Gimmie a Brake HELP

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macman340

macman340

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Ok MoPar people need your help, swapped the 7 1/4 for an 8 3/4 & added new BBP Nitro aftermarket axles, I had to drill out the the stud holes to accommodate the larger studs and hog out the centers to fit over top of the new axle centers.
The end result is I'm about an inch out from covering the shoes ???
So what drums am I looking for & they will be underneath 14" Rallye wheels!
Thanks

IMG_1009 (1).JPG


C10023A7-9822-48D3-9053-C7A6A6D18C47.jpeg


7DC91A10-2062-44E5-9027-98B0D8BC7185.jpeg
 
Are those axles intended for use with A body brakes? Are they original a body brakes? I believe the a body brakes are narrower and your axles are intended for b c or e body brakes.

Call Cass at dr. Diff. He will talk you through it.
 
d55dave said:
Are those axles intended for use with A body brakes? Are they original a body brakes? I believe the a body brakes are narrower and your axles are intended for b c or e body brakes.

Call Cass at dr. Diff. He will talk you through it.
Click to expand...
Thanks
after further investigation under the axles site states
"Tech Note:
These 'A body' axles are meant to be used with 'B body' brakes, OEM 'A body' brakes will not fit.

So guess I'm taking everything apart & starting over! any chance the pads and guts are the same???
 
macman340 said:
Thanks
after further investigation under the axles site states
"Tech Note:
These 'A body' axles are meant to be used with 'B body' brakes, OEM 'A body' brakes will not fit.

So guess I'm taking everything apart & starting over! any chance the pads and guts are the same???
Click to expand...
No, I dont think so. With these axles your wheels are going to be farther outboard as well. Check your fender to tire clearance.....
 
The OE '72 & down 10" shoes were 1.75" wide, all the other 10" shoes including '73 and up A-bodies are 2.5" wide. Looking at that pic, You may get away with just getting
the 10X2.5 drums and installing them, You would just have less swept area than the drums were capable of. The backing plates & shoes for 10X2.5's should be easy to come
up with. They were used a lot & forever................................Yeah I'd check the tire to quarter lip for sure, if They've added that much to the axle length.........
 
The axle flange offset is different between the small bolt pattern A-body brakes and the large bolt pattern 10x2.5’s. You can’t interchange backing plates or drums. If you have axles intended for BBP brakes, you can’t use SBP backing plates with bbp drums, the offset on the backing plate is different.
 
Yeah Yeah, I know, just the same looking at that pic I'd find a used drum & slip it on and see how much it's off. If it were close and You could lathe the edge back some at
least You could move the damn thing around while You find, bead-blast & paint/powdercoat the new stuff. I'm guessing w/o looking them up, but those axles use green
style bearings huh?
 
Killer6 said:
Yeah Yeah, I know, just the same looking at that pic I'd find a used drum & slip it on and see how much it's off. If it were close and You could lathe the edge back some at
least You could move the damn thing around while You find, bead-blast & paint/powdercoat the new stuff. I'm guessing w/o looking them up, but those axles use green
style bearings huh?
Click to expand...

Yeah, if you “knew” you’d realize it’s not even going to be close.

The offset on the backing plates is different by a half inch. But it’s not in the right direction. The SBP plates are a 1/2” shallower than the BBP plates. And the BBP drums are 3/4” deeper. The BBP axle flange is only about 5/16” further out. So, how much are you going to turn off those brake drums?

Here’s your backing plate measurements
Converting rear drum brakes from SBP to BBP

And your axle flange offset
C787B1ED-8B06-416E-BB14-DD73E4A4BBFE.jpeg
 
72bluNblu said:
The axle flange offset is different between the small bolt pattern A-body brakes and the large bolt pattern 10x2.5’s. You can’t interchange backing plates or drums. If you have axles intended for BBP brakes, you can’t use SBP backing plates with bbp drums, the offset on the backing plate is different.
Click to expand...

A little lost in translation, the original axles were BBP, not sure the donor car!
 
72bluNblu said:
Yeah, if you “knew” you’d realize it’s not even going to be close.

The offset on the backing plates is different by a half inch. But it’s not in the right direction. The SBP plates are a 1/2” shallower than the BBP plates. And the BBP drums are 3/4” deeper. The BBP axle flange is only about 5/16” further out. So, how much are you going to turn off those brake drums?

Here’s your backing plate measurements
Converting rear drum brakes from SBP to BBP

And your axle flange offset
View attachment 1715144028
Click to expand...
Homework,Homework,Homework, this was an original BBP setup but one of the backing plates was damaged, so not knowing the difference I purchased a set off a fellow FABO member cleaned them up all new hardware and presto there not the right ones!

So to making things totally clear/fuzzy with the right BBP A body backing plates should/will fit the original BBP drums I just spent hours on, or just start over and get the B body set??
 
Killer6 said:
Yeah Yeah, I know, just the same looking at that pic I'd find a used drum & slip it on and see how much it's off. If it were close and You could lathe the edge back some at
least You could move the damn thing around while You find, bead-blast & paint/powdercoat the new stuff. I'm guessing w/o looking them up, but those axles use green
style bearings huh?
Click to expand...

Yes green bearing setup AXC8.75-28.0
 
macman340 said:
Homework,Homework,Homework, this was an original BBP setup but one of the backing plates was damaged, so not knowing the difference I purchased a set off a fellow FABO member cleaned them up all new hardware and presto there not the right ones!

So to making things totally clear/fuzzy with the right BBP A body backing plates should/will fit the original BBP drums I just spent hours on, or just start over and get the B body set??
Click to expand...

All BBP backing plates for a given size are the same. All the 10" BBP brakes are 10x2.5", it doesn't matter if they were for an A-body, B-body, E-body, FMJ, whatever. They're all the same.

I'm not entirely sure what all of your current parts are, although it's clear you have some SBP brake parts in there. What you need to do is pull the backing plates you have and measure them using the process I outlined here, making sure that the "bumps" for the e-brake cables aren't holding the plate up. Converting rear drum brakes from SBP to BBP

Then you'll know for certain what plates you have. You already have BBP axles, so, there's no way you're going to make SBP brake components work. None. So you need to get a set of BBP brakes, and that means 10x2.5" drums, 10x2.5" shoes, and backing plates with the correct offset. The hardware you can re-use, but that's it (brake spreader bars, springs, e-brake levers and hardware, etc).
 
Last edited:
72bluNblu said:
Yeah, if you “knew” you’d realize it’s not even going to be close.

The offset on the backing plates is different by a half inch. But it’s not in the right direction. The SBP plates are a 1/2” shallower than the BBP plates. And the BBP drums are 3/4” deeper. The BBP axle flange is only about 5/16” further out. So, how much are you going to turn off those brake drums?

Here’s your backing plate measurements
Converting rear drum brakes from SBP to BBP

And your axle flange offset
View attachment 1715144028
Click to expand...
What I know is what I see in the above pic. I agree with what You've got there spec-wise, but what I see is a piss-load more than 5/16" of exposed shoe, and the angle
is actually hiding more unseen. Me-thinks there is something like 2.5" backing plates on there...........If it was simply a matter of axle offset, there would be almost no
shoe visible because the "extra" surface beyond the inner lining edges would cover most of that 5/16"
 
Killer6 said:
What I know is what I see in the above pic. I agree with what You've got there spec-wise, but what I see is a piss-load more than 5/16" of exposed shoe, and the angle
is actually hiding more unseen. Me-thinks there is something like 2.5" backing plates on there...........If it was simply a matter of axle offset, there would be almost no
shoe visible because the "extra" surface beyond the inner lining edges would cover most of that 5/16"
Click to expand...

It doesn’t matter.

We know he has BBP axles. You can clearly see in the picture that those are SBP drums that had the lug holes hogged out to fit on the BBP axles, same for the center register.The OP even told us that’s exactly what he did.

So, we’ve already got mismatched parts. Are the backing plates SBP or BBP? I honestly don’t know, which is why I told him to measure them. The space showing past the drum in the picture is meaningless with the info we have now.

No mismatch of SBP and BBP parts is going to work properly. Anyone that takes a lathe to drums to make some random, unknown mismatch of brake parts fit together instead of buying/finding the right parts is an idiot. The right parts will fit without modification, they’re not hard to find or terribly expensive, and they’re the most important piece of safety equipment on the car.
 
72bluNblu said:
It doesn’t matter.

We know he has BBP axles. You can clearly see in the picture that those are SBP drums that had the lug holes hogged out to fit on the BBP axles, same for the center register.The OP even told us that’s exactly what he did.

So, we’ve already got mismatched parts. Are the backing plates SBP or BBP? I honestly don’t know, which is why I told him to measure them. The space showing past the drum in the picture is meaningless with the info we have now.

No mismatch of SBP and BBP parts is going to work properly. Anyone that takes a lathe to drums to make some random, unknown mismatch of brake parts fit together instead of buying/finding the right parts is an idiot. The right parts will fit without modification, they’re not hard to find or terribly expensive, and they’re the most important piece of safety equipment on the car.
Click to expand...
They are ONLY the brakes!!!!:rofl:
 
72bluNblu said:
It doesn’t matter.

We know he has BBP axles. You can clearly see in the picture that those are SBP drums that had the lug holes hogged out to fit on the BBP axles, same for the center register.The OP even told us that’s exactly what he did.

So, we’ve already got mismatched parts. Are the backing plates SBP or BBP? I honestly don’t know, which is why I told him to measure them. The space showing past the drum in the picture is meaningless with the info we have now.

No mismatch of SBP and BBP parts is going to work properly. Anyone that takes a lathe to drums to make some random, unknown mismatch of brake parts fit together instead of buying/finding the right parts is an idiot. The right parts will fit without modification, they’re not hard to find or terribly expensive, and they’re the most important piece of safety equipment on the car.
Click to expand...


Will 11x2 1/2 fit with my 14" ralley's
WTB - 10x2.5 Drums & backing plates
 
macman340 said:
Will 11x2 1/2 fit with my 14" ralley's
WTB - 10x2.5 Drums & backing plates
Click to expand...

Well, I have a set of factory 14” road wheels on a set of 11x2.5” brakes with the finned style drums, but I don’t know specifically about 14” rallye’s.

The outside diameter on the finned drums is 13.62” at the widest part. The 14” rims I have on there are pretty narrow, they’re just a set of rollers for me, so it’s possible a wider rim with more backspace might not work. You’ll have to measure the inside clearance on those 14’s.
 
yes 11x2 1/2 drums from the b or c body cars work with 14'' rim centers , you must have the brake backing plates as well . just did it on a dart for a customer . we repatterned the drums , do to him ordering the r/e with the 4''bp . and we had to turn the rim reg hub on the axles to fit his 4'' bp rims and left a small thickness of reg for the drums . you will not need that done .
DSC00089.JPG
DSC00029.JPG
 
pomonamissel said:
yes 11x2 1/2 drums from the b or c body cars work with 14'' rim centers , you must have the brake backing plates as well . just did it on a dart for a customer . we repatterned the drums , do to him ordering the r/e with the 4''bp . and we had to turn the rim reg hub on the axles to fit his 4'' bp rims and left a small thickness of reg for the drums . you will not need that done . View attachment 1715144863 View attachment 1715144864
Click to expand...

He ordered axles with the big bolt pattern axle flange offset, but the 5x4” bolt pattern?

That’s...different.
 
macman340 said:
Will 11x2 1/2 fit with my 14" ralley's
WTB - 10x2.5 Drums & backing plates
Click to expand...
The 11x2.5" drums fins & all will clear standard 14x5.5" Rallye's with room to spare. There is room for more backspacing if You have custom width items, but it would be
really tight to the fins, I can't say whether it would affect heat dissipation negatively or not.
Couple of questions;
1) What width shoes did You install, 1.75", or 2.5"?
2) Is this drum to backing plate gap identical on both sides right now?
3) You stated "The original axles were BigBoltPattern, not sure about the donor car", and "this was an original BigBoltPattern setup, but one of the backing plates was
damaged". Where are the drums that were on it to begin with? or did You purchase the 8.75 sans drums/brakes/hardware?
My observation, You probably just need A) the right shoes if they're not the 2.5" ones(they appear seated, square, and the w/cyl. struts look straight?),& B) 2.5" drums.
 
Killer6 said:
The 11x2.5" drums fins & all will clear standard 14x5.5" Rallye's with room to spare. There is room for more backspacing if You have custom width items, but it would be
really tight to the fins, I can't say whether it would affect heat dissipation negatively or not.
Couple of questions;
1) What width shoes did You install, 1.75", or 2.5"?
2) Is this drum to backing plate gap identical on both sides right now?
3) You stated "The original axles were BigBoltPattern, not sure about the donor car", and "this was an original BigBoltPattern setup, but one of the backing plates was
damaged". Where are the drums that were on it to begin with? or did You purchase the 8.75 sans drums/brakes/hardware?
My observation, You probably just need A) the right shoes if they're not the 2.5" ones(they appear seated, square, and the w/cyl. struts look straight?),& B) 2.5" drums.
Click to expand...
 
Killer6 said:
The 11x2.5" drums fins & all will clear standard 14x5.5" Rallye's with room to spare. There is room for more backspacing if You have custom width items, but it would be
really tight to the fins, I can't say whether it would affect heat dissipation negatively or not.
Couple of questions;
1) What width shoes did You install, 1.75", or 2.5"?
2) Is this drum to backing plate gap identical on both sides right now?
3) You stated "The original axles were BigBoltPattern, not sure about the donor car", and "this was an original BigBoltPattern setup, but one of the backing plates was
damaged". Where are the drums that were on it to begin with? or did You purchase the 8.75 sans drums/brakes/hardware?
My observation, You probably just need A) the right shoes if they're not the 2.5" ones(they appear seated, square, and the w/cyl. struts look straight?),& B) 2.5" drums.
Click to expand...


Different backing plates are on the way!& ordering the drums from Rockauto, will my new wheel cylinders I all ready have have work with the 2.5 shoes / Brakes or do I need all new hardware!
Thanks
 
Thanks everyone that helped here at FABO, the new backing plates did the trick, all back together & hopefully ready to roll!

IMG_0509.JPG
 
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