I've been looking at the Hurst roll control/line lock kits on Summit and eBay, then looked at the Hurst plumbing diagram and have a problem with it.....someone on another thread said something about a car not passing tech IF you went from the master cylinder to the roll control/line lock solenoid, then to a proportioning valve which splits to the right front and left front brake lines.

Here's the link to the Hurst plumbing diagrams
http://static.summitracing.com/global/images/instructions/huu-1745000%282%291.pdf

In this picture you can see my plumbing system(although the lines aren't hooked up to the master cylinder), the 1/4" line goes to the front brakes from the master cylinder to the adjustable proportioning valve, then the front lines split off from there. Ideally I'd like to just be able to run a new line from the master cylinder to the roll control/line lock solenoid , then connect my existing line to the solenoid on the output end. I don't see a problem with this, the lines are split in the proportioning valve and the pressure would be constant for both lines because of the proportioning valve. Any thoughts or info about tech at the track?
http://s348.photobucket.com/albums/q329/boarder022/1967%20Chevelle/?action=view&current=IMG_0088.jpg

I think you might have a few things confused. I'll try to help....

A line lock is usually installed in the front line, before it splits to both wheels. Put it in the line out of the masterm before it goes into any proporting valve or distribution block.

Proportioning valves basically do one, sometimes two things. The main thing, is they balance the pressure to the front and rear brakes, in order to keep one set from locking up way before the other pair. Usually the rears like to lock up first, in a power disc/drum situation. If you are using an aftermarket adjustable proportioning valve, you'll probably want to install it in the line out of the master that goes to the rear brakes. This will allow full pressure to the fronts, while limiting some pressure to the rear preventing them from prematurely locking up.

The factory prop valve setups can be a little more complicated, but not much. If it has a wire, that's for the brake light on the dash. They still proportion front to rear, but if you lose pressure on one end or the other, the piston inside the valve moves and turns on the dash light to warn that you've got trouble. Sometimes the factory prop valve also acts as a spitter for the front brakes as well by having 2 outlets.

So, my suggestions are: if using a line lock, install it on the front line out of the master cyl. Use a Tee fitting or the factory prop valve to split the front line out of the line lock to connect to each front wheel. If you are using an adjustable aftermarket prop valve on a disc/drum setup, install it on the rear line out of the master. If you're doing anything a little differently, like disc/disc, or super skinny front tires or something, I'm not sure if the above advice will hold true.

My car has regular sized 235/255 tires, and power disc/drum. It's plumbed with a line lock on the front line out of the master to a tee fitting split to each front caliper. I have an adjustable prop valve on the rear line to the rear drums. After a bit of trial and error finding the correct adjustment on the rears, the setup works great! The line lock really helps with stick shift burnouts, and holding the car on the line before launching.

Thanks for the reply....I'm not confused though, and I pretty much understand how braking systems work, I'll describe my setup as simply as I can:

1. Dual reservoir master cylinder, front reservoir for front disc brakes.
2. 1 line from each front(1/4") and rear(3/16") master cylinder reservoir to aftermarket proportioning valve, which has 1 port out for the rear discs and is adjustable, 2 ports out to the front discs.
3. No distribution block or tee anywhere other than on the rear diff, and the proportioning valve itself for the fronts.
4. This is a 4 wheel disc setup with hydroboost, that's why there's an adjustable proportioning valve for the rear brakes....obviously so they don't lock up first.
5. I don't think the line lock on the rear disc brakes would help me at all, but the disc/disc setup is a little different.

What I was saying is that the Hurst directions do not show any illustrations where the line lock is installed between the front brake reservoir and the proportioning valve, which is what I'd like to do. I want to know if there's any tech problems at the track with doing it how I would like? Doing it this way would allow the line lock solenoid to be mounted easily on the inner fender well, as well as minimal re-doing of brake lines. My question is about tech at the track, not whether or not it will work....I know it will work, since it's the same thing as holding the brake pedal down. I've not been to the track yet and don't want to do it twice if I don't have to, not to mention theres virtually nowhere to mount it down low to the frame or inner fenderwell with everything else in the way....I"d have to make some kind of bracket and do some funky line bending and routing just to do the same thing the way I want to do it:yes: As for the disc/disc setup and front/rear proportioning, this might be a different animal but every one of these illustrations, especially SSBC's takes note to say there's nothing other than line between the master cylinder and the proportioning valve. I'm guessing this is because they want the valve to do what it does without anything else going on.

Look, I didn't mean to step on your toes. You didn't mention disc/disc, nor did you mention what type of prop valve you have. Apparently it's not the typical adjustable one with one inlet and one outlet. Your post was pretty confusing, and I just tried to help.

I dont see why you couldn't hook the line lock right out of the master. Like you said, its just the same as you holding the brake pedal. The reason Hurst shows the line lock AFTER the factory prop valve is to keep your brake light on the dash functioning. If you hooked it before the prop valve, the brake light might be on when you set the lock ,and release the pedal. Other than that, it's no different than hooking it before the prop val;ve.

Mine is mounted to the bottom of the master with a really short line going right into it. The track tech has never questioned it.

If your question is about what the tech guys are looking for, you'll have to ask them.

I run a completely separate front/rear setup with the adjustable prop valve for the rear and a Line Lock on the front. No mystery prop valve routing or plumbing, and it works great. I just adjusted the rear until they locked up just after the fronts do (4WDB).

I understand your question, and it's cool that you want to make sure you pass tech, but only the tech guy knows what he's looking for in your case. We'd love to help ya, but we don't know what that tech guy is looking for!

Chris, I'm sorry if I sounded a bit offensive, I didn't mean it that way and I do appreciate your help. It's my fault, I didn't even think to mention the disc/disc and forgot about the single adjustable separate prop. valve since it's not what I'm using. The prop. valve I have only has a provision for a brake lights switch, not the warning light on the dash so I won't be using the dash light other than when my e-brake is set. I've decided to wait for now to see what the tech guys say at the track, then go from there. Thank you for your help:beers:

Scott, I thought about doing a totally separate system but decided against it....maybe I should have, would've saved some money in the process since the prop valve is over $100.

Your proposed set up would cause no issues at our track. (NHRA)

I can tell you mine goes from the master to the linelock and then to the prop valve. The car has been to 4 different tracks and run for 14 years this way.

I think if you check NHRA rules, the LL has to go after the proportioning valve. This was discussed recently, try a search of 'line lock'. What you can get by with at any particular track may vary. There was discussion of why this might be a safety issue in one of the threads, but I don't remember the facts now. It's an age thing!!
John

Thanks for the replies guys....after looking at the way the system is in there now, it wouldn't be much trouble to take the front lines off the prop valve since they're at right angles and close to each other right now, put them into a tee and run 2 new lines to and from the line lock as well as plug one hole in the prop valve. I could do all this and mount the line lock solenoid on the inner fender, but I'd have to do the plumbing before I put the inner fender back on....otherwise it'd be almost impossible to do. I still think I'll wait for now though, as I just bled the brakes last week and nothing leaks....I don't need anything additional to fix/install as I'm trying to get it driveable and to the track by Apr. 10th as it is, and I still don't have any of my new windows except the complete vent window assemblies. I think phocksphyre is probably right, it's probably a safety thing and any GOOD NHRA track would catch this...I'd hate to have to do it twice.

Guy is just looking for info - not a dispute. What I can find says NHRA wants it after the PV. Again, tech guys don't always inspect the cars like it's a National Event. Maybe next time ask the tech guy if it's OK. Again, in one of the old threads here on TC it was explained why it was a possible safety problem.

http://www.hotrod.com/howto/49619_brake_line_lock_install/index.html

http://www.turbobuick.com/forums/brakes-suspensions-tires-wheels/264117-nhra-line-lock-rules.html

http://forums.stangnet.com/500374-nhra-legal-line-lock.html


http://www.hotrodders.com/forum/line-lock-105989.html

I don't have access to a rule book, but don't find recommendations for placement between the MC and PV. Maybe a call to Hurst or one of the other manufacturers would give you a better answer.

John