Has anyone thought of custom machining a brake mouting flange?

[Double nickel]

is the backing plate flange and the bearing housing one piece or is the backing plate flange just a slip on over the axle tube?

 

[Captainfab]

No. I was talking about making the backing plate flange that is used with the 11" brakes on the 9.5" 14 bolt that could be welded to the 8.5" 10 bolt housing. I don't know if an 'adapter' could be made that would just be bolted to the existing flange on the 10 bolt. The bolt holes between the two are just too close to each other. Plus the difference in the brake offset needs to be considered as well. What about a disc brake conversion for the 8.5" 10 bolt? Or do most people prefer to stay with drums?

 

[Captainfab]

is the backing plate flange and the bearing housing one piece or is the backing plate flange just a slip on over the axle tube?

The backing plate flange is just welded to the axle tube at the correct location for the brake offset. The bearing is installed into the end of the axle tube that is machined for the bearing.

 

[Caman96]

No. I was talking about making the backing plate flange that is used with the 11" brakes on the 9.5" 14 bolt that could be welded to the 8.5" 10 bolt housing. I don't know if an 'adapter' could be made that would just be bolted to the existing flange on the 10 bolt. The bolt holes between the two are just too close to each other. Plus the difference in the brake offset needs to be considered as well. What about a disc brake conversion for the 8.5" 10 bolt? Or do most people prefer to stay with drums?

Yes, the bolt holes are too close and I doubt any adapter could work. It would have to be a new weld on flange. GM did produce this 8.5 axle with correct flange for 11” brakes for Suburbans. Why every 8.5 didn’t come like this was a mistake.

 

[Captainfab]

Yes, the bolt holes are too close and I doubt any adapter could work. It would have to be a new weld on flange. GM did produce this 8.5 axle with correct flange for 11” brakes for Suburbans. Why every 8.5 didn’t come like this was a mistake.

That is what I was offering to fabricate. A backing plate flange for the 11" backing plate that has a 3" center hole for the axle tube on the 8.5" 10 bolt

 

[Caman96]

That is what I was offering to fabricate. A backing plate flange for the 11" backing plate that has a 3" center hole for the axle tube on the 8.5" 10 bolt

Just a thought since you have experience with this stuff, but what about just re-drilling the backing plate itself, instead of reworking a flange? Even if the original 11” backing plate flange holes had to be filled somehow.

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[Orpedcrow]

Or even come up with a centering ring for the axle and a template for drilling the 11” backing plates?

 

[Caman96]

Or even come up with a centering ring for the axle and a template for drilling the 11” backing plates?

Yes, I’d thought of that too earlier. You’d need a .036 ring same thickness as backing plate. I wonder if that ring wouldn’t benefit with a slight “hat” type lip on it that faced inward.

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[Captainfab]

Just a thought since you have experience with this stuff, but what about just re-drilling the backing plate itself, instead of reworking a flange? Even if the original 11” backing plate flange holes had to be filled somehow.

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Yes the original bolt holes would have to be filled and then sanded smooth if a guy were to drill the 10" backing plate hole pattern in them. The drilling jig wouldn't be an issue. A thin centering ring like that might be a little tricky to machine. The cost of this would be as much if not more than a pair of weld on flanges. I guess it is more a matter of what the majority of people would rather do.

 

[Double nickel]

The backing plate flange is just welded to the axle tube at the correct location for the brake offset. The bearing is installed into the end of the axle tube that is machined for the bearing.

This is exactly what I needed to know for the brake swap I am doing