A body 4.5 bolt pattern conversion brake questions

[party340]

Hello
I need to know what brake parts I need to go from 4 inch to 4.5 inch bolt pattern on the rear. The rear is an 8 3/4 on a 67 dart. Im going with yukon axels. Do they make a drum with the 4.5 bolt pattern for 1 3/4 brakes? If not what do I need to do?

[71DartGuy]

I dont think you will find drums with the BBP for 1.75 in shoes. I am doing the same conversion right now and from what I understand, any brake setup that comes from a rear that has the BBP (B-body 8.75, 8.25, or even 9.25 rear should work). You'll have to grab everything from the backing plates to the drums. I think the SBP stuff has a different offset so they wont work right. I've got Yukon axles on my dart too and they have the same offset as the b-body axles (2 1/8 instead of 1 3/4).

[drag duster]

a "good" machine shop can drill your drums to work with the new axles

[John Kunkel]

Unless ordered otherwise the Yukon axles will come setup for the wider brake drum so you'll need the entire setup (backing plates, shoes, hardware, drums) from a 2 1/2" drum 8 3/4" or 8 1/4" rear end (9 1/4" is different}.

If you want to retain the 1 3/4" brakes you can special order the axles that way and redrill the drums.

[nhdriver]

Originally Posted by John Kunkel

Unless ordered otherwise the Yukon axles will come setup for the wider brake drum so you'll need the entire setup (backing plates, shoes, hardware, drums) from a 2 1/2" drum 8 3/4" or 8 1/4" rear end (9 1/4" is different}.

If you want to retain the 1 3/4" brakes you can special order the axles that way and redrill the drums.

Absolutly, having the wider brakes will increase the stopping power,which the A body's were never known for.

[bbeckwith]

I have my two cents to add.

You can order your axles to use the 1.75" drums, I am assuming you mean the old 10" x 1.75" oddball drums for an a-body, however, you will then have axles with the smaller size centering ring and you will need to drill your drums for the big bolt pattern. The problem here is your wheels will need the large center ring, necessitating you make a ring to fit over the smaller one, which will make it necessary to remove it if you need to pull your drums. Maybe you could get the axles made with the large center ring, but then you couldn't use the 10x1.75" drums with the smaller size center. Much easier for you to pull the entire brakes from a car with 10 x 2.5" or 11 x 2" drum brakes with the large center ring, your wheels will fit without using any spacers, or having to drill any drums. I got some 11" drums/backing plates from an old Plymouth Fury at the junk yard. I would suggest you hit the junkyard, or check on e-bay, but get them before you buy your axles so you can tell them (axle mfgr) which brakes you have so they will send you the correct length axles so your drums wont rub on the backing plates.

Hope I haven't confused matters thoroughly for you. I had to learn the hard way and am now sitting on parts I will have to e-bay later.

[nhdriver]

Good plan, ditch the 4" bolt pattern if you can, wheel selection is small for the 4" & you can upgrade the front brakes w/ the newer A body spindles and A arms & change the front to 4.5" pattern at the same time.