|09-18-2013 05:32 AM|
I looked hard at Brembo slots.Seems to me they are somewhat selling snake oil.I also talked to a number of people that bought them.In the real street you have to be putting the vehicle into a road race situation or a very fast race only car for them to have the effect they are suppose to have.
Back on topic,there are a number of upgrades to say a 11" drum.Now I have seen ppl drill holes in the backing plates.For me I wouldn't do that for a number of reasons and maybe the core reason is I would have a fear of weakling the backing plate where the shoes,wheel cylinder is mounted.As for drilling the drum surface braking area,it is the sum total of the shoes surface to drum that makes it a upgrade or not.To take anything away from that is counter productive.
|09-17-2013 11:05 PM|
|malc||Here´s a slotted disc.....|
|09-17-2013 10:20 PM|
|1Gary||I went to the Kelsey-Hayse brake school in the late 1960's and at that time a T-bird's dics brakes where going for $300 bucks a side.Everyone was predicting doom and gloom for the auto industry.Boy did we get that one wrong.Look how cheap you can get dics pads now and how advanced they have gotten.|
|09-17-2013 01:25 PM|
Back when drums were the only brake system avaialble every trick in the book and then some more were tried. You name it:
- Bigger diameter drums for larger but in the same line of cars were used such as using station wagon or light pick up brakes on sedans.
- A highly popular conversion with racers were the use of Buick's aluminum drum with a cast iron wear surface.
- Air supplied to the backing plate which was drilled. This was done as ram from the developed vehicle speed or from heater fans ducting fresh air into the backing plate. Even liquid cooling of the shoes was tried complete with pumps and mini radiators.
- Higher coefficient of friction such as metallic shoes was used, this quickly exceed the strength of the bell shaped drum and increased wear to a fantasticly fast rate.
- And yes drilling the friction surface and/or holes into the face of the drum which proved to be downright dangerous was tried with mixed result but was shortly banned at all tracks by rule.
None of this proved satisfactory, while we racers looked to Europe where disks were common, the American manufacturers claimed that disks could not work on big, heavy American cars. This claim rather flew in the face of Budd streamline railroad passenger cars having disk brakes sine the late 1930's and military aircraft using disks since the 1940's. It took Detroit a long time to arrive at the disk as this battle palyed out through the 1950's and most of the 60's.
The last input to my list, the drilling of drums and the fact it proved to be not very effective if not dowright dangerous is because of the different way drum brakes stress the rotating stopping surface compared to a disk.
1) The disk's rotor is fully supported by structure. The pads apply a compressive load to the rotor by squezzing it. The rotational load is taken in shear, that is an angle in plane with rotation.
2) The drum is partially supported by structure, it is essentially a bell where the forces have to migrate from the applied zone through a 90 degree angle into the top of the bell or hub. In the hub the forces react into the axle in shear as they do ina disk but getting there is a lot different route. The opposite end is open and unsupported, this creates whats called an overhung moment when the btrakes are applied that wants to bend the friction surface away from the expanding shoe. This puts the mounting face and friction surface of the drum under tension and bending where the frication surface becomes the hub, tension and bending being any material's directions of least strength. Then to compound the strength issue these tension/expansion forces are expected to make a 90 degree turn from the friction face into the hub. The drum would like to explode. Then as it heats, it gains dimension in diameter which is to say it is moving away from the brake shoe, This is fade (or at least one component of fade) which causes the driver to step harder so the shoes will chase the drum which makes more heat, eventually the whole is so hot the brake fluid boils. At that point there is no more braking. Add to this situation the mouth of the drum (did I say bell) being unsupported expands outwardly more then the supported hub end a condition called bell mouthing (imagine that) so the brake shoe is losing contact area which drives the temperature of the available contact area to even hotter temperatures.
History and experience of us old farts show that messing around with drum brakes is simply non-sense. This was a well travelled road that finally arrived at disk brakes in America starting in the late 1960's, but what a battle to get there.
|09-17-2013 07:29 AM|
As far as only wanting ONLY first hand experience on something, one need not hit one's thumb w/a hammer to know it will hurt.
Good luck on whatever you decide.
|09-16-2013 10:58 PM|
Food for thought...
The following was first posted on another forum. The subject is drilled rotors, thought of by many as a universally accepted "good thing". So if this is about rotors, what does that have to do w/drums, you may ask? Well, many of the same "improvements" and "advantages" to drilling rotors are said to apply to drums as well.
|09-16-2013 09:35 PM|
|xxllmm4||Thanks for all your input... Now if anyone has had REAL experience directly related to drilling drum brakes feel free to chime in|
|09-16-2013 09:30 PM|
already answered your questions,,,no arguements coming from me. I have tried aluminum drums,riveted shoes,custom shoe material,different bore wheel cylinders...
drilling holes in drums is stupid,it allows water and elements in. drums do not work well wet.If you are racing,then use racing brakes.If you road race,dont use drum brakes.
Its not the brakes that stop your car,,,brakes only turn friction into heat. The "TIRES" stop the car
|09-16-2013 08:57 PM|
Yes I have made my mind up. I was kind of looking for input from people who have ACTUALLY had experience on the subject.
I could care less if their $99 for one or ten. I have a drill press and drills... Cost to me is $0.00
|09-16-2013 08:50 PM|
|09-16-2013 08:38 PM|
Looks like Brothers actually sells them now. 71-87 Drum Brake - Rear - 1/2 Ton - Cross-drilled - Brothers Chevy & GMC Classic Truck Parts
|09-16-2013 04:59 PM|
Providing the drum brakes are adjusted correctly and the hydraulic system free of air and the fluid is dry, using good brake shoe compounds like was mentioned already, along w/cooling ducts (if needed for the way the vehicle's being driven), and possibly going to a larger shoe/drum combo like was done years ago (using police/station wagon drums often gave added width and/or diameter), or possibly swapping the cast iron drums out for aluminum drums like were found on some G-body cars (and possibly others) will be about as good as rear drum brakes are going to get. I say possibly because even though they saved a little weight and cooled better, the aluminum drums were still rather small. Fine for a street/strip vehicle but not so much for road racing.
|09-16-2013 03:46 PM|
|09-15-2013 05:05 PM|
One of my friends races in NASA (no not Space NASA) any the drilled rotors get replaced a lot faster than OEM solid rotors due to cracks propagating from the holes in the surface. There is a company that makes very high end shoes called muscle car brakes Muscle Car Brakes
They make some very trick stuff if the prospect of discs doesn't fit your needs
|09-15-2013 04:03 PM|
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