drilling brake drums

benand117 · Sep 12, 2011

Look guys just because i play in the truck a bit doesn't mean i don't take care of it. It gets taken apart and cleaned all the time. this time it just happens to be because it blew a wheel cylinder, and from that it looks like a seal. So all the wheel cylinders and seals will be replaced, and the shoes that have been soaked with brake fluid. drums and other shoes are in good shape.

gimpyrobb · Sep 12, 2011

Somewhere(I think it was Tom) I heard they do drill drums to help with heat dissipation. In my opinion, holes drilled in the drum wouldn't let in any MORE mud than what would get in there anyway. I have had some pretty nasty mud in my brakes after I went for a romp in the goo. Also, I don't think the holes would help bring the brakes back faster. Once the pad gets wet it will still need a certain amount of friction to heat it up and dry out the material.

benand117 · Sep 12, 2011

I think you missed a few doghead.

A/C Cages · Sep 12, 2011

Check your local DOT if its legal to drive it on the streets with modified holes drilled in them. In Florida its a hit and miss if you drill them. I do know that you can't drill them on a WV drum and still be legal because my sandrail had them drilled and it was the only thing holding me back from getting it street legal. I changed them over to original drums in the rear and they gave me a plate. Then I put the drilled ones back on it. lol

Tanner · Sep 12, 2011

Drilling the drums can set you up for crack & stress points to form, leading to drum failure.

I wouldn't recommend it.

'Tanner'

Unforgiven · Sep 12, 2011

Yes, brake drums can be drilled. It is NOT to relieve heat. It is to relieve trapped gasses created by the heat. As the brake shoe vaporizes it makes a layer of hot gasses that gets stuck between the metal drum and the shoe. That make the drum brakes fade on long downhill applications. Drilling the drums will allow the hot gasses to escape.

In addition, drilled drums will allow water to escape. So having no brakes as a result of fording some water can be decreased if not eliminated. The shoes will dry much quicker. Knowing this, you have to apply a light pressure to the pedal while fording. This keeps the sand & muck out.

Properly sized, spaced, & chamfered holes will not affect the strength of the drum, nor induce cracking. Defer the drilling to a brake expert.

http://http://www.chtopping.com/CustomRod4/

rickf · Sep 17, 2011

Just remember that you are compressing a rotor and spreading a drum. Put a hole in the wrong place and when you hit the brakes hard the drum will come apart.

Rick

bearboley · Sep 17, 2011

Unforgiven said:
Yes, brake drums can be drilled. It is NOT to relieve heat. It is to relieve trapped gasses created by the heat. As the brake shoe vaporizes it makes a layer of hot gasses that gets stuck between the metal drum and the shoe. That make the drum brakes fade on long downhill applications. Drilling the drums will allow the hot gasses to escape.

In addition, drilled drums will allow water to escape. So having no brakes as a result of fording some water can be decreased if not eliminated. The shoes will dry much quicker. Knowing this, you have to apply a light pressure to the pedal while fording. This keeps the sand & muck out.

Properly sized, spaced, & chamfered holes will not affect the strength of the drum, nor induce cracking. Defer the drilling to a brake expert.

http://http://www.chtopping.com/CustomRod4/

Well said.

Tanner · Sep 18, 2011

Unforgiven said:
Yes, brake drums can be drilled. It is NOT to relieve heat. It is to relieve trapped gasses created by the heat. As the brake shoe vaporizes it makes a layer of hot gasses that gets stuck between the metal drum and the shoe. That make the drum brakes fade on long downhill applications. Drilling the drums will allow the hot gasses to escape.

Nicely worded, but still it goes against what drum brake engineers say...

An incorrect explanation sometimes given for brake fade is heated brake shoes evaporate to generate gas that separate them from the drum. Such effects are easy to imagine, but physically impossible, due to the large volume of gas that would be required for such an effect. A 'gas bearing' - as envisioned - would need gas replenishment as fast as the drum moves, since it has no gas on its surface as it approaches the pad or shoe.

'Tanner'

wdbtchr · Sep 18, 2011

My

for what it's worth, if you think about it the whole inside of the brake drum is open next to the backing plate. Water can get in or out all it wants. I've always understood the brake fade from imersion if from the wet friction pad and the brake drum. I ain't no rocket scientist or brake expert. :roll:

Floridianson · Sep 18, 2011

wdbtchr said:
My for what it's worth, if you think about it the whole inside of the brake drum is open next to the backing plate. Water can get in or out all it wants. I've always understood the brake fade from imersion if from the wet friction pad and the brake drum. I ain't no rocket scientist or brake expert.

I like that thought. Plain and simple. [thumbzup]

drilling brake drums

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