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Thread: U-JOINTS, How hot, How long
06-12-2011, 08:20 PM #1
U-JOINTS, How hot, How long
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.
Last edited by dpeter; 07-25-2011 at 07:48 PM. Reason: spelling2000 GMC YUKON SLT, 5.3L tow pkg, G80 rear/w 3.73 gear
06-12-2011, 08:37 PM #2
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- Mar 2007
- Grand Prairie, Texas
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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.
06-12-2011, 08:46 PM #3
Thanks +10. does it need to be worked while hot or does the heat just ruin the plastic and make it workable?
06-13-2011, 05:45 AM #4
Here is the factory recommend procedure.
Universal Joint Replacement Nylon Injected Ring Type
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.
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 flushwith 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.
Last edited by Bigg Ron; 06-13-2011 at 05:49 AM.
06-13-2011, 04:13 PM #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.
07-21-2011, 11:18 PM #6
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.'98 K1500 Suburban LS 5.7 L 4L60E NV246 ARB
'92 Ford Explorer XLT 4x4 4.0 L A4LD BW13-54 Trac-loc rear
"My toys were the greasy cogs and springs and pistons that lay around all over the place, and these, I can promise you, were far more fun to play with than most of the plastic rubbish children are given nowadays." Danny in Roald Dahl's Danny The Champion of the World
07-22-2011, 11:58 AM #7
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- Feb 2007
- Blog Entries
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.Christopher
1991 Chevy Suburban 1/2 ton 2WD w/ chevy SBC 350-3/4 ton drivetrain upgrade w/4.10 gears 199K miles
2005 Saturn ION-2 Stock 255K miles
1982 Bronco, 1993 Bronco (sold), 1971 M35A2 Deuce and a Half
There are 10 kinds of people, those who understand binary, and those who dont...
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07-22-2011, 12:24 PM #8
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 torch99 K1500 Suburban LT "THE BEAST"
Hypertech III, K&N, true dual
07-25-2011, 02:43 PM #9
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
Last edited by MrShorty; 07-25-2011 at 02:46 PM.
08-05-2011, 11:27 PM #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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