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Discussion Starter #1 (Edited)
Need to replace U-joints in my 2000 Yukon. I understand that they are held in place by injected plastic that must be heated or burned out before they can be disassembled/replaced. Is this true? How does one go about doing this and can you damage the driveshaft by overheating? How do you know when you're done cooking the plastic out? I have the means to heat from propane torch to oxy-acetylene rose bud torch tips.
 

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Just start torching them with either type torch, keep a hose or fire extinguisher nearby in case anything gets out of hand.
You only need the torch hot enough to start the plastic melting, you dont need to get the metal red hot, and if things do get out of hand be careful with the water so you dont cool the ears to fast and warp them, should only take a few minutes with the torch.
Dont worry about the old u-joint grease burning cause your gonna replace it anyways.
 

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Discussion Starter #3
Thanks +10. does it need to be worked while hot or does the heat just ruin the plastic and make it workable?
?
 

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Here is the factory recommend procedure.
Universal Joint Replacement Nylon Injected Ring Type

Removal Procedure
Never clamp propeller shaft tubing in a vise. Clamping propeller shaft tubing in a vise could dent
or deform the tube causing an imbalance or unsafe condition. Always clamp on one of the yokes and support the shaft horizontally. Avoid damaging the slip yoke sealing surface. Nicks may damage the bushing or cut the lip seal.


1. Support the propeller shaft in a line horizontal with the table of a press.
2. Mark the propeller shaft in order to show which end connects to the transmission and which end connects to the rear axle.
3. Place the universal joint so that the lower ear of the yoke is supported on a (30 mm) 1 1/8 in socket.


4. In order to shear the plastic retaining ring on the bearing cup, place the J 9522-3 on the open horizontal bearing cups and press the lower bearing cup out of the yoke ear.

5. If the bearing cup is not completely removed, lift the cross, and insert J 9522-5 between the seal and bearing cup being removed. Continue pressing the bearing cup out of the yoke.
6. Rotate the propeller shaft and press the opposite bearing cup out of the yoke.

7. Disassemble the cross from the yoke.
8. Remove the remaining universal joint parts from the yoke.

9. If you are replacing the front universal joint, remove the bearing cups in the slip yoke in the same manner.
10. Inspect the retaining ring grooves for plastic.
11. Inspect the bearing cup bores for burrs or imperfections.
12. Clean the remains of the sheared plastic bearing retainers from the grooves in the yoke.

13. The sheared plastic may prevent proper seating of the new bearing cups.


Installation Procedure


1. Remove the bearing cups from the new universal joint journals.

2. Coat the needle bearings in the bearing cups with a thin layer of the grease that is present on the journal.
3. Apply the grease with your finger.

4. Install one bearing cup partway into one side of the yoke.
5. Turn the yoke ear towards the bottom.


6. Install the cross into the yoke so that the trunnion seats freely into the bearing cup.
7. With the trunnion seated in the bearing cup, press the bearing cup into the yoke until it is flush
with the yoke ear.


8. Install the opposite bearing cup partway into the yoke ear. Make sure that the trunnions are started straight and true into both bearing cups.

9. Press the opposite bearing cup into the yoke ear. Work the cross all the time. Check for free unbinding movement of the trunnions in the bearing cups.

10. Press the bearing cup into the yoke until the bearing retainer groove clears the inside of the yoke



¡ Continue pressing until you can snap both retainers into place.

¡ A small amount of chassis grease may help the snap ring seat in the bearing cup groove.

12. If the retainer does not seat, spring the yoke slightly with a firm blow from a dead blow hammer.


 

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Discussion Starter #5
Hey bigg Ron, no mention of heat in this how to. I found no mention of heat in any of the "professional" write ups either. I will assume that the aplication of enough force will shear the plastic so no heat is needed.
 

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Any feedback on the factory procedure? I need to replace my ujoints and am trying to decide if I want to tackle it myself, or pay someone else to deal with the plastic retainer. I have a C frame press for doing ball joints, and I've used it on regular snap ring retained ujoints, but I'm not sure if I will be able to put enough torque on it for the plastic retainers.
 

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When I got the u-joints done on my Suburban, I pulled the driveshaft and brought it to my local driveshaft shop with new u-joints where for around $20 they torched the plastic retainers, and swapped the 2 u-joints. The only hassle was bringing the driveshaft to the shop. Definitely have the shop do it if you have a spare vehicle to bring the driveshaft in.
 

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I fugured a ball joint press would do it to but it didnt budge them, I took it down to my usual mechanic and they torched it and it was like a fountian of plastic that came out. I would have never thought the plastic would have stood up that well to the press but it did, it literally takes 2o seconds and you are done with a torch
 

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I just got them changed. My little propane torch was enough to get the plastic to move. Since I've never seen it mentioned, there are two small "holes" that you can see on each yoke ear, filled with plastic, where they injected the plastic. I found it best to heat that part first, so the plastic in the hole would be melted to allow the plastic in the rest of the yoke to flow out. After that, it was just like any other u-joint. Often needed a whack with the hammer to loosen the seized metal, but they pressed out just fine with my C-frame press.

One last question. The ujoint attaches to the yoke at the rear diff with straps. I didn't see any retainers when I took these off, but I also didn't see any mechanism for centering the driveshaft on the yoke. There appeared to be some recess machined into the yoke for the retaining clips, so I put them on (they fit ok so I don't think there's anything wrong with using them). I was just wondering if those are necessary, or what method others have used to center the driveshaft over the rear yoke.

Edit: I thought I'd sticky this thread. Ujoints are a fairly common repair, and this thread seems to have a pretty good amount of information for the DIY'er
 

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Discussion Starter #10
Finally got around to tackling the changing of the U-joints. Did not use heat but used a large gear puller to press/pull the cups out. Just a bit challenging with only one set of hands but once set up it was pretty easy. As soon as the plastic sheared the caps came out easily and I used a 1/16 inch punch to push out the plastic plugs at the injection site and the remaining plastic came out in two halves. With no more trouble than I had I would think a hydraulic press would have no problem and without the open flame.
Good luck to all who attempt this repair with whatever method you choose.
 

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I used a 20 ton press on them with no heat. It broke the plastic no problem. That press has more than paid for itself. So far the truck is vibration free.
 

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First time I did mine I had never heard of the plastic rings. It was until I got out the hot wrench and the plastic cam squirting out of the hole that I figured out what was going on. My 1 ton arbor press was not enough to break the plastic. but once warmed up with the propane torch it was easy after that.
Since the factory did not put rings in the groves you will likely need to spend some time getting the rust out of the snap ring grooves so that the ring will seat fully.
 

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The grooves for mine were in the ujoint bearing cups, no cleaning required. The trick was pressing the cups in just far enough to accept the clip, but not too far, and still keep the cups straight. So far the driveshaft hasn't fallen out of the truck, and I took it out for a severe muddy beating 2 days ago.
 

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I just experienced this for the first time this week. I have a large c-clamp that I've been using for over 20 years to do universal joints and it's now trash. Finally I cut the old joint out and decided to use heat hoping I could get the old cups out. Well that plastic started coming out like crazy. Cups tapped right out. Very frustrating. One day I hope I can get my hands on the sumbitch that comes up with this stuff.
 
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