Pinion brake?

[rustystud]

Thank you.

I think I need to get a brake pressure gauge and map out the pressure vs pedal location.

I hate reinventing the wheel but I'm looking at all options, and a more reliable air/hydraulic 2 circuit master cylinder seems like a good research project..

There is a formula for calculating stroke and bore size to pressure and all that jazz, and I don't think I'll be able to get to that high pressure unassisted without a 10' long brake pedal, heh.

So, for now, I guess I'm researching 2 separate things. Replacing the air/hydraulic system, and an emergency/parking brake... The shaft mounted one from what I hear is crap, even when it's working properly.

I've been eyeing shutoff valves, different master cylinders, and a whole bunch of stuff to see what might work.

The maximum brake pressure I can get without the brake booster is 500 PSI. That's basically standing on the pedal and using the steering wheel to pull me in.
I'm not really sure what you're trying to do here. There is already a dual brake master cylinder on the later Deuces that works great. Going with a more modern brake booster would make it more reliable. Or just replace the whole system with a totally modern Hydraulic system that utilizes a hydraulic pump like the larger Chevy trucks have.

 

[TechnoWeenie]

The maximum brake pressure I can get without the brake booster is 500 PSI. That's basically standing on the pedal and using the steering wheel to pull me in.
I'm not really sure what you're trying to do here. There is already a dual brake master cylinder on the later Deuces that works great. Going with a more modern brake booster would make it more reliable. Or just replace the whole system with a totally modern Hydraulic system that utilizes a hydraulic pump like the larger Chevy trucks have.

It's my understanding the dual master from the AF A2 uses a bracket that's unobtainium, and the cylinder itself is hard to come by.

I'm not opposed to other options like a completely different hydraulic master.

 

[davidb56]

we used to hall around 2500 marines aboard our LPH in the 70's.. I trained many of them how to get drunk in port and get into fights with the SP............very quick learners. hahahahaha

 

[rustystud]

we used to hall around 2500 marines aboard our LPH in the 70's.. I trained many of them how to get drunk in port and get into fights with the SP............very quick learners. hahahahaha

I have no doubt that they learned quickly ! We were warned about getting in trouble with the Shore Patrol. If caught we were to expect some pretty rough treatment. It was your own fault if caught, so no whining afterwards !

 

[rustystud]

It's my understanding the dual master from the AF A2 uses a bracket that's unobtainium, and the cylinder itself is hard to come by.

I'm not opposed to other options like a completely different hydraulic master.

OK. The bracket is hard to find, but the master cylinder was used by a few modern trucks. So it's still available. I didn't realize your truck has the single master cylinder, so going with a totally different system would be the best option for you. Myself I prefer the Chevy/GMC medium truck brake system with a hydraulic pump powering the brakes. Something along the lines of the "Kodiak" would work great. Plenty out there in wrecking yards.

 

[gimpyrobb]

Thank you.

I think I need to get a brake pressure gauge and map out the pressure vs pedal location.

I hate reinventing the wheel but I'm looking at all options, and a more reliable air/hydraulic 2 circuit master cylinder seems like a good research project..

There is a formula for calculating stroke and bore size to pressure and all that jazz, and I don't think I'll be able to get to that high pressure unassisted without a 10' long brake pedal, heh.

So, for now, I guess I'm researching 2 separate things. Replacing the air/hydraulic system, and an emergency/parking brake... The shaft mounted one from what I hear is crap, even when it's working properly.

I've been eyeing shutoff valves, different master cylinders, and a whole bunch of stuff to see what might work.

Look up threads by "spicergear". He used a hydromax from a medium duty truck in his deuce. Said it worked pretty good.

 

[Squizzbiscuit]

I see this thread is going in a different direction. But, for what it's worth, I run a pinion brake on the rear of an off-road buggy/rock crawler (rockwell 2.5t axles). As most of you implied, it would not make a viable service brake for on-road. Braking power is amplified by the gearing of the axle but with that gearing comes all the slop/backlash as the brake is applied. I have an auto-locker in the axle which keeps the rear-steer forces to a minimum but it's still uncomfortable if you're not expecting it. I have an issue with chatter in certain situations as the braking force and momentum reverberate through the gear slop, axle-shafts and tires.

I have no way of telling hydraulic pressure at the caliper but I'm certain it does not need to be much. I have an adjustable prop valve set as low as possible and it still brakes harder than the two front disks at the wheels.

As far as parking brake via cable, there are certain Cadillac Eldorado calipers that fit the bracket. They accept both hydraulic input with a manual e-brake arm.

 

[TechnoWeenie]

As far as parking brake via cable, there are certain Cadillac Eldorado calipers that fit the bracket. They accept both hydraulic input with a manual e-brake arm.

This is the knowledge I love getting.... Obscure references that no one would think to check until someone pops up and says 'hey, check this out'...

 

[banditt1979]

In a parking brake application, could you drill holes on the rotor and use a large pin, where you pulled up on the lever and it sent the pin through the caliper to lock the axle?

 

[Squizzbiscuit]

In a parking brake application, could you drill holes on the rotor and use a large pin, where you pulled up on the lever and it sent the pin through the caliper to lock the axle?

You can do whatever you want, all you need is a welder and some imagination. Popsicle sticks wouldn't hurt either. It would be a bit of fabrication but I'm sure a pin would lock the driveline. If you slam that pin in during ANY motion, I bet that rotor shatters like a grinding wheel.
I'm trying to include photos of the bolt on kit I used to help with your imagination.

 

[banditt1979]

You can do whatever you want, all you need is a welder and some imagination. Popsicle sticks wouldn't hurt either. It would be a bit of fabrication but I'm sure a pin would lock the driveline. If you slam that pin in during ANY motion, I bet that rotor shatters like a grinding wheel.
I'm trying to include photos of the bolt on kit I used to help with your imagination. View attachment 876707View attachment 876708View attachment 876709

Popsicle sticks, didn't think of that...