How does a line lock work?
 

I realize that it locks the front brakes, but how? And how hard is it to install? Any links for me?

solenoid switch activates the front brakes...

OK, cool. Here's a link I found. Now for the stupid question, can a line lock also be used as a parking brake?

No. Well sort of. The selonoid is only designed to work for a little while. If you left it on it would burn itself out. It is also not good to leave hyd pressure on for long periods of time. It will leak down some and your "parking brake" will no longer be parking but rolling. It is designed to be used for short periods of time 10 to 15 seconds.

Thanks, that's exactly what I wanted to know.

Main purpose is to lock front wheels while you a do a burnout at the drag strip, but it also can be used instead of your parking brake for making graceful uphill starts at a stop sign. (without any backward drift).

Here is my writeup:

http://forums.corvetteforum.com/show..._id=119&arch=1

Line un-locks?????
 

Guys,
As a keen drag racing fan, I've seen my fair share of cars fitted with line locks, but for a long while I've been thinking that they're designed "bass ackward". Let me explain. When they are fitted as directed, you plant your foot on the brakes, locking all FOUR brakes on. You flick the switch and the solenoid closes a valve on the front brake circiut and the brake fluid does not flow from the front brakes back to the master cylinder when you take your foot off the brake. Of course, the rear brakes release and the wheels spin when you hit the gas.

Trouble is, if the car goes sideways and you need to correct, the front wheels are locked on and there is not a lot you can do but turn the wheel and hope (!!!!) it straightens up. You can release the transbrake but, as soon as you touch the brakes again, the rear wheels will slow down as well. Not ideal!

However, what if the line lock was inserted in the REAR brake system? When disengaged, all four brakes would apply when you touched the pedal, but when engaged, it would prevent fluid from reaching the rear brakes. This way you could get the tyres spinning, but you could modulate the speed of the car by using the brake pedal that operated the FRONT WHEELS ONLY. This would appear to be a far better way to use a line lock. Obviously, we're talking rear wheel drive!! Anyone got any thoughts on this?

Regards from Down Under :cheers:

aussiejohn

Line locks have a safety fiture built into them. You can apply the line lock and then hit the brakes and the fluid still passes through the line lock. This is prevent the linelock from accidently being applied at the wrong time and then you go for the brakes and have no front brakes.

Also, if you used the line lock on the rear, you would still need 3 feet to do a burnout in a manual car.

John Holmes could do it...

technically, the linelock doesn't apply pressure to the front brakes.. What it does is to lock in pressure.. To activate the linelock you'll have to step on the brake first, then push the linelock button and hold it. Do the burnout and when you are done, release the button and that'll release the front brakes..

You will find you can push the line lock and then apply pressure and it will work the same way. Pressure passes one way through the line lock and gets trapped from returning. This is a safety feature to prevent you from locking OUT your brakes.

mine actually seems to lock out the front brakes when I push the button... but mine is a cheap linelock (Biondo)

For those drag racers i was thinking why couldn't you put in a brake prportioning valve that you turn by hand.. Have it pop out of carpet or whatever near the drive shaft tunnel. Pull up to burn out box turn valve closed then when you hit your brake only your front brakes receive the pressure. Do your burn out and lossen up the valve. 70% of braking is front tires and if you are on the drag strip all the time then proportioning isn't that critical or you can proportion it the way you want and count the number of turns? BAM

what do you think. I've always wondered about that and a lot cheaper than a line lock

no takers? :rolleyes:

That is OK for an automatic but a stick you would be doing some fancy foot work. A line Lock is not that expensive.

true

Proportioning valves don't shut off completely, They just reduce the pressure at a maximum of 1000psi. So you'd sill have brake drag on the rear tires.

Besides, on a Vette you should have both a line lock and a prop valve...

That is what I thought but was not sure about that. Thanks for the info