Question about 31 spline axles BB and brakes.

[Gator809]

I'm planning on converting my 1969 9" to 31 splines, and having a set of big bearing ends welded on so it can be done all at once.

Here is where I am hitting a stumbling block, when I change the ends, I know the the stock 10" brake backing plates won't bolt up. I know there are several different BB ends to chose from, which one would allow me to go to a pick your part yard and get the entire backing plate drum assembly from a car or truck in 1 shot. And yes I have looked for a BB bronco housing complete here with no luck. I'm sticking with drum brakes at the moment for low cost and bolt on vs higher cost and fab work for discs.

In simpler words, which easily available BB ends and drum brake setups will work with stock replacment 31 spline axles in a 69 housing.

Thanks in advance

Hank

 

[Skuzzlebutt]

As long as you're doing that much to it you might as well convert to disks at the same time.

 

[sstlaure]

I agree on the discs, total for the brakes would be ~$400, but you'd also need the disc/disc master cylinder. (Do you have disc up front?)

My friend has a BB housing, but the spring shackles have been rotated. PM me if you are interested. I can ask how much he'd want for it. It looked fairly clean from what I saw of it.

 

[Gator809]

To answer a few questions, yes the front end will have disc brakes, I plan on using a 76 Mc for the disc drum combo since I have 4 wheel drum at the moment.

I am looking at using the drum combo in the rear at the moment because if I can find out what ends and drum setups I can use, I can probably swing the ends, and all the drum parts for about $100. And since I am having to go thru both axles before winter hits, time is a factor. I just moved to the mountains, and a 2wd F-150 aint the best winter vehicle around here. And since I only make so much a week, it kinda limits my budget also.

However if you can tell or show me a cheap safe and easy to put discs on the rear of a 9" please let me know. The main obsticle I've seen is either having to have a rotor drilled out for the bolt pattern, or some sort of spacer/bushing to then center it on there. I know about the roundy round caliper brackets, and ch*vy calipers and hoses, it just the rotors I'm not happy with. I want to keep with stock easy to get at any parts store parts. Most of the bronco parts house kits don't fall there. The rotors are drilled out with a pattern just a bit larger then 5-5.5 so the rotors center themselves on the studs. A nice solution, but you can't just walk into a parts house and get a replacment.

Any help is appreciated.

Hank

 

[Amac70]

If your converting to 31spline axles your new axles shouldn't have a problem slipping through the a rotor. I believe its gernerally only a problem with the old axles haveing to be ground to fit throught the rotors.

 

[YellowBronc]

I may be asking a dumb question here but why won't the 10" brakes work with the 31 spline axles? Mine do. I might be misunderstanding on what you're trying to do, sorry.

 

[jeffdukovac]

Question about 31 splines

I am kind of going thru this but a different way.

I have a BB housing that I believe is an early BB housing. I aquired a set of brakes that are 11 x 1.75. Waylon and I placed the brakes on and used his old 28 spline BB axles in it without the 3rd member in place.

I have a 1 inch clearance between both axles. This leads me to believe that the axles relate to what size drum brakes you want to run.

Let me know if I need more clearance between the shafts.

Jeff

 

[flint_knapper]

The bc bronco rear disc uses a '80 cj5 front rotor I
think, have to check. but it is 5X51/2 bolt pattern
just like the bronco.

 

[TOFIC]

Welcome!! I see from your posting you are a new person in the illustrious clan of Bronco owners.

To answer your basic question, what would be the bolt on solution for your rear brakes a few candidates come to mind.

First and foremost is the 78/79 Lincoln Mark series car. If your rear lucky it will have rear discs and the BB pattern. An easy bolt up. Also will have the MC and distribution valve( dont know the real name of it) you need. Bought my setup for cheap and am working on getting it into my 73.

The above also came with drums. Again, a good candidate. unbolt them and bolt them up.

The large Mercury/Ford cars of the same vintage. Especially the station wagons. Check the pattern and grab them. I am almost sure they will fit your machine. If you find an early (74-76) Mercury Grande Marquis wagon, check for the hydroboost unit. If you don't want it, I will make you a attractive offer for it.

I have never checked but you might want to look at the 78/79 Ford heavy half ton 4x4 pickups. They may have what your are looking for.

Keeps us informed we are all curious about modifications.

TOFIC

 

[DirtDonk]

...but why won't the 10" brakes work with the 31 spline axles? Mine do. I might be misunderstanding on what you're trying to do, sorry.

Not a dumb question. I think it's the difference between big bearing and small bearing. Not 28 and 31 splines. Did you buy 31 spline axles to fit your existing housing? If so then that's why. In his case, Gator is changing the whole tube end/bearing housing so his brake backing plates won't have the same bolt pattern.
BTW Gator 809, I may have a set for sale if you need them. I'm not ready to convert to disc's yet, but since I'm not working and my Bronco is just sitting...
Can you say, "cannibalize"?

Paul

 

[YellowBronc]

Not a dumb question. I think it's the difference between big bearing and small bearing. Not 28 and 31 splines. Did you buy 31 spline axles to fit your existing housing? If so then that's why. In his case, Gator is changing the whole tube end/bearing housing so his brake backing plates won't have the same bolt pattern.
BTW Gator 809, I may have a set for sale if you need them. I'm not ready to convert to disc's yet, but since I'm not working and my Bronco is just sitting...
Can you say, "cannibalize"?

Paul

Ok, I think I'm on the same page now. Not sure what I was thinking. I seen "big bearing" and not being able to use 10" brakes. Mine has the big bearing but still has the 10" brakes so it had me puzzled for a minute. I remember now that when I was getting axles for mine I did run into trouble as the '74 had a run of rear ends that's now called by most, a "medium bearing" axle. It has the small bearing bolt pattern but with the big bearing utlized. It's probably to hard to try and find this setup in a junkyard/U-pullit so I now see where this is going.

.........and sorry I don't know what other vehicles would work as donors for the 11" drum setup.