Jarod340
Active Member
What's my issue.....please help I'm so lost at this point
Rear drums rubbing
- Thread starter Jarod340
- Start date
-
What's my issue.....please help I'm so lost at this point
Super-Cuda
MOPAR .. Move Over, Plymouth Approaching Rapidly!
Got a pic of the drums? Front and back side. Also, did you use the same backing plates that came with the rear end? Im thinking there is a difference in the 10" backing plates with the small bolt pattern and the 10" plates with the larger bolt circle.
Couple of possible issues-
1: You can't mix and match parts from the 10x1.75" brakes and the 10x2.5" brakes. Which also means, you can't use the 10x1.75" backing plates with BBP axles and the 10x2.5" brake set up. If you re-used your backing plates, that's the problem.
2: Moser sells axles that use the small bolt pattern axle flange offset, but that have the large 5x4.5" bolt pattern. Those axles are intended to be used with the 10x1.75" brakes, with the new 5x4.5" bolt pattern needing to be drilled on the OLD drums. They can not be used with the 10x2.5" brakes, because the axle flange offset is different between the SBP and BBP axles.
1: You can't mix and match parts from the 10x1.75" brakes and the 10x2.5" brakes. Which also means, you can't use the 10x1.75" backing plates with BBP axles and the 10x2.5" brake set up. If you re-used your backing plates, that's the problem.
2: Moser sells axles that use the small bolt pattern axle flange offset, but that have the large 5x4.5" bolt pattern. Those axles are intended to be used with the 10x1.75" brakes, with the new 5x4.5" bolt pattern needing to be drilled on the OLD drums. They can not be used with the 10x2.5" brakes, because the axle flange offset is different between the SBP and BBP axles.
Professor Fate
Push the button, Max...
There IS a difference. What did the backing plates come off of?
You can see in this picture the difference in the axle flange offset between the BBP and SBP axles. With factory axles it's easy to tell, all you need to know is the bolt pattern to identify the flange offset. If you re-drill factory SBP axles for the 5x4.5" pattern, you have to use your SBP 10x1.75" brakes and re-drill the drums. Simple. Moser messes that up a little, as I mentioned earlier, they make axles that have the SBP flange offset with the large bolt pattern. Because they're not re-drilled, they look like BBP axles. But the axle flange measurement is for a SBP axle. Those axles also MUST use SBP 10x1.75" brakes with re-drilled drums.
The axle flange offset means that the backing plates have a different offset from the end of the housing. You can measure this to determine which backing plates you have, if you aren't sure. It's a little hard to tell, but in this picture the bottom 1/3 of the backing plate is hanging off the bench. That's so the outer lip of the backing plate is flat on the bench. To do that you have to hang the bottom part of the backing plate that has the emergency brake "bumps" off the bench so the backing plate sits flat.
With the e-brake bumps off the bench and the outer lip of the backing plate flat, measure from the axle flange mount down to the bench. If you have a 10x2.5" backing plate, that measurement should be about 1.75". If you have a 10x1.75" backing plate, that measurement is more like 1.25". Not all tape measures are equal and not all backing plates and benches are flat, but that's a half inch difference so you should come up with something that's about an 1/8" from one of those measurements, which will tell you if you have the 10x1.75" SBP backing plate or the 10x2.5" BBP backing plate.
The axle flange offset means that the backing plates have a different offset from the end of the housing. You can measure this to determine which backing plates you have, if you aren't sure. It's a little hard to tell, but in this picture the bottom 1/3 of the backing plate is hanging off the bench. That's so the outer lip of the backing plate is flat on the bench. To do that you have to hang the bottom part of the backing plate that has the emergency brake "bumps" off the bench so the backing plate sits flat.
With the e-brake bumps off the bench and the outer lip of the backing plate flat, measure from the axle flange mount down to the bench. If you have a 10x2.5" backing plate, that measurement should be about 1.75". If you have a 10x1.75" backing plate, that measurement is more like 1.25". Not all tape measures are equal and not all backing plates and benches are flat, but that's a half inch difference so you should come up with something that's about an 1/8" from one of those measurements, which will tell you if you have the 10x1.75" SBP backing plate or the 10x2.5" BBP backing plate.
Last edited:
rustycowll69
Well-Known Member
when I did something similar to this about 50yrs ago, I got axles, complete backing plates and finned 11in drums from an early 70 wagon and sent the axles off to someplace in CA to have the axles shortened and resplined. It worked super slick.
Yup, one option is to use C-body or truck BBP axles and have them shortened. E-body, and some B-body BBP axles can’t be used because of the way the axle diameter changes over the length of the axle. Some of the axles from those body’s have the wrong diameter where the splines need to go for an A-body.
Although nowadays those axles aren’t super easy or cheap to find, and when you add in shipping costs you could easily spend almost as much or even more than the $300 you could buy a brand new set of axles from DoctorDiff for. And then you don’t have 50 year old axles either.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
- Joined
- Jan 19, 2014
- Messages
- 24,871
- Reaction score
- 12,218
You can figure out the degree of interference by installing washers on the studs between the drums and the flange, until the drum spins free. Then you can figure out what to do about it.
-
