Steering, brake fade

[RichardT10829]

Hey folks just looking for some suggestions regarding the braking and steering. When I am out and about the steering is perfect when I first start, but even after a few turns on the roads I am finding that the brakes are less and less effective, and by the time I get back home my brakes steering is negligible.


My linkages are all setup and I believe the clearance from the shoe to the drum is ok... With the brakes off I can step on the track below the sprocket and the drum turns without it binding.

My situation cannot be normal as the machines would be useless before even getting to the battlefield.... And they went on long runs !

[rob love]

Are the drums turned and clean of scoring? Full surface area is the key to preventing brake fade.

What is the contact area of the shoe's arc? Remove the drums and see what portion of the shoe is actually doing the work.

Are the shoes and drums clean? For this you must also remove the drums and inspect. The shoe linings and the drum surface area should be clean enough to eat off of. Any accumulation of grease will compromise the braking. making you have to apply the brakes harder and resulting in more brake fade. Potential sources of grease are the wheel seals and the brake adjusters, as well as grease added to the rub points between the shoe and the backing plate.

Are the drums round? You have to remove the track and axle shafts to test for that. Watch the fingers around those ice scrapers though if you are going to spin the drum around to test.

What are your driving habits? If you are constantly going past 90° then brake fade will be the result eventually. If you are dragging the brakes for long periods as opposed to a short hit, that may also be the problem.

Last, and this is kind of the wildcard: What are the composition of your linings. Since we don't have the luxery of the old school materials, the new stuff is not necessarily better.

Long story short, you will have to pull the drums to know for sure. Even though they may have been done not that long ago, you have the symptoms of a problem.

[RichardT10829]

Brand new woven linings oversized and profiled to match the drums which were cleaned up pristine on a lathe. No grease inside that I can see

[Richard Farrant]

Originally Posted by RichardT10829

Brand new woven linings oversized and profiled to match the drums which were cleaned up pristine on a lathe. No grease inside that I can see

Hi Richard,
Don't I recall that your shoe linings were a little too thick and you hand finished them with a sander or something? As Rob says, remove the drum now to see the face of the shoes to check how much contact area you have. Did you renew the hub oil seals?
Another problem with new type lining material is that it is not like asbestos where you could bed them in quick, this stuff will not bed in quickly and can glaze if you try to.

regards, Richard

[motto]

I hesitate to respond not being a carrier owner but as Rob suggested, perhaps driving technique has something to do with the problem or perhaps the way the vehicle is used with many turns over a relatively short distance. From what I know of drum brakes any of them will fade if worked too hard so dragging them is a no no and little jabs are preferable. At speed this must be done very carefully as the vehicle will spin out with little provocation.
Driving a U/C is not as easy as one might think. They can be quite treacherous, I know that much.
If the carrier has track displacement, (did they all have it?) is it fully operational and rigged correctly so as you are not relying entirely on the brakes? i.e.;brakes coming on too soon.
How hot are they when fade becomes apparent? They should function ok until they are damned hot.
Just some random thoughts as I am interested in the topic.

David

[RichardT10829]

I apply them with jabs rather than drags. I have noticed last night that when I go to take second the carrier stops (loses it's momentum immediately).... I must be just catching the shoes ? Which I am sure would make them heat up real quick. Also my foot pedal travel is very short before the brakes are applied. ( almost immediately) what sort of brake pedal travel should I have ?