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TechnoWeenie
Site Supporter
Location: Nova Laboratories Joined: Tue Oct 25, 2011 Posts: 18446
Real Name: Johnny 5
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So, for those not familiar with the M35a2 deuce and a half.. it has an Achilles heel - Its brakes.
It uses an air over hydraulic system that's prone to leaks, and is single circuit. Lose air = lose brakes. Brake fluid leak = no brakes... GOOD LUCK EVERYONE!
So, I saw they make parking brakes for the pinion shaft.... couple hundred bucks .... These are open diffs so braking the pinion shaft while moving won't have the desired outcome...
But, I'm trying to figure out a way to have more reliable parking brake (which also sucks), while having an emergency brake that can at least start to slow the truck down.
Is there a way to tee into the existing hydraulic brake lines with a manual hand brake, or a small electric pump that you hit a switch and it just charges the line to 1000PSI and essentially locks the brakes? Any way to limit that? Adjustable pressure regulator that I can set to whatever I think is reasonable pressure, eg maybe just before they lock up so I can still slow down fast in the event of a main brake failure but not lose control?
Thoughts? Ideas?
I don't know shit about any of this, and I'm slowly finding bits and pieces but I'm not grasping the whole picture here.
_________________NO DISASSEMBLE!Thomas Paine wrote: "He that would make his own liberty secure, must guard even his enemy from oppression; for if he violates this duty, he establishes a precedent that will reach to himself."
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Fri Jul 29, 2022 11:28 pm |
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Massivedesign
Site Admin
Location: Olympia, WA Joined: Fri Mar 11, 2011 Posts: 38307
Real Name: Dan
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CQBGopher knows a bit about hydraulics. <—- that is the most I know.
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Sat Jul 30, 2022 4:12 am |
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Old Growth
Site Supporter
Location: Nisqually Valley Joined: Wed Oct 5, 2016 Posts: 4834
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Remember that the pinions in your deuce spin 6.72 times faster than your brake drums do. Pinion brakes run HOT if used for stopping the truck. They have lots of leverage though.
You can just fabricate a hand operated master cylinder to actuate the pinion brakes. Just like a “cutting brake” or buggy type of brake used by off-road folks for rock crawling or turning during wheelies. Just a pull-lever mounted to a master cylinder. We have one on our skidder that operates the brake on the winch.
I have deuce axles in our mud truck and put pinion brakes on it over 20 years ago. It has 16.00x20s on bead locks (53” tall) and stops great. But they get hot if you drive on the street.
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Sat Jul 30, 2022 6:13 am |
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Old Growth
Site Supporter
Location: Nisqually Valley Joined: Wed Oct 5, 2016 Posts: 4834
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This is our ol mud pig. It’s been around for about 25 years.
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Sat Jul 30, 2022 6:19 am |
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Old Growth
Site Supporter
Location: Nisqually Valley Joined: Wed Oct 5, 2016 Posts: 4834
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I built this one about 20 years ago as promotional/show truck. I think we used the “Chucks Trucks” pinion brake kit on it.
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Sat Jul 30, 2022 6:28 am |
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hartcreek
Location: Union Gap Joined: Sun Mar 27, 2016 Posts: 1722
Real Name: Randall Knapp
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I am familiar with single circuit brakes. Why do you not replumb your brake lines so that you have dual circuit? Instead of using air for the booster you could use hydraulics like a P30.
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Sat Jul 30, 2022 11:21 am |
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TechnoWeenie
Site Supporter
Location: Nova Laboratories Joined: Tue Oct 25, 2011 Posts: 18446
Real Name: Johnny 5
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hartcreek wrote: I am familiar with single circuit brakes. Why do you not replumb your brake lines so that you have dual circuit? Instead of using air for the booster you could use hydraulics like a P30. Because there is no point when there's only one output from the master cylinder? I'm not opposed to finding a way to integrate a dual circuit master, but 2 axles in rear and one up front would result in less power to the rear and more to the front... correct? Unless a proportioning valve is used...? I'd like to do away with the airpack and single circuit altogether, at a reasonable cost..... But settled on asking questions about things like the pinion brake as an emergency/parking brake..
_________________NO DISASSEMBLE!Thomas Paine wrote: "He that would make his own liberty secure, must guard even his enemy from oppression; for if he violates this duty, he establishes a precedent that will reach to himself."
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Sat Jul 30, 2022 11:55 am |
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Rix86
Site Supporter
Location: Shelton Joined: Sun Nov 17, 2013 Posts: 5838
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Old Growth wrote: I built this one about 20 years ago as promotional/show truck. I think we used the “Chucks Trucks” pinion brake kit on it. I thought Odie built that.
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Sun Sep 18, 2022 8:00 am |
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Old Growth
Site Supporter
Location: Nisqually Valley Joined: Wed Oct 5, 2016 Posts: 4834
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Rix86 wrote: Old Growth wrote: I built this one about 20 years ago as promotional/show truck. I think we used the “Chucks Trucks” pinion brake kit on it. I thought Odie built that. Odie owned it, but I built it. Every inch of it. Next time you see it, notice it has my old shop name CNC engraved into the front frame crossmember/spring hanger. I also built Odie’s red tacoma to. These are the day it left the shop on rollers. That’s Odie strapping it down.
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Sun Sep 18, 2022 8:54 am |
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CQBgopher
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Location: WA/MT Joined: Thu Sep 6, 2012 Posts: 8285
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_________________ Rara Temporum Felicitas Ubi Sentire Quae Velis Et Quod Velis Dicere Licet. ― Tacitus "Well, nobody's perfect." ― Osgood Fielding III
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Wed Sep 21, 2022 7:51 pm |
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