Joined: Tue Mar 12 2013, 11:31AM
Location: Germany
Posts: 70
I have a 74 chrysler newport and I wonder if there are bigger disc brakes for the front and disc brake conversions for the back available. I have 20" wheels, so size wouldn't be a problem. All I can find are Mustang II brakes made by wilwood. (I don't even know if Mustang is the name of the brake or they really mean the car).
It seems that there are no larger front brake rotors available for the 1974-78 C-body cars. You will need to engineer your own adaptation of something. The Mustang II refers to the Ford Mustang of 1974-78 vintage. Quite similar to the Ford Pinto in regards to front brakes and suspension. Conversion kits for rear discs are available. You must research the aftermarket brake suppliers. Hope this helps some.
Joined: Mon Oct 10 2005, 10:24AM
Location: The Netherlands
Posts: 160
Find a modern car with 4.5" boltpattern and use/modify their rotors to use on a turned down disc or drumbrake hub. Then you have to fab an adapter to mount the brake caliper.
It's not rocket science but you'll to have a good idea of the forces working on brake parts.
Joined: Tue Oct 11 2005, 01:33AM
Location: Calgary, Alberta
Posts: 5893
I used a TSM rear disc conversion kit forf the back and with the stock front discs the car stops on a dime. Every bit as solid as the 4 wheel abs setup on my Jeep.
Joined: Wed Aug 11 2010, 10:15AM
Location: E WA
Posts: 1230
rage607 wrote ...
I have a 74 chrysler newport and I wonder if there are bigger disc brakes for the front and disc brake conversions for the back available. I have 20" wheels, so size wouldn't be a problem. All I can find are Mustang II brakes made by wilwood. (I don't even know if Mustang is the name of the brake or they really mean the car).
Can you find vented rotors for your car or get a stock set drilled. The braking force is proportional to the area of the brake pads and has nothing to do with the size of the rotor. Bigger rotors do give better heat dissipation for repeated stops but then so do vented rotors somewhat.
Lots of vendors have rear disc conversions for the Chrysler 8 3/4 " rear end if that is what you have.
I have the Summit rear disc conversion on my 67 Polara Convertible along with a Wilwood master cylinder and proportioning valve. The car has a 73 front disc setup. The installation of the rear disc brakes is a little tricky and I believe that you need the rear axle end play as tight as you can to do it properly.
I am up in the air about the rear discs. The car does stop really really well but I am not sure that it was worth the hassle and expense.
Joined: Tue Mar 12 2013, 11:31AM
Location: Germany
Posts: 70
Yeah ok. I got that. I have the 8 3/4". So I get a set of rear disc brakes and maybe other rotors for the front. There are sets with vented rotors for the front with new, bigger calipers.
Joined: Fri Aug 05 2011, 08:06PM
Location: Brisbane Australia
Posts: 132
I have been researching this allot in the past month and the results are interesting
To exceed the piston and pad area of the brakes you currently have, you would have to go up to a 6 piston calliper. The 2 3/4" single piston has 20% more effective area than the 4 pot willwoods. There is a factory 3" piston calliper around, but pretty much unobtanium unless you live in the US and can browse wrecking yards
200 series Toyota Landcruisers have a 4 pot calliper that is roughly equiv in area and fits the 1 1/4 inch (32mm) thickness discs we have - weight saving aprox 5-6lbs a side. Porsche cayenne rotors are probably cheap where you live and a pretty good option for you, I am looking at local Aussie ford products for mine
The only advantage of the $600-1000 bling kits kicking around is weight reduction, anything using 4x45mm pistons and thinner discs is less braking than you have now unless it has 14" rotors
The rear discs really are not needed unless you are autoxing or circuit racing, with a well sorted proportioning valve, you would probably never know the difference
edit, hang on you have an autobahn... ok the rear discs may be useful with regular 100+ mph driving
Joined: Wed Dec 21 2005, 07:34AM
Location: indiana
Posts: 791
flj wrote ...
Can you find vented rotors for your car or get a stock set drilled. The braking force is proportional to the area of the brake pads and has nothing to do with the size of the rotor. Bigger rotors do give better heat dissipation for repeated stops but then so do vented rotors somewhat.
A larger dia rotor, with the OEM pad located at a larger radius from the hub's centerline vs OEM, will absolutely create greater braking force. And drilled rotors can be an invitation for stress cracks at the holes.
Joined: Mon Oct 10 2005, 10:24AM
Location: The Netherlands
Posts: 160
Imo, rear discs can also benefit stop&go citydriving. Whenever I'm in the busy parts of my town doing a lot of stop&go driving, I sometimes can feel the brakeforce deminish a bit.
Joined: Sun Jul 18 2010, 11:11PM
Location: DFW
Posts: 811
There is a lot of misinformation in this thread. First, vented rotors are not the same as larger rotors. Most cars with disc brakes have vented rotors. Vents are the vanes running down the middle of the rotor (as seen from the edge) between the two braking surfaces. Only a few cars have solid rotors these days and they're generally found on the rear.
Drilled rotors are a crap shoot. The drilling helped more with antique brakes that had excessive outgassing. The holes now are used for styling and weight removal. Be sure your rotors have CAST IN holes with radiused edges. Holes drilled after casting tend to create stress risers that lead to cracking.
Slotted rotors are a better answer to outgassing than holes. It doesn't matter which way they sweep.
Larger rotors give you a better heat sink. That is important. Brakes convert rotating energy into heat energy by friction. The larger the rotor the more heat it can dissipate. The problem is that stuffing a big heavy rotor on the car will hurt the acceleration. My 14.2" AMG rotors weighed 37 pounds EACH. That doesn't include the weight of the hub. That's just the brake disc. Try spinning that up by hand. It'll demonstrate why size matters.
Caliper size and number of pistons does not make a difference in braking ability until you get to maximum performance braking system. You can make just as much pressure with a small caliper as you can a large caliper. Check out my brake math spreadsheet: http://3gduster.com/brakes.html
The benefit gained from larger calipers is the ability to use a larger pad. The multipiston calipers press a bit more evenly on the longer pads than a single piston. In fact, many multipiston calipers have smaller leading pistons to help reduce the tendency to wear the leading edge of the pad more than the trailing edge.
Front brakes do about 70% of the stopping work. That's why they're so much larger than the rear brakes on most cars. Rear discs are helpful when it comes to frequent braking and high performance use. They dissipate heat easier than drums. A bonus is that they tend to be easier to modulate at lockup and are easier to service.