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Improve drum-brakes

I have a special 1975 2-ton truck with drum-brakes, but installing disk-brakes is too costly. Is there anyway to improve drum-brakes ? Like rapid intermittent braking, like on an ABS-system ?

I read about electric brakes on trailers, but is there something to install on the brake-lines to improve braking?



Thanks for your expert opinion



Jules Nijst.



PS I learned well about ABS from your earlier replies !

Look for the GM pickups that came out with the mechanical/hydraulic rear ABS systems. These had a link to the body where if it leaned too far forward during braking, it would prevent the rear brakes from locking up. But you’ll need every component involved with this brake system.

This is as close to ABS in the rear brakes you’re going to get.

Tester

The problems with drum brakes are they don’t do well if you drive through deep water and get water in the drums. And, they can fade due to heat build up in long downhill runs or when carrying loads at the capacity of the vehicle.

What is you specific issue of problem with the drum brakes on your vehicle? They make drum to disc brake conversion kits for trailers. Perhaps there are later year PU trucks of the same brand that came with disc brakes that would allow you to convert your truck to disc. I’d wouldn’t get involved with any ABS systems, but standard hydralic brake parts should be able to handle either disc or drum brakes as far as master cylinder and brake lines are concerned. Disc brakes run hotter so you may need to upgrade your brake fluid if you can find the parts for a conversion.

Hi Tester,

Thank you for your speedy answer, what an amazing forum !

I read about having only disk-brakes on the rear-wheels by Tom & Ray from April 2001, where they actually argue against using only disk-brakes on the back (2000 Ford F150 XL Short Bed Regular Cab pickup, which Ford stopped the next year).
Uncle Turbo describes the problems drum-brakes potentially have, which was why I was hoping to improve the drum-brakes, rather than install disk-brakes.
Thank you for your reply,

Jules

My last reply seems to have vanished… Thank you too for your quick reply Uncle Turbo !
I actually have a militairy truck, which I’d like to drive through water and heavy loads up / down the hils…
Installing disk-brakes would be prohibitevely expensive as no standard parts would fit; a major mechanical job.

I was hoping on some device that would intermittently applied pressure and released it and that at 10 times per second. Like braking, let go and braking again at 10 x / sec.
Of course playing with the brakes is potentially life-threatning for others too, i.e. if the device stayed in the release-position… no brakes…, OK you’d need an overdrive, but still

Just if I managed to build some device like that, what effect would it have on the braking, any idea ?

Thanks for all your answers !

Jules

Rapid pulsation of the brakes, such as 10X per second, will not “improve” braking.

ABS does not “improve” braking. A vehicle will stop in less distance if ABS is not activated, because every time the ABS releases the brakes the stopping distance increases.

ABS is designed to prevent the wheels from locking, that’s all. It doesn’t make a vehicle stop in a shorter distance. There are people who tell horror stories of ABS-equipped vehicles that, due to extremely limited traction, JUST WON’T STOP.

If you’ve got a military truck with drum brakes you’re pretty much stuck with the original equipment. I wouldn’t advise making any major changes. Military trucks are designed to be driven up and down hills, and through water, with heavy loads. I don’t see the problem.

What, exactly, are you trying to “improve?”

Hi McParadise, thank you for your reply !

I guess I was hoping the pulsating might drive the water form the brakes or help cool the drums, but I relize that is a bridge too far. Also if the drum-brakes locked up for whatever reason, might the pulsating not help to brake in a straight line too ? instead of skidding with a heavy load at the back.

You’re right about being stuck with the original militairy equipment. I see now clearly that I’d better improve my driving-style offroad than mechanical improvements.

Thank you all for an enlightning experience and willingness to share your experience

Bless your souls !

Jules.

Rigging up a “pulsing” gizmo to your brakes is very risky and I’m not sure what it would accomplish. Driving a vehicle with drum brakes is different but drum brakes are quite effective if they are in good working order.

Assuming your brakes are in good shape. Whenever the drums get wet you need to apply light brake pressure with your left foot as you maintain speed with the right foot on the gas. Keeping the vehicle moving helps use centrifical force to spin the water out of the drums. Applying the brakes creates friction, which makes the brakes warm, and the heat dries up the remaining water. Soon you can feel the brakes pulling down the speed of the truck and you can let off the pressure with your left foot.

Going down long hills is a matter of keeping your speed down, downshifting to maximize engine braking, and applying pressure to to the brakes to take off 5 to 10 mph and then letting off the brakes so they can cool a bit then applying them again to take off another 5 or 10 mph, resting them to cool them and so on.

Since disc brakes have become so common driver’s aren’t used to drum brakes anymore. If you learn how to change some of your driving techniques you can be perfectly safe using drum brakes. They stopped every car and truck on the road for roughly 50 years before disc brakes took over. Disc brakes are better, no doubt but you can do fine with drum brakes if you understand how to work within their limitations.

Drum brakes are just fine. 95% of the heavy class8 tractor trucks and semi trailers use them with a lot more weight than you’ll be using. Everyday hundreds of thousands of trucks go down steep grades with full loads with no problems. Problems come from driver error and poor adjustment.

Make sure the system is in adjustment, the shoes have some lining and the drums are true. Are you talking air or hydraulic brakes on this 2 ton military truck?

is it a deuce and a half? If so why modify the thing to disks???

I’ll side with benzman. This sounds like a lot of unnecessary expense and time for very little benefit.
In my younger days I helped a friend out on a few weekends by driving one of his 2 tons delivering oil field mud. Thirty thousand pounds, drum brakes, and no problems even on the downgrades.

Just my opinion here, but I think if you get into trying to tweak the brakes with some kind of ABS or hydraulic gimmick you could be opening up a can of worms; possibly something fatal or leading to litigation if something went wrong.

"ABS does not “improve” braking. A vehicle will stop in less distance if ABS is not activated, because every time the ABS releases the brakes the stopping distance increases."
I agree with the above statement. I bought a NEW Dodge 1500 a few years ago with 4-wheel ABS. There were several times it took longer to stop than it would have with standard brakes.

If pumping your brakes rapidly makes the truck stop better, then maybe your idea has merit. How to do it without a risk of the brakes deciding not to work at all would worry me a lot.

FWIW, I have the situation of having a hill with a stop sign at the bottom directly opposite my driveway. When the hill ices up, my experience has been that stopping our Toyota which has ABS is a straight line is much more difficult than stopping our other cars. However, that might not apply if all the brakes turned on and off at the same time instead of turning on and off at random. I am not a fan of ABS. Adds complexity. Doesn’t seem to work effectively on slippery surfaces.

I too think you’d be getting into high expense and difficulties for no real gain. I have ABS, and like many others are underwhelmed. ABS is designed to halp maintain control during braking, and it trades off braking distances to do so. On icy roads it’s downright horrible.

But, if you’re using original equipment pads you might be able to gain some braking power by switching to a different pad material, like ceramic or even metallic.

Gentlemen,

I am overwhelmed by all the responses !

You’ve all got me convinced to leave the pulsating of drum-brakes well alone.
You also convinced me that drum-brakes are the next best thing to throwing out an anchor at the back. Sudden stop though…
ABS needs more distance to stop, but might to do it in a straight line, if all works well, but a million trucks prove it is not required.
All this experience points in the same direction for me.

Thanks again for all your time and efforts.

Jules Nijst
PS My truck is a Austrian Steyr-Puch Pinzgauer. (http://www.real4x4forums.com)

If you you want something better, BUY something better. 1975 2-ton trucks had marginal brakes (by todays standards) and trying to improve the 1975 system would be loves labor lost. You have to DRIVE a '75 2-ton. You can’t just sit there and steer it…

You will benefit most from making sure the brakes are in top shape, with fresh fluid, all air bled out of the system, good shoes and good drums, good wheel cylinders and master cylinder, correctly adjusted. There is absolutely no modification you should try to what is likely and extremely-well designed system.

Dude, you own a MILITARY vehicle that is intended to ford streams, handle rough terrain in all conditions (dry and dusty, wet and muddy) and is fully capable of performing under the most demanding conditions. Those drum brakes are best suited to those conditions! The military isn’t known for under-designing those type of vehicles.

Even if you don’t plan to use it under those conditions, it’s never going to be a truck that can stop on a dime and shouldn’t be driven like that anyway IMHO. I wouldn’t give up all the BENEFITS of the drum system just to gain in one area. That thing would be a blast to own and drive just the way it is. That’s my 3cents anyway (probably 2 more than you wanted!).

Hi Twin Turbo,

Indeed it is a blast to own this one and without power-steering you really pull on the steering-wheel at slow-speeds, so nothing my wife would touch…

I must also admit, I have not had a problem with it, as it is in mint-condition. It is just like all else when you fall in love with it: How can I get it better ?

I have been convinced by you-all to enjoy her the way she is: ugly, fat and heavy: 2 ton, but a beauty in my eyes…

Jules

One point not made concerning ABS is the system is designed to prevent wheel lock-up and allow the driver to STEER AROUND the hazard.