Front drum to disc conversion

[71SatelliteSebring]

Good morning! I retired from the Air Force a few years ago and I'm finally getting a chance (now that I have a garage and the time) to revive/upgrade my first car.

It's a 1971 Satellite Sebring. The rear end has already been upgraded to an 8 3/4" with 11" drums. It still has the factory drums on front with no brake booster (manual). I was eyeballing the Wilwood setup that converts the drum to disc.

I am looking at part number 140-11020 which is the black 4 piston caliper and 11" rotor. I would also order the hose kit 220-8307. Additionally, I was looking at master cylinder 260-16854-BK (1" bore) or the 260-16791-BK (15/16" bore) which is the Mopar specific 4 bolt master cylinder with pushrod.

Note 1: I do not plan on adding a booster (leave it manual).
Note 2: My rear end is an 8 3/4" with 11" drums from a Road Runner. I plan on leaving it as is.

My questions are:
1. Do I necessarily need a proportioning valve? If I do need the proportioning valve I see that Wilwood offers some master cylinders with a proportioning valve as a kit which leads me into my second question.
2. What's the concensus on the bore size of the master cylinder....15/16" bore or 1" bore? Based on what I've read on other posts the 15/16" is what I'm leading toward. Again, I'd probably pick up the 4 bolt Mopar specific one from Wilwood.
3. Am I missing anything or failing to consider anything?
4. Off the wall question.....what is that black wire that goes to the threaded post on the brake distribution block?

Thanks for your input in advance.

 

[Timmayy]

Everything I've ever seen about drum to disc conversion with rear drums has needed the proper proportioning valve. I did the conversion on my 69 Dart years ago. No power booster and factory rear drums. I still needed the p-valve.

 

[Ray70Chrg]

First, Thank You for your service to our Country. Welcome to FBBO with your '71 Sat. I love those '71-'72 models. I'll let others chime in on your tech questions, and I'll be watching this thread because I plan on doing something similar.
Welcome from Arizona.

 

[Doorkicker]

HA! I just converted my 66 Charger (front) this past weekend and will be putting on the rears later this week.

I went with the 6 piston up front (140-10740-DR) with the 220-8307 hose kit. For the rear I'm going with 140-5591-DR.

There's a few things to make sure of... for the rears (assuming you're updating) - make sure you get the kit for the right bearings... there are up to three variations depending on the bearing you have in your 8 3/4.

The fronts are ridiculously easy to install. Wilwood really did their homework and their instructions are good. But I'm happy to share a few lessons learned, albeit they're minor.

As for master - I'm also manual. I'm not running a Wilwood master (not yet). I'll get you the part # for the master I have and the proportioning valve. Keep in mind... I rebuilt the entire brake system when I got the car about a year ago. All stock drums all the way around. I did replace the proportioning valve and the mater at that time, which was for drums, of course. But I'm not planning on changing for the disk conversion. I will revisit when I get a Wilwood master... but that's much later and if needed.

I've bedded the pads and everything is broken-in now and it stops on a dime. Pretty crazy how much the improvement is.

​

 

[71SatelliteSebring]

HA! I just converted my 66 Charger (front) this past weekend and will be putting on the rears later this week.

I went with the 6 piston up front (140-10740-DR) with the 220-8307 hose kit. For the rear I'm going with 140-5591-DR.

There's a few things to make sure of... for the rears (assuming you're updating) - make sure you get the kit for the right bearings... there are up to three variations depending on the bearing you have in your 8 3/4.

The fronts are ridiculously easy to install. Wilwood really did their homework and their instructions are good. But I'm happy to share a few lessons learned, albeit they're minor.

As for master - I'm also manual. I'm not running a Wilwood master (not yet). I'll get you the part # for the master I have and the proportioning valve. Keep in mind... I rebuilt the entire brake system when I got the car about a year ago. All stock drums all the way around. I did replace the proportioning valve and the mater at that time, which was for drums, of course. But I'm not planning on changing for the disk conversion. I will revisit when I get a Wilwood master... but that's much later and if needed.

I've bedded the pads and everything is broken-in now and it stops on a dime. Pretty crazy how much the improvement is.

​

So you're not running the Wilwood master yet. OK. I assume you're running a stock type disc master cylinder then? The part number for the master and proportioning valve would be cool. I'll be a happy camper when I get it upgraded.

 

[Big Bad Dad]

Do you have 14"wheels? Want to keep them? If so, many disc conversions require 15" wheels. Don't get an unpleasant surprise late in the process. But I recently did a conversion and kept my old 14" wheels by going with the Dr. Diff kit.

 

[71SatelliteSebring]

Do you have 14"wheels? Want to keep them? If so, many disc conversions require 15" wheels. Don't get an unpleasant surprise late in the process. But I recently did a conversion and kept my old 14" wheels by going with the Dr. Diff kit.

Currently running 14" Rallye wheels. Going to move to the 17" Year One Rallyes or 15" Weld Draglites. I appreciate the warning on wheels sizing. Yes, that would be a nasty surprise.

 

[Ron H]

Had some fun on the conversion on my ride; but this was elevated by adding power brakes compounded by other hassles with the kit I ordered that doesn’t sound like you should encounter. Yep, P valve is necessary. A ‘check for’ is the brake pedal position and travel. Make sure the ‘home’ position won’t bind against the brake light switch. On the other end is that the rod won’t stop by bottoming out in the MC. I’d doubt you should encounter any hassles with pedal ‘ratio’ since this becomes a thing when converting to power brakes from a manual system. Just my 2 pennies.

 

[Doorkicker]

So you're not running the Wilwood master yet. OK. I assume you're running a stock type disc master cylinder then? The part number for the master and proportioning valve would be cool. I'll be a happy camper when I get it upgraded.

Exactly, not yet. That's the next step after the rear disks are in, which is not as easy as the fronts, BTW. Also, the mater is a real pain to swap out... so want to plan that our perfectly before cramming up under the dash to chase those bolts - again. Yes... I had planned to move to disk eventually, so the master is a basic disk/drum option.

Here is the proportioning valve: 1967-70 Mopar B-body Distribution Block, Disc or Drum
This is my current master: 1967-70 A-Body Disc or Drum, 1967-70 B and C-Body, 1970 E-Body Drum Brake Factory Style Mopar Master Cylinder, 1

Yeah... just with the fronts on it's a completely different animal.

 

[Gus chiggins]

Everything I've ever seen about drum to disc conversion with rear drums has needed the proper proportioning valve. I did the conversion on my 69 Dart years ago. No power booster and factory rear drums. I still needed the p-valve.

Wouldn't hurt to use the 7/8 rear drum wheel cylinders instead of the 15/16 brake drum cylinders

 

[Timmayy]

Also, I used the stock master cylinder in my 69 Dart and it works fine.