Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

why am I killing my U-Joints?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by foxman, Mar 5, 2002.

  1. foxman

    foxman 1/2 ton status

    Joined:
    Oct 22, 2001
    Posts:
    251
    Likes Received:
    0
    Location:
    Detroit MI
    Why does my 90 K5 eat up U-Joints, only a 1/2" add a leaf in the rear, yet I have had to replace front and rear (on the rear drive shaft) already in a 4 month period. The ones I'm buying are called "Brute Force" and come with a lifetime warranty, too bad the warranty doesn't cover my labor. Any ideas on what is the cause? Thanks guys.... 8YERCJ<----get this plate for your K5!
     
  2. Pugsley

    Pugsley 1/2 ton status

    Joined:
    Jan 16, 2001
    Posts:
    3,556
    Likes Received:
    0
    Location:
    Tucson, Arizona
    My first thought would be a bent/twisted driveshaft - or the axle pumpkin centerline being off in relation to the transfercase centerline (U-joints don't really like compound angles). I've also never heard of "Brute Force" 'joints - maybe try Dana/Spicer replacements?
     
  3. four_by_ken

    four_by_ken 1/2 ton status

    Joined:
    Jun 9, 2001
    Posts:
    3,806
    Likes Received:
    0
    Location:
    Allenton, MI
    I have heard of Brute Force and have used them. I was pleased with them.

    Held up behind a 454 and 35 inch boggers.

    Not sure on your problem though... (trying not to insult here, but...) Are you sure you installed them correctly?

    Ken H.
     
  4. rampage

    rampage 1/2 ton status

    Joined:
    Mar 20, 2001
    Posts:
    2,261
    Likes Received:
    73
    Location:
    Humboldt/Pacifica, CA
    After you install them do you fill them with grease (assuming they have the zerk fitting)? Also do they rotate freely once installed? I know that after I press the caps into the yoke I have hit the cross in order to push the caps out slightly on the yoke to make it move freely. Just a thought.
     
  5. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    I think that Rampage has most likely hit on the answer. Many times the caps are pressing against the end of the cross after the u-joint has been pressed (or pounded /forums/images/icons/shocked.gif ) into place. You need to make sure that the caps are pressed back against the retaining clips, so that the u-joint moves very freely. Otherwise the caps will overheat and burn the grease. Then you're soon feeling that oh-too-familiar vibration. /forums/images/icons/mad.gif
     
  6. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    7,385
    Likes Received:
    0
    Location:
    Atlanta
    I'm running brutes and haven't had one fail yet.
    Only a few things I can think of that would cause that failure so quick.
    1st being the driveshaft is bottoming out. You sure you have enough travel in it?
    2nd being bent or out of phase drive shaft. ALL Drive shafts vibrate PERIOD. The only exception is if the u-joints are at a zero degree operating angle. The design of a drive shaft causes the vibration to cancel out so that it is not transmitted to the drivtrain where you would feel it. This is accomplished by "Phasing" the u-joints. The joints are phased 180 degrees of each other. So when the one joint begins to Oscillate the joint on the other end of the shaft oscilates 180 degres out of phase and it cancels out any vibration that would be transmitted.
    Now a few way's this gets out of whack is the angle on one end of the shaft is not close to the same as the other. On a drive shaft with a slip shaft you can put the shaft together out of phase if you ever slide it appart at the splines. Your 90 came with a one peice driveshaft so unless you have gone to a fixed yoke that shouldn't be an issue.
    Did you install a degree shim when you put in the add-a-leaf? Are you have some vibration problems?
    Any dents in the drive shaft?
    Take a straight edge and make sure the driveshaft is not warped.
    I have also heard of people with slip yoke shafts like the one that would have come on your truck, having the splines wear on the transmission aned and the shaft will bind as a result. THis can cause u-joint failure also.
     

Share This Page