Hydraulic line lock for parking brake

[flynntuna]

What would be the pros and cons in using a line lock as a parking brake?
I read in another thread of someone using one as their parking brake and it intreagued me. Aside from not having a mechanical method to stop the car in the rare event of a hydraulic failure, is there any reason not to use one. it would seem to be a way to simplify the build.

[NAZ]

Do not use an electrical type "line-lock" for a parking brake. These type line-locks are normally open and powered in the closed position, which is exactly what you want for a line-lock. I have two line-locks, one for the front brakes and one for the clutch release and both work great for those applications. I also have a hydraulic block valve tied into the rear brake line that was made for a parking brake. You can get a manual valve made by Scat at Summit Racing for $24.97, part number SVW-70291. I used a Speedway Park Lock purchased from Speedway Motors for $29.99 for my hot rod but have purchased the Scat unit also. Either will work and for the $$ it's way easier to set these up as a parking brake than fabricating a mechanical parking brake which is what I would have had to do. Don't forget to buy brake line adapters for them.

I've flown airplanes that come equipped with these manual valves as a parking brake and they work great. I used the manual valve on my build so I could run 12.9" rear brakes and 15" wheels when I want to go drag racing (better selection of drag slicks in 15"). The trick is to push the brake down and then push the manual valve in while slowly letting up on the brake pedal. To release the parking brake just push on the brake pedal again.

Yes, there is no "emergency brake" when using these units. But really, what's the chance you'd loose two separate braking systems on your car that would require an "emergency brake"?

[Samiam1017]

flynntuna
i think you might have seen i was using it i believe I'm using the same part number as naz. the only thing i would add to what he said was that i'm also using the willwood pedal with dual masters using the single Subaru unit i might have a concern but i think you could use two reservoirs and that may ease the mind if a line broke you could at least still stop the car.

[DaveS53]

If your car will be inspected by the state, a hydraulic parking brake is not likely to pass. These days no new car has an emergency brake, but they all have parking brakes, but they are never part of the hydraulic brake system.

[iblackwe]

This is really intriguing as I would love to ditch the annoying park brake lines that run through my system. What do you think you could in turn run in the rear for brake system?

[flynntuna]

If your car will be inspected by the state, a hydraulic parking brake is not likely to pass. These days no new car has an emergency brake, but they all have parking brakes, but they are never part of the hydraulic brake system.

This is the vehicle code for California...https://law.justia.com/codes/califor...0-26458.5.html
I think I'm good.

[flynntuna]

flynntuna
i think you might have seen i was using it i believe I'm using the same part number as naz. the only thing i would add to what he said was that i'm also using the willwood pedal with dual masters using the single Subaru unit i might have a concern but i think you could use two reservoirs and that may ease the mind if a line broke you could at least still stop the car.

I'm also using the Wilwood pedal system.

[DaveS53]

This is the vehicle code for California...https://law.justia.com/codes/califor...0-26458.5.html
I think I'm good.

A hydraulic parking brake fails the very first paragraph requiring separate operation.

[Samiam1017]

im sure it will come down to a state by state allowance PA it will pass

[NAZ]

Not sure what your goal is or your reason for thinking about using a hydraulic block valve for holding your juice brakes on for a parking brake. For me it was a desire to have the largest rear brakes that I could fit 15" wheels over and those bulky Wilwood combination calipers FFR sells had to go.

There are lots of ways to get a parking brake and still have large rotors or rid yourself of routing two cables through a chassis. There are a couple of outfits making pinion mounted parking brakes for various vehicles. Google TSM Manufacturing or pinion mounted parking brakes to see what I'm referring to. Or use this link Ford 8.8 Pinion Brake – Postal Mopar Industries, LLC.. If you've got fabrication skills you may be able to retrofit a go cart disc brake on the pinion. And if you don't want any cables running to the cockpit you can use an electrical parking brake actuator. Stores like Speedway Motors should carry these. And if you want to stay with the large bulky calipers that have the integral mechanical parking brake these can also be operated with an electrical actuator so you don't have to route cables in a conventional manner.

[flynntuna]

A hydraulic parking brake fails the very first paragraph requiring separate operation.

Your right, does say that. But, the second paragraph says if the two systems are connected in any way, the failure of one part shall not affect the second part. With two master cylinders though wouldn't that cover that issue? I'll have to call a couple of brake and light inspection shops to get clarification. Maybe three. Best two out of three

[Mark Reynolds]

Here is the Breeze parking brake valve:
http://www.breezeautomotive.com/deta...p?prod_id=1000

[NAZ]

Another good option Mark. The dirt track boys use something similar for blocking off the right front brake to help turn in. I was going to use one until I decided I better put a position switch on it & an indicator lamp on the dash to show when it was not fully open. That way it could never be shut off with no pressure on the line and the driver not know it. Maybe it's just me but I could see someone turning it off and I get in and drive off with no rear brakes. The styles I used are spring loaded to force the valve open the first time you step on the brake -- idiot proof.

[blomb11]

Your right, does say that. But, the second paragraph says if the two systems are connected in any way, the failure of one part shall not affect the second part. With two master cylinders though wouldn't that cover that issue? I'll have to call a couple of brake and light inspection shops to get clarification. Maybe three. Best two out of three

@flynntuna what did you end up doing for your parking brake solution? I am going to be using the dual Wilwood brake master cylinders and am looking into a hydraulic parking brake. A hydraulic line lock would make it much cleaner if it can pass CA DMV inspection.