How do you stop a m809 if the brakes fail?

[319cssb]

I know downshifting through the gears will slow down, but then?
How do you stop without hitting something if you need to stop faster? And find out the brakes won't slow you?

 

[NDT]

Aim for the least expensive thing in front of you.

 

[simp5782]

emergency brake. tighten the knob as you pull it up.

 

[319cssb]

Have you ever had the brakes fail on you in your M809?
Not sure but are they not single circuit brakes?

 

[simp5782]

I have a 816 and a 813 truck that do not have brakes at all that I never have fixed. I mope them around the yard or around the local streets slowly using the emergency brake to stop but i never get over about 15mph.

 

[Bulldogger]

My first impression was to kill the engine, but a diesel can keep going if it can pull hard enough on the fuel source and especially if it has an engine driven mechanical pump.

Aim for a row of Prius' I guess...

BDGR

 

[simp5782]

My first impression was to kill the engine, but a diesel can keep going if it can pull hard enough on the fuel source and especially if it has an engine driven mechanical pump.

Aim for a row of Prius' I guess...

BDGR

pulling the manual shut off in center dash will kill it dead in the water as it closes the fuel feed completely.

 

[162tcat]

I've had the brakes fail. If they were working fine but have a line ruptured or something to that effect you will usually have two pumps of minimal breaking. Use them wisely and downshift while applying the E break. This is a great reason to check your break fluid level before every trip! If you lose brakes just because the system has a slow leak and the MC gets too low, that is absolute stupidity on your part.

Also, if you kill the engine that will severely limit your ability to downshift unless your synchro's are in amazing condition. You won't be able to bump the RPMs way up to shift into another gear. If that happens, you're in a panic situation with no breaks and no power steering. Best bet is to leave the engine running, downshift, apply the E break and look for soft ground to drive on which will slow the truck down naturally or safe place to "crash" if all else is unavoidable.


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[porkysplace]

emergency brake. tighten the knob as you pull it up.

That's a parking brake and not going to do much with any weight or speed other than come apart.
Might give you a feel good moment but won't stop the truck.

 

[simp5782]

That is why you twist the knob as you pull it to increase pressure slightly as you pull up... It will stop a truck... It will stop a wrecker going 25mph as it slows enough combined with downshifting to stop it. It does work so don't try to negate the fact that it will come apart... It will hold up in a stopping situation. It is a decent sized shoe. Don't always look at the negative side of something won't work.

 

[Floridianson]

Aim for the least expensive thing in front of you.

Yep and don't think a telephone pole will if you have enough speed.

 

[swbradley1]

Since I was doing about 45Mph when I pushed on the brake pedal of my 813 and realized I had no brakes I'd say it was a pucker up moment. Even with a remote reservoir I had no "two pumps" and I know darm good and well the parking brake is just that, a parking brake, not an emergency brake.

In too many of the trucks I have seen even the parking brake isn't going to help in a full up emergency. If you have time you might be able to use it to slow you down but a panic stop you are going to hit something. If the engine and power steering are still working at least you have a choice in what you hit.

In my case I just didn't panic. It isn't like the trucks accelerate so fast we are bunched up on another bumper so you may have time to make a decision. I just began down shifting as the truck slowed until I got it slow enough to pull into a parking lot. Then I turned around and drove it home in first gear with my hand on the parking brake and went slow that I knew the brake would stop me.

The biggest thing I can say is just try not to panic. I've had stuck throttles and blew out brakes on two vehicles and I don't give a rat's azz what they say about dual brake systems, NEITHER helped in my brake failures. No brakes period when the fluid went.

 

[162tcat]

Since I was doing about 45Mph when I pushed on the brake pedal of my 813 and realized I had no brakes I'd say it was a pucker up moment. Even with a remote reservoir I had no "two pumps" and I know darm good and well the parking brake is just that, a parking brake, not an emergency brake.

In too many of the trucks I have seen even the parking brake isn't going to help in a full up emergency. If you have time you might be able to use it to slow you down but a panic stop you are going to hit something. If the engine and power steering are still working at least you have a choice in what you hit.

In my case I just didn't panic. It isn't like the trucks accelerate so fast we are bunched up on another bumper so you may have time to make a decision. I just began down shifting as the truck slowed until I got it slow enough to pull into a parking lot. Then I turned around and drove it home in first gear with my hand on the parking brake and went slow that I knew the brake would stop me.

The biggest thing I can say is just try not to panic. I've had stuck throttles and blew out brakes on two vehicles and I don't give a rat's azz what they say about dual brake systems, NEITHER helped in my brake failures. No brakes period when the fluid went.

Sounds like I got lucky! I pushed mine and it slowly went to the floor so I realized I wasn't going to have any breaks. I started to slow down by downshifting and had one more push that slowed me down a little more before it was totally gone. Mine was a seal in the wheel cylinder that let go. The wheel cylinder was NOS so I replaced all with Wagner parts from the auto parts store.


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[doghead]

If the brakes don't stop you, something will...

https://www.ispot.tv/ad/IZfM/at-and-t-wireless-ok-machanic

 

[Recovry4x4]

I can tell you, it's uncomfortable at best. Had it happen twice, one I deserved. 20,000# deuce wrecker was my fault for not checking drums before my first test drive. Second was 35 MPH in a deuce tractor flat towing a cargo truck. Got I't down to a few MPH before the intersection, then bled out quite a bit of air with the horn. Split a steel brake line. Had to be faulty to split.

 

[Ajax MD]

Have you ever had the brakes fail on you in your M809?
Not sure but are they not single circuit brakes?

They are indeed, single circuit brakes. There is a fair amount of discussion in the Deuce sub-forum about upgrading them to the Air Force dual-circuit master cylinder.
If they are successful, I'm hoping the procedure can be adapted to the older 5 tons. One guy just completed the upgrade but is having some sort of air leak.

In the meantime all you can really do, is do your PMCS and check on things regularly and frequently. Pay attention to the "feel" of the pedal when you drive (I realize that a sudden, total failure can occur without warning). The jump in gearing from 4-3 is big. I can make a smooth downshift from 5-4, but 4-3 is difficult to get the synchros spun up in time. Bleed off what you can by downshifting, then get outta the way.

Drive like a motorcyclist and try to always leave yourself an "out." At 52 mph maximum, you really have no business in the left lane. If you're in the right lane and lose your brakes, you can (hopefully) dive off the road. I'd eat a ditch or a utility pole before I'd plow into a car with my truck if I have a choice. Just like pilots, we need to put the safety of others before ourselves. Don't use a Prius as a crash pad.

Ok, now that all the dire warnings have been said, if you're doing your maintenance and inspections, you're probably worrying too much.

 

[porkysplace]

They are indeed, single circuit brakes. There is a fair amount of discussion in the Deuce sub-forum about upgrading them to the Air Force dual-circuit master cylinder.
If they are successful, I'm hoping the procedure can be adapted to the older 5 tons. One guy just completed the upgrade but is having some sort of air leak.

In the meantime all you can really do, is do your PMCS and check on things regularly and frequently. Pay attention to the "feel" of the pedal when you drive (I realize that a sudden, total failure can occur without warning). The jump in gearing from 4-3 is big. I can make a smooth downshift from 5-4, but 4-3 is difficult to get the synchros spun up in time. Bleed off what you can by downshifting, then get outta the way.

Drive like a motorcyclist and try to always leave yourself an "out." At 52 mph maximum, you really have no business in the left lane. If you're in the right lane and lose your brakes, you can (hopefully) dive off the road. I'd eat a ditch or a utility pole before I'd plow into a car with my truck if I have a choice. Just like pilots, we need to put the safety of others before ourselves. Don't use a Prius as a crash pad.

Ok, now that all the dire warnings have been said, if you're doing your maintenance and inspections, you're probably worrying too much.

On a 5 ton you would be better off upgrading to full air brakes over some kind of dual circuit hydraulic conversion.

 

[WillWagner]

Make a trap door in the floor....

 

[Two Stroke Madness]

I've installed pinion brakes fed from a hydro boost system from a dodge truck. I was even able to use the emergency brake pedal from the same truck for it. In conjuction with the parking brake they slow the truck down pretty well.

Am I the only 5-ton owner with four pedals?

 

[wheelspinner]

Can I just say that threads like this make me realize just how much I love my air brakes!!