70 Newport Disc Conversion Plumbing

[smiles16]

Looking for advice.

I am getting ready to convert my 1970 Newport (factory power drum) to disc brake.
I bought the parts shown in the pic including the single piece cast iron combination valve.
I'm reading some conflicting information online.
DO I EVEN NEED TO INSTALL THIS?
Several, including "The Ram Man", have stated it is completely unnecessary and you can run the factory drum plumbing between the master cylinder and the rubber lines.

Can others with some real world experience please shed some light on this?

 

[3C's & a D?]

I would replace the original lines with new ones even if the old ones would fit. They're 50+ years old now. Brake fluid absorbs moisture and the lines rust from the inside out. I had to "panic" stop my '71 Newport custom one time. The line from the master to
distribution block split a crack about an inch long parallel to the line, spraying the engine compartment with brake fluid and losing front brakes. Luckily the distribution block did its job, and the rear brakes were just enough to prevent disaster. You're already doing quite a bit of work, whats a little more?

 

[MONC440]

I would use the combination valve if it were me. Is it 100% required, no but the factory used them for a reason. If they were not needed the factory would not have used them because they cost money.

 

[smiles16]

I would replace the original lines with new ones even if the old ones would fit. They're 50+ years old now. Brake fluid absorbs moisture and the lines rust from the inside out. I had to "panic" stop my '71 Newport custom one time. The line from the master to
distribution block split a crack about an inch long parallel to the line, spraying the engine compartment with brake fluid and losing front brakes. Luckily the distribution block did its job, and the rear brakes were just enough to prevent disaster. You're already doing quite a bit of work, whats a little more?

My lines are relatively new. The rubber hoses will be replaced though.

 

[smiles16]

@Big_John ?
You were very adamant in some other threads regarding using factory disc hardware in other posts. Do you have any input on this?

 

[Big_John]

@Big_John ?
You were very adamant in some other threads regarding using factory disc hardware in other posts. Do you have any input on this?

The '70 Chrysler with factory disc brakes doesn't have that combination valve. Instead it used a separate "metering valve" that helped balance the brakes front to back. My '70 300 has this.

So, because you don't have that metering valve, I think it would be a good idea to use the combination valve. It sure can't hurt.

Coincidently, while looking for something else, I happened upon this article on rebuilding the combo valve. Something to consider.
1970 - 1976 Mopar Combination Valve Rebuild | Muscle Car Research LLC

 

[Snotty]

When I converted my drums to disk on my '70 Newport, I used a valve off of a '71 New Yorker with factory disks. Have had no problems and the brakes work fine.

 

[smiles16]

When I converted my drums to disk on my '70 Newport, I used a valve off of a '71 New Yorker with factory disks. Have had no problems and the brakes work fine.

Was it the single piece combination valve?
Did you have to re-bend any lines?

 

[Snotty]

Was it the single piece combination valve?
Did you have to re-bend any lines?

Single piece, yes. No, the lines mated up with no problems.
I did need to replace the rubber brake lines to the disks from the ones I had purchased. Turned out, the disks I got were from '71, not '73. That made a difference in the parts I had purchased. Be sure of what you have.

 

[wyrmrider]

I would use the combination valve if it were me. Is it 100% required, no but the factory used them for a reason. If they were not needed the factory would not have used them because they cost money.

I converted my 69 polara to 73 NY front discs I had the power booster but never installed it, needed it even wife could use non power disc brakes
to stop the rear wheel slide I out smaller rear wheel cylinders or you could use an adjustable proportioning valve
I think I removed a check valve from the master cylinder but I do not remember but the need is widely available
drum brake master cylinder worked fine but check the smaller front reservoir I (compared to disc master) more often

with either drum or disc i had problem with fronts locking going down hill in snow so I just held the parking brake release up and used the parking brake for rear only so i kept my steering not going fast just steep with chains on rear

i did not do any thing about combination valve or change any plumbing except longer rear brake hoses and new fronts I had added an additional leaf in the rear, actually custom built a rear spring pack to stiffen without raising too much old springs were sagged,, SW springs too tall etc use full length plastic interlinners as zinc were worn out

 

[smiles16]

I got everything cleaned up and repainted. Booster and new master installed. Saving the combo valve for last.
Unfortunately, this will take longer because I found my upper control arm bushings shot and the dust boots torn on all the ball joints.
Going to rectify those issues before I slap the new spindles in.
Currently waiting for ball joint socket and parts.

 

[smiles16]

It's all back together and back on the road. I'd say the swap was worth it so far, but not gonna lie, getting that combo valve swapped in place of the original distribution block sucked. Ended up having to cut 4 of the 5 lines off and redo them. I did not rebuild the combo valve (5 port cast iron type), but I did run it through a few heated pinesol cycles in the ultrasonic followed by a heated evaporust ultrasonic cycle. Thing came out like new.
I also learned I had been driving the car with no rear brakes. The line had been cut and the rear port plugged. Looks like someone thought that was easier to do that instead of replacing the rear cylinders, but whatever. It's done now.
There's only one thing I left out, and not sure if I truly need, but I'll let you guys weigh in: Do you really need the Caliper Pin Positioner Clips???
In what I've found researching, Chrysler did away with them in the later Fuselage years while stull using KH brakes. My FSM for 1970 shows them, but my calipers and such were from a '72.
Seems to be functioning fine without them.
The anti rattle clip pulls the caliper back once you release the brake, and the bushings hold/guide the pins in place, so I'm struggling to see why Chrysler felt the need to use the positioner clips to begin with.

 

[smiles16]

Nobody answered the last post, but I did go ahead and buy a set. New pads rattled a bit when not applied, so figured this would solve it.

 

[3C's & a D?]

Nice that you got the job done! Sounds like it was a bit more involved than expected. No rear brakes? I hope that wasn't the reason for the swap.

Caliper pin positioner clips? I didn't realize they were called that. I thought they were anti rattle clips, which seemed strange because they usually wear out and start rattling. So I take them off with no issues. I always use the wire clip in the bottom picture.

 

[smiles16]

Nice that you got the job done! Sounds like it was a bit more involved than expected. No rear brakes? I hope that wasn't the reason for the swap.

Caliper pin positioner clips? I didn't realize they were called that. I thought they were anti rattle clips, which seemed strange because they usually wear out and start rattling. So I take them off with no issues. I always use the wire clip in the bottom picture.

That was not the reason for the swap. I needed new drums (out of round and one had a chunk out of the side) and shoes for the front anyway. Instead of spending the money to do that job right, I decided to just swap out the discs. I actually was unaware the rears weren't working. I just thought the fronts sucked that bad. I had pulled the rear drums off for inspection when I bought it and it looked as though they had been working, but I was obviously wrong.

I still haven't installed the pin clips yet. I'm not losing sleep over it. They rattle just enough at idle speed to make it sound "junky" and tick me off. It's on my to-do list.