Pinion brakes

[50BMG]

Thank you for your input those were good reasons not to run pinion brakes,I wish I had that info before my purchase.

 

[Jbulach]

Resell them, or put them on for emergency brake only.


Sent from my iPhone using Tapatalk

 

[silverstate55]

Here's a few reasons not to.

1. The previously mentioned braking issue in the wet. But since you're going to use it to augment your braking, I guess that's a moot point.
2. You're going to add this to the existing braking system? Are you going to change the master cylinder to keep it separate? Because you'll want it on it's own circuit. (More to come on that)
3. You'll need to do a lot of work to change over the braking system in the truck since we've kinda outlined the need of the change to the MC. (But you'd be better served changing over to a USAF dual circuit "stock" setup) More money you're going to have to spend.
4. Going back to #2, why do you want it on a separate system? Well that's because the pinion brakes are going to overheat and boil fluid in a hurry on the road. This could be a dangerous issue on a single circuit system.
5. Even if it's a secondary system, it's still likely not legal to have. (And from what I've seen of CA road law enforcement) You'd be advertising that fact with the design of the axles/system. You might talk them out of it being illegal if it's a secondary system, but while they're there, I'm betting they'll find some other issue.

I went down this path a few years back. It's simply not going to be beneficial to a well maintained and functional stock system. I still would like to swap over to the USAF dual circuit system on my truck though for safety.

When brake fluid gets hot enough to boil, you are now inducing condensation (aka moisture) into your braking system and rust will attack anything & everything within. Lose-lose all the way around.

 

[porkysplace]

When brake fluid gets hot enough to boil, you are now inducing condensation (aka moisture) into your braking system and rust will attack anything & everything within. Lose-lose all the way around.

But they look cool .

 

[Timeline98]

So, would this be a recommended OH S#!t solution if the Main Brakes were to fail? I'm thinking in case of emergency PULL UP on Handle/Lever!! It would only be there as a supplement to the factory braking system used rarely if ever (or if off-roading at a snails pace).

I have an A3 but often wondered about an emergency stopping solution. There is the parking brake, but will that work to stop the truck?

 

[98G]

So, would this be a recommended OH S#!t solution if the Main Brakes were to fail? I'm thinking in case of emergency PULL UP on Handle/Lever!! It would only be there as a supplement to the factory braking system used rarely if ever (or if off-roading at a snails pace).

I have an A3 but often wondered about an emergency stopping solution. There is the parking brake, but will that work to stop the truck?

No, and no.

Neither pinion brakes nor the park brake are adequate to appreciably slow 14,000lbs from highway speeds.

Your A3 has the dual circuit brakes. That's the best solution going. That, and diligent maintenance.

 

[Timeline98]

Hypothetically speaking, IF you were to lose your brakes in a Deuce and a half, How would you try stop it? (maybe down shift?)

I'm just thinking the pinion brake has to be better than nothing? (Or a tree, passenger car, etc.)

 

[98G]

Hypothetically speaking, IF you were to lose your brakes in a Deuce and a half, How would you try stop it? (maybe down shift?)

I'm just thinking the pinion brake has to be better than nothing? (Or a tree, passenger car, etc.)

Kill the engine, downshift, pull the parking brake but expect it to melt, pick something nonliving to hit.....

I agree pinion brake should be better than nothing, just not enough.

I haven't seen a satisfactory solution. Again, your dual circuit A3 brakes are the best answer...

 

[rustystud]

Kill the engine, downshift, pull the parking brake but expect it to melt, pick something nonliving to hit.....

I agree pinion brake should be better than nothing, just not enough.

I haven't seen a satisfactory solution. Again, your dual circuit A3 brakes are the best answer...

Basically "98G" said it all. Look for something non-living to hit. Even semi-trucks with their "maxi-cans" will not stop just using the emergency brake. In all testing of emergency brakes on buses and semi-trucks the emergency brake is only suppose to stop the vehicle up to speeds of 5 MPH . That's correct, 5 MPH ! That is all Federal Law requires. Driving a medium to large truck requires constant vigilance. It is nothing like driving the family car. That is one reason I hated going out on the wrecker and towing a 60ft bus back to the shop. Driving a vehicle with a combined length of over 100ft requires your head to be on a swivel at all times ! Especially on the freeway in heavy traffic !
Driving a deuce is not that bad but it still is over 3 times the weight of an average car. That can cause a lot of damage to you and anyone near you. So maintaining your brakes should always be your number one maintenance concern ! and watching out and constantly thinking about what is going on around you and how you should react if something should happen, should be your number one driving concern when your behind the wheel.

 

[Floridianson]

Though is was at five mph the truck should stop in 20 feet with just the emergency brake pulled and truck aired up. I would be willing to bet if I was pull just my parking brake on my 915 she will lock up at higher speeds just going to be a long stopping distance. Would hate to try it though. The S cam on my trailer will lock them up to if the trailer becomes disconnect. With air brakes the adjustment is the important thing. Even automatic slack adjusters can fail to adjust. As said I would forget the pinion brake. With the Deuce yes I would pull the engine shut down if a emergency came up. The best thing for a system like the Deuce or 809 series is to KNOW the slave cylinders are in good working order. From there then is a good working master and air pack.
Here are the guide lines for 20mph. The figures would then go up as the speed increase. I guess they figure if your air brake system can be within the guidelines for 20mph then it should stop at higher speeds just need more footage. The problem would be the DOT officer could not make use do a 70 mph emergency stop as things could go very wrong. So they just could have us do one at 5 mph. Never seen a Dot officer test the brakes that way they just measure the throw.https://www.law.cornell.edu/cfr/text/49/393.52

 

[gimpyrobb]

Kill the engine, downshift, pull the parking brake but expect it to melt, pick something nonliving to hit.....

I agree pinion brake should be better than nothing, just not enough.

I haven't seen a satisfactory solution. Again, your dual circuit A3 brakes are the best answer...

You say down shift in an A3. Would down shifting an auto do anything if the motor is stopped?

 

[Jbulach]

I don’t think shutting down a runaway vehicle of any type is the best idea?


Sent from my iPhone using Tapatalk

 

[98G]

You say down shift in an A3. Would down shifting an auto do anything if the motor is stopped?

You got me. I wasn't thinking A3 until the last sentence.

That being said, yeah, killing it and downshifting should still be effective as long as the initial speed was high enough where the lockup TC is locked. (A3s have a lockup converter don't they?)

 

[98G]

I don’t think shutting down a runaway vehicle of any type is the best idea?


Sent from my iPhone using Tapatalk

Depends. On an M35A2 you don't lose much by killing it - there's no power steering.

In your M925A2, absolutely don't kill it - the power steering is must have. But then, your M925A2 has full airbrakes with springbrakes so it's something of a moot point.

Edit to add - this reminds me of an incident a few years ago. Through incompetence I ran an m931A2 out of fuel at highway speed on I-70. Long downhill stretch near Columbia MO. I coasted for a mile or so before stopping. I never lost power steering and the engine was being turned. (For your amusement, this was the day I learned the switch on the dash changes where the fuel Guage looks, but not where it pulls fuel). This may merit some experimentation under controlled circumstances...

 

[Jbulach]

Monkeying around trying to shift any transmission without power sounds like a bad idea in a runaway to me... what do you gain by shutting the motor off?

 

[98G]

We may be working from slightly different baseline assumptions. I'm envisioning coming up in a light that suddenly changed and mashing the brake and having the pedal go to the floor. (And I'm also thinking m35A2)

The question at that point is what stops the truck in the least distance. I'm thinking a killed engine will provide more resistance than a running engine. The difference probably isn't major..

Granted, you've already screwed up if a light surprises you and you need to touch the brakes before several downshifts.

 

[50BMG]

Man when you guys hijack a thread you don't mess around.I'm gonna try the pinion brakes and report back on the results, cause it seems like nobody knows for sure.I thank you all for the imput.

 

[porkysplace]

Man when you guys hijack a thread you don't mess around.I'm gonna try the pinion brakes and report back on the results, cause it seems like nobody knows for sure.I thank you all for the imput.

Why bother posting a thread when your mind is made up and you only want opinions that are the same as your's , you ask why not use them and it was explained in detail , but you don't want to hear that .

 

[50BMG]

I posted to get peoples opinion on the subject, I got a lot of different ideas but nobody seems to know for sure.If you don't want discussion then don't reply!

 

[Timeline98]

My intent was to help justify a secondary/emergency braking solution. For me, even if it was a one time use and I saved someone else's life or my own, it would have been worth the money. Good Luck with the install. I hope you reply back with the results of the installation and testing thereafter.