first off i want to say hello, i bought my 80 bronco in march and have been working on it ever since (what was that ford stood for?) anyway i'm hooked and love this thing, even though everyone i know cannot figure out why.... we go muddin and i pull em out!!!! well here's my problem, i need to rebuild the cv joint in the rear driveshaft and don't have a clue what i'm getting myself into with this... can i just do away with the coupling and buy two u-joint sraps and bolt the center u-joint to the xfer case or do i absolutely need this contraption... i have no lift on the truck and have never seen anything like this on any 4X4 i've ever owned (mostly 67, 68, 69, 70 longbeds) any advice in this situation is appreciated and hopefully i can just ditch the thing, i'm assuming it's there to make less drive line angle but i don't see how the angle is that bad considering what i've had before... thanx.... great site btw!!!!

 

Welcome to FTE and the Big Bronco Forum. We will do our best to get you the most accurate information we can.

The short answer is NO. You need the complete double-cardon U-joint assembly in there.

The reason you need it is this. The Bronco rear suspension articulates too far for a single u-joint at the rear of the transfer case. However, that puts three u-joints in the same driveshaft. Well, everyone knows that a driveshaft with three u-joints needs some sort of center support (i.e. a carrier bearing). Oops! The Bronco driveshaft is far too short for one of those and needs the ability to "bend" further than a single u-joint can allow. So, the solution is the double-cardon u-joint assembly that has been used in every Bronco since 1966.

The assembly is unique in that it contains the centering ball and spring that provides the necessary support to the middle u-joint (the aft spider in the double-cardon unit) so that the driveshaft behaves properly as it cycles through the full range of motion required by the rear suspension. Without these components, the driveshaft would simply behave like a two-piece driveshaft with no carrier bearing to keep it aligned... ad if you have ever driven a vehicle with the driveshaft that long and had the carrier bearing fail, you know what will happen. (...and how expensive the replacement of the mangled parts is). Hope this info helps.

Now, you could try going with just one u-joint in place of the double-cardon unit. However, remember that the driveshaft angle required by the rear suspension travel will destroy it in short order because it can't articulate far enough. It will also leave the rear driveshaft too short leaving it possible for the two halves of it to separate at the slip-shaft (and the aft half of the rear shaft will drop into the street) or the slip-shaft will extend so close to the ends of the splines that the torque will shear off the ends of the splines.

 

so how much does it usually cost to rebuild this and how complicated is it? i have a haynes maual somewhere, i just moved yesturday and found this problem in the micky d's drivethru... you know, clunk clunk clunk echoing off the building... "wtf is that noise!!!!" lol... i pulled it apart and found most of the bearings sitting in the bottom of the ball... what i can't figure is how do you put it together without all the bearings in the u joints from falling out....

 

It isn't too bad. A lot of the guys here have rebuilt their own. It's easier with a vice to hold things while you work especially when it comes to getting the ball and spring back in there. I haven't done it myself, (buddy of mine with a shop who owed me a favor when mine died). Guys, I am asking for your input here... help with the details if you can.

 

ok so i got the parts today and i'm going to start this tomarrow, from the way it looks i have to put the cv joint together first then install it onto the driveshaft right? i'm looking again and cannot figure this out and haynes makes it even more cloudy...

 

take it to your local napa i am sure it wouldnt cost you very much. perhaps they could even show you??

 

I had a difficult time deciphering the haynes manual too. Neither my Dad or I could figure it out and eventually took it down to a professional and they completely rebuilt both of my fronts and rears.

Mine were shot. They had to have all the internal splines cut off and new ones welded back on. Every U-Joint was toast, etc. Rust powder blew out when the shafts changed length. When they were done, they cleaned them up and repainted them. They were brand new.

It only cost me $300 total for all of that. I imagine just to have what you want done is a lot less. Point being, it shouldn't cost you a whole lot if you don't do it yourself. (I like doing all my own work, but that's one I couldn't figure out.)

 

good news is a buddy of mine up here in maine (there is a big bronco following) just gave me the driveshatf out of his 93 5 spd... we don't know if this is going to work or not... any input on that? i'm not going to be driving very much with his in there it just we're in the middle of moving and need the truck!!!!

 

It's hard to say since the drive shafts were different lengths depending on the transmission. I have a feeling it won't match up, simply because they didn't use the same transmissions in 1980 as they did in 1993.

 

just checked bronco graveyard and it looks like the 93 is about an inch longer.... this shouldn,t cause too much of a problem right? all other specs are the same

 

I just built the rear shaft out of pieces for my Cummins powered Bronc, and the double cardan rebuild isn't a big deal. It looks scary, and it did make me nervous the first time I saw one, but it requires little more than typical u-joint techniques.

 

ok so you cannot use the 93 driveshaft in the 80.... the cv heads are completely different... i don't think changing the yoke will even work

 

I suspected that. The newer shafts end in a flat plate that bolts to the vehicle.

If you get the super strength u-joints from Napa, I think the entire rebuild kit for the shaft will cost you about 150. The regular joints are quite a bit cheaper, maybe a 100 for the whole deal? I get parts at shop cost, though, so I'm not sure what they'd cost otherwise. Do you live in NY?

 

Rebuilding the carden is not that hard. I've done it twice in Auto Zones using their vice. The problem is sometimes the centering ball has ruined the shaft it sits on.

You could replace the carden with a standard u-joint, BUT, you must change the angle of your diff to be paralell to you transfercase output. You'll notice that your diff is point to your carden. Also, I would expect you would need to lengthen your shaft. I have thought of doing this many times. (its a whole lot easier to rebuild a standard shaft.)

The reason this thing is there is because it runs smoother. Not for articulation. (A Jeep and a Scout both have a much shorter shaft without the carden) Ford in their wisdom, decide to make the Bronco a luxery ride.

 

Yeah, that driveshaft isn't going to work for you.

When I rebuilt mine a few years ago, it wasn't that bad. I think I had everything back together in under 3-4 hours. The centering piece is the worst part to get in, but once you see how it comes apart you will figure it out pretty quickly.

The only mistake I made is that my u-joints are greaseable, and the way they fit into the yoke because of the bump of grease joint they won't rotate far enough to come out. So I basically installed them backwards. I realized it a little too late and couldn't get it back apart. I could only press it together and worry about it next time I have to replace the u-joints. And of course the zerk fitting is inaccessible because of the angle.