Today I was removing some ujoints from a couple of GM drive shafts,These are the ones held in by injected plastic. I was taught to lightly heat the yoke until the plastic melted and it just squirts out the holes it was put in by then you can drive out the caps using your favorite manor.I use 2 sockets in my bench vise to push out the caps, Anyway I must have done a hundred shafts this way never had a problem until today! Today I had a shaft on my bench and was warming up the joint to melt the plastic well as soon as the plastic started to flow out of the cap the cap blew out of the yoke like a bullet! and nailed me just to the left of my nose, I'm not sure how I got hit because I was not directly inline with the cap. I'll have a bruise and I got some scuffed up skin along with a small scratch in my prescription safety gl***es but if I hadn't been wearing real safety gl***es I'm sure I'd have lost my left eye today ! Ever since needing gl***es I have always made sure they are true industrial grade safety gl***es today that paid off in a big way! You would think that the pressure would have just pushed out the rubber seal not launched the cap out of the drive shaft! I did 3 more joints after this one and everything went fine but I did make sure that they weren't remotely pointed in my direction!
Thanks for sharing that and luckily it was not worse for you. Just by taking the time to post something can help many others avoid a similar incident. A lot of us on here know our way around the shop, have a lot of common sense and take precautions I'm sure but sometimes its the things we wouldn't have remotely considered that gets us. Some may reply to this post saying they would have not had it pointing towards them or a million other things they would or wouldn't have done but who knows what little oversight or thing may sneak up and bite them in the *** if it hasn't already. Many people will never post to warn anyone else either, they'll just pretend they never make mistakes.
Thanks for that! and note I didn't think I was "in the line of fire" even though I never expected this to happen I wasn't right over the yoke when it did. As an ex EMT and involved with the Safety committees in every shop I worked at after making EMT I always try to be conscious of safe working habits.
Glad to hear your okay. Do you think if it was put into the vice with the sockets first and then heated it might be safer? Just a thought.
Safety posts are always a good idea. Had hot grease get me once heating control arm bushings. Pushed the seal out and SPLAT!
Thanks for the warning I have done them very simular to the way you describe and also with the large hammer way too, Ive never had that issue. Thanks Much for the heads up. maybe have to "cage" those ****ers some way, like mounting a semi tire like idea but smaller? glad you werent perminently damaged
I had a stubborn ball joint do that once. The heat melted the nylon insert and formed a seal around the ball, no zirc to release pressure. It sounded like a shotgun and took a 1" chunk out of the concrete floor before it ricocheted around the shop. Luckily the only casualty was my underwear.
Got hit in the chest one time doing this same thing.went through my t-shirt and broke the skin.8 stiches later i still have a scar to show and tell....
I don't fear death so much as I fear death under embarr***ing cir***stances. I really don't want St. Peter to greet me at the pearly gates with "We never got one in that way before." I really don't want to be known in Heaven as "the one who tried to..." or to be teased for all eternity about the spectacular manner of my earthly demise. So, thanks for the safety tip concerning a risk I'd never thought about.
BTDT, the plastic and grease burns like hell too, I place a loose C clamp on them now, you can tell when they give <grin> without the excitement!! BTW, place the plastic ****** down so the **** does not shoot into the air and your hair.
I guess that's why I just press them out, I don't use heat. Good that you can still see the computer screen.
Happened to me once. I always stay clear of line of fire, even though I wasn't expecting it to fly. Working at floor level, it put a dent in the ceiling! With the winter corrosion around here, the heating helps release the plastic as well as the rust bond.
Who woulda thunk? You try to do everything right, anticipate possibilities and the unexpected bites you on the *** ..... thats how the pros get hurt. That was a close one.
kinda happened to me as well, except I was out of the way (whew), but it m***acred my big shop clock on the wall!
I can't be the only one who has never heard of u-joints "held in by injected plastic". what are you talking about?
It's how they do some of the throwaway kind. They're doing away with the clips and such. Only place I've seen 'em is a Mazda pickup.
Started in the 1960s on GM cars, it's called a Saginaw Ujoint. I just do like normal ujoints and support the "loose" yoke or the cross with two supports, and whack the driveshaft on the center of the yoke where it joins the tube, it's not hard to break the plastic free.
I had this happen when they first came out,I soon figured out if you warm up where they are injected first, and then go slowly around it will ooze out the hole, I haven't had that happen in over 30 yrs and I use to do a lot of driveshafts.
I have done it hot grease burns twice, yep you got the joint to hot and that why it exploded, its been along time ago but I did it too. MrC.
They use the same plastic injection in GM collapsable steering shafts. Not meant for shear forces. Will break free without heat as mentioned earlier.
I did that the first time back around 1990. I purposely take the time to cut the seals with the oxy/acet torch before I start heating the stubborn caps. I don't fire off the torch unless a couple good SOLID swings from my 3 lb hammer won't break the the injected plastic. It seems like the plastic they use now is tougher to break than the '70's and '80's shafts.
Here you go. I have never used a torch to get one out. The tool I use. OTC 3 in 1 ball joint tool although HF has a knockoff for about 40.00 clamped on the yoke of a driveshaft I had laying around. I couldn't id it so it got to be the demo unit. Checking to make sure that the cup of the joint is centered A few turns with the ratchet and socket and it pops loose. I had a video but the batteries in the camera died. A little tap with the magic hammer to finish getting the cup out Pull the cup off Press the other cup out the other side far enough to get the cross out and the knock it out of the yoke. Instead of tapping the cups in with a hammer I press them in with the tool. It saves a lot of looking for needles. Usually I will slip the new cross into place and into the cup to hold the needles while I press it into place That's it. No hot plastic, no smashed thumbs and no lost needles when you put the new one in.
Great thread.............THANKS for the warning...........never knew that was a risk! Mr 48chev.....thanks for the tutorial......... Ray
It works equally well on U joints with internal or external clips. When I worked on a dairy farm I used it under trucks with pto shafts without taking the shafts out of the truck. This is the HF knockoff http://www.harborfreight.com/3-in-1-ball-joint-u-joint-c-frame-press-service-kit-38335.html I've seen it on sale for less pretty often though. A friend who has his own shop used to borrow mine until he bought one of these.
I just thump 'em out with a BFH and a proper drift. Fergit the heat, just THUMP 'em !!! (you'll be glad ya did!) he, he....
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