Best Brakes for Buck

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The OEM stuff is great if you don't have to replace all the parts (other than the knuckles), in which case you will spending $$$ for replacement parts. Keep in mind - you must factor the expense of new wheels with the 4.5" BP, unless you already have those. When you do the conversion the expense of pulling/buying the stuff from a salvage yard is only a fraction of the overall expense. The FMJ setup might be the least costly alternative.

What about the Scarebird alternative?

As someone posted above, I also have the factory SBP KH disc setup and my 1971 340 Duster stops very well. I have wider 15" SBP wheels for larger rubber.
 
I already have the 8.25 rear in my scamp, I was just thinking I may can use the disc setup from the rear of a liberty or cherokee. It looks like it will swap over with little modification.
 
I'm thinking FMJ spindles and brackets, but I just don't want to trust the used calipers and rotors. I may still look into the "at the wheel" kit from CPP and use the Dr. Diff adapters for the upper ball joints. ( since this will come with all new stuff already). My wheels are actually uni-lug on the front since the previous owner already converted the rear to BBP. My rear wheels were purchased in a set of 4 BBP, so I still have two more 4.5" BP wheels that match and I can keep the same tires.


By the way, What is the scarebird alternative?
 
I just did the disc/bbp swap this summer on my 72 Duster.

I used 74 dart uppers,and spindle with new 78 volare calipers(larger diameter piston)and brake hose.(no 11.75 adapters in my yards for months :( )

Got all the new bearings,balljoints,seals,bushings,tierods etc.

Had to switch the spindles side to side to clear my 72 and prior swaybar assembly.

Iam using a non-name brand adjustable prop valve till I can get new brake line/valve from fine lines.

All told Iam probably in the "swap" around $450 including the initial purchase of the boneyard parts.

OklaCarcollector gave some good info in his post on what to look for.

If you get the chance do a search in the brake section, I found TONS of info in it...esp for the swaybar issue.


ps: should add the price is due to some Buddy deals...EG :Cheap
 
71Sc@mp said:
I'm thinking FMJ spindles and brackets, but I just don't want to trust the used calipers and rotors. I may still look into the "at the wheel" kit from CPP and use the Dr. Diff adapters for the upper ball joints. ( since this will come with all new stuff already). My wheels are actually uni-lug on the front since the previous owner already converted the rear to BBP. My rear wheels were purchased in a set of 4 BBP, so I still have two more 4.5" BP wheels that match and I can keep the same tires.


By the way, What is the scarebird alternative?
Click to expand...

As I said early in the thread, I would take the calipers and trade them in on remanufactured ones. If the rotors are good they are just as good as new ones. If you happen to get some nice ones that were USA parts they will be better than the new ones you get now since most of the new ones are imported.

I would advise you to read the post found at the link below before ordering parts.

http://www.forabodiesonly.com/mopar/showpost.php?p=1969865632&postcount=11
 
Rock auto
High Performance/Heavy Duty
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POWER STOP Part # AR8309XPR Extreme Performance Drilled and Slotted Rotors
Front
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+ Sold in packs of 2; Price reflects cost of each individual item, not the pack$80.79
 
Rock Auto


RAYBESTOS Part # FRC4103 Friction Ready - Pads Not Included, Remanufactured; Professional Grade
Front Left
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$22.79$10.00$32.79
RAYBESTOS Part # FRC4104 Friction Ready - Pads Not Included, Remanufactured; Professional Grade
Front Right
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$22.79$10.00$32.79
 
..but really,rebuilding calipers is so easy unless badly corroded.
..rear discs? 80 % of your braking is from the front.
..and make sure you get the hydraulic ratio correct..read 1" bore master max.
 
72bluNblu said:
Exactly! :thumbup:

You can usually pick up those spindles for under $100 at the local yard, and the adapters only cost $50 from Dr. Diff.



Gonna have to disagree here.

The 11.75" rotors are a HUGE improvement over stock. All of the cars I've swapped and driven so far have been from the stock 10.98" rotors to 11.75", and it is a noticeable difference. Based simply on the radius of the disk, the increase in braking force is at the rotor is about 8% vs. the stock rotors. And then there's the fact that the 11.75" rotors, even using the stock calipers, have a larger braking surface (because of the larger swept out area). That means it will take longer to heat them up, and that you have more surface area to cool them down. There's a reason the bigger, heavier later cars used 11.75" rotors -they work better.

And since the rotors cost pretty much the same, and you use the same calipers, the only real cost above and beyond the 10.98" set up is $100 for the caliper brackets. I suppose if you really want to get technical you need 15" rims to run the 11.75" rotors too, so that could be an extra cost if you have 14's and were planning on keeping them. But I can't imagine wanting to keep the 14's on a driver anyway (no good tires whatsoever). Maybe for a restoration car, but then you wouldn't be switching to disks anyway.

For $100, a 8% increase in braking force is pretty darn good. And if its really a driver, you may need the those extra few feet. I know I've been in a couple of situations in the last 40k miles with my Challenger where a couple of feet might have meant replacing some sheet metal. People drive stupid.
Click to expand...
How do you get a larger swept area if the pads and calipers are not larger as well ? Might get better cooling due to heat dissipation but that's all . Or maybe not , can you explain please .
 
jerry6 said:
How do you get a larger swept area if the pads and calipers are not larger as well ? Might get better cooling due to heat dissipation but that's all . Or maybe not , can you explain please .
Click to expand...

I did. The brake rotor has a larger diameter, which means that although the brake pad is the same size, the brake area is larger.

If you figure the outside of the rotor is 11.75" and the width of the braking surface is 1.8" ( I measured it),

then the total braking area is π (11.75/2)^2 - π(9.95/2)^2 = 30.67 square inches for the 11.75" rotors

For the 10.98 rotors the braking area is π(10.98/2)^2 - π(9.18/2)^2 = 28.5 square inches

The pad is the same size, but because the outer diameter of the rotor is larger, so is the circumference of the rotor. So at any given moment the pad area in contact with the rotor is the same, but the pad "sweeps out" a larger area on the rotor because it travels a longer distance in doing so. This doesn't directly improve braking force, but because the pad is acting over a larger area the brakes are dispersing the energy of braking over a larger area. Also, there is more surface area to disperse the heat energy once the braking is done. 30.67 vs. 28.5 doesn't sound like a big difference, but that's a 7.6% increase in braking surface.

But the biggest advantage is still the increase in braking force. The larger diameter of the rotor means that although you have the same force applied by the brake pads, the force acting at the hub is larger. The larger diameter means the force applied by the pads has a larger "lever arm". Just like using a ratchet with a longer handle, the force applied is multiplied directly by the length of the lever arm. Longer ratchet, more power. Larger diameter rotor, more braking power.

For a 11.75" disk, the center of the brake pad is roughly 4.975" away from the center of the rotor. For a 10.98" disk, that distance is 4.59". So, if you take 4.975/4.59, you'll find that the braking force is going to increase by 8.3%, even though nothing but the rotor diameter changed.
 
Thanks 69Mope for the parts info, and to all for their input. Oklacarcollecto, I knew you meant to use the remaned calipers, and I would too, but I was just thinking that if I am going to spend close to $400 for the parts, plus time going and pulling (which I could only do on a saturday and I count my time as money), plus time cleaning and inspecting and I'm sure I will have to make more than one trip to the local parts store simply because that is the nature of the beast, why not just buy a kit from CPP or Master Power Brakes or Summit, or someone who offers an "at the wheel" kit and have all the parts come at once on my time and clean?
 
Okay , don't agree with the analysis , but I've been out of touch wit this for 30 years .Clamping force does not increase because you have a larger disk unless the clamp ie pads caliper increase in size as well , don't think the lever comparison applies . If you have a vise grip and increase the spinning disk diameter you would have more rotating mass with no increase in the clamp size , how would it increase clamping force ?
Guess I've been out of school way to long . My brain hurts . You're probably right though , very confusing .
 
Visualize it this way, a tire/wheel spinning on a tire balancer, if you try slowing it down by pushing a 2x4 against the lug nut area and try slowing it down the same way on the tread face, the second way is much easier. I don't know the terminology for it (like leverage) but if it was not true then all cars including race cars would have 9 inch rotors.
 
69MOPE said:
Visualize it this way, a tire/wheel spinning on a tire balancer, if you try slowing it down by pushing a 2x4 against the lug nut area and try slowing it down the same way on the tread face, the second way is much easier. I don't know the terminology for it (like leverage) but if it was not true then all cars including race cars would have 9 inch rotors.
Click to expand...
Dont they have larger pads and calipers as well ? Heat dissipation is another reason for larger disks , less fade after repeated stops .
I better stop brain hurts :banghead::violent1:
 
jerry6 said:
Okay , don't agree with the analysis , but I've been out of touch wit this for 30 years .Clamping force does not increase because you have a larger disk unless the clamp ie pads caliper increase in size as well , don't think the lever comparison applies . If you have a vise grip and increase the spinning disk diameter you would have more rotating mass with no increase in the clamp size , how would it increase clamping force ?
Guess I've been out of school way to long . My brain hurts . You're probably right though , very confusing .
Click to expand...

It doesn't increase the clamping force, it increases the total braking force.

Torque= Force x length of moment arm

The total braking force acts as torque at the spindle, even though the calipers clamping force acts out on the rotor. The longer the torque arm, the greater the total braking force, even if the clamping force at the caliper doesn't change.

Maybe I'm not explaining it very well, but that is the physics, whether you agree or not.

Torque_animation.gif


69MOPE said:
but if it was not true then all cars including race cars would have 9 inch rotors.
Click to expand...

Exactly. Especially the race cars. The advantage to going to 12", 13", 14", etc rotors isn't the upgrade of the caliper, its the increase in the length of the torque arm because of the larger radius of the rotors. Now, most of those systems also use better calipers, which adds to the total stopping force. But, if the size of the rotor had no effect, all of the rotors would be as small in diameter as possible to decrease rotating mass. This would be especially true for race cars. They'd have really awesome calipers and tiny little rotors to save weight and rotational mass. Instead, they have HUGE rotors.

Same for cooling. Its all about surface area. Yes, the larger rotors have more mass, which makes more material that needs to be cooled down. Size for size, the heavier rotor will take longer to cool down. But surface area is more important than mass, so even though the larger rotor has more mass, it will still cool faster because of the larger surface area. It will also take longer to heat up, which is another advantage.
 
If you can skid the front tires with the smaller disc then the bigger unit is just not worth the effort, IMO. Every day driving, especially on a lighter A body, never gonna notice and I've driven both set ups as well.

If you plan on beating the snot out of the car running autoX, etc, then the big brakes are useful from a heat dissipation standpoint.

IMO, it's more about I got this big brake set up then it is about utility in most cases. Much like most of the guys that I know who installed rear disc... Most don't ever use them to their full potential. It's eye candy and ego.

For me, if I can find a complete set up with a 10.87 rotor that needs maybe a turn, that's a better value than another $100+ in brackets and 100-150 in new rotors on a daily driver.

Like I always say... Pick your parts, Pay your money!
 
Just pulled another set of pin-calipers, adapters and rotors (reinforcement ribs on the back, too!) for a whopping $65.38 at Northwest Auto Recycle Tuesday. Stumbled across a '76 Cordoba that nobody had gotten to while getting the interior trunk panel protector (the black plastic piece in the rear of the trunk, covers the wiring) for the SMPM '76 Dart they are restoring.
I'll take the extra swept area with this brake set up over the 10.87"s
 
crackedback said:
If you can skid the front tires with the smaller disc then the bigger unit is just not worth the effort, IMO. Every day driving, especially on a lighter A body, never gonna notice and I've driven both set ups as well.

If you plan on beating the snot out of the car running autoX, etc, then the big brakes are useful from a heat dissipation standpoint.

IMO, it's more about I got this big brake set up then it is about utility in most cases. Much like most of the guys that I know who installed rear disc... Most don't ever use them to their full potential. It's eye candy and ego.

For me, if I can find a complete set up with a 10.87 rotor that needs maybe a turn, that's a better value than another $100+ in brackets and 100-150 in new rotors on a daily driver.

Like I always say... Pick your parts, Pay your money!
Click to expand...

I'm really tired of hearing the "if I can skid the wheels" braking argument.

There is SO much more to it than that. Just because a single rapid impulse can lock up your brakes doesn't mean that you have the best braking possible. Otherwise we could all run 9" drums. The more important braking comes when you DON'T lock up the brakes with a single rapid impulse. And don't think for a second that the force needed to lock up your brakes with a single rapid impulse is the most force you can apply. You can apply MORE braking force if you add it progressively rather than in a short impulse, and still stop faster.

The 10.98 (they're not 10.87") rotors are plenty sufficient for most drivers, I totally agree there. But don't kid yourself, the 11.75" rotors are better, even in every day driving. I immediately noticed the difference when I upgraded from 10.98's to 11.75's, and that was driving on the street. Hell, that was driving down the block. It really is a noticeable difference, especially if you're running larger, wider tires with a modern compound.

If you can get the 10.98" rotors out of the local yard, by all means, do it. Absolutely all day long and twice on Sunday. But if you have the opportunity to run 11.75's you'll immediately notice the difference, even on a daily driver. If you already run 15" rims, and need a set of rotors anyway, upgrading to the 11.75" rotors is $100 for the caliper brakets. And you don't even have to bleed the brakes again.

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I think I will be heading out to the local Pull-A-Part this Saturday to see what I can find in the way of FMJ Spindles, brackets, calipers(for cores), and possibly rotors. Deff new hoses and lines, I will order the Dr. Diff adapter, and I'll try to find the 10.98" setup for now and upgrade to the 11.73" later depending on what is avail. Should I grab the prop valve or just buy a new adjustable? I'll have to order the lower ball joints, but by the time they arive, I should have all the used parts clean and painted and ready for install. Any thing I'm missing?
 
..check your lower ball joints before ordering new.
..they can have some wear and still be fine,the weight of the front end keeps them snug and tight unless you're bouncing around on potholes or such.
 
71Sc@mp said:
I think I will be heading out to the local Pull-A-Part this Saturday to see what I can find in the way of FMJ Spindles, brackets, calipers(for cores), and possibly rotors. Deff new hoses and lines, I will order the Dr. Diff adapter, and I'll try to find the 10.98" setup for now and upgrade to the 11.73" later depending on what is avail. Should I grab the prop valve or just buy a new adjustable? I'll have to order the lower ball joints, but by the time they arive, I should have all the used parts clean and painted and ready for install. Any thing I'm missing?
Click to expand...

If the car is fresh and still has good brakes then grab the proportioning valve with the lines between the master cylinder and the valve. If you decide not to use it you can always sell it for a profit.
 
I figure I will need to change the lower ball joints, simply because they never have been to my knowledge, and the car was sitting on jackstands for a few years in the back yard. Probably a good idea to replace as many joints/bearings as possoble. All th bushings are new poly units.
 
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