......
I'm rebuilding an AC Cobra which is fitted with an LS1 and 4L60E transmission. I've sourced an IRS from a 300ZX which I've fitted to the car. I've adjusted the crap out of the handbrake but I can't get it to hold the car when standing.
The handbrake operates some drum brakes in the rear hubs. These brakes are independent from the rear brakes which are the traditional discs/calipers. I've replaced both of the hubs and also the brake shoes. Still no luck in getting the handbrake to hold the car. I'm assuming that if the car is not being 'driven' forward by the engaged torque converter, there's a better chance the handbrake will hold the car. The only other thing I can think of is that the handbrake lever is not providing enough 'leverage' to apply enough force to the drums to hold the car. Note the linkage between the handbrake lever and the drums are dual cables.
Any suggestions appreciated.
I'm rebuilding an AC Cobra which is fitted with an LS1 and 4L60E transmission. I've sourced an IRS from a 300ZX which I've fitted to the car. I've adjusted the crap out of the handbrake but I can't get it to hold the car when standing.
The handbrake operates some drum brakes in the rear hubs. These brakes are independent from the rear brakes which are the traditional discs/calipers. I've replaced both of the hubs and also the brake shoes. Still no luck in getting the handbrake to hold the car. I'm assuming that if the car is not being 'driven' forward by the engaged torque converter, there's a better chance the handbrake will hold the car. The only other thing I can think of is that the handbrake lever is not providing enough 'leverage' to apply enough force to the drums to hold the car. Note the linkage between the handbrake lever and the drums are dual cables.
Any suggestions appreciated.
The tcc isn't locked until you're at a cruising speed. Locking the converter while you're sitting still will kill the engine out, similar to letting a manual transmission clutch out too early.
I'll also mention again the parking brake was only designed to hold the car from rolling, not to stop it after it's rolling. The parking brake is a very simple system, especially the drum in hat design as you have described. Either the cables are pulling the shoes far enough to engage the drum/hat or it isn't. If it's not you need to make the cables pull on them harder. Could also be an issue with the spreading mechanism, or the hand brake isn't pulling the cables enough.
bottom line locking the tcc is not the answer to your issue.
I'll also mention again the parking brake was only designed to hold the car from rolling, not to stop it after it's rolling. The parking brake is a very simple system, especially the drum in hat design as you have described. Either the cables are pulling the shoes far enough to engage the drum/hat or it isn't. If it's not you need to make the cables pull on them harder. Could also be an issue with the spreading mechanism, or the hand brake isn't pulling the cables enough.
bottom line locking the tcc is not the answer to your issue.
Thread Starter
Staging Lane
Joined: Dec 2020
Posts: 88
Likes: 16
I guess I mis-understood the purpose of the TCC wire and when the torque converter is locked. If its only locked when cruising speed is reached, then this is not my problem.
As for the parking brake, agree it is meant to hold the car from rolling, not stop it when it is moving.
I'm certain the shoes are contacting the drums when I apply the parking brake, as the brake lever 'throw' is shortened when I adjust the shoes to be closer to the drums (there is an adjustment hole in the the hub which allows adjustment of the piston which moves the position of the shoe).
I'll check the cables and the handbrake lever - I suspect there is not enough pressure being applied to the brakes either due to the routing of the cables or the lack of leverage from the hand brake lever. Thanks for the suggesitons....
As for the parking brake, agree it is meant to hold the car from rolling, not stop it when it is moving.
I'm certain the shoes are contacting the drums when I apply the parking brake, as the brake lever 'throw' is shortened when I adjust the shoes to be closer to the drums (there is an adjustment hole in the the hub which allows adjustment of the piston which moves the position of the shoe).
I'll check the cables and the handbrake lever - I suspect there is not enough pressure being applied to the brakes either due to the routing of the cables or the lack of leverage from the hand brake lever. Thanks for the suggesitons....
TECH Fanatic
Joined: Sep 2008
Posts: 1,643
Likes: 526
Not sure what e-brake lever you have but I have used a few with internal rear e-brakes and I had to adjust the cable so it's quite tight when it's not applied . Also the brake shoe adjustment should just "lightly" scuff the rotor in the relaxed position.
