if you take a driveshaft out make sure to mark the orientation.
i like to use a centerpunch and make three dots in a triangle or similar, so they are a bit more obvious than just one mark. Ink or paint can wash off but not a punch mark so I'd normally do both just in case it gets washed off.

I think it's likely you simply lost the original orientation of parts and maybe you can figure that out by trial and error.

I shortened the one in my 122 to install overdrive and then took the driveshaft to a place to have it balanced, they welded a washer or two on and all was fine. they balanced all the parts together on a lathe and I guess they had to support the center bearing during that process. it wasn't super expensive to do.

it is critical that it is balanced or you will feel a sort of a droning noise and vibration from under the floor that increases with speed.

I've changed the rubber mount for the center bearing and I'm trying to remember what it looks like in the 700 series, I think it has a similar rubber part that holds the center bearing and if so it might turn to gush and sag. in my 66 122 it had a doughnut and in the 67 it was a larger rubber part so I used the 67 version. you need the right one for the 700 series. It's a good time to change it, rubber fails due to age. cars with manual transmission seem to need them sooner.


I've put strips of rubber in there under or over the existing rubber to adjust the height before. yes as springs and suspension sag or are modified that can throw it out of alignment. of course the rear axle moves up and down and it needs to move but if it's sitting on the ground on it's tires it should be fairly straight clean and re-lube the splined shaft.

some U joints have a grease gun fitting, some do not, if it does check that the grease zert isn't interfering with the other parts.

changing U joints at home can be a bit of a struggle, I like to soak the whole affair in oil mixed with solvent and give it a good brushing with a paintbrush then dry down,, clean it up well before any disassembly, give the whole thing a good bath , you can use a bristle brush and WD 40. There is no point fighting grit.

I'll usually just select the right size sockets to use as "pushers" or to surround the cup and just use a bench vice to press it together. I have a lathe so I can make various pushers but most of us have some selection of sockets that will work as pushers.. If I encounter resistance it means stop. It's quite easy for the rollers to get bound up at the end of the spider. you can damage them if you try pressing and the rollers aren't placed right.

after you get the clips in make sure they are seated ok and you can give things a tap with a plastic hammer or aluminum drift to try to seat them a bit and check to make sure there is no resistance as you bend each joint, look for binding.

I think if you pay attention to the previous notes on orientation and you may be faced with disassembling and reassembling once or twice but you probably don't need to have it balanced but you may need to experiment to find that place where it doesn't vibrate. there are only so many possibilities. I dont think it will go out of balance on it's own, but if the shaft is off center and moving about it's center, for any reason it's also out of balance.

try to keep the parts clean , remove any rust from the circlip area you dont want to be fighting it as the clearances are tight so you dont want dirt or rust to be trapped between the cups and the holes or you will just be fighting it and applying excessive pressure.

the bearing cups are hardened and quite brittle so avoid smacking them too hard, try to find a piece of steel or a socket so it bears on the outside of the bearing cups, make sure it can sit square and flat against the cup. the center of the bearing cups is a bit weak because it's fairly thin there. the cups are a bit brittle because they are hardened.

make sure as you go you dont loose any rollers, its a good idea to spread out paper to work over so if one goes astray you can find it and if you drop a part it doesn't pick up any grit. if any speck of dirt or grit gets inside the bearing cup it will destroy it in short order. if that happens , disassemble clean well and re-grease.

if it feels bound up you can try giving each bearing cup a bit of a whack to seat it against the circlip, or give the spider part a whack to try to drive it outward toward and into the bearing cup, this is just seating the parts, dont be too brutal.

make sure they can move freely and and don't feel bound up before you reinstall it.

if you need the bearing you can order that often you can just record the bearing number and go to a local bearing retailer. try that if the prices you are finding seem over inflated, same with most seals they are not usually really maker specific, usually metric and the code identifies them. the U joint is also not brand specific. It is used in other cars. the rubber bearing holder is of course proprietary.

the bolts that hold the flange at the ends are hardened use the OEM bolts there. I'd mark those for orientation as well they are part of the balance.



if parts are too dry and you have a bit of rust it is possible to put so much force on it with a vice that you may squeeze and cause distortion so be diligent about how much force you put upon it and if it seems excessive try taking it apart and look for any scoring , dirt etc that may be hampering the installation of the cups. Its tempting to put a long pipe on the handle of your vice but try to resist that by lubing and cleaning the parts well. you cna use a hydraulic press if you have access to one.


you can probably get the first cup in about half way and make sure the bearings aren't trapped and install the opposite cup about half wway from the opposite side, and make sure nothing is bound before you press the cups all the way in to get the circlip groove to reveal. check that all the rollers are present and aligned properly before you press the cups right in. you dont want one of those rollers lying sideways at the bottom of the cup or you will end up cracking the cup, so make sure every one is present before you give it the last squeeze to get the clips in.


you should not be able to feel any play whatsoever in the new U joint, but it should move without any binding too.


I have a whole driveshaft I removed form a 88 740 sedan sitting here but I am likely not close enough that it's practical with the shipping, I took it out and set it, and most other parts aside thinking maybe I'd need one but that's probably unlikely. I'm in Vancouver BC. Canada

I thiink where that flange conects to the transmission ethere is a bushigng and a seal int here and they may leak so if you seal oil there you might deal with that.

Its rare but I had one with a manual transmission and there is a "sprag bearing" in there ( a bearing that turns one way and locks the other way) it failed and the failure was quite interesting. it felt like it slipped out of gear, reved up and then reconnected very suddenly and with a "loud bang" I bought the car with that fault but it wasn't disclosed. It's in that area and not so hard to change. that can break the main shaft of the transmission. I've only seen that happen once.

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