hi all, got a 62 buick electra 225 rag top in the shop, it has a vibration something horrible around 45-50 mph. i pulled the drive shaft, and the front most u-joint and the rear u-joint were powder. this car has a 2 piece shaft with a carrier bearing, and what i would call a compound u-joint [2 u-joints very close together just after the slip yoke]. i replaced the two obvious u-joints due to them being pretty brinnelled/powder/rust. the actual carrier bearing rolls smooth, and the rubber housing looks decent [not all dry rot, etc., given the age]. after the front and rear joint change, it cut the vibration in half, so i'm thinking the 'compound' joint arrangement is also in need of attention. my question is, [as in 25 years of wrenching, i have never had a u-joint arrangement like this apart], is there anything special involved in changing these u-joints? i seem to remember o/t ford rangers having a set up like this, but 'we' always sent them out for repair. also, due to this set up, we sent this shaft to our local fleet pride [local drive shaft service place, not sure if it's a national chain], and they bailed on us, said couldn't get parts [funny, as NAPA lists all the parts]. so, long story short, any special instructions for this before i start on it? thanks for any help you can send my way, tbill
I believe 2 piece drive shafts have to be phased out of alignment, some even have splines that only go one way. I had a Chevy van that had a bad vibration after I installed new joints, a millrite friend of mine took it out and turned the joint alignment about a quarter turn at the center joint and vibration was gone.
It could be any or all of what others have suggested - bent shaft, thrown weight, etc. but many (all?) of those double-Cardan 'constant velocity' U-joints (what you call the 'compound U-joint') have a little pin arrangement between the Cardan-joint crosses to keep everything in line, and this may be worn or broken.
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