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Want more stopping power for your 1/2 or 3/4 ton brakes?

Discussion in 'The Garage' started by Triaged, Mar 24, 2003.

  1. Triaged

    Triaged 1/2 ton status

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    I was looking to upgrade my s10's brakes (going to put 12" rotors in using G-body parts) and found this.
    This is a pad for a 96 Cop suspension Caprice. (#614)
    [​IMG]

    This is the standard pad (#52)
    [​IMG]

    The #'s interchange with most brake manufactures...you just have to add the proper prefix and sufix to get the type you want (ie Raybestos BD614M for a BruteStop pad).

    The #614 pad has about 30% more area than the #52 pad.

    I haven't tried this yet as I have almost new #52 BruteStop's at all 4 corners...but I'll be putting them on the s10 in the summer (with larger rotors and calipers) and on the k5 when the ones on there wear out.
     
  2. bablazer73

    bablazer73 1/2 ton status

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    Wow! I am gonna hang pads and calipers on my 87 today, I'll scope them out and post agian later.
     
  3. jhrody

    jhrody 1/2 ton status

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    so these will slap right on a 3/4 ton axle?
     
  4. bablazer73

    bablazer73 1/2 ton status

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    well, I tried to find them and had no luck. Napa wanted 78.00 for their version. Advanced auto wanted 65.00. Nobody stocked them and said 3-4 days to get. So I had to pass and use the 20.00 pads. I could "almost" justify the cost, but only have today for the next week to do brakes. And they needed to get done last week!!
     
  5. ntsqd

    ntsqd 1/2 ton status

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    All that increasing the pad area will do is increase the wear life of the pad because it will increase the friction material volume. It won't increase your stopping power. Cop cars go thru pads at a really high rate which is why GM put in a pad with more friction material volume.
    Same is true of drums, increasing the width of the shoes is a wear life bonus. You have to increase the diameter of the drum to get more braking torque.

    To increase braking torque you need to either increase the effective (not actual) rotor diameter or increase the clamping force. Changing pad compound also has an effect on braking torque, but racers typically leave that for last as a brake fine tuning method.
    By effective rotor diameter I mean the diameter (actually the radius since we're talking lever arms) thru the centroid of the pad. That is your 'lever' length, not the OD of the rotor.
    Clamping force can be increased a couple ways. Reduce the deflection in the system (Braided stainless hoses, fixed calipers - not sliders, all 3/16" or -3 plumbing - no 1/4") or by increasing the piston area of the calipers. A piston area increase, if not done well, can throw the whole leverage ratio balance off though, so be careful there.

    There is rumor of a D52 type caliper with a slightly larger piston than the common 2-15/16" I have yet to find an application.

    btw, in my last position I was an R&D Design Engineer for wilwood.
     
  6. 88Silverado

    88Silverado 1/2 ton status

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    Another reasonable option is to get the Performance Friction Z-Rated pads. These are a ceramic composit type of pad and breaking actually gets better when they get hot.
    I swapped these onto my 71 Elky and fast-hard breaking improvement was very noticable. Price was only $35 from AutoZone who carry's this line.
     
  7. Blue85

    Blue85 Troll Premium Member

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    I spoke to a brake technician in the area that everyone recommended as the best truck guy. He says that he and his friends have all had 70's and 80's GM fullsizes forever and that the only way they found to improve the braking power of trucks with bigger tires was to use organic brake pads. He told me not to even mess around with ceramic, Z-rated, etc, but that the organic pads (whatever they are) would really make the truck stop with authority.

    I have no idea if this is true or not, just relaying what I heard. Does anyone know of an "organic" pad?
     
  8. ntsqd

    ntsqd 1/2 ton status

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    Most of the High perf pads are designed to operate with some heat in them. Like the 'metallic' pads of old, they need heat to work their best. Pads that will work the best for slow speed off road are not these. Rarely does a 4x4 get high perf street pads up to operating temp. In this type of application the best pads appear to be the BruteStops and wilwood 'D' or 'E'' compound. Wilwood offers a 'J' compound that has promise, but I've yet to try them.
     
  9. IGOR

    IGOR 1/2 ton status Premium Member

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    I am installing rear discs on my 14 bolt under my '72, right now -

    I heard that the new 3/4 ton Dodge has larger diameter rotors (with the same bolt pattern) - I tried to get some, but of course nobody carries them yet - cuz they were too new - but that was like 2 months ago... Of course it might be interesting trying to get a caliper for those, as the OE is probably ABS...
     
  10. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    [ QUOTE ]
    I spoke to a brake technician in the area that everyone recommended as the best truck guy. He says that he and his friends have all had 70's and 80's GM fullsizes forever and that the only way they found to improve the braking power of trucks with bigger tires was to use organic brake pads. He told me not to even mess around with ceramic, Z-rated, etc, but that the organic pads (whatever they are) would really make the truck stop with authority.

    I have no idea if this is true or not, just relaying what I heard. Does anyone know of an "organic" pad?

    [/ QUOTE ]
    I have found the EXACT opposite after a bit of driving. The organic pads will glaze BAD after a few hard stops and after that happens the stink. The carbon matalics don't seem to have this problem. So yes the orgnaics do stopp better at first the carbons beat them a way;s down the road. I hear bhtat a sloted rotor makes the glazing problem better on the organics but try to find a slotted rotor for a 75 Jimmy.
     
  11. HarryH3

    HarryH3 1 ton status Author

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    [ QUOTE ]
    but try to find a slotted rotor for a 75 Jimmy.

    [/ QUOTE ] Grim, check with Tim at www.4x4iron.com He's carrying a selection of slotted rotors for our stuff now. /forums/images/graemlins/thumb.gif His CK5 username is Butch.
     
  12. rebelk5frk

    rebelk5frk 1/2 ton status

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    [ QUOTE ]
    but try to find a slotted rotor for a 75 Jimmy.


    [/ QUOTE ]

    Just bust out the trusty drill press and slot your own /forums/images/graemlins/eek.gif /forums/images/graemlins/eek.gif /forums/images/graemlins/eek.gif /forums/images/graemlins/wink.gif
     
  13. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    [ QUOTE ]
    [ QUOTE ]
    but try to find a slotted rotor for a 75 Jimmy.

    [/ QUOTE ] Grim, check with Tim at www.4x4iron.com He's carrying a selection of slotted rotors for our stuff now. /forums/images/graemlins/thumb.gif His CK5 username is Butch.

    [/ QUOTE ]
    Well how about that.
    Still I'm happy with my brakes now that I did the rear disc. I finnaly have them ballanced out and I'm just before lock up on the fronts. That's with 35's on Half ton gear. For being a 6k beast it stops remarkably well.
     
  14. 70~K5

    70~K5 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    I spoke to a brake technician in the area that everyone recommended as the best truck guy. He says that he and his friends have all had 70's and 80's GM fullsizes forever and that the only way they found to improve the braking power of trucks with bigger tires was to use organic brake pads. He told me not to even mess around with ceramic, Z-rated, etc, but that the organic pads (whatever they are) would really make the truck stop with authority.

    I have no idea if this is true or not, just relaying what I heard. Does anyone know of an "organic" pad?

    [/ QUOTE ]
    I have found the EXACT opposite after a bit of driving. The organic pads will glaze BAD after a few hard stops and after that happens the stink. The carbon matalics don't seem to have this problem. So yes the orgnaics do stopp better at first the carbons beat them a way;s down the road. I hear bhtat a sloted rotor makes the glazing problem better on the organics but try to find a slotted rotor for a 75 Jimmy.

    [/ QUOTE ]
    You have to properly "bed" in your pads to keep this from happening. I takes time to do this right.
     
  15. Triaged

    Triaged 1/2 ton status

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    I always thought that the coefficient of friction would go up as the area increased? The same as with using a wider tire? I guess pads must not have any load sensitivity...never even thought about that.

    At any rate the added pad life will be enough to make it worth it for me. Right now I get about 10kmi on a set of pads and I have gotten tired of changing pads in under a year. I have the BruteStop on my s10 as well as the k5 and I like them a lot. They grab well right from cold and I have never got them to fade. They are a bit tricky to modulate though (but maybe that is because the s10 is has too good of a booster)

    While I've got you here what are your thoughts on drilled slotted or drilled and slotted rotors for a high performance street car? Any performance gain and where would it come from if any? What about accelerated pad wear? Are they worth the cost?
     
  16. 70~K5

    70~K5 1/2 ton status

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    [ QUOTE ]


    While I've got you here what are your thoughts on drilled slotted or drilled and slotted rotors for a high performance street car? Any performance gain and where would it come from if any? What about accelerated pad wear? Are they worth the cost?


    [/ QUOTE ]
    Hey Triaged check out what Carrol Smith says in "Engineer to Win" on slotted rotors. He has a pic in the book of a style thats easier do do than the standard way.
     
  17. Triaged

    Triaged 1/2 ton status

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    I am slotting some the "Hard Way" for our FSAE car. I got one finished and have one left to do (and no they don't have any holes in them because I am worried about them getting too light)....but Smith doesn't have much to say on why in "Engineer to Win" (just some pics on how to be lazy /forums/images/graemlins/rolleyes.gif) but there is a bit more info in "Tune to Win". The few things he does say still don't answer my questions. He says to slot your discs but that drilling them is better because it removes more mass from the disc and also that they are more prone to crack. The difference in price between a slotted and drilled (Raybestos BruteStop) rotor and a plane Raybestos is $125 vs. $70...$55 more each. Just wondering if it is worth the extra $110. Will it brake that much better than a plane one? Will it last longer? Will the pads last longer or shorter? I don't think the weight removed from them will make any difference...just worried about durability.
     
  18. CCRider

    CCRider 1/2 ton status

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    As far as the calipers , I had them on my 3/4 ton 10 bolt I sold , and if I remember correctly they were off a 3/4 or 1 ton van , and had a 3" piston , made a considerable difference in braking power , I believe they were an early 80's gm van caliper though !! sorry I can't be of more help , but they're definately out there and fairly cheap iirc !! returned my small pistons for cores , didn't know the diff at the counter . Good Luck..............CC /forums/images/graemlins/k5.gif /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif
     
  19. 70~K5

    70~K5 1/2 ton status

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    I wish I had bought a copy of Prepare To Win when it was out. Just waited to long. I have Tune to Win and Engineer To Win though. With Smith either you love his writings or hate them doesn't seem to be many people in the middle.
     
  20. ntsqd

    ntsqd 1/2 ton status

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    Coefficient of Friction is native to the pad's compounding, not it's area. You've got X force acting on a given area. Then you increase the area. What happens ?

    Lowering the tire pressure changes it's applied cF because of the tire's ability to conform to the irregular ground shape. Not an option with a disc pad. The pads can't wrap around the rotor like a tire can around a rock.

    If not done carefully drilled rotors will crack in short order. It's all about eliminating stress risers. Slotted rotors don't seem to have near the trouble although they certainly are also stress risers.

    I don't have a good feel for whether a drilled rotor will out perform a slotted rotor, or where one would be preffered over the other. I think slots have an advantage in that they will have some degree of 'cleaning action' on the whole pad face, i.e. - no glazing.
    Originally pads outgassed a lot as they got warm and holes or slots were needed to evacuate the gasses from btwn the rotor surface and the pad surface. With current pad compounding I don't believe this is necessary any more. If you tend to push a pad beyond it's upper ideal operating temp, then holes or slots may be a good thing for preventing fade.

    One of the tricks used by road racers is to have their rotors cryo-treated. This is a form of heat treat (except muy cold) that greatly increases wear life and reduces warping.
     

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