C3 Half-Shaft UJoints

[Pat Bush]

Hello all -

Am working on my 71 Automatic rear suspension. Picked up a new set of half-shaft ujoints and am having a rough time with the flange side installation. These seem WAY TOO TIGHT and the retaining clips seem to be pushing out on the flange. They seem to be fine on the half-shaft side. The flange is difficult to move when installed. Not like any other U-Joint installation I have ever done. I can see nothing obviously wrong in the flange assembly or half-shaft and this was working just fine....

I bought Dana Precision joints and they only list one part number for the ujoints. I have had the same results no matter which U-Joint I install. Flange? Joint? Can someone recommend a joint that will work with no hassle? Is there something I am missing here? Is there some difference in flange assys I am missing? Yet all the books only list one joint????

Thanks in advance -

Pat

[Dave McDufford]

Re: C3 Half-Shaft UJoints

Depending upon how you took them apart you may have bent the flange. Set it on a flat surface and see if it rocks (don't ask me how I know that). It is not as easy to do as it looks.

Dave

[Joe L.]

Re: C3 Half-Shaft UJoints

Pat------

The half-shaft u-joints ARE different than any other u-joint installation. That's why I usually recommend that folks take them to a driveline shop for replacement.

As Dave mentioned, it's VERY easy to bend the u-joint flange during the u-joint removal and re-installation process. The only way to prevent this is to support the flange with a special fixture which is bolted up to the flange during the removal/reinstallation process. An old spindle flange will work well in lieu of the special fixture.

Even doing the installation using a fixture for flange support, you often end up with "tight" u-joints. Tapping on the center body of the joints between trunnions will often loosen them up.

[Pat Bush]

Re: C3 Half-Shaft UJoints

Joe ---

You were oh so right. Wouldn't have thought it but when I put a dial indicator on the flange, it flexed like a bandit. I did a little engineering and made a 1/4" plate steel backer plate, drilled appropriate holes, bolted the flange on, and voila, no issues -- they went together beautifully and they aren't tight at all now. I would be happy to post the plans if you would like them.

Thanks so much for your help!

Pat