Line lock as an emergency brake?

[Polar Bear]

Let me kick this one out to the greater collective knowledge here- while wheeling down a super steep ridgeback descent, I had to stop to get out and spot an obstacle. Fully loaded for camping, the e-brake was not up to the job of holding rig (properly adjusted too) and I had to rely on the transmission park pawl to secure the truck while I reluctantly got out.

Which got my gears turning: at the drag strip they use a line lock to apply the front brakes only when they enter the water box for their burn out to warm the tires. They apply full brake pedal, throw the switch which prevents the applied brake pressure from dropping at the front axle once the pedal is released, and the rear axle is free to spin up for tire heating unencumbered by the brakes.

Now my question is this- could this system be safely adapted as an emergency brake if installed for all four wheels? I'm sure there are a few track refugees around this place that have more familiarity with this system than I do, please enlighten a luddite

I know that Allpro Offroad made a caliper and rotor setup for the driveshaft of Tacoma and mini trucks, but I'm looking for a cheaper solution that doesn't entail paying 500 bucks plus modifying it to fit an 80.

 

[Polar Bear]

Something like this:

http://www.jegs.com/webapp/wcs/stor...ctId=460241&storeId=10001&sType=&pgGrp=search

 

[TheBigBoy]

Its been done a few times. You will need a different type of line lock. Works great as an anti theft device also.

 

[Polar Bear]

Its been done a few times. You will need a different type of line lock. Works great as an anti theft device also.

That would be pretty humorous to watch somebody try to overcome the braking of all four wheels after successfully hot wiring the ignition.

Correction- pretty humorous to watch them do it to someone ELSE'S vehicle. Not so funny when the effing dirtbag is in your vehicle...

I'll do a bit more searching for the correct line lock.

 

[Riad]

I vaguely remember bringing this up years ago and I was told, in some states it might be illegal and serious safety hazard? So if there's any reason your break system fails and/or has leak, your line lock will fail as well. For a trail only truck it's probably a non issue to an extent. Emergency brake should be a standalone system that should be independent of the standard brake system. I thought of putting discs on both side if the transfer case but haven't had a chance to look into the details...my 0.$02.

 

[Polar Bear]

I vaguely remember bringing this up years ago and I was told, in some states it might be illegal and serious safety hazard? So if there's any reason your break system fails and/or has leak, your line lock will fail as well. For a trail only truck it's probably a non issue to an extent. Emergency brake should be a standalone system that should be independent of the standard brake system. I thought of putting discs on both side if the transfer case but haven't had a chance to look into the details...my 0.$02.

The more research I do on this, I'm seeing that same concern voiced- that the valves will leak down and that the use is only intended for temporary application.

I'm going to have to keep looking into this. Maybe the rotor-caliper-driveshaft thing it's the only viable solution.

Still searching...

 

[Riad]

Something like this probably can be retrofitted with minimal cursing and

http://www.sky-manufacturing.com/new/detaproduct.php?id=142

 

[cruiserfj45]

I think it would be perfect in your situation. Not intended for everyday use because your factory parking brake would not be altered. However for those times when you need that extra braking force it is there. All three systems would have to fail in order for things to go bad.

 

[e9999]

if you put a shaft brake on only 1 side, you may want to lock the center diff too.

 

[Polar Bear]

That looks pretty decent, and costs about half of what I recall the other setups being. Shouldn't be too tough to retrofit.

Since I run part time hubs up front, the CDL switch is almost always on in daily use, so no problems there. Also, this would be more of a wheeling only use (for extra steep grades), where as I can just use the emergency brake for daily street use.

Thanks everyone!

 

[dorton]

I really like the t-case ebrake setup. I've read some who said the effort needed to engage them is excessive, and the holding power is just ok. I'd like to try one myself.

Sent from my SPH-L710 2

 

[Howard705]

Commercial trucks/bucket trucks/tow trucks with hydraulic brakes used to use Micro-Lock brake locks-like the line lock but not for leaving parked/unattended. Like holding your foot on the pedal when you want to winch/etc. No different chance of failure than having line or anything blow when going down a steep hill.

 

[Polar Bear]

Commercial trucks/bucket trucks/tow trucks with hydraulic brakes used to use Micro-Lock brake locks-like the line lock but not for leaving parked/unattended. Like holding your foot on the pedal when you want to winch/etc. No different chance of failure than having line or anything blow when going down a steep hill.

I think the failure the previous comments were addressing was the inline valve leaking down pressure. Is this product constructed differently?

So this micro-lock would be used when you are winching from inside the vehicle? I'm trying to visualize the usage/limitations. I drive various commercial trucks, but all mine have air brakes so I'm assuming these locks are for short term application only.

 

[rockrod]

The electric line locks are for intermittent use, as in just for a few seconds. They don't have duty cycle to leave activated for long. Not a good idea.

Mico lever locks can be used for extended periods. They do leak down though and most have an audible warning buzzer that sense line pressure leaking down.

Neither are truly failsafe because there is no redundancy that the mechanical cable operated parking brake provides.

Wilwood makes a small mechanical brake caliper that is designed to work as a parking brake. It acts on the same rotor the main caliper does.

 

[Polar Bear]

The electric line locks are for intermittent use, as in just for a few seconds. They don't have duty cycle to leave activated for long. Not a good idea.

Mico lever locks can be used for extended periods. They do leak down though and most have an audible warning buzzer that sense line pressure leaking down.

Neither are truly failsafe because there is no redundancy that the mechanical cable operated parking brake provides.

Wilwood makes a small mechanical brake caliper that is designed to work as a parking brake. It acts on the same rotor the main caliper does.

Ahhh. This is the info I was looking for. I wasn't aware of the shorter duty cycle in line locks.

The friction method may end up being the better solution for this application.

 

[LandBruiser69]

In my previous experience using line locks, I don't see why they wouldn't work. Also, I have never had them leak either. First off, in drag racing you simply install them onto your front brake lines. All they are is an electrically actuated valve. Now, the setup I had on my car you just pushed in the brake petal which pushed fluid to the brakes...effectively locking them. Then you held the red button I had on the side of my t-handle shifter until you released it the brakes stayed locked in the front. In order to use it for an e-brake, all you need to do is change the switch from a momentary push button to a single pole toggle switch. And vuala... Locked brakes. Now, the only negative I see to this method is that if your battery dies, guess what... Your line lock will release and down the hill your truck goes.

 

[LandBruiser69]

The way you could keep that from happening would be a valve that "fails to closed" in other works if you lost power to the valve it would close. But the only way I would isle that is if the valve was unidirectional locking. So that if it did fail, you could still get fluid to the brakes when you pushed the pedal and the valve was closed. I really don't think that would be safe though.

 

[Reelitchy]

Ok just scanned over this thread, if you just need temp brakes to look at an obstacle, or backup for the park Paul and e brake couldn't you just take a croquet mallet with you and move your seat up to hold it on the break. Just a thought

 

[rockrod]

I know a guy I used to wheel tellico with. He tried one of those drag racing style line locks to park his manual trans equipped jeep on a steep hill in trail 12. The lock didn't hold and since the trans was in neutral you can imagine what happened next. We spent the rest of the day recovering the jeep about 100 yards down a hill side. Don't use these for this purpose. It's not safe.

Mico is the way to go, but even those are not a long term park brake. The only truly safe mechanism is a mechanical brake on the transfer case output or one that acts on the rotor.