Drilled brake drums

[serialk11r]

Holy crap, so much effort :O

I considered trying this to the rotor hats as a DIY rotor weight reduction but decided it wouldn't be worth the time. Some all iron rotors have holes cast into the hat all around so structurally it should be fine.

[IsaacCarlson]

Update:

I drove the truck for a couple of hours today and hauled some wood. I don't really feel like I'm even using the brakes anymore. I can't describe it. I touch the pedal and the truck just slows right down, like it has velvet brakes powered by some sort of galactic fuel cell. It's like magic, and eerily smooth. I find myself trying the brakes randomly, just to feel the lack of anything resembling "normal brakes"....if that makes any sense.

Overall, I have to say I am more than satisfied with the results. I did remove the proportioning valve at the same time as this mod, but it only makes it sweeter. There was no fade at all today, and I had more confidence going down hills and into turns. The brakes felt the same every time I used them, smooth and strong.

I have driven trucks with 4 disk brakes, and was not happy with the feel. They always felt grabby, like the truck wanted to slow down faster than I wanted it to. These drilled drums feel much better than disks and are easier to control. They are not grabby at all, and respond exactly to pedal input. I had heard this from others who drilled their drums, but never expected it to be so literal. They really are better than disk brakes, and there is no chance of stuck/rusted guide pins, warped rotors, frozen calipers, or pads wearing unevenly. I have had to fix more disk brakes than I can count. Drums? Ummmm, let me see....less than 5.

This is a big thing for me. A total game changer. If people could try drilled drums, I really think they would leave disks in the dust...haha, dust.

I really like having some extra brake power in the rear now. The truck doesn't feel nose heavy and stays level when stopping. The proportioning valve was cutting rear pressure at only 200 psi, meaning there was only 125 psi of braking pressure left after opening the shoes, since it takes ~75 psi to overcome the return spring tension. Now I can have as much pressure as I need, 400 psi, 800 psi, or even 1200 psi, if needed.

The big double piston calipers up front help balance the braking force, but I think the drums have the advantage, since they require less line pressure to achieve the same stopping force. The only reason the fronts work as well as the rear is because of the double pistons multiplying the pressure. Single piston calipers would never have a chance at balancing with the drums.

I am giving this project a score of 20 out of 10, because it is WAY better than I ever expected it to be. I am tempted to put drums on the front too.

If anyone is on the fence with drilled drums, I say go for it. As long as you use your brain when drilling, you will be just fine. Every part of the shoes must be swept by a hole or you get streaking, uneven wear, and hot spots. Keep things balanced. Need I say more?

Disclaimer: I removed my proportioning valve along with drilling the drums. It is not neccesary to do this. Messing with the proportioning valve may be dangerous and should only be done by those with the proper know-how. I take no responsibily for the outcome of actions performed by those who read this. Be safe. I think that is all I need to say about that.

That is the end of this review. If you have any questions, feel free to ask. I am more than happy to answer them. If you are not comfortable drilling your drums, but would like them drilled, let me know, I may be able to help.

[serialk11r]

Out of curiosity, how much mass did your holes remove from the drum? I am considering doing this to the rear brake rotor as I can't use an aluminum hat with the parking brake.

[IsaacCarlson]

I didn't remove much mass, a little less than .4 lbs, and these drums weigh over 30 lbs each. That comes out to about 1.3%.

The hardest part is making sure the holes are in the right spots to sweep the entire shoe.

[Chrysler kid]

The prop valve probably had more effect on your rear power than the drilling.

My understanding of drilled drums was that it's only beneficial in applications with high heat and heavy use. you don't typically see a drum glowing red hot

Watch for cracks, that cast iron can get heat spots really quickly. A drilled rotor is typically internally vented and has extra structure to prevent cracking where as a drum does not.

[IsaacCarlson]

Yes, I know that the increased pressure is helping me stop better. That it why I increased it. The drilling lets the dust out and helps with cooling, resulting in much smoother brakes.
Drum brakes collect lots of dust, and it can be a problem. I have to clean out the drums on the car quite often because of the dust buildup. It causes drag, noise, and reduces braking. The brakes are always better after I clean out the drums, and it stops better too.

[Baltothewolf]

Originally Posted by Chrysler kid

The prop valve probably had more effect on your rear power than the drilling.

My understanding of drilled drums was that it's only beneficial in applications with high heat and heavy use. you don't typically see a drum glowing red hot

Watch for cracks, that cast iron can get heat spots really quickly. A drilled rotor is typically internally vented and has extra structure to prevent cracking where as a drum does not.

Well... If he is loaded with 3x the truck weight, at 13k, I would consider that 'high heat and heavy use', yes?

[Giles_K]

Originally Posted by Chrysler kid

The prop valve probably had more effect on your rear power than the drilling.

My understanding of drilled drums was that it's only beneficial in applications with high heat and heavy use. you don't typically see a drum glowing red hot

Watch for cracks, that cast iron can get heat spots really quickly. A drilled rotor is typically internally vented and has extra structure to prevent cracking where as a drum does not.

So the benefits in a typical car are probably not worth considering?

Looks like it's doing a great job for trucks though.

[IsaacCarlson]

Like I said before, the holes evacuate the dust that would otherwise build up inside the drum. We are all familiar with how dirty drum brakes are when you open them up. I will get some pictures next time I open them up to see how they are doing. I will be checking on the fronts very soon to see how they are doing. I can't see anything without taking them apart because of the shields. I may just remove them.

[IsaacCarlson]

I want to post an update on the drilled drums.

They still work great! No dust, no noise, no fading. Always the same feel on the pedal and the seat.