Re-Rebuilding the 440-493 in a 1970 Charger

[1 Wild R/T]

Your turn the piston in to retract it for new pads, generally trying to turn it out doesn't do much because there's a one way sprag built into the piston... pushing it out is typically accomplished by repeated application of the parking brake and the normal brake.... The piston has a inner hub with Acme threads, that attaches rotationally to the piston through a sprag but it directly applies thrust which is how the parking brakes are applied... The lever that the parking brake cable attaches to acts upon an acme thread screw that is inside the caliper...


I was gonna post pictures that show how it works but my old computer died & the new one is "different" I can't do nearly as much as I could before...

 

[Kern Dog]

That all sounds confusing.

 

[1 Wild R/T]

It's a complicated way to make parking brakes work & it can be a PITA to get the rear brakes working correctly because of it...
However the other common design with a little drum brake inside the rotor weighs quite a bit more

 

[Kern Dog]

I just watched a Youtube video on a rear brake overhaul of a 1999 Mustang. It is simpler than I thought.



I am missing a few parts that this guy had but I doubt that it would make the night and day difference that I'm looking for.
He had small stainless steel slider things that allow the brake pad tension springs to slide on. I don't recall ever seeing those when I got this kit. In fact, it seems that most everything from Dr Diff is a matter of "Figure it out for yourself". His prices and quality of parts are great but he isn't much for instructions or schematics. There are too many instances of vendors that are like this. I don't need my hand to be held on every step but to install something NON stock, a basic set of instructions would save some trouble. It isn't like this stuff is in the factory service manual. The Classic Auto Air instructions were better detailed but still generic in nature and they were vague in many areas. My Dakota Digital gauge setup was excellent. The instructions covered everything in great detail.

 

[Kern Dog]

I looked on a few sites in search of high performance replacement pads. Only Rock Auto showed pads that look like these.

These have the ears on the side and the wire tension springs on top.
The high performance ones I see elsewhere don’t have that spring.
These pads don’t look so good.

The edges are chipped and there are some cracks.

These look highly metallic to me. I’m guessing they are semi metallic.
From my limited knowledge of brake pads, these are supposed to be a good choice. I’m curious if a replacement set would be okay or if the aftermarket stuff from
hawk or EBC is worth the cost. I wish someone had this stuff in stock locally.
I hate ordering stuff, waiting for it then finding it is wrong when it arrives.

 

[1 Wild R/T]

1082 is the basic number for that pad, 2005-2011 Mustang rear Different companies use assorted numbers before & after to designate what lining grade it is but as long as it says 1082 it should be the right pad...

 

[Kern Dog]

1082 is the basic number for that pad, 2005-2011 Mustang rear Different companies use assorted numbers before & after to designate what lining grade it is but as long as it says 1082 it should be the right pad...

Cass wrote this....

"The kit uses '94-'04 Mustang Cobra brake calipers and pads. You can borrow the special tool to retract the rear pistons from a parts store like AutoZone."

Is that 1082 number in reference to a Ford factory replacement?

 

[1 Wild R/T]

Cass wrote this....

"The kit uses '94-'04 Mustang Cobra brake calipers and pads. You can borrow the special tool to retract the rear pistons from a parts store like AutoZone."

Is that 1082 number in reference to a Ford factory replacement?

I need to re-check the number, as I posted above that number is 2005-2001 which is what I thought you posted.... Be back shortly..

 

[Kern Dog]

It sure would be a strange thing to have something as simple as a crappy set of pads be responsible for the brakes never feeling great.

 

[Mopar Hunter]

I had good luck with ceramic pads.

 

[1 Wild R/T]

I still think the 1082 is the correct pad for that caliper...

1082 is an industry standard number, could fit a Cobra or a Cadilliac....

 

[padam]

I would replace those pads. I think semi metallic stop better than ceramic.
I like Wagner thermo quiet pads. However, my wife was going through them so fast the last time I did her minivan I used Wagner Severe Duty iirc. Those things stop! Seems like the braking force increases as you stop, but that may just be my impression. Now I have been driving on them for a couple years, they will last me a long time.
From what I’ve read, the really aggressive pads like Hawk will chew through the rotors in time.

 

[padam]

I should add that you should probably concentrate your efforts on the fronts, they should do most of the stopping.

 

[NoCar2023]

Wagner or Bendix - generic part number 627.

Greg, do you have an adjustable proportioning valve on the car?

 

[fesser]

Since there is adequate pressure, that seems to rule out anything upstream. These are the calipers in the back:

View attachment 1386127
Yeah… insert your FORD jokes here!

Well now you went and took all the fun out of it.
Seriously though, I am watching this to see how it ends. Better than Yellowstone.

 

[Kern Dog]

Wagner or Bendix - generic part number 627.

Greg, do you have an adjustable proportioning valve on the car?

There is no proportioning valve of any kind. The system is plumbed through this distribution block:

I suspected that the block could have been causing a flow restriction to the rear but the high pressure I measured proved me wrong there.
Now I'm looking at the brake pads being to blame. I'm unsure of how to proceed. There are some aftermarket brake pad companies that sell "high performance" compounds.
The Raybestos pads on my 2007 Ram 1500 have been really impressive and they are just stock replacement. They are the best that I have had. Even the OEM Mopar pads weren't this good. I wonder if a premium Raybestos set would be a step up from what I have now.

 

[NoCar2023]

Raybestos SP627XPH Raybestos Specialty Performance Brake Pads | Summit Racing
I would also add an adjustable proportioning valve.

Summit Racing SUM-G3905 Summit Racing™ Adjustable Brake Proportioning Valves | Summit Racing

Free Shipping - Summit Racing™ Adjustable Brake Proportioning Valves with qualifying orders of $99. Shop Brake Proportioning Valves and Distribution Blocks at Summit Racing.

www.summitracing.com

 

[Kern Dog]

I don't see the need for a proportioning valve when the rear brakes are not locking. I can get the fronts to skid but so far, the rear will not.
I just bought these:

The local NAPA store had these as their "premium" pads for this caliper. Hybrid of semi-metallic and carbon metallic for superior braking with less dusting.

Hardware kit....

I learned not too long ago that these calipers have pistons that have to be screwed back in instead of squished back in with a C clamp.

To rotate the piston, you can rent a tool or use a "cube" like this:

It has multiple patterns to fit many models. 3/8" drive so any common extension can be used. This is weird.
The NAPA guy said if I don't like the pads, he will refund the cash.
If the pads work 15-20% better than the existing ones, I'd be happy with that. IF I get the rear brakes to skid before the fronts, the addition of an inline proportioning valve will be needed.

 

[64fury74charger]

I don't see the need for a proportioning valve when the rear brakes are not locking. I can get the fronts to skid but so far, the rear will not.
I just bought these:

View attachment 1386667View attachment 1386668

The local NAPA store had these as their "premium" pads for this caliper. Hybrid of semi-metallic and carbon metallic for superior braking with less dusting.

View attachment 1386670

Hardware kit....
View attachment 1386671

I learned not too long ago that these calipers have pistons that have to be screwed back in instead of squished back in with a C clamp.

View attachment 1386675

To rotate the piston, you can rent a tool or use a "cube" like this:

View attachment 1386672

It has multiple patterns to fit many models. 3/8" drive so any common extension can be used. This is weird.
The NAPA guy said if I don't like the pads, he will refund the cash.
If the pads work 15-20% better than the existing ones, I'd be happy with that. IF I get the rear brakes to skid before the fronts, the addition of an inline proportioning valve will be needed.

That little square has been a very useful tool for many years in my toolbox. Gets the job done in tight spaces.

 

[fesser]

I don't see the need for a proportioning valve when the rear brakes are not locking. I can get the fronts to skid but so far, the rear will not.

Not being any kind of brake expert, I have to ask... Wouldn't being able to lock the fronts be an indicator that they are getting more than enough pressure, and not being able to lock the backs be an indicator that they are not getting enough. I would think being able to distribute some excess from the fronts to the rears, via a proportioning valve, might be worth playing with. Seems like the MC is making a fixed amount of pressure and you are tasked with trying to distribute it exactly where you need it.