Rear disc brake upgrade?
#3230608
05/02/24 09:32 AM
05/02/24 09:32 AM
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Joined: Jan 2003
Posts: 13,369 Marion, South Carolina [><]
an8sec70cuda
OP
I Live Here
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OP
I Live Here
Joined: Jan 2003
Posts: 13,369
Marion, South Carolina [><]
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Are rear disc brakes a big improvement over drums? I know up front they are a big improvement, but the fronts do most of the work. My car needs help in the braking department...it's right at 3800 lbs and runs mid 8s. I have Aerospace Components front discs, but I'm thinking of using Wilwood for the rear. Does anyone foresee any issues mixing the two? I have the MP master cylinder...can I still use this if I switch to the rear to discs?
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 18 spline 4 speed, Dana 60 '71 Demon, 340, low gear 904, 8.75 '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: Rear disc brake upgrade?
[Re: an8sec70cuda]
#3230621
05/02/24 11:17 AM
05/02/24 11:17 AM
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Joined: Dec 2021
Posts: 1,144 Loudoun County, VA
Brad_Haak
super stock
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super stock
Joined: Dec 2021
Posts: 1,144
Loudoun County, VA
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I don't know if your 'Cuda sees any real street use these days, but I see the "race" disc brake kits are very clear about being track only. I'll take a a s.w.a.g. that repeated stops with short cool-down intervals warp the rotors on those lightweight parts.
2021 Challenger 6.4L Scat Pack 1320 100% stock: 1.680, 11.894 at 113.75 (DA 175 ft) weight reduction, wheels, tires, Hellcat air box: 1.661, 11.686 at 115.97 (DA 710 ft)
1973 Challenger 452 ci street/strip [2008] pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
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Re: Rear disc brake upgrade?
[Re: an8sec70cuda]
#3230649
05/02/24 01:23 PM
05/02/24 01:23 PM
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Joined: Jan 2003
Posts: 2,924 A shed in England
Tig
master
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master
Joined: Jan 2003
Posts: 2,924
A shed in England
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Made a huge difference to mine, once I fitted the correct master cylinder. Pretty sure I changed from 1" to a 7/8ths", needed too much pedal pressure with the 1" master cylinder. I knew I'd made a 140+ pass when I had to use two feet on the pedal at the end of the track No problems now Edit: I used a wilwood street kit with parking brake BTW.
Last edited by Tig; 05/02/24 01:23 PM.
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials. 9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge. RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
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Re: Rear disc brake upgrade?
[Re: FurryStump]
#3230651
05/02/24 01:27 PM
05/02/24 01:27 PM
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Joined: Jan 2003
Posts: 13,369 Marion, South Carolina [><]
an8sec70cuda
OP
I Live Here
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OP
I Live Here
Joined: Jan 2003
Posts: 13,369
Marion, South Carolina [><]
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I will most likely get a "street" brake kit for the rear. I do have a transbrake. The front has Aerospace Components' pro street brake kit. They can be a pain to deal with and I've had some issues w/ the calipers. That's why I'm wanting to use a different brand now.
What's on it now is marginal. Most of my racing is 1/8 mile, but at 1/4 mile tracks. Obviously shutdown isn't an issue there...which is why I've let it go this long. Trying to haul this thing down at an 1/8 mile track can be tricky. It needs a parachute, but the car needs a lot more before I can put one on...so that won't happen anytime soon. It still has the stock fuel tank and no bracing from the cage to attach a chute too.
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 18 spline 4 speed, Dana 60 '71 Demon, 340, low gear 904, 8.75 '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: Rear disc brake upgrade?
[Re: Neil]
#3230692
05/02/24 06:26 PM
05/02/24 06:26 PM
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Joined: Jan 2003
Posts: 8,166 Plymouth, MI
Blusmbl
master
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master
Joined: Jan 2003
Posts: 8,166
Plymouth, MI
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I saw a noticeable improvement going from drums to the basic 11" rotor Wilwood kit on the front of mine, and then a little improvement going from drums to the 11" street Wilwood kit on the rear. The bigger 12.19" rotors don't always fit under 15" wheels so I erred on the small side. Mixing front and rear manufacturers shouldn't matter, but like Andy said it is dependent on caliper piston size and rotor size too. You can fix mismatches with a proportioning valve as long as it isn't too far out front to rear.
'18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III - 11.37 @ 118
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Re: Rear disc brake upgrade?
[Re: Blusmbl]
#3230707
05/02/24 08:23 PM
05/02/24 08:23 PM
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Joined: Mar 2009
Posts: 2,464 Sydney,Australia
tex013
top fuel
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top fuel
Joined: Mar 2009
Posts: 2,464
Sydney,Australia
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once I hit 125+ I found 10"rear drums were not happening anymore . Cadillac style rear discs fixed that .
Tex
New best ET 10.259@129.65 . New best MPH 130.32 Finally fitted a solid cam, stepped it up a bit more 3690lbs through the mufflers New World block 3780lbs 10.278@130.80 . Wowser 10.253@130.24 footbraking from 1500rpm Power by Tex's Automotive
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Re: Rear disc brake upgrade?
[Re: tex013]
#3230724
05/02/24 09:18 PM
05/02/24 09:18 PM
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Joined: Jan 2003
Posts: 31,049 Oregon
AndyF
I Win
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I Win
Joined: Jan 2003
Posts: 31,049
Oregon
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once I hit 125+ I found 10"rear drums were not happening anymore . Cadillac style rear discs fixed that .
Tex Yeah 10 inch drums might give up at 125. We ran the larger 11 x 2.5 station wagon drum brakes on the back of a Valiant road race car and they worked fine well past 125. Finally moved to rear discs once the car was going more than 150 mph on the straights.
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Re: Rear disc brake upgrade?
[Re: an8sec70cuda]
#3230811
05/03/24 12:21 PM
05/03/24 12:21 PM
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Joined: Dec 2006
Posts: 2,115 Byron, NY
W.I.N. Racing
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top fuel
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Posts: 2,115
Byron, NY
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I have Aerospace Components front discs, but I'm thinking of using Wilwood for the rear. Does anyone foresee any issues mixing the two? I have the MP master cylinder...can I still use this if I switch to the rear to discs?
Mixing and matching properly sized components from different Mfg' shouldn't be an issue, The key is properly sized components. I have even swapped one MFG caliper on to a different MFG brackets without any issues. The master cylinder dia needs to be sized correctly for teh amount of piston area being installed. You may get lucky with the one you have but more than likely you will need a new (different size) one. Drum brakes require more fluid volume than a disk system.
'01 P1500, Blown/Inj BAE,/Veney ,Bruno/CS2,Dana 60 '01 Dodge 3500 S Cummins Auto, Fresh air kit, 4" Exhaust, '05 Dodge Magnum R/T - Too Much to list '60 Willys CJ5 '01 International LPX - Project,DT466, Allison '64 Plymouth Valiant, Inj 528 Hemi, 2spd
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Re: Rear disc brake upgrade?
[Re: an8sec70cuda]
#3230829
05/03/24 03:23 PM
05/03/24 03:23 PM
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Joined: Oct 2005
Posts: 271 Anchorage, Alaska
metallicareload
enthusiast
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enthusiast
Joined: Oct 2005
Posts: 271
Anchorage, Alaska
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FWIW, I’m only hauling down from 111 MPH or so, but the car is pretty heavy @ 4100+. And it’s mostly a street car, with a good amount of Autocross during summer. I’ve been using Doctor Diff’s 11.7” rear disc brake kit for 60,000+ miles and has worked great through all the above. Proportioning valve installed, but it’s wide open, and 15/16” master cylinder
440, 4-Speed, 3.54 1968, when Dinosaurs ruled the Earth
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Re: Rear disc brake upgrade?
[Re: metallicareload]
#3230933
05/04/24 07:24 AM
05/04/24 07:24 AM
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Joined: Jan 2003
Posts: 8,028 Tulsa OK
Bad340fish
master
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master
Joined: Jan 2003
Posts: 8,028
Tulsa OK
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I added willwood discs to the rear of mine in 2018 when I put the Dana in. I have had the front forever. The front kit has vented rotors the rear kit is a drag race kit with drilled rotors. On the street there is not a huge difference in braking. At the track it is substantially better. I made the first turnoff at the house of hook, that turnoff isn't meant for people running the 1/4 mile lol but I was committed so I stayed with it and had no trouble.
These rears have been on since 2018 and have done 4 drag weeks, the pads and rotors still look great. The fronts also seem to be lasting longer with the rears added.
68 Barracuda Formula S 340
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