Okay here is the problem, and before you say it, its not the paint. I have blasted one of the two of my original U joint flanges (out of frustration) and the other is still painted.
Both will not take the universal joint, both are original flanges, both held universal joints and I extracted the old ones. So pretty easy peasy just pull the caps on the U joints slide
the little buggers in and press them in, done like dinner.
Except
They won't fit. I have the old joints measured them against the new U joints and they are identical.
So the issue appears to be that the U joint has thinner caps on the tops of the cup and a longer shaft inside the cup.
I note that the U joint flange also has no tapered shoulders like the half shaft (they fit the half shaft) it does not allow the U joint to tip into place.....so am I the only person having issues?
I have two sets of U joints here. One is from the Corvette suppliers and the other is a set of spicers, both will not go into the U joint flange.
Note the flange does not have grown down shoulders.... what gives?

HELP!!

 

Not sure I understand. Are you saying that after pulling the caps off, you can get one end of the u-joint trunnion into the bracket but the trunnion is overall too long to clear the bracket cap loop on the other end and go in?

 

If the old joint and new joint are dimensionally the same you may have accidentally closed up the gap between the cup bores on the the flange and/or the shaft pressing out the old joints. In other words bent them.

Tom

 

Its a good habit to get into if you have a spare to bolt it up to the back to prevent this from happening,

 

Hmmm that may be it. Anyone got a flange laying around with a Caliper and give me an accurate inside measure? I will check it closely tomorrow and if I have to do a reverse bend with the press to open the inside edge wider.

 

Yes
It may be as mentioned that while pressing out the old U joints I may have closed the gap stopping the U joint from tipping into the flange.

 

Not sure, if I find out they are bent inwards what the best way is to straighten it. My first thought is to put the unit on a chunk of steel with the cup receivers over the edges and attempting to straighten the back of the unit without putting any weight on the cup. Otherwise trying to straighten the back with the cups being pushed against will cause the cup to collapse?

hmm I have a hand hydraulic unit with hockey pucks that may work?

 

Several options:

1. Driveline shop

2. Machine a steel or aluminum or brass bar about 12 inches long with the same OD (or about .001 - .002 inch thinner) as the u-joint cap. Use to check flange straightness and as a pry lever to straighten flange as needed. This is likely what a driveline shop would do.......except they already have the straightening bars. I believe the shop's bars actually have a very slight taper to make the job easier for them.

Anything else is trial and error. If you go on-line and use Google, you can find articles on how to do this job. Others have had this same issue in the past.

For half-shafts (not driveshaft) you can buy a very thick solid machined/tapped steel plate to use as a backing flange to keep the flange straight. This is what I have done. Zip and others should have them for sale. I think I used Volunteer Vette to buy the ones I have.

Larry

 

Thanks for that
I have a 1/2 steel plate that is 6" x 6" I am going to drill the flange bolt patter into the plate and tighten the flange down to the plate and see if that moves the cups outward. If it does I will see if it will remain that way once I loosen. The secondary option is I have lots of trailing arm shims, some very very thin. I could stick 2 side by side covering the "ring" that would normally be inset into the spindle flange and then re-torque to see if the thin shims can flatten the obvious arc that must be in the U Joint flange. As you say it will be trial and error thing. When I do go to press the new ones in, I will keep it bolted to the 1/2 inch plate steel so it does not happen again.
This is 100% my fault and not knowing the U joint flange would not take a pressing out of the Joint does not help. What is worse is I have done this before and never experienced the bend so its not a "lesson learned and not followed" thing. As for the backer plate, if I had known one existed I think I would have clued in that their could be an issue here
Such is the life of a wrench head.
Just thought of another possibility. I have an old spindle flange and spindle. I may slide the flange onto the spindle to give the flange support. Then cut up the thin trailing arm shim into 1 inch lengths and sit them in the ring imprint in the spindle flange and then sit the U joint flange onto the Spindle flange and torque them down in stages and see if that takes the bend out, otherwise I pack it all up and take to the driveline shop here on Monday.

 

Here is the Guru Level Question of the Day
Lets suppose for a moment that it was me and I bent the flange when I was pressing the U joint out. That would have occurred when removing the cups, agreed? Which still leaves the U Joint inside the U Joint flange (minus cups)....how did it come out if I can't get the other one in? Sorta ruins the whole concept of bending during pressing out? Its the only part I find a tad baffling otherwise this all makes sense....until you get to that part Don't say the U joint was smaller because I have old and new and have checked shoulders, and length and they are the same and I can't get originals in either, on either flange. The winning answer gets a free ride on Musks Mars Relocator
So my answer is Powder Coating, AGAIN. Perhaps when heated it wants to close? If you check other threads that people have indicated the same problem, strangely all of the pics show a Powder coated Flange? Metal wants to return to its original position. If that original position had a bend in it, then forcibly changing that is a permanent solution, but heating it reminds the metal molecules that it was forced to do something against its will.......or is the dope I am smoking too strong
So- so far powder coating the driveline has caused the cardboard innard of driveshaft to come loose requiring me to cut open, remove rebalance the shaft. Now it appears it has farked with the flanges as well. So there may be a message here for those considering on powdercoating their driveline parts?
I think 99% of the problem is powder coating or heating to dry a spray paint, or GM (explained next message) and 1% is bending during the extraction that somehow lets the person extract the old U joint but won't let a new one in...

 

I will try and answer your other questions this evening when I get back home.

A brake cylinder hone will remove paint and powder coating inside the flange mounting ears to provide a best fit for the u-joint caps. But don't remove too much material, since you want an interference fit.

Larry

 

Paint in the cups is not an issue, solved that problem. Its getting the U joint into the Flange.
I think that people that know of this brace that you can buy to keep your flange braced while extracting may be contributing to the myth that the brace is needed unintentionally.
Let me give you a scenario you can ponder.
1) I buy brace
2) I bolt brace to U joint flange
3) I press out Joints
4) I remove joint
5) I remove brace
6) I send to powder coater
7) I get back bent U joint flange
8) I put brace on and tighten it which suddenly straightens the flange again.
9) I press in U Joint
10) I remove Brace and install into Spindle Flange re-straightening the U joint flange and I am a "winner"
This scenario suggests heating caused the bend but here is another Scenario

Scenario 2
1) I buy brace
2) I bolt brace to U joint flange
3) I press out Joints
4) I remove joint
5) I press in new U Joint
6) I remove Brace and install into Spindle Flange and tighten U joint flange and I am a "winner"
In scenario 2, you had a GM bent Flange
As an experiment I am going to bolt the U joint flange to the Spare Spindle flange first thing and my bet is the U Joint goes in without difficulty because I am removing the bend just like the flange plate tool does, a bend caused by powder coating or as in Scenario 2 a GM produced slightly bent flanges and didn't care because they knew once torque was applied to the spindle flange union, it straightened it out. The Evil GM strikes again

Meanwhile we think its us pressing out the U joint without a backer plate.
Remember this, we are talking of a time where a company had a Jig to create frames for a C2 and still could not get body mounts remotely close to correct without, in some cases, 7-8 shims so were not talking "thousands of an inch" when it came to GM engineering at the time.

 

Not sure if this applies or not.... but when feeding the new joints into the flanges mine would not quite rock in. They were a little beefier. I ground a tiny bit from the cross and it went. Do your old ones drop back in?

 

porta power very slow and gentle will open them up if that’s the problem

 

Okay I am now a tad baffled(even more than I was before) I measure inside edge to inside edge on halfshaft and its 61.7mm
I take the U joint and it drops in place without a hitch.
I measure the U joint flange inside edge to inside edge and its 61.8mm BUT because there is no slopping shoulder on the flange like the drive shaft it will not fit, even though the flange is wider
I feel like I have grade 2 in UniversalJointology here. If I measure outside edge of flange cups to outside edge I get 98.8mm on driveshaft and 98.9 on Flange which means the U joint flange is not tipped inwards at all
So I need someone with a U joint flange laying around to do a measure inside and out,please
Because "theoretically what is stopping the U joint from dropping into the flange is there is no sloped shoulders. For me to get this to drop in I would need at least 3/16ths more at the top of the Flange which is crazy
I have these U joints https://www.volvette.com/SU62D.html
I also have these U joints https://www.dennysdriveshaft.com/p40..._greasabl.html
Both have the correct cap size and both have the same shaft length with caps removed and both have the same overall length when caps compressed
So I can press these into the half shaft with no problem but can't get these into the freakin U Joint flanges to save my life
So its gotta be the shoulders of these new U joints preventing the end rod dropping into the cup holder?

 

So a demo for you, there are two pictures below. I try this with the non spicers with smaller shoulders and the same thing occurs. I took the same U joint that would not fit the opening on the flange Picture 1 and dropped it into the Half shaft Easy Peasy

 

I used threaded rod, and made a little tool to open up the distance ever so slightly. I got my u-joint in, and caps on, but could not get the caps in far enough to install the retainers until I spread the distance a bit, then they popped right in there.

 

The volvette universals

 

I am going to have to open this up more than a little bit, so something else is wrong here and so far I have no idea what it is, clips go in fine on half shaft so the caps are the right size the body is the right size and the U joint fits fine in the half shaft, just cannot tip it into the flange, I have tried all the scientific stuff including distorting my face and squinting my eyes, so its gotten serious now

 

Dennis, this area of the two joints (yellow ovals) seems to be somewhat of a limiting factor in your installation efforts. How does this area of the two joints you're trying compare to the original U-joint?




Is it possible to dremel some additional clearance on the joint? You 'll want to do it on both ends to ensure balance remains the same, although this distance from the center of rotation should hardly affect it. Or chamfer the edge of the U-joint flange slightly, similar to the half shaft retainers?

GUSTO