I have a 85 fullsize Bronco, 5.0, manual with a 9in rear end. What would be my best option to put some sort of locker in the rear end. The only purpose for this truck is to be a trail / off road rig. It is driven to the places I play in, not a trailer queen. My requirements are doesn't cost an arm and a leg (ARB Air Locker) and will give the better traction (I have an open diff now) for the cost and s durable and will last for a good long time. Looking for info on spools, mini spools (and difference there) welded gears, lockers, limited slip, etc. Any help would be very much appreciated. Thanks all.
A salvage yard is a good place to look, get a "9in Ford limited slip "chunk", get a new set of clutches and a shim kit from someone like Reider Racing, and a set of heavy-duty clutch springs from Ford for the clutch pack, get someone to set it up for you, unless you know how. If your ring and pinion are in good shape, you can transplant it, (keeping the same ratio front to rear). Important, though, is to know how many splines are on your axles, you will either have 28 or 31 spline axles. A new rear "chunk" won't fit unless it's for the same spline count you have. You may need to shim the pinion to ring-gear depth, but sometimes not. New grease, some limited slip additive, a few figure-eights in a parking lot somewhere to wet the clutches, and you're set. That's the best way to go, in my opinion.
Stay away from spools, or welded gears, spools are for strict off road, not "road friendly", and don't weld the gears, just don't.
Spdloader
While you're looking, if you find a Lincoln Versailles, in good shape, the rear axle is "9in, and will bolt in to your Bronco, and give you rear disc brakes to boot. Most of those were limited slip, too.(The Versailles was like a Granada, with a Lincoln front end on it. Hard to find now)
The 85 Bronco's Ford 9" had 31 spline axels ONLY. All Lincoln Versailles
9 inch disc brake rearends have 28 spline axels.
If you find a complete limited slip third member in the same gear ratio as your Bronco, that would be an easy simple solution. In order to rebuild the clutch pack you have to disasemble the gear set (not a job for the novice!). Once you step into setting up the gears (again not a job for the novice!) the true Detroit locker is the only way to go!
Salvage yards will sell the third member as a separate unit, which is why I suggested he be sure of the number of splines. He didn't say whether his truck was original or not, and may not know, and a lot of people swap in the axles from the older, stronger trucks, i.e., the older Bronco and F series that had the 28 spline axle. The Lincoln Versailles is a common up grade around here, when you can find the axles, and the parts all gel. Rebuilding a "9in third member is tough, but still a cheaper alternative to buying a new setup, even if he has to pay someone to set it up. If he's in North Carolina, I'll do it for him.
31 splines is stronger than the 28 isn't it? I always thought it was. Anyway my Bronco has the 28 and from what I understood it all depended on what gears you ordered and if it was locker or not. The year wasn't a distinguishing was to determine that splines the axle are.
Well, it's been my experience that the 31 spline axles strip under the load of a high horsepower or high torque engine, quicker than a 28 spline will. Most of the people I know, or, knew, in the truck aftermarket used the late '70's axles when they could. The 31 spline axle has more mating surfaces than the 28, but the 28 spline mating surfaces are deeper. This is only an opinion, based on what Ford guys did when I was in the business full time. I realize things have changed somewhat in newer tech, but old tech pretty much is what it is. Of course, someone will disagree, but that's what is great about this forum, a multitude of opinions.
The difference between the 28 and 31 spline axels is not so much the spline count as the massive difference in the axel shaft size. If you have enough torque and traction you can rather easily twist the entire axel shaft on a
28 spline axel, kinda like a rubber band. I have a car that did that to both axels with a 9 inch Lincoln Versailles 28 spline axel set and a new Detroit locker after only eight quarter mile runs. After custom 31 spline axels and a new 31 spline Detroit locker, the same car has gone dozens of
1/4 mile runs and the 31 spline axel shafts and splines still look like new.
There were a number of years where the Ford truck 9 inch 31 spline axels had very inferior manufactured axels and the soft splines are very warn on almost every one you look at in any wrecking yard.
I don't have it in front of me now but I did have a really cool book (I got from an old guy who spent about 50 years running a wrecking yard) that gave every dimension (length, spline count, wheel lug spacing, bearing size etc.) for every axel shaft for every year American car and light truck.
Your Bronco is a pre 76 isn't it? The earliest broncos had 28 spline axels, there were a number of years with both, depending on various things, by '76 all Bronco's came with 31 spline axels. No eighties vintage Broncos with 9 inch rear ends (they started to faze the 9 inch out in the mid eighties) came from the factory with 28 spline axels.
Mine is definetly a 9in. So... I'm almost as far as you can get from NC. I grew up in Rock Hill, but I'm in Oregon now (better mud, rains more). So I will probably go the locker route. I have someone willing to do the install and the locker for $350. Is this a fair price, or should I laugh and leave? THanks for all of the advice and info. I have gotten alot of good info from the forum in the past. Now if I can just find out why it sometimes just shuts off and stays that way for a few days. (stupid electrical short). Merry CHristmas all
Tim B.
p.s. I have no idea if the truck is original or not. When I got it there were alot of things wrong with it. I just want it to be reliable on the trail and work to get me where I wanna go. It sure looks better now and hell it even passes emissions out here. Buuuut, just dies every so often when it wants too.
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