Re: Want to upgrade 4 wheel drum to 4 wheel disc???
[Re: 71PurpleDodge]
#1750219
02/09/15 08:17 PM
02/09/15 08:17 PM
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Joined: Jan 2003
Posts: 28,068 Irving, TX
feets
Senior Management
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Senior Management
Joined: Jan 2003
Posts: 28,068
Irving, TX
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It has been done countless times.
You can drop the money for a kit or come up with your own stuff.
For a typical use car it's easier to follow the road well traveled and get the relatively inexpensive kits out there. Dr Diff has some good stuff.
SSBC and some of the other popular companies out there have a tendency to use oversized master cylinders which leads to a super hard bake pedal.
Be aware that if you go larger than 11.75" rotors you might run into clearance issues with 15" wheels. Some multi-piston calipers can cause wheel fitment issues too.
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon
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Re: Want to upgrade 4 wheel drum to 4 wheel disc???
[Re: 71PurpleDodge]
#1750220
02/09/15 08:19 PM
02/09/15 08:19 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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I've heard that going to 4 wheel discs is great and others say it is the cats' a$$. Doc (on here) has kits and his rep for parts/service/tech is unsurpassed. I have a pair of SBP and BBP rotors and I am going to weld brackets to the 8&3/4's for slider discs but I ain't got to it yet. I'm thinking the only thing that could trip me up is the axle endplay but I am going to get it right at zero & see how it turns out. Not a specific ans but here's a BTT for ya
live every 24 hour block of time like it's your last day on earth
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Re: Want to upgrade 4 wheel drum to 4 wheel disc???
[Re: RapidRobert]
#1750221
02/09/15 08:23 PM
02/09/15 08:23 PM
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Joined: Jan 2003
Posts: 28,068 Irving, TX
feets
Senior Management
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Senior Management
Joined: Jan 2003
Posts: 28,068
Irving, TX
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I ran the 4 wheel AMG brakes on the hot rod for years and never had a problem with axle thrust. I had factory style bearings and no provision for end play adjustment.
I know I put more than 13,000 miles on the car like that but I did check it when I put it together.
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon
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Re: Want to upgrade 4 wheel drum to 4 wheel disc???
[Re: 71PurpleDodge]
#1750222
02/09/15 08:35 PM
02/09/15 08:35 PM
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Joined: Aug 2013
Posts: 518 Georgia
Steve Bryant
mopar
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mopar
Joined: Aug 2013
Posts: 518
Georgia
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Last year I converted the front brakes on my 1970 Barracuda and I followed the Disc-o-tech instructions and it worked out great. http://www.moparaction.com/tech/archive/disc-main.htmlI bought lowered (2") Spindles from PST just to drop the nose a tad and I bought the caliper adaptors from E-Bay. The calipers, master Cylinder and booster I got from the local parts store. Aside from the PST calipers I don't think I paid more than $400 for the rest. As yet, I have not converted my rears and I may not. The rears are not used as much and most of the local guys prefer drums in the back. The lessons I learned are: 1) Buy the MC new if possible. I bought a rebuilt one and it was defective. 2) Buy a name brand prop/dist valves if you are going back to stock. I should have bought inline first instead of the cheap Ebay valves I tried to use. 3) Go ahead and replace the metal lines while you are at it. Mine were full of crud and they are not that expensive. 4) Many people prefer the pin-type calipers and I am no exception.
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Re: Want to upgrade 4 wheel drum to 4 wheel disc???
[Re: 71PurpleDodge]
#1750224
02/09/15 09:04 PM
02/09/15 09:04 PM
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Joined: Jan 2003
Posts: 31,045 Oregon
AndyF
I Win
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I Win
Joined: Jan 2003
Posts: 31,045
Oregon
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Everything you need can be sourced from www.doctordiff.com Probably the first step is to just put the 11.75 front disc brakes on there and leave the rear drums alone. That setup should be good for any street car. It will also for track use up to 120 mph or so. The 11.75 kit requires 15 inch wheels. If you want to step up to bigger brakes then you need larger wheels. I run 13 inch rotors on my '65 Coronet but I have 17 inch rims.
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Re: Want to upgrade 4 wheel drum to 4 wheel disc???
[Re: 71PurpleDodge]
#1750226
02/09/15 09:36 PM
02/09/15 09:36 PM
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Joined: Dec 2007
Posts: 18,157 Mass
DAYCLONA
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 18,157
Mass
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I've been doing the 4 wheel disc upgrades on customers cars for a decade +, if your budget is under $1000, I'd recommend you source factory front calipers/rotors/knuckles/brackets/etc for up front, generally I prefer the 2 pin 70-4 B/E body calipers, your choice on going 10.95 or 11.75 front rotors, and or later full floater calipers...
for the rear, I generally prefer the SSBC rears, which are Thunderbird rears, or the Dr Diff Cobra rear set up, your choice...
If you go with SSBC don't use the master cylinder/power set up, just junk, run a Mopar master, I generally run a Bendix dual diaphram booster and a disc/drum master in the 1" to 1 1/8" bore max depending on the caliper bore sizes chosen front to rear...
If you do a full 4 wheel disc conversion, you don't need a factory proportioning valve, you could use your factory drum distribution block if desired...I generally prefer to run the rear line directly off the master, same with the front, except you need to tee somewhere during the run from the master to both front wheels,...if you can't achieve a 70/30 to 60/40 front/rear brake bias choosing the proper sized calipers, you may have to install an adjustable PV valve in the rear line to raise the front bias to the desired ratio...
If your going to use a booster, I generally use either the single or dual diaphram units (Chrysler/Midland/Bendix) generally I find the single boosters are good for about 800 -1000 psi line pressure, and the dual diaphram Bendix units I've achieved as much as 1500 psi, but 1200+ is avg for the dual Bendix....
Don't take no short cuts, buy quality stuff, replace any lines or components you suspect are worn/junk, there's plenty of help here on Moparts if you get jambed up on your install
Mike
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Re: Want to upgrade 4 wheel drum to 4 wheel disc???
[Re: AndyF]
#1750227
02/10/15 05:04 AM
02/10/15 05:04 AM
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Joined: Feb 2010
Posts: 18,493 Granite Bay CA
Kern Dog
Striving for excellence
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Striving for excellence
Joined: Feb 2010
Posts: 18,493
Granite Bay CA
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Quote:
Everything you need can be sourced from www.doctordiff.com
Probably the first step is to just put the 11.75 front disc brakes on there and leave the rear drums alone.
I feel like Kid Rock following Mick Jagger here since Andy F is well respected, but here goes: I had the 11" discs and 10" drums in my 70 Charger and it stopped great. I didn't like seeing the brake drum through my rear spokes so I decided to switch the rear to discs by buying a kit from Dr Diff. Great stuff, no complaints with the quality, but....Rear discs made no difference in my car. They made no difference in my friends 71 Challenger. These cars stop great with the disc/drum setup. If the rear wheels lock up too easily, you can step down one size in rear wheel cylinders until the front locks before the rear. If I was running Rally wheels or Magnums where you couldn't see through them, I'd stick with drums. Shoes are cheap and the design carries with it OEM reliability.
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