Drums to discs, do brake lines need to be changed?

[JR_Charger]

Asking specifically for the 72 Charger. I'm sure the distribution block and rubber lines will need to change, but I haven't seen anything about changing the metal lines.

 

[1STMP]

You'll need more pressure going to
the pads which requires a smaller
bore master cylinder. Your brake
lines don't necessarily need to
to be changed if they're in good
condition.
Also, a dual diaphram booster is
recommend for a 4 disc system.
As a reference, my lines and hoses
are 1/8" I'd, MC bore is 1.031, dual
diaphram booster, 2lb residual check
valve in both line circuits.

 

[JR_Charger]

My brake lines are new. Haven't even finished putting it all together yet. I'll have to run drums for a while but will switch to discs later.

Surely the lines on the rear axle have to change, since they go straight to the wheel cylinder.

 

[1STMP]

My brake lines are new. Haven't even finished putting it all together yet. I'll have to run drums for a while but will switch to discs later.

Surely the lines on the rear axle have to change, since they go straight to the wheel cylinder.

Agreed, but changes will be minimal
as far as bending angles go.
Lengthening requires an in line
connector. Though this opens
the opportunity for more/future
leaks. Done right, no worries.
The entire line need not be replaced.
You're going to have hoses to the
calipers. Allow 2-1/2" to 3" travel.

 

[JR_Charger]

Travel? How can the calipers move in relation to the axle?

 

[Don Frelier]

Rear discs are kind of a waste.

 

[1STMP]

Travel? How can the calipers move in relation to the axle?

Suspension travel.

 

[JR_Charger]

Rear discs are kind of a waste.

Kind of - but in the same sense, styling a car is a waste too.

Suspension travel.
View attachment 1447374

That's not what my rear suspension looks like!

 

[RemCharger]

Travel? How can the calipers move in relation to the axle?

99% of newer vehicles have floating calipers. Hence the need for a flexible hose.
If you use a fixed caliper with pistons on each side then they could be straight steel line.

 

[1STMP]

Rear discs are kind of a waste.

Not really as far as maintenance goes.
Changing pads is half the work of
changing shoes, turning a rotor is
cheaper than turning a drum, less
brake fade equals better braking
performance, improved clamping force
when set up correctly. Easier dial in
with more definable finite adjustments.
Not to mention cost and availability
of replacement parts, and those of
the weight conscience.
Not only that, calipers
just look cool peeking out from
behind your wheel spokes.
Please understand. Not trying to
open up the great brake debate here.
Manufacturers designed brake
systems to meet the challenges of
the day. But technology has
advanced, which is why just about
every top producer of performance
vehicles run a 4 disc system.
Keep what you got as long as it's
working for your style of driving.

 

[Don Frelier]

Not really as far as maintenance goes.
Changing pads is half the work of
changing shoes, turning a rotor is
cheaper than turning a drum, less
brake fade equals better braking
performance, improved clamping force
when set up correctly. Easier dial in
with more definable finite adjustments.
Not to mention cost and availability
of replacement parts, and those of
the weight conscience.
Not only that, calipers
just look cool peeking out from
behind your wheel spokes.
Please understand. Not trying to
open up the great brake debate here.
Manufacturers designed brake
systems to meet the challenges of
the day. But technology has
advanced, which is why just about
every top producer of performance
vehicles run a 4 disc system.
Keep what you got as long as it's
working for your style of driving.

My experience is that rear shoes last 80-100,000 miles. And I've never had a drum go bad on a rear.
My Dakota has over 190k with original drums.
My son has a 98 ram 3/4 ton HD with 290k on it original drums in the rear.
My charger has full steel wheels so you wouldn't see the brakes any way.
And yes I'm not running any road courses.

 

[RT SE 440]

They still use drum brakes on semi trailers so can't be that bad

 

[JR_Charger]

Semis run tires until they blow too . . . "Cheap" could be a higher priority than "safe" and "effective."

 

[64plymouth]

I sold many sets of rear brakes & turned plenty of rear drums in my auto parts days. (1985-1998)

 

[RemCharger]

Semis run tires until they blow too . . . "Cheap" could be a higher priority than "safe" and "effective."

Can't comment on relation to blown tires, but on the brakes the terms I would use are " more than adequate " and " without expensive overkill/over thought"