What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Junkyard AAM 14bff (factory disc) pinion question (bought it, pics added)

nutt7

nutt7

1/2 ton status
 Premium
Joined
Dec 30, 2010
Posts
839
Reaction score
471
Location
Ahwatukee, AZ -> JBLM, WA
I have brake issues on my drum braked 14bff. I know I need at least one drum. It costs $100, plus shoes, springs, the other drum, etc. I saw an AAM 14bff with the factory discs at the jy for $175 (the donor van is gone). I want factory disc brakes with a parking brake. I am aware of the fact that I would need to relocate perches and shock mounts and about the metric studs.

Two things hold me back. One, the tubes are a little wider than mine. Mine is about 3.46" by my calculations and the jy one is about 3.54". However inaccurate my measurements, they are about 1/4" in circumference different. I was hoping not to add larger u-bolts to the cost. Maybe the old ones will fit?

Second and more importantly, the pinion nut was backed off about half way. Not sure if a person did it or it worked loose. Since I was only on a recon mission, I didn't bring tools to pop the cover and inspect. When I go back, what should I look for in terms of possible damage due to a loose pinion nut? I know I can just drop my guts into this housing, but I read that the pinion has a different bearing and I would like to keep the axle as Frankenstein free as possible to ease future part hunting and r/p setup. Advice?
 
I don't know much to tell you except to look at the pattern closely, the general look it over as well. I would wonder if someone swapped the yoke and then didn't put the nut on very far as an indication of parts removal. Does the yoke slip off easily? Or does it have to be hammered off?

You have my attention with your comment about swapping internals though! ! Is that true?
 
It appears that the pinion nut has been that way for a minute. There was a little grime behind it on the threads. I couldn't slide the yoke off by hand...but I didn't try toooo hard.

And yes, the old 10.5 14bff internals will fit directly in the newer GM AAM 10.5 14bff. Not the 11.5, and not the dodge version. The outer flanges are different and the shafts MAY be different lengths but I'm not 100% on that.
 
So then I would wonder, if the bearings are tight, if someone thought about pulling the yoke , but couldn't. . ?

For that price I would be very interested. Maybe you could haggle the price some since it has been messed with.

And now , thanks to you, I need to look into axle stuff!
 
Did you check wheel mounting surface width? Van axles are traditionally wider than truck axles.

Also, loose pinion nut almost guarantees diff work.
 
Something is up with that axle. If gears need to be reset, or the pinion bearing changed, it will cost you more than the axle. I did this on my first donor axle. Yes, axle swap could have been cheaper than my fear change, before I had to have a bunch fixed on the new axle.

And u bolt size change doesn't matter, as you should be using new u bolts anyways. They are not safe to reuse.

If the extra $100 or so for a new drum is going to break the bank, I recommend not getting into an axle swap
 
1977k5 said:
Did you check wheel mounting surface width? Van axles are traditionally wider than truck axles.

Also, loose pinion nut almost guarantees diff work.
Click to expand...

Yes, and it should match my front instead of being a tad shorter.

dhcomp said:
Something is up with that axle. If gears need to be reset, or the pinion bearing changed, it will cost you more than the axle. I did this on my first donor axle. Yes, axle swap could have been cheaper than my fear change, before I had to have a bunch fixed on the new axle.

And u bolt size change doesn't matter, as you should be using new u bolts anyways. They are not safe to reuse.

If the extra $100 or so for a new drum is going to break the bank, I recommend not getting into an axle swap
Click to expand...

I have to balance these facts with the benefits for sure. The disc brake is a bonus and is the biggest draw. I can set gears and change bearings and can access a large vise to do the crush sleeve myself if need be. The extra $100 isn't as much as the problem as feeding a decent amount of money into a brake system I don't really like. In terms of u-bolts, I have read a lot arguing both sides. To me, it's another fastener. If the nut threads on it well and it's not visibly damaged or stretched, I'll reuse it. I'm open to more education though.

Hoss7979 said:
Just convert yours to disc.....
Click to expand...

I want a good e-brake...especially since some day I want to go manual transmission. That's the ONLY reason I haven't considered the standard disc swap.

To be honest, if I buy this axle, I'll likely swap my stuff in it despite the bearing difference (I can just swap the whole pinion flange assembly and make a note to myself about the bearing). I was just hoping to sell my old one but don't want to give someone a janky set-up.
 
Well if anyone cares, I bought the axle. Getting it out of the burb was fun. Backlash is good at 0.006 +/- 0.001. As far as the eye and ear, the pinion and its bearings seem just fine and the yoke isn't loose. At first, I plan on adding some lock tite to the nut and using it. I'll add a torque stripe so I can easily see if it moves. If it does, or if anything is noisy, I'll rebuild the pinion retainer.

On the outside, besides minor rust, everything seems good and came apart fairly easily. The bad: one hub had some water in it. Probably happened when the yard checked the gearing in the rainy PNW. Thankfully it's all in that one side. I'm working on cleaning the bearings to see if they're useable but I'll likely have to replace them and the seal, even though the seal came off very nicely and might even be useable. Didn't even warp the metal body. If the bearings are salvageable, I'll try and reuse the seal too (with a light coat of black rtv on the body). If one of those parts doesn't work, new bearings and seals. If you can't tell yet, I either like to rebuild all or nothing when it comes to parts. I'll either hold off until something goes awry, or go all out and make sure nothing does.

Since I have a proper tape measure at home I found that the axle appears to be the same width as mine at 67.5-68" wms-wms. Perches are 48-3/4" center to center.





 
sweetk30 said:
time for beefy perches from diy4x or ruff stuff.

then if you got time and want perfect and not look back try this one. http://eastcoastgearsupply.com/i-6697418-gm-14-bolt-solid-spacer.html

also swap this in to fine tune stuff . http://www.summitracing.com/parts/wil-260-11179/overview/
Click to expand...

I love Kert's stuff, but I have my eye on the ruff stuff perches. I don't know much about the crush sleeve eliminators...it makes me question the purpose of a crush sleeve and how the eliminator substitutes in there. I understand preload, but what else does a crush sleeve do and why ever use one if a spacer can work?

In terms of brakes, I plan on going hydro boost and using a disc/disc master and prop valve if I can find a jy one that jives with the burbs dimensions. That wilwood looks like it'll be a good buy though...I'll add that to my wish list, thanks.
 
I'm not positive but I'd say they use crush sleeves just for ease of mass production. They have a wider range of use than a single spacer would.
 
@JoshHefnerX I just read some of your build. I'm glad I had my driveshaft fitted with 1350 u joints a while back (long story) so I can buy a conversion joint to 1410. I thought to check it but forgot. I'm also going with ord for tabs, perches, plates, and ubolts. I hear you with the old perches too. Those 3/8 perches burn through cut off discs in no time. My ebrake lines are a little rough but hopefully useable. My brake cables both run on the left so I hope I don't need to mod them. Did the rear brake line work out ok? I'll have to use my splitter and I hope it bolts up
 
You must log in or register to reply here.

Latest Posts

Top Bottom