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HELP!! can you incorrectly replace rear u-joints?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by foxman, May 13, 2003.

  1. foxman

    foxman 1/2 ton status

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    I didn't think it was possible. I'll lay out the scenario for you.
    Bought the truck about 2 years ago. When I bought it it drove fine for 6 months with no vibrations. one day it started to vibrate and in the next couple of days the rear u-joint (on the rear shaft) was terribly sloppy and the truck vibrated verry bad to the point where it couldn't be driven. I replaced the joint and the truck seemed to drive like new again. Then 2 months later, the vibration started again, and it was the rear joint again. I then replaced both joints on the axle and it drove fine again. Then another 2-3 months later, the rear is vibrating. and every time since then it starts to vibrate sooner and sooner, now it's like a week before it starts to vibrate again. Here's the thing...

    Truck is stock 90 k5 (1500) no lift.
    When the rear joint is pulled, it looks fine, only the bearings are completely dry. I use the best i can find (brute Force) u-joints, and still the same problem. I'm ready to take it to a drive line shop. My guesses are: the first time the u-joint (rear, rear) went it warped the end of the driveshaft and is now out of allignment/ballance. Guess # 2 is that My way of installing u-joints is wrong. Here's the procedure(I've done this many, many times)
    -Remove drive shaft, (Take off u-joint straps.)
    -Remove inner clips from rear joint
    -support driveshaft in vise
    -use old socket and extension to drive out one bearing cap, then drive out other end.
    -after removing the cross, clean and replace with new joint
    -this involves taking off 2 caps and tapping the bearing caps into place with a ball peen hammer.
    -once caps are fully seated, place new clips to secure bearing caps into place.
    -Then crawl under the truck, line it up the best you can, and bolt it in.
    -tighten the straps down, and be careful not to strip them, because you know you will be doing the same thing in a matter of weeks!!!

    Rear diff bearing seems tight as well...

    Please!! Help me I am fed up, I hate taking any of my things in to pay someone elyse to scratch their head and do the same thing I can do, for $70 an hour..


    Thanks


    Jeremy
     
  2. monte0172

    monte0172 1/2 ton status

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    The best thing ive found for that is to buy a greaseable ujoint and make sure it gets greased at least once a month.
     
  3. sled_dog

    sled_dog 1 ton status

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    you said yourself that you use brute force joints, they are ungreaseable and you said they are alywas dry when you pull them. Recommendation is use greaseable joints.
     
  4. jakeslim

    jakeslim 1/2 ton status

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    i have used greasable brute force u-joints. good advice above, grease them once a month and you should be able extend change intervals.
     
  5. HarryH3

    HarryH3 1 ton status Author

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    [ QUOTE ]
    once caps are fully seated, place new clips to secure bearing caps into place.

    [/ QUOTE ]
    There's a step missing right after this one. When the caps are "fully seated", they are pressing against the end of the cross shaft. This generates lots of heat and bakes out the grease. /forums/images/graemlins/eek.gif Then the bearings self destruct. /forums/images/graemlins/frown.gif Since your truck isn't lifted, it takes longer for the joint to fail than if it was a lifted truck. The joint works much harder in a lifted truck and will fail much quikcer with this type of install.

    To prevent this, install the clips, then tap the cross shaft such that you seat each cap against it's clip. Now you can install the U-joint and it will last a long time. The U-joint should move VERY easily through its range of motion once it's installed properly. /forums/images/graemlins/thumb.gif
     
  6. fredekr

    fredekr Registered Member

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    I don't have a lot of experience with failing ujoints. I'm wondering about what my local driveline guy told me. First of all, he said he recommended greaseable joints until the last few/several years when spicer's sealed became better so now he recommends those, but realizes that it's a religous discussion so doesn't push it. /forums/images/graemlins/grin.gif

    But what I'm really posting about is not greasable vs. sealed but rather the "seating caps fully" issue. He showed me that before you put the spicer ujoint in you press the caps together until they "click" -- when the sealed ones are new the caps aren't seated. Otherwise when you put them in the bearing caps don't quite fit in the shaft. But Harry's suggesting that when you do this it'll cook the grease out? /forums/images/graemlins/confused.gif I know that when I put new joints in mine, they definitely *didn't* fit until I "seated" the caps... and they truned very easily once I seated them and had it all bolted up...

    Someone clear this up for me!

    thanks,
    Kevin
     
  7. TxK5Blazer

    TxK5Blazer 1/2 ton status

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    A Little trick I learned was if they fit tight then give the shaft two taps with the hammer on the end of the shaft it will free up the u joint till it moves freely. I had my machine shop guy show me this trick works great for me. Be sure to check your yoke on your rear end there may be little keepers built into it and maybe not if now you need to put the c clips in there too or you could lose your end caps had that happen this past weekend .....Jason
     
  8. 84_Chevy_K10

    84_Chevy_K10 Banned

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    My driveline guy says to use non-greaseables too. I told him I'd give them a try and I let him sell them to me. He sells the HD type Neapcos and Spicer both, I bought the HD Neapcos because he said that they're just as good.

    I haven't drove my truck a whole lot since the install so I can't tell you for sure my opinion on them. He said that they're MUCH stronger than greaseables. I don't really know if I believe him, a few years ago, Fourwheeler Magazine did a test and found that greaseables were just as strong.

    I am giving these a try, and if they don't work out, it's back to greaseables from here on out.

    I can tell you though, the driveline guy sells much nicer heavy duty u joints than that crap that Napa, Autozone, and Blain's Farm & Fleet sells.
     
  9. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    Dude, I had the SAME EXACT PROBLEM. Read HarryH3's post, he's the one who hooked me up with the fix. Click Here for my old post. It's easy to forget to make sure the caps are seated correctly under the STRAPS that hold it to the pinion yoke. Mine are still good all these months later, and these are made in China. Got some spicers I bought for when the Chinese ones failed, but they're still in the box. Read my post, pay special attention to Harrys reply after I thanked him. /forums/images/graemlins/usaflag.gif
     
  10. sled_dog

    sled_dog 1 ton status

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    I have another issue, my u joint seems wrong for the pinion yoke. I mean that when I installed the joint I could slide it side to side in the pinion yoke between the little ears on it. There is about a 3/8" gap if I put one side against one ear. So when I installed my joint one of the end caps was slightly off the u joint shaft and now it slides back and forth in the end caps. Anyone have an idea why the joint is like this? I tried a brute force then when I went to install a greasable generic I realized it was exactly the same. The u joint that was in the truck before was literally fused in the yoke and took some beating to remove.
     
  11. bajaviking

    bajaviking 1/2 ton status

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    What kind of rear diff. do you have?
     
  12. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Sounds like someone swapped axles and used a hybrid u-joint. Take your old u-joint and compare it to the new one. You can also take the old one with you to make sure the new joint is correct.
     
  13. sled_dog

    sled_dog 1 ton status

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    its a standard 10 bolt its gear matched with 2.73s to my front so I think they are factory. I can't compare to my old joint because the one I removed a while ago was destroyed. I mean end cap cracked and all needle bearings just plain gone.
     
  14. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    I don't know about 10 bolts, but I think they pretty much all came with 1310 sized yokes. Maybe a swapped shaft? Measure across between the yoke tabs and the shaft yoke between the grooves and check here to find the size matching info...
     
  15. sled_dog

    sled_dog 1 ton status

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    I have 2 driveshafts. One has 2 bad u joints and one does this. I would rebuild the other shaft but I worry its just gonna be the samething.
     
  16. foxman

    foxman 1/2 ton status

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    Great Ideas,
    I did notice one problem that I have though... In order to "seat" the end caps into the shaft and put the spring clip on, I have to tap the ends in all the way. once the clips are on, no matter how hard I tap on the joint it still remains pretty stiff in motion. Maybe the end of the shaft is a little warped from hammering on so many times.I could mabe trim down a clip, I noticed that replacement clips seem to be wider than the originals. Another Q: how much to ballance a driveshaft? I'd like to get this done just to eliminate my suspition...

    Thanks and please keep the ideas rollin' /forums/images/graemlins/ears.gif

    Jeremy
     
  17. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    When you're puting the new caps in it's really easy for one of the needle bearings to slip and get caught between the top of the trunnion (cross) and the cap. I had this hapen a few times during my "new u-joints every week" ordeal. Pull the caps back off and make sure there are no needle bearings in the bottom of it. If you have a 6" vise this would be better for seating the caps than tapping them in with a hammer. The proceedure I use for reassembly is:
    1. press one cap partway into one side of the yoke.
    2. put trunnion into yoke and seat it all the way into the partially installed cap.
    3. put the yoke in a vise and tighten the jaws so the cap is seated flush with the surface of the yoke.
    4. open the javs of the vise and put a socket on the cap, then squeeze the vise jaws until the cap is pressed in about 1/8" farther than it would be if it was seated against the retaining clip
    5. open the vise and install the retaining clip. there should be space between the retaining clip and the cap.
    6. put the other cap in the other end of the yoke, put tit in the vise and start to press it in. once its started, slide the trunnion into this cap, make sure the arm is centered in the cap so no needle bearings get pushed into the bottom of the cap.

    Now the arms of the trunnion should each be partly in both of the caps. No matter which side you slide the trunnion to, it should remain supported by the bearing caps on both arms. (does that make sense?)

    7. tighten the vice to seat the other cap, loosen the jaws and use the socket to seat it far enough to install the other retaining clip. This should have pushed the other cap back against the clip you already installed.

    Now tap on the other two arms of the trunnion to seat the caps all the way against the clips. The u-joint should rotate freely now, if it doesn't pull it all apart and do it again. Unless the needle bearing caught under the bearing cap is not what is causing your problem. /forums/images/graemlins/shocked.gif

    Hope you are able to understand my explanation. Good Luck. /forums/images/graemlins/thumb.gif /forums/images/graemlins/usaflag.gif
     
  18. 90K5

    90K5 1/2 ton status

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    sled dog - do you use the clips on the rear joint where it goes into the axle's yoke? I forgot mine once and it did the same thing...holds them in side to side
     
  19. foxman

    foxman 1/2 ton status

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    A question on u-joint play. With the caps seated and all clpis installed after about 300 mi down the road, I can pull on the rear drive shaft and there is little amounts of play in the front and rear ujoint. tha typpe of play I'm talking About is not twisting type of play, it's where yoyu try to move the joint side to side. should there be any play, how do you get rid of it? I think this is causing a little bit of a vibration.

    Thanks,

    Jeremy /forums/images/graemlins/grin.gif
     
  20. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    That kind of play means you will need new u-joints soon. When you get underneath and try to shake the driveshaft, there should be no movement between the bearing caps and "cross". It's when you first allemble them to the driveshaft yoke that you check for "play". The cross of the u-joint shoulg rotate back and forth very easily in the bearing caps. If it's tight, then you haven't seated your caps all the way. Or maybe you pounded the yoke ears and they closed up a bit when you put them in? Good Luck.
    /forums/images/graemlins/usaflag.gif
     

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