Hurst Roll Control/Line Lock question

[70 RR]

If I plumb the Hurst solenoid in the position in the picture, will it work?

 

[bm02tj]

I would put it past the metering block
If it comes out as two lines tee them back together install roll control then split back to two

 

[70 RR]

I would put it past the metering block
If it comes out as two lines tee them back together install roll control then split back to two

There isn't a lot of room to work past the metering block, there is about 4" and then the proportioning valve. Disc brakes in front and drums in the rear. Aside from redoing the entire system (which I really don't want to do) what are my options? What is the reasoning behind installing the solenoid aft of the metering block as apposed to forward? Thanks.

 

[70 RR]

So I think I have this figured out. I would have to disconnect the front brake lines to the metering block plug one side (lets say the side going to the left front brake) run a new line out of the metering block (outlet right front brake) to the "inlet" of the solenoid and a line from the "outlet" of the solenoid to a "T" fitting and connect both front brakes to that?

 

[Jeremiah]

That is more or less how I do it on my sticks cars. That way you pump up the brakes, hold the button and have both feet to work with. Less the button fly and away you go. If it was me I'd wire a two step into the equation for burnout rev control. I usually use an adjustable proportioning valve on the rear and "T" the lines to each front caliper from the line lock itself to keep it simple. Don't forget to route the brake lines around the front to get them away from the bellhousing area.

 

[70 RR]

Thanks guys, I'll give it a shot.

 

[krowbar]

So..back to the original question. Would it still work the way he has it laid out in the first post? If not, please explain.

 

[mopar 3 B]

If it was put ahead of the portioning valve as soon as the brake pedal was released with no pressure on the rear brakes the portioning valve would over center. That would not be good right?

 

[krowbar]

Wouldn't that just effect the brake warning light?

 

[Jeremiah]

It would work just fine although the operation would be a little different than what I described above. You would hold the line lock button, pump up the brakes (front) and then release the button. This way you control the brake with the pedal not the button. This may be ideal for a foot brake drag race car.

 

[krowbar]

Now I'm really confused. I don't understand how that would work. Press switch, then press and hold brakes.Then let off the switch? I don't think you're suppose to press on the brake while the switch is activated. I've heard that screws up the solenoid.

 

[70 RR]

I still haven't installed the line lock. My first post showed pictures detailing my installation plan and I was told that wouldn't work. I decided to try to install the solenoid downstream of the factory prop valve but to me that didn't make sense so I decided to research further. I ran into a guy at the track with a 68 Dart that was equipped with line lock and it was installed exactly the way I originally planed on doing it. He assured me it works fine with no issues. Maybe I'll give it a shot and see what happens. I'll let you guys know how it turns out.

 

[Jeremiah]

It will totally work the way you originally described it. The "proportioning valve", if stock to the car's year of manufacture, is simply a junction block/low pressure switch. Sorry for not being more clear.

 

[krowbar]

Just spitballin here but indulge me. If you hooked the line lock to the rear line, then plumbed the solenoid backwards. i.e. in line into the out on the solenoid and out line into the in on the solenoid. Would you be able to turn on the line lock and isolate the rear brakes so they are not on when you step on the brake pedal. Basically feathering the front brakes for a super long low rpm burnout???

 

[Jeremiah]

Now I'm really confused. I don't understand how that would work. Press switch, then press and hold brakes.Then let off the switch? I don't think you're suppose to press on the brake while the switch is activated. I've heard that screws up the solenoid.

The line lock is going to do one of two things depending on how you design the system:

a) It is going to hold pressure in the front brakes while you have the solenoid activated after you pumped up the brakes and let off of the pedal. This allows the front brakes to hold the car while I do the two-step tango with the clutch and gas pedal.

b) It is going to prevent pressure from building in the rear brakes while you stand on the pedal. Once the front brakes are pumped up you can turn off the line lock to restore 4-wheel braking. This setup works good for an automatic because you have to hold the brake to heat up the tires.

Sorry if my explanation did not make sense the fist time. Or the second time lol. Think about it this way - you are either holding pressure in the front braking system or blocking pressure from the rear braking system.

 

[70 RR]

Got it! Thanks for the explanation that did make it more clear.