68 Charger Disc / Drum conversion done - A couple problems/questions regarding distribution/proportioning

[Indetrucks]

Hi fam,
I recently picked up a 68 Charger with power drums all around and decided to install front discs on it from Pirate Jack.

The previous owner had already installed this Inline Tube distribution block, description says it's good for either disc or drum.
-Can I leave it installed to go along with my newly installed disc brakes?
-Am I correct in assuming it's only a distribution block and NOT also a proportioning valve? (the eBay listing for this block also says proportioning valve in the title)

I completed the front disc brake job, bled the Master Cylinder prior to install and bleed all 4 corners in the correct order. However, I did not yet install the provided proportioning valve.
The brake pedal feels very soft and almost goes to the floor. It feels unsafe to drive IMO. When on the rack and in gear, the rear drums lock up with very little pedal pressure. Also worth noting, when I bled the brakes with the someone in the car providing the pump/hold method, the rear brake reservoir on the master aggressively shoots brake fluid out the top unless the pedal was pressed ever so slowly. I had to keep the cap on the bleed the system.

Last questions:
-Will installing the provided rear proportioning valve AFTER the distribution block fix my soft pedal/rear drums locking up?
-Is there a better solution or combination distribution block/proportioning valve combo I should be using?
-What is a "hold off valve" and do I need one? Inline tube mentions using this or this rear hold off valve with their distribution block I currently have installed.

I was going to install the proportioning valve today, but won't if the experts say otherwise.
Thank you! I appreciate your time and opinion on this Sunday morning

 

[Sixpactogo]

Hi fam,
I recently picked up a 68 Charger with drums all around and decided to install front discs on it from Pirate Jack.

The previous owner had already installed this Inline Tube distribution block, description says it's good for either disc or drum.
-Can I leave it installed to go along with my newly installed disc brakes?
-Am I correct in assuming it's only a distribution block and NOT also a proportioning valve? (the eBay listing for this block also says proportioning valve in the title)

I completed the front disc brake job, bled the Master Cylinder prior to install and bleed all 4 corners in the correct order. However, I did not yet install the provided proportioning valve.
The brake pedal feels very soft and almost goes to the floor. It feels unsafe to drive IMO. When on the rack and in gear, the rear drums lock up with very little pedal pressure. Also worth noting, when I bled the brakes with the someone in the car providing the pump/hold method, the rear brake reservoir on the master aggressively shoots brake fluid out the top unless the pedal was pressed ever so slowly. I had to keep the cap on the bleed the system.

Last questions:
-Will installing the provided rear proportioning valve AFTER the distribution block fix my soft pedal/rear drums locking up?
-Is there a better solution or combination distribution block/proportioning valve combo I should be using?
-What is a "hold off valve" and do I need one? Inline tube mentions using this or this rear hold off valve with their distribution block I currently have installed.

I was going to install the proportioning valve today, but won't if the experts say otherwise.
Thank you! I appreciate your time and opinion on this Sunday morning

For sure you need to have the master cylinder cover on and secure before pushing the pedal down. I guess you already learned that. As for the the distribution block, I believe a distribution block is just that. It supplies the same pressure to the front and back. A proportioning valve has an orifice that sends less pressure to the rear because disc's require almost double the pressure.
IMO, the first thing to do is install that proportioning valve
The question I have is whether you have manual or power brakes?
If your car had power brakes, it had a single diaphragm booster. You would need to upgrade to a dual diaphragm booster.

 

[Don Frelier]

Aaargh!

 

[Indetrucks]

The question I have is whether you have manual or power brakes?
If your car had power brakes, it had a single diaphragm booster. You would need to upgrade to a dual diaphragm booster.

The car came originally with power drum brakes and the new disc kit came with a new dual Bendix style power booster

 

[Sixpactogo]

Hopefully when you get that Prop valve on you will be golden.

 

[Indetrucks]

Prop valve in, brake pedal still soft and going to the floor. Bled the master, no bubbles and bled the brakes multiple times, no air. The car DOES stop and will lock up the brakes, but the pedal is literally on the floor.

Do I need to delete the Distribution Block that the previous owner installed back when it had drums all around?

 

[Bird 426]

Bad master cyl? Sounds like something is going somewhere, no fluid loss?

 

[Indetrucks]

No fluid loss.
Perhaps I need to delete the distribution block and put a metering valve in its place?

 

[Krooser]

My experience is that those Chinese prop valves are junk...

 

[Sixpactogo]

Prop valve in, brake pedal still soft and going to the floor. Bled the master, no bubbles and bled the brakes multiple times, no air. The car DOES stop and will lock up the brakes, but the pedal is literally on the floor.

Do I need to delete the Distribution Block that the previous owner installed back when it had drums all around?

So.......Is this to say you have both the proportioning valve and the distribution block installed? Disc brakes require almost double the pressure compared to drum brakes. That is the reason for replacing the distribution block with a Prop valve. It reduces the pressure to the rear brakes so as not to lock them up during normal braking.

 

[Indetrucks]

So.......Is this to say you have both the proportioning valve and the distribution block installed? Disc brakes require almost double the pressure compared to drum brakes. That is the reason for replacing the distribution block with a Prop valve. It reduces the pressure to the rear brakes so as not to lock them up during normal braking.

Ye, they are both installed. Should I remove the distribution block and just run the rear prop valve?

 

[Sixpactogo]

Ye, they are both installed. Should I remove the distribution block and just run the rear prop valve?

Yes

 

[Mackman]

I finally solved my similar issues by installing a Wilwood adjustable proportioning valve in the rear brake line before the provided prop/dist. valve/block.

 

[Sixpactogo]

Ye, they are both installed. Should I remove the distribution block and just run the rear prop valve?

I would be interested in seeing how you plumbed both of those in. Got any pictures?

 

[Indetrucks]

I would be interested in seeing how you plumbed both of those in. Got any pictures?

I do not and I just had surgery, so it will be hard to provide in the near term.
But it's very basic, both lines out of the dual master going in to the dist. block. From the block, front two lines to l/r front calipers and rear line from the dist. block goes to prop. valve and then to the rear T-splitter

 

[Sixpactogo]

My guess is that would more than likely cause your soft spongy pedal. Good luck getting it and yourself healed up.