help! keep snapping u-joints

[LAYNFRM]

i have a 91 k5 with a 208 transfer case, and a 12 bolt rearend, and a 6 inch lift on 36's, and i keep breaking u-joints all the time. i have the DIYX rear shackle flip & switch and a zero rate (stock location), and with the stock driveshaft, i broke multiple u-joints. i just had a new driveshaft made, got a new transmission yoke, and had spicer u-joints put in it (been breaking spicers and precisions), and put it in monday afternoon. it broke about an hour ago on my way home, and i can't figure out why. do i need some sort of 2-link setup to keep the axle more stable or something? any help would be greatly appreciated.


tyler

 

[4X4HIGH]

You should check your u-joint angles.

One thing i noticed when i did my ORD shackle flip is that it moved the axle forward 1". So assuming your shackle flip has done the same and you haven't corrected u-joint angles i'll bet you have a bad bind in the rear u-joint and that's the one that keeps breaking.

 

[LAYNFRM]

so do you think using the zero rate to move my axle back an inch will solve my problem? if not, what can i do? i had thought that using the shackle flip was going to be correcting my angles for the most part. now that you mention it though, when i just got it and did a temporary lift, i had blocks on it, and never had this problem. i'm used to airbags and 4 links, so actually keeping leafs on a truck is new to me, lol

 

[resurrected_jimmy]

Most likely you need to rotate the axle up towards the t-case to correct the pinion angle. This can accomplished by having your zero rates milled to the correct angle.

 

[LAYNFRM]

alright. thanks. i dunno how to figure the angle out that i need, cause it doesn't look like a bad angle right now. any tips?

 

[BigBen]

There was a great writeup on Pirate as far as driveline angles, but I don't have the link with me right now. Somebody here will have it though.

 

[supersize75k5]

alright. thanks. i dunno how to figure the angle out that i need, cause it doesn't look like a bad angle right now. any tips?

go to any driveline website, dicks or tom woods for example had a diagrame and a how to for finding your angle.

 

[xtrmjoe]

6" lift on a blazer frame is a lot of angle for ujoints. You could get a cv rear drive line so that you could aim the pinoin straight at the tcase. With ujoints you have to have the angles the same to offset the vibrations, so it usually means your pinoin is much flatter. You could also lower the tcase to help the angles out.

 

[wforicv]

Here you go:
http://www.pirate4x4.com/tech/billavista/PR-shaft/index.html

 

[copedrake]

make sure that the yoke coming off of the spindle of the pumpkin is not damanged. did you or the previous owner throw a driveshaft before? that or maybe banging it on the trail. if that yoke that two of the caps sit in isnt right, the u joint wont be right and it will keep breaking them. this is what happened to me before.
good luck

 

[onlychevy6]

12 bolt rearend, and a 6 inch lift on 36's, and i keep breaking u-joints all the time.

on my 78 blazer with the 6 inch lift and 12 bolt. i was doing the same thing. i added 6 degree shims and made some spacers that go between the frame and the transfer case support brace. Which dropped it down about 1/2 in. no more issues after that.