How much resistance on front disc brakes

[jstaples2]

Update: The rear cylinder on the powered disc/drum MC is a larger diameter than the rear cylinder on the manual drum/drum MC, so swapping out the rear piston is a no-go. I called Cass at Dr. Diff today and he helped me get sorted out. Glad I called, he was a great help.

I'll update with pics once it shows up and I get it bolted on.

 

[Polara_500]

Hope you have it sorted out finally.

 

[70bigblockdodge]

Update: The rear cylinder on the powered disc/drum MC is a larger diameter than the rear cylinder on the manual drum/drum MC, so swapping out the rear piston is a no-go. I called Cass at Dr. Diff today and he helped me get sorted out. Glad I called, he was a great help.

I'll update with pics once it shows up and I get it bolted on.

That's good to know but I'm not sure across the board that holds true. The plug may be different with push rod hole but the pistons need to be the same or it will constantly light the brake light failure switch.

 

[jstaples2]

The new MC from Dr. Diff came in on Saturday and I bench bled it and installed this morning. Installation went fine and it bolted up nicely. I bled the brakes at all 4 tires but didn't realize I had the e-brake on. So I'll do that again tomorrow and give it a test drive.

 

[jstaples2]

The wife just let me know the brake lights were on. Looks like the brake pedal doesn't quite sit where it used to and the pedal doesn't engage the switch any more. Need to figure that out next.

 

[jstaples2]

Update:
Re-bled the brakes today and topped off the MC and took it for a test drive. What a difference. I get a nice, light pedal travel, and can bring the car to a stop quicker. I didn't try to lock up the brakes or anything, but did a series of quick stops and long slow downs. I'm happy.

The wife just let me know the brake lights were on. Looks like the brake pedal doesn't quite sit where it used to and the pedal doesn't engage the switch any more. Need to figure that out next.

I did find the brake light switch and bracket that mounts it. There's a bolt up under there and looks like it will allow me to adjust it down/up, but I think I'll need a 3rd elbow to get at it. I have a feeling that the bracket the new MC is mounted on dropped the brake pedal down an 1/16 of an inch causing the gap.

 

[twostick]

That'll do it. That bracket appears to be about 3/16 thick so it will space the MC out from the firewall and lower the brake pedal.

You could buy an adjustable push rod to raise the pedal back up or adjust the brake light switch down to hit the pedal in its new location.

Kevin

 

[Polara_500]

Good to hear it's on the track to drivable.

 

[65sporty]

I will have to ck out Dr. Diff, I wouldn't have thought to even look at a later model aluminum master cyl.

 

[fury fan]

i read somewhere just yesterday that mid 70s dodge trucks had manual disc/drum...i have no more info. someone here will know.

Old thread, but good info in it - should be a sticky!

I did a disc conversion on my 68 Fury using the original MBrake pedal, a MC from a mid-70s Dodge 1/2-ton with Manual Discs, just as mentioned above, and one of the combination valves from Inline or FineLines.

Worked like a charm, no pushrod issues, no adapter plate, and car stops A1. I like the feel and longer pedal travel of MBrakes, so this will be the parts combo I use on any future disc conversion.

And whomever said to not use that original brake shop again - BULLSEYE! What a rookie error to not install the proper MC!