Brake Failure - what to do

[dr deuce]

We all know that the stock CCKW/DUKW or Chevy has a single brake system. As such you should keep it in tip top shape especially hydraulic wise. But you should also have a plan in case the un-thinkable happens: total brake failure.

In case of failure, do the following:

Go for the parking brake and after initial contact between the lining and the drum, pull it for all it is worth! The parking brake can hold a CCKW on a hill with no problem. It can also lock up the wheels if applied quickly, It CANNOT slow the truck down. The area is too small to act as a regular brake. It will heat up instantly and become useless. Your only hope is to attempt to lock the wheels. The alternatives are not too pleasent.

This HAS been done in a total brake failure situation that a friend of mine had with his CCKW. He remembered what I told him (above) and did that in down town Salem MA and it prevented him from running over the local Police car in front of him.

AND before someone dismisses the whole notion of this or total brake failure, he did not loose any line, hose, wheel cylinder or anything associated with the brakes. He had a wheelbearing failure and the tire, drum just kind of rode out on the axleshaft, uncovering the brake shoes on that drum and allowing all the fluid motion to be used by that cylinder and none of the others!


Steve AKA Dr Deuce

[joel gopan]

Apparantly, the guy did not perform PM, and check his truck over, wheel bearing failure takes a while and is easily detected. There is noise, looseness(wheel wobble), possibly leaking grease, it is not a sudden thing without warning. The symptoms are all spelled out in the TM. Must have been one of the left rears, as they are the only wheels that can ubscrew a wheelbearing nut, the fronts do not have enough axle to ride on. It pays to walk around and inspect your truck to see if it is all going to come with you. I like to quote Chuck Yeager. "Why wait for trouble?" (I spent 2 1/2 hours with him in my MB)
Joel

[dr deuce]

I GIVE UP!!!!!!!!!!!!!!!!!!


BRAND NEW RESTORATION

[dr deuce]

Instead of saying that this is good advice in case something drastic like this happens, AND it has worked in one case I personally know of, what do we do? Talk about PM. Well it had less than 1000 miles since a total restoration. It was meticulosuly restored by a machinist. An outer race apparently spun in a split hub.

If he had run over a stick and pulled a hose off, would that be a failure of PM?

Everyone else remember this tip. It may save your life or HMV


Steve AKA Dr Deuce

[joel gopan]

I did not comment on the quality of the advice, it is good advice to have a working Parking Brake. (Mine needs adjustment) I'll stand by my statement as it hopefully will alert owners to pay attention to their wheels, properly maintained trucks will not fail instantly and there should be warning signs. These are not high speed Interstate Highway speed demons, they are relatively slow trucks and normally will indicate warning signs. These faults are known as PM Indicators in military lingo, and if caught early, will be very simple to remedy, and emergencys will be minimised. One of the theories behind the scheduled maintenance such as the 6000 Mile Interval as listed in the LO9-801 (6000 Miles!), is that they will be removed cleaned and repacked, this gives the mechanic the chance to visually inspect the components of the hubs for signs of pitting, overheating, wear, dirt etc. (6000 Miles) 6000 miles is quite a distance, failures are gradual if the bearings are properly serviced. The National guard had a program for annual maintenance on their trucks that got little use, one wheel a year would be removed for service, and that would determine if the others got pulled. This is more than just a hobby, I am involved in MV Maint with Gov't Agencys, rebuilders and Museums. It helps to know your product. Had I not been injured in the Army, I would be a retired AM General factory tech rep by now.
Joel

[armydriver]

Thanks for the tip Doc. It is important to have good brakes and we can all probably give an account when we were glad we did while driving our old trucks. I look forward to the tips and advice we get on this site.

[dr deuce]

When I helped the owner fix the problem. I suggested that I inspect all the other ones. We did and found one other wheel hub had a loose inner WB outer race. The bearing showed no visable signs of distress.

If someone ever has this condition, email me off line and I will tell you the fix for this situation.


Steve AKA Dr Deuce

[joel gopan]

Please explain inner WB, outer race. I am kind of mixed up on this one, I assume this is the spilt axle, and the inner WB is mounted on the spindle, but that bearing uses the inner race, and I think this what you intended to describe. This is a good time to remind split axle owners to stock up on the Retainers for the wheel seals. They are unique and are not found at local parts sources, and are easily ruined if not installed/removed with care. Not many are familiar with wheel seals that stand still.
Joel

[dr deuce]

It was an outer (pressed in) race that was loose. I think it was the inner bearing , but my memory from ~5 years ago on which one it was , well...


Steve AKA Dr Deuce

[joel gopan]

I got it!
It would be nice if all CCKW owners could have a Motor Sargeant to watch over their truck. I am just lucky, and have just Jim Seavey to pick on. Having a second set of eyes to call on is nothing to be ashamed about, it helps avoid problems.
Joel

[bobc]

While driving the 40 cckw around the lot using the winch and boom to move vehicles around I was really surpised at the braking capacity of the parking brake,it will kill the engine if I forget to disengage it after using the winch,I also use it for service brakes since I haven't had time to pull the master cylinder,since I don't get off the property with it it works ok,once I decide what I'm going to do with it I'll start at the master and work my way into all the wheels,thats the nice thing about a halftrack,you let off the gas and they stop quick,alot of rolling resistance. But if I ever get a streetable truck it will be a good thing to remeber.Thanks.

[John D]

Guys-If such sudden brake failure should occur, whatever the reason, is there any problem with also just shutting the ignition off and leaving the drivetrain engaged?

John

[joel gopan]

If all else fails, it may slow you some but it will not be much help at 35 -40 MPH, and you will not be able to downshift.
Joel

[dr deuce]

Besides what Joel said, if you restart the engine soon after, you may have a muffler full of raw gasoline! Can you say BANG!


Steve AKA Dr Deuce

[joel gopan]

There is another consideration to locking up the propeller shafts with the Handbrake, there is a good possibility it will put you into a skid, as the wheels on the same side of the rear and intermediate axle may lock at the same time.
A short story
I lost the brakes on a 2 1/2 ton Engineers Machine Shop Van (Couse Van)M-46 Chassis, weighing 24,000 lb, and went for a 5 mile wild ride in the White Mountains of New Hampshire, passing two Company convoys of about 15-25 vehicles before I coasted to an uphill stop. The Spoeedometer exceeded 60 MPH and was in 3rd Gear rated for 25MPH. Compression means little with momentum in a loaded 6X6. I was the last vehicle, and was about to catch Hell from my CO for "showing off". He made Colonel.
Joel

[dr deuce]

Lock up and skid is a definate possibility, but the alternative is usually worse i.e. plowing into something for which your bumper will ride over like a small car for example with children in the back seat.

I will take my chances skidding rather than being totally out of control!

I have had my cargo CCKW in a sideways direction a couple times stopping hard in wet conditions with NDTs with the regular brakes. Scarrier than any amusement ride!


Steve AKA Dr Deuce

[joel gopan]

Probably the best thing to do is to have your undercarriage and braking system in trustworthy condition, don't push your old CCKW too fast, do drive it defensively, being alert for the unknown. There are some that want to appear macho and make their truck scream, and show off their double clutching ability, practice that where there will be nobody to hear you miss or grind a gear. Save your good driving manners and best "Ipana grin" for the spectators at the parade. I will never forget the convoy I was part of, going thru New Hampshire or Vermont, with the Engineers Shop Van, it had about 12' of tailpipe that ended up vertical just to the rear of the drivers side of the cab, any acceleration above idle would result in a blat from the exhaust ,(400 miles of it) we were passing thru a small town that was having a parade, I frightened a horse being ridden by a teen age girl, it reared and threw the girl. I did not stop, and have felt guilty for years.
Joel

[dr deuce]

Again, this is not a replacement for proper maintenance etc.

A few years ago, I had a hose failure on my car and due to a design problem, the ABS kept trying to work and reduced my brakes to nothing!
But for pure chance, this would have happened at 5 PM entering a tollbooth area in the passing lane with no place to put the car and with lines at the booths! Your natural reaction would be to use the parking brake which may or may not have stopped the car and may or may not have put the car into a skid while turning to the right. After a couple days, I realised that the correct thing to do would have been to turn to the left after the break in the guardrail and go that way because all the cars had to stop at the toolbooth coming towards me and would have seen my headlights crossing in front of them. Had I gone to the right, all the cars would have been going my speed and my chances of making to the breakdown lane would be very slim.

This is a plan in case the unforseen, unexpected or unplanned for happens. Much better to have a plan ahead of time. Proper contingency planning AND proper maintenance!

Steve AKA Dr Deuce

[armydriver]

No bigger or better truth can be spoken than your last sentence Doc. it is better to have a plan. Thanks Jim