4 wheel disc help?

[68cudahemi]

68 barracuda with factory drum all around to 4 wheel disc brakes.Factory were manual and i want to keep manual brakes.Which m/c should i get and should i go with a adjustable proportioning valve? Also do i need to change line diameter for more fluid flow?If so what size?

 

[Vs29H1B]

68 barracuda with factory drum all around to 4 wheel disc brakes.Factory were manual and i want to keep manual brakes.Which m/c should i get and should i go with a adjustable proportioning valve? Also do i need to change line diameter for more fluid flow?If so what size?

Why not just go disc front / drum rear?

Unless you are autocrossing/Pro Soloing this car, the difference between drums vs. disc in the rear is hardly noticeable. The front disc do about 80 percent or more of all the braking based on the brake bias.

If you wish to pursue the rear disc conversion, check out the www.moparts.org message boards, go there and look for Doctor Diff. He has complete conversion packages available, including rear disc conversions (I believe these may be Ford Explorer rear discs adapted to the 8 3/4 rear).

Check out this thread for Doctor Diff info.
http://board.moparts.org/ubbthreads...96&Words=+cnxt&topic=&Search=true#Post4978372

 

[rjsjea]

Wilwoods on all fours and run a 7/8" wilwood mc, wilwood inline prop valve. That way everything will match.....(i got issues with matching stuff). Good time to replace the lines, or at least a good flushing.

 

[68cudahemi]

I talked to summit today which is where i got the disc brake package from.They also said to run a 7/8 bore m/c and an adjustable proportioning valve.

 

[wracks71]

i got a late model modified master cyl. from dr. diff. it looks good in the box because i haven't got it on yet,hopefully in a couple weeks! it comes with an adapter and you can get a nice adjustable pushrod with it. cass seems like a good guy and good to deal with.

 

[daniel_depetro]

My Duster had power front disc brakes from the factory with a 7-1/4" rear end. I built an large bolt pattern 8-1/4 rear (3.55:1 & Dana Trac Lok limited slip) which came out of my 1973 Dart Sport 340 and used 1995 Jeep Cherokee rear disc brakes on it. It was cheap (got my complete set-up for ~$200.00 shipped including new pads & rotors), easy to find parts for, and kept everything "Mopar".
I bought a new aluminum master cylinder kit (1-1/8" bore aluminum master cylinder & aluminum 4 bolt - 2 bolt adapter) from the Mopar Action guy (R. Ehrenberg) off eBay for $90.00 shipped.
I also used the correct Jeep brake hoses which cost me $45.00 out the door at the local Advance Auto Parts.
Everything works awesome together, I absolutely love the combination!
I tried locking it up on slick/wet roads and the car stays nice and straight.

 

[autoxcuda]

Why not just go disc front / drum rear?

Unless you are autocrossing/Pro Soloing this car, the difference between drums vs. disc in the rear is hardly noticeable. The front disc do about 80 percent or more of all the braking based on the brake bias.

If you wish to pursue the rear disc conversion, check out the www.moparts.org message boards, go there and look for Doctor Diff. He has complete conversion packages available, including rear disc conversions (I believe these may be Ford Explorer rear discs adapted to the 8 3/4 rear).

Check out this thread for Doctor Diff info.
http://board.moparts.org/ubbthreads...96&Words=+cnxt&topic=&Search=true#Post4978372

Even in autocrossing/pro solo, you're really see the benefit of the rear disks. The autocross courses are not long enough to really get the brakes cooked up.

On the track or lengthy HARD mountain driving you'd have a difference.

 

[autoxcuda]

My Duster had power front disc brakes from the factory with a 7-1/4" rear end. I built an large bolt pattern 8-1/4 rear (3.55:1 & Dana Trac Lok limited slip) which came out of my 1973 Dart Sport 340 and used 1995 Jeep Cherokee rear disc brakes on it. It was cheap (got my complete set-up for ~$200.00 shipped including new pads & rotors), easy to find parts for, and kept everything "Mopar".
I bought a new aluminum master cylinder kit (1-1/8" bore aluminum master cylinder & aluminum 4 bolt - 2 bolt adapter) from the Mopar Action guy (R. Ehrenberg) off eBay for $90.00 shipped.
I also used the correct Jeep brake hoses which cost me $45.00 out the door at the local Advance Auto Parts.
Everything works awesome together, I absolutely love the combination!
I tried locking it up on slick/wet roads and the car stays nice and straight.

I think that is a VERY slick way to go. The 8 1/4 is cheaper than a 8 3/4, it stroung enough for most applications under 400 hp and small block without a lot of torque, it's lighter than a 8 3/4. And the Jeep conversion for $200 is awesome and its got parking brake and you can buy parts for it at the local parts store. =P~

Of course looking at the original poster username, a 8 1/4 will not cut it behind a Hemi.

 

[daniel_depetro]

They should fit just the same on an 8-3/4" :dontknow:
In the mid 1990's I swapped in an 8-3/4" rear into a 1970 Charger we had (original 318 auto car; we ran it with a 354 HEMI & A883 4-speed transmission) I used the entire original drum brake set-up off the 8-1/4" rear (or was it a 7-1/4"? I forget...)

There are a couple simple reasons why I went to rear disk brakes:
1.) My original drums were shot (not even working; everything was junk) and would have cost as much to replace than converting to rear disks.
2.) Disk brakes are fast/simple to work on/replace.
3.) Maintenance free (no adjustments) once set-up.

It all added up to a no brainer to me.
Also high speeds & water will not affact a disk like they can a drum brake set-up.

 

[res1vw21]

tell me more about the jeep brakes if you would

 

[daniel_depetro]

What do you want to know?
I have quite a few pictures and such...
It's a direct swap/bolt on.
The center hole bore needs to be enlarged a tiny bit (~1/16"?) to fit over the ends of the 8-1/4" axle. I used a die grinder doing small steps until it fit all the way on.
You'll need the Jeep hoses if you didn't get them with the salvage yard "kit".
That's it.
Put the brakes on it and enjoy!

 

[cys68]

don't forget to change your metering valve along with the proportioning valve. If your set on running 4whl disc you will need a 4whl disc metering valve. When I converted my manual 4whl drum to frt disc/rear drum I had nothing but problems, and as soon as I put the correct metering valve on its been clear sailing! I got mine from master power brakes

 

[needsaresto]

Whats the lighter setup,drums or discs?

 

[65 Dartman]

. . . . . . and used 1995 Jeep Cherokee rear disc brakes on it. It was cheap (got my complete set-up for ~$200.00 shipped including new pads & rotors), easy to find parts for, and kept everything "Mopar".

I was not aware they put rear discs on regular Cherokees. I know they came on Grand Cherokees pretty much standard. IIRC those look like the 97 or so variety; on the earlier models the calipers were located about the 3 o'clock position. Got a photo shoot of how it was done?

 

[daniel_depetro]

I'm glad you caught that, usually I make very certain I put Grand Cherokee to make sure nobody get confused, however I guess this time I failed.
Anyways these were from a 1995 Jeep Grand Cherokee with rear disks (obviously).

I don't know which is lighter, but I would think the disks are, especially how I run them (I trimmed the excess knobs, brackets, dustshields, and am not using a parking brake set-up).
I would think spinning that small rotor has to be easier than turning a good (large diameter & thick) brake drum (think rotating mass).

This is my mock up to make sure everything was going to actually work out:

 

[daniel_depetro]

New Dana Trac Lok for $239.00 shipped off of eBay:

Dana limited slip, 3.55:1 gears, and new bearings installed:

Final assembly:
You can see where I took off the eyelet for the parking brake cable holder and rounded that corner smooth. You can also see where I cut off the nub where the parking brake shoes rested against when not in use. Not necessary to remove them, just thought I would shed the weight since I wasn't going to use the parking brake anyways.

You'll have to scroll to the top of this page to find the finished product.