70 Challenger brake caliper problems

[moparleo]

Take some photos of the complete caliper, bracket set up. What are the casting numbers on the original calipers ?
Fill through the hose hole with a penetrant like WD or PB Blast or whatever you like. Let it sit at least 24 hours caliper face down.
Use a C-clamp and an old brake pad to compress the piston. Once you get the piston to move, remove the clamp. Put the pad on the outside and stuff rags etc... between the piston and the pad. Using an air hose nozzle, apply air to the brake hose opening to force the piston out of the caliper. Keep your hands/fingers out of the area.

 

[Wags70ss]

Here's the casting number. I'm getting remans from NAPA tomorrow. If they are actually remans, they should fit. If they do, I'll have to turn in the old ones for the core charge. I won't be able to work on it over the weekend, so I'll let you know next week what I figure out.

 

[Wags70ss]

The originals still had brake fluid in them. I doubt penetrating oil would do much.

 

[moparleo]

Drain the brake fluid out. You wouldn't use brake fluid to loosen a rusty bolt, it is chemically nothing like a penetrating oil.
DOT 3 brake fluid is glycol( alcohol) based.
Because brake fluid absorbs water, the brake lines( metal and rubber), master cylinder, wheel cylinders and calipers will all corrode from the inside out. If the fluid hasn't been changed in over 5 years, for safety the entire hydraulics in the brake system should be serviced ( read replaced ) New calipers, brake hoses, steel lines, master cylinder, wheel cylinders should all be replaced. The proportioning valve can sometimes be rebuilt. But you can count on the system being full of rust/water/corrosion.
Brake fluid should be changed just like any other fluid on a regular basis.
Every 3-5 years , always with brand new from a sealed container. Once you pen a bottle of brake fluid it starts to absorb moisture from the air.
Here is some good info on the different types of brake fluid from a major, quality brake system manufacturer.
https://centricparts.com/getmedia/2...Centric-White-Paper-D5-Brake-Fluid-Basics.pdf
https://centricparts.com/getmedia/a...nical_Whitepaper_D1-Brake-Fluid-1A_8-2018.pdf

 

[hemi71x]

Here's the casting number. I'm getting remans from NAPA tomorrow. If they are actually remans, they should fit. If they do, I'll have to turn in the old ones for the core charge. I won't be able to work on it over the weekend, so I'll let you know next week what I figure out.

What you have are known as "WIDE MOUTH" Calipers.
They were a one year only design like that on the caliper body.
The 1971 up E body, and later years Kelsey Hayes, single piston caliper used somewhat of a different design body caliper.
Those Wide Mouth calipers are extremely hard to find in this modern day and age.
DO NOT turn them in as cores at your parts store.
Eat the core charge and keep those calipers, and sell them here on this forum.
They are worth BIG BUCKS, $$$$$$$$, to the restorer, and person that knows what they are.
You want to know what i sold a rebuilt pair of those wide mouth calipers at, write me a pm message and we can have a conversation with one another.
Jim V.
hemi71x

 

[hemi71x]

Ya I always do that. Problem is that I can't get the pistons out of them. I even put heat on them with my torch and they won't break loose.

Wow, sounds like the pistons are really stuck in their bores, even putting the flame wrench to the calipers.
I have used this method in getting stuck pistons out, and so far have gotten every one out, that i attempted.
Pumping them out with chassis grease using a grease gun that will build up lots of pressure behind the piston, forcing the piston out of the bore.
I block the hose fitting threads off with a bolt, and i use a grease fitting screwed into a flare nut fitting where the bleeder screw would go in the caliper.
Then pump away, with the grease gun, building up hydraulic pressure, and before you know it, the caliper piston brakes free, and the piston is on the way out of the bore.
Has never failed me, but maybe, i haven't run across a pair of calipers that have been sitting on the ground for the past 30 + years or so.
Give it a try, you don't have anything to loose.
Jim V.
hemi71x

 

[hemi71x]

In all the years that i have been messing around with Mopar brakes, and suspension systems, i have run across this only two times in my lifetime, working on these cars, and parts.
Come to find out there are some differences in machining of the caliper mount brackets that mount the caliper to the bracket, and the bracket to the spindle.
Hard to explain here in print, but i have found out that some caliper castings, are machined with a "flat" area to them, and others are just cast with a taper to them that didn't require machining.
So one time i was mix matching rebuilt calipers, with caliper mounts that i had on hand.
Couldn't figure out why i was having difficulty mounting calipers to the mounts.
Had to drag out all my spare parts out of storage, and lay parts down, side by side to figure it all out.
So sometimes mix matching calipers, caliper mounts, that didn't come as a mate to one another, you might have an issue.
I worked on the replacement calipers mounting area to get them to fit, and work.
But what are the odds that it's going to happen to you?
Ran across this issue one other time, but then, i knew what to look for, so i got that corrected, quick.

 

[moparlee]

Here she is, running after 42 years! Now if I can just get the damn brakes fixed!

Wow, look at that VIN number. Never seen one with so many 9's

 

[Challenger RTA]

Wow, look at that VIN number. Never seen one with so many 9's

Nein! Nether have I.

 

[Wags70ss]

So, I received my "remanufactured" calipers. One is the same as all the others (won't fit) , the other one is some weird caliper not even close to mine, that's boxed wrong!

 

[Wags70ss]

Ok, so I have super rare "wide mouth" calipers. Apparently they don't exist, and when they do, they are hundreds of dollars.

1.Where can I find new pistons for them?

2.Do they take a special rebuild kit?

3.Where can I find bolt bushings for them?

 

[Wags70ss]

Next question.... Can I change it over to the more common design? How complicated is that?

 

[Wags70ss]

In all the years that i have been messing around with Mopar brakes, and suspension systems, i have run across this only two times in my lifetime, working on these cars, and parts.
Come to find out there are some differences in machining of the caliper mount brackets that mount the caliper to the bracket, and the bracket to the spindle.
Hard to explain here in print, but i have found out that some caliper castings, are machined with a "flat" area to them, and others are just cast with a taper to them that didn't require machining.
So one time i was mix matching rebuilt calipers, with caliper mounts that i had on hand.
Couldn't figure out why i was having difficulty mounting calipers to the mounts.
Had to drag out all my spare parts out of storage, and lay parts down, side by side to figure it all out.
So sometimes mix matching calipers, caliper mounts, that didn't come as a mate to one another, you might have an issue.
I worked on the replacement calipers mounting area to get them to fit, and work.
But what are the odds that it's going to happen to you?
Ran across this issue one other time, but then, i knew what to look for, so i got that corrected, quick.

So you used a grinder to cut the replacement caliper down to fit? I thought about that, but didn't want to destroy brand new calipers.

 

[Wags70ss]

Here's one of the calipers from NAPA.... obviously boxed wrong.

 

[hemi71x]

So you used a grinder to cut the replacement caliper down to fit? I thought about that, but didn't want to destroy brand new calipers.

You don't "destroy" them, but modify them to fit and work properly, around the caliper mounting area.

 

[Challenger RTA]

Here's some info.

 

[ted s]

napa ones correct?

 

[Wags70ss]

napa ones correct?

Look at the picture!

 

[Wags70ss]

You don't "destroy" them, but modify them to fit and work properly, around the caliper mounting area.

Yes I understand that. I assume you grind metal off them until they fit the caliper brackets?

 

[Wags70ss]

Does anyone have any of the brackets that will fit the more common calipers? Do I need to change the rotors as well?