New front drive shaft binding (Help!)

[cgbexec]

I am doing a frame off on a 1976. I did a 3.5" lift with new extended radius arms. I also did a NV3550 Trans swap mated to the stock re-built transfer case. The case is clocked in the stock position. I ordered new drive shafts from Jeff's Bronco Graveyard. I gave them the new measurements and ordered a set of rockwell drive-shafts.

I installed the front drive shaft last night and it will only turn about 1/4 revolution before binding. The angle does not look that severe, but it is binding at the double joint at the transfer case. This is only a 3.5" lift. Why is it binding? See pictures below.

 

[Broncobowsher]

I see there is no body on, but it still looks like there is a lot of lift. Maybe more then 3½". To me it looks like the CV is at the maximum angle. Unbolt it from the axle and try turning it by hand. Depending on at what point of rotation you are at will be how steep the the CV can bend to. Since it has to rotate 360° what ever the minimum angle is, that is the steepest you can run that CV.

 

[73bronco]

It looks like that is a steep angle at the case. With the body on it my free up but it is hard to say. It looks like more than a 3 1/2" lift to me as well. Try to pull it off and turn it by hand to make sure the shaft is good. I think it is just too big of a lift without the body on for that shaft to work freely. Good luck!

 

[SpareParts]

I agree, wait till you load the susp. You should not have any problem with that lift and CV shaft.

What deg. C bushings are you running?

With 5 1/2" lift and the Cage ext. arms I'm running a 2 deg. bushing and have plenty of CV angle left. I also am running a doubler so my front DS is 34 1/2" long.

Hope it helps.

David

 

[SaddleUp]

24 degrees is about the maximum angle on the CV using a 1310 CV. 1330 is about 21 degrees maximum. Both can be relieved with grinding to get about 28 degrees. These are all numbers given to me by one or two of the driveshaft builders when I was having problems with breaking the center pins in the rear CV.

Looking in the pictures that frontend looks like it's tilted back too far. Usuallly the front u-joint angle is off some which is a compromise to get enough castor but the further you roll it back the worse it gets. While the front joint will live this way for off road use it also adds to the CV angle and it will not live if it binds. If it doesn't turn freely as is without the load on the suspension then you can expect the same offroad when either the suspension is unloaded or the frontend is articulated from one side to the other. I.E. While it may stop binding after weight is added it is still going to break offroad.

Some possible options to correct it:
1: Decrease the angle on the frontend. (You may be able to switch to a different C bushing that will lessen the angle but that still has enough castor, other than this the knuckles would need to be busted loose and rotated which normally isn't an option unless there is an unlimited budget)
2: Raise the transfer case in the frame. (This will depend somewhat on the rear driveline as well and you don't want to put the motor into the radiator but raising the t-case will relieve the angle some there)
3: Grind the CV at the points where it is binding to relieve it to increase the angle it will work at. (You can squeeze 3 to 7 degrees out this way over that of the stock CV)
4: Switch to a High Pinion Frontend. (I know one person who had to do this to correct the same problem, he ran a strap on the drivers side for 1 1/2 years or so to keep from trashing the driveline but finally swapped to the HP frontend to correct the same issue)
5: Change to a regular driveline with a single joint at each end. The CV limits the angle at which the driveline can be run but allows the pinion to be pointed at the T-Case which usually makes it so the angles are less severe. In the case of the frontend though pointing the pinion straight at the t-case is sometimes not an easy option since it requires breaking the knuckles loose and rotating them to maintain enough castor. If the angle is bad enough it may actually be better to swap to a regular driveline which may end up with angles that are closer to the way they are designed to work.

 

[kontinu]

I have 5.5 inch lift with Toms extended radius arms with 2 degree C bushings. I had the same driveline issue. I had to grind out the cv a little with a dremmel and it made all the difference. No problems offroad now.

 

[cgbexec]

The funny thing is that the front suspension is loaded in these pictures. If I let the front suspension droop, it would hang about 4 to 5 inches lower. The front springs are 18.5 inches compressed. Originally when I first installed them, they were about 21". Over time they settled down to the 18.5". I weigh 245lbs. When I lift myself up on the front frame I get slightly less than 1" of additional compression. So even with the body on, battery installed I am only going to get an additional 1/2" of compression if that.

I bought the front suspension system as a whole unit from Jeff's Bronco Graveyard. It is their 3.5" Bullit Proof suspension system that comes with everything including the Fabritech extended Radius Arms. If I remember correctly they came with 4 degree bushings. I triple checked when I installed them. They are in correctly.