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Rear Drum to Disc Conversion
#1
I am upgrading the handling of the car based on answers to my previous thread.  All parts are ordered and work will begin end of the month.

THOUGHT to convert Drum to Disc for the rear.  I researched the forum and there are different setups being discussed and got a bit confusing...so I thought to ask specifics.

I HAVE POWER BRAKES.  Disc in front and Drum in rear.

1) Which kit would you reco for this job?

2) Do I need to change the booster to handle disc in the rear?
3) Do I need to add proportional valve also??

Any other things to consider.

Rush
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#2
One way you can go, that a lot of people over look, is to replace the whole rearend. If your rear end doesn't have posi or the gears you want, you can swap in an 8.8" rear end out of a Ford Explorer. I swapped one in my car years ago and its been holding up really well. You get factory disc brakes, 3.73 gears, factory posi, and 31 spline axles all in one shot. Just another idea for ya. You can do a search on here, its been discussed a few times.

Kevin

1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

[Image: 28ivsix.png]




                                                                                             
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#3
there is a set of brackets made and sold by "Mustang Steve" that utilize 2004 Cobra brakes- works well, nicely made. I 1st used Baer Brakes, but their brackets are cast aluminum and I had one fail and destroy a wheel. When I called them aabout a replacement caliper, they would not even admit that their calipers are just 2004 Cobra calipers, nor would they tell me that these calipers use slightly thinner pads than the Mustang calipers.

You'll want an adjustable rear proportioning valve to dial in the amount of braking pressure and you may benefit from getting a gauge to test line pressure to make sure you are in the proper ballpark as disc brakes take something like 900-1500 psi line pressure and drums are like 600. Needing a different master cylinder is a distinct possibility.

Most of the conversions won't fit stock or aftermarket 15" wheels, so if you are not upgrading wheels, don't upgrade the rear drums.

Drum brakes aren't bad-there are a couple of cheap tools that make servicing them easier than trying to manage with pliers and a big screwdriver. They work fine even for spirited driving, but they will fade to some degree-I think people overestimate the value of rear disc brakes as the front of the car does the lion's share of work. It can be done for about $500.00 but even having done it, I'm not sure it is worth it.

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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#4
Your existing booster is fine. Most people do not replace the existing (factory) proportioning valve or master cylinder. Rear disc brakes also require lower operating pressures to prevent them from locking up. An adjustable proportioning valve will enable you to fine tune the front/rear bias. The smaller reservoir for the rear brakes will require you to keep an eye on the brake fluid level as the rear pads wear and the pistons do not return as far. Self adjusting drum brakes keep the fluid level at the same level as the shoes wear, which is the reason for the smaller reservoir.

Mustang 360 has a couple of articles:

http://www.mustangandfords.com/search/?q...conversion



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#5
There's also an article floating around the forums outlining swapping in some Crown Victoria rear discs onto the stock 9" axle (just gotta buzz the bottom of the axle tube flanges flat to accommodate - from there it's pretty much a bolt-on deal) - which I believe are very similar in size to the Explorer discs Kevin mentioned with his Explorer rear-end swap (which is a great idea, BTW).

Lots of different ways to skin this cat. Wink

Eric

[Image: mach1sig2.gif]
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#6
(03-06-2017, 01:41 PM)Mister 4x4 Wrote: There's also an article floating around the forums outlining swapping in some Crown Victoria rear discs onto the stock 9" axle (just gotta buzz the bottom of the axle tube flanges flat to accommodate - from there it's pretty much a bolt-on deal) - which I believe are very similar in size to the Explorer discs Kevin mentioned with his Explorer rear-end swap (which is a great idea, BTW).

Lots of different ways to skin this cat. Wink

The Lincoln Versailes used a disc brake 9 " also.  I had one in my Bronco II.

Kevin

1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

[Image: 28ivsix.png]




                                                                                             
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#7
Bolt on using stock components is the best way to go, in my opinion. That makes it easy to find replacement parts, not to mention cheaper for cheapskates like me. Replacement parts for specialty items can be hard and expensive to obtain.

Here are a couple of websites with instructions:

http://www.boyerfour.com/mustang/rear/sm...rd_8_9.htm
http://ynned.tripod.com/crown_vic_discs/index.html
http://www.jalopyjournal.com/forum/threa...ds.358587/

These may not work with 14-inch wheels and may require upgrading to 15-inch or larger.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#8
I was thinking of you when I mentioned using the Crown Vic parts. Wink Big Grin

Eric

[Image: mach1sig2.gif]
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#9
One thing I DON'T want to do is wreck my original numbers matching open dif 3.25 rear axle. I would however like to consider adding a 9" 3.50 locker type rear axle and disc brakes would be a bonus. I am not hijacking this thread, but do any of you know of such a rear end that is easily available and be a direct fit in the Mach 1 with staggered shocks and at present 14" wheels? This might be a good way for 1973stang the  to go also.
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#10
(03-06-2017, 04:11 PM)Mister 4x4 Wrote: I was thinking of you when I mentioned using the Crown Vic parts. Wink Big Grin

goodone



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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