Drilled Brake Drums

| I have an off-road vehicle which has drum brakes. I don't want to try | converting to disc brakes, but I would like to improve the ability of the | brakes to function after getting thoroughly wet.

I read the following article... However, other than getting the water out, which is your goal, it's so much bullsh*t, since brake materials made today don't out-gas.

" So what is the purpose of (drum) venting? Just its name implies, it allows the air between the shoes/pads and drum/rotor to escape. Without venting, a cushion of air can develop between the shoes/pads and drum/rotors, reducing braking efficiency. Venting also helps cool the drums and rotors, reducing heat which is a major cause of brake fade. According to Vince, this also results in an average of over 50% longer brake life. Another benefit of venting is that it practically eliminates water-fade, because water is thrown out of the drums by centrifugal force."

Crap man my Jeep eats drum brakes for breakfast because of mud as it is. Punching a bunch of holes in the drums to let more in isn't my idea of an improvement.

That also would make them run cooler wouldn't it? I would think this would do the opposite to what you have in mind. Heat dries things.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Ed Price wrote:

I'm interested in this also but curious. If it is a good idea and low risk, why can't I find anyone selling drilled drums? I did a quick search on "drilled brake drums" in google and couldn't find anyone selling them already drilled....

I'd have to agree with the jeeper up there on this one. Never heard of drilling drums & seems to me that for off road it would be the last thing ya wanna do. Why introduce a way for MORE stuff to get in & wreck your brakes. On old asphalt bikes we did years ago we "swiss cheesed" the backing plates to help the brakes cool but never saw the drums drilled on the braking surface. Good luck.

The drums are drilled in the side, not on the braking surface. The idea is that it will help to cool the brakes. Nobody is going to sell them like that, so it's a do it yourself type thing.

The downside of all this is that it lets all sorts of crap into the drums, on the springs, etc. If it were for a street car that never saw bad weather then it's probably ok. In any environment where it's dirty, wet, dusty, etc the downside of exposing the springs and working parts to the elements likely out weighs any performance gain from colling the drums faster.

Used to be done on the old Corvairs that would pretty much fade brakes entirely when at all wet. Some of the water can escape from pure centrifugal force as speed build up. Plus when you use the brakes, the water that may have soaked the shoes will turn to steam and holes in the shoes and/or drums allow more of it to escape. Try to find a local brake shop familiar with venting drum brakes. I never noticed all that much extra wear.

I don't have much of a problem with mud and debris, just fairly clean water soaking the brakes. You bring up an interesting question, when you talk about the linings getting soaked. Do linings really absorb water, or does the water stay of the surface? Is there a type of lining material to use that minimizes the "soaking"?

Ed

Dunno. On the Corvair, the brakes would pretty much become non-functional when wet. Which made it a bitch to drive across the street in Moab where the creek ran right across the road.

I dunno if they really absorb water that much, or they just get a good surface coating that turns to steam when the brakes are applied. On a disk system, usually the puck will drag enough to dry it off. On a drum, the water tends to stay longer...only takes a few minutes of light brake to dry them, but if you forget to do this every time, you got no brakes. The drilled drums and shoes let the steam escape and water fade is pretty much unnoticeable.

Whether this would be a good idea on a mud bogger rig is another question, can see how lotsa crud would end up in the rear brakes, although with the rather loose fit around the edges typical anyway, not sure it a few extra holes would add much.

I have 8 half worn front disk pads sitting here, and a couple drum shoes all with water damage.

4 are glued on and 4 are riveted on.

The pads have separated from the backing due to water swelling. These pads will then compress when the piston pushes on them, and then swell back into their warped shape.

When they swell back, they push the caliper piston back in. This means when you hit the break pedal, it hits the floor on the first pump to get the pistons back out, then the second pump to make the pads grab a bit.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Well, that sure sounds like an experience to avoid! So, it seems that there are different brake lining materials, and the kind you have is not very water resistant. So, what kind of lining material should you try to get if you want maximum resistance to water soaking of your linings?

Ed