Parking brake/Parking pawl removal

[LightBnDr]

So I'm about to start a new project. A build that has never been done. I need some feedback on my question that will appear at the end of this ramble.

I run a 42RE transmission behind a 4.0L. For those unfamiliar it is a 4 speed trans. That uses an overdrive unit in a separate extension housing on the rear of the trans. Just like all of the 46-47-48REs that most are used to. Just a smaller scale. All of the same internal designs.

I'm going to remove the overdrive unit along with the entire housing and adapt a front case half of another tcase in its place. No worries on fluid passage issues or on how to adapt the tcase to the trans.

One of my biggest concerns is when I eliminate the overdrive unit I also lose my OEM parking linkage and pawl. So that leaves me with no park position.

I'm 100% out on a prop shaft brake unless it's invisible.

My main question is are there any recommendations on how to create a park function? Whether it be a mechanical out of the box idea or a single piston master cylinder that only applies the rear brakes with a ratcheting handle? Has anyone ever done this before personally? Creating a parking brake that they felt safe enough to walk away from on a sketchy climb?

Would love pics or links of extraordinary ideas. Thanks guys


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[lowbudgetjunk]

Hell I am always sketched out on the parking pawl alone. Should be interesting to see the ideas

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[Pumpkin]

Re:

What about the old manual line locks that used to come on old wreckers and forklifts?

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[TRUCNUT]

in line hydraulic line lock to the rear

 

[TBItoy]

Re:

Our scissor lift has a hydraulic cylinder that extends and engages a hole in the wheel to hold it stationary when you are not driving.

I've thought about building mechanism that has a positive mechanical engagement on a brake rotor or pinion yoke and using using air pressure or an electric solenoid to release it.


You could always use ball valve line locks for a parking brake.


On Toyotas I reroute the parking brake cable to the firewall and use the parking brake handle to pull the brake pedal down. Easy 4 wheel parking brake. I've mashed the pedal and locked it down many times with the trans in neutral (manual) to get out and winch when moving trees or recovering other vehicles.

 

[LightBnDr]

Freakin genius ideas. So normally I would get all huffy and puffy about someone not researching the net but gimme a quick physical breakdown of how an in line lock to the rear would work. As far as walk me through how I would use it?


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[Beerj]

Someone will correct me if I'm wrong but I believe it's just a valve inline on the brake line running to the rear. Depress the pedal, close the valve and release the pedal. I thought about using that as a cutting brake and while it's not as graceful as dual pedals or real cutting brakes I think it would still get the job done.

 

[paradisepwoffrd]

Re: Re: Parking brake/Parking pawl removal

Someone will correct me if I'm wrong but I believe it's just a valve inline on the brake line running to the rear. Depress the pedal, close the valve and release the pedal. I thought about using that as a cutting brake and while it's not as graceful as dual pedals or real cutting brakes I think it would still get the job done.

This is correct. It basically holds the hydraulic pressure in the line going to the caliper/cylinder.

Biggest downside to line lock is they can leak down over time. Not to bad for temp use on the trail but I'd think twice if u need to leave in park for a long time. Also is very dependant on how good your brakes are, if using an existing system.

It would work for a cutting brake. If needing a quick/easy solution the Mico electronic locks are flip of a switch, and you can stab the brakes before or after flipping them on. They are pricy though.

 

[paradisepwoffrd]

Re:

I know you said no prop shaft brake. Along the same lines as what Nick mentioned: steel plate that attaches to output flange with holes drilled around the circumference and a cable/electric/air/hydro actuated rod/piston that engaged in the holes.

I like a mechanical connection, but something electric could be made to apply when the shifter was in park position.

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[Toddy]

All pro off-road has a rear out put parking brake kit for Toyotas. Check it out.

 

[LightBnDr]

Eehhhh man I guess it's worth looking at a prop kit.

Ok so that's exactly what I was thinking as far as line lock operation. I've never used one but seemed pretty self explanatory.

Other dilemma is that in a line lock situation I need constant 12v to a solenoid in order to activate a lock. When I travel or when she's at home in her private slip my batt is disconnected.

Thinking about a mechanical handle like TBItoy's idea. Making a lever that would depress the brake pedal and lock.

Keep the ideas comin guys. Great think tank


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[Toddy]

I think the 12 volt line locks lock them selves. You have to press the pedal after you flip the switch to unlock them.

If you can make it work a ball valve is simplest. You could always mount it and build a small handle inside rather then having the valve inside.

 

[ftoy516]

i have Swagelok Quarter Turn ball valves on my buggy.
(one for the Front and one for the Rear)

They work great...you can press the brakes and turn the valve to hold the pressure in the line, let off the brakes get out and do what you need to do. it doesn't really matter how steep it is it will hold the buggy. As long as the braking systems is in good working order it should NOT leak down...it is only holding the pressure in the system...so if there are no leaks, it should not leak down over time.

I debated for a long time on the way i wanted to go for parking brake options, and the reason i went with the Quarter turn ball valves is that if you use something that needs 12v it causes a lot of extra headache (wiring...if you leave it on for long periods of time it could drain the battery...a Solenoid could go bad, ect...) ball valves are simple!

You may have more plumbing depending on were you mount them if you have split systems thou. i mounted my with in reach when i am strapped in...so that meant i had to plumb the lines for the front system in to the valve and then back out for the front, which is a lot of line to make that happen (but it was what i wanted) i use them a lot to help when i have to work the Clutch, Brake, and Gas, when getting started on something really step (Hand throttle would be better but i don't have that.)

 

[LightBnDr]

That sounds perfect!!

Can you shoot me some good pics? Showing your valve and brand etc? Routing and such? Where do I get those?


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[LightBnDr]

Bump. I was hoping for some good poop reading this morning


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[RustyC]

I personally would try to make a mechanical solution vs using hydraulic brakes to do the job. Yes the brakes will work but have more components to fail. Simple and mechanical you can trust 100% is the way to go.

I have 1/4 cutoff/ball valve to my rear brakes, work good but it will bleed the pressure off enough to drive through if forgotten about.

 

[LightBnDr]

Good to know. I'm open to ideas. Seems the mechanical or electrical line lock is the most popular. I'm not opposed to a mechanical version

I really liked the E brake style lever-ish-kinda idea to manually depress the brake pedal with a lever. That way it's kinda always in the way unless released.

Would like to know more about the ball valves though.


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[ftoy516]

I am still trying to get the pictures off the camera (its charging)

here is a link to the valves that I used....I went from npt to invert flare...but wished that I would have went to 3AN (I feel like that is a better mechanical connection) but I was learning so it is what it is. and I had never build anything until this, so it was a learning experience.

 

[ftoy516]

 

[LightBnDr]

Freakin awesome. Thank you for taking the time to shoot pics and a link. I'm gonna do some research and figure out what will work best for mounting locations then I'll post up a build thread on the doubler and P brake design.

Thanks for the quick response and ideas guys


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