The shop manager said it's the excess metal on the last CV joint which is making contact when installed. He took the back part of the shaft, disassembled the yoke, and milled down the surfaces on the protruding edges so that it can now bend a few more degrees without binding. Gonna put it back in tonight...keeping fingers crossed...
As much as workshops out there claim to be 'the experts' they don't know s*&t when it comes to Buicks. My example may give you some comfort in your tribulations. I wanted the Dynaflow on my '63 Wildcat 401 replaced with a '66 ST400 and took it to the local 'experts'. Ye gods .... I gave them ALL the bits, including the crank spigot from Russ, a '64 crossmember. ST400 yolk. Everything! 1: They fitted the crank spigot then had to remove it again because 'there was a ridge that needed grinding off' ... sigh, I told them that when I dropped the car off. 2: They cut the driveshaft too short and had to remake it, adding days to an already tight timeframe (I was leaving the US to go home) 3: All fitted but now there's a terrible vibration. I question them about the flex plate - "we lined it up with the dowel pin" - how I held my temper I don't know becasue there is NO f***ing dowel pin, they were out and out lying at this point. I made them pull the cover plate and sure enough, the flex plate was about 120 degrees out of synch. with the crank. More delays while they undid everything and rotated the flex plate. Now there was another problem - I'll never know if they made it up because they were pissed with me or what - the car wouldn't start out in 1st gear. Days lost as they put it aside and finally claimed a 'ball' was missing from the trans. That wasn't all that went wrong tho - the inbuilt trans cooler in my rebuilt radiator sprang a leak. No parts available so we had to go with an external cooler. It seems when things go wrong, they go COMPLETELY FUBAR. Good luck and if all else fails, get someone on this forum who knows what they're doing to supply you a good shaft.
I've got it bolted back in now, less the torquing on the pinion flange bolts. Too late at night here to fire up the impact gun, don't wanna piss off the neighbors. Good news is, the yoke is flush with the pinion flange, and I can turn the shaft by hand much easier. No real binding that I can tell. I'll zap those bolts to torque with the air tools first thing tomorrow morning, then see how it goes.
Bad sign: zapped 2 bolts down and now the shaft is binding again. Haven't taken it off the stands yet, just gotta zap the other 2 bolts and see what happens, but not looking promising at this point.
Where do you have your jack stands positioned, under the rear axle? Or is the axle at full droop? Obviously the later could cause some issues, just thought I'd mention it.
The stands are under the rear axle, wheels about 6 inches off the garage floor. Fourth pitch: swing and a miss. The shaft is a-rumbling and a-clanking like before. Shop manager wants to see the vehicle, so he's sending a flat-bed out to bring it over to him. Hope we can find out where in the hell this thing's gone wrong...I want to say we're getting closer, but this shaft just won't turn once it's bolted in place.
Hopefully they can figure out what the issue is. I'd suspect the first tech didn't re-make the shaft properly, after he took the liberty to change the design in the first place. Best of luck getting the problem solved!
And away she goes. Flatbed tow truck just loaded up my '67 and took her off to driveshaft wonderland. It's out of my hands, now.
Okay, the saga is over. It took two days with the vehicle up on a lift at the driveshaft shop, but they've gotten it done. The shop manager said the material on the rear CV joint was still grinding together, and in some positions, the back u-joint was actually hitting the pinion flange retaining nut. He shaved off a lot more material from the CV yokes, and finally got the shaft to turn free without grinding or binding. The angle of the rear axle was still problematic, he said. The shaft is turning without interference, and the ride is smooth, but the angle of the driveline is still extreme enough that the rear CV joint will likely burn out in short order. He recommended taking the vehicle to a suspension shop to adjust the angle of the rear axle and straighten out that last CV joint a bit. So, I just took it to another shop, and in one hour they undid the torque link on the rear and lengthened it some more. The driveline angle is now a bit flatter, and the CV joint angle is less extreme. I'll post some pics in a bit. I now have a new and fully-functional drive shaft. At last.
Here's a shot of the 4th driveshaft before it went in: This was the angle of the rear CV joint at the pinion flange: After getting it back from the driveshaft shop, and a visit to a frame shop, the rear CV and pinion angle looks like this:
