Front Drive Shaft Update

[ORSO]

Beat me to it. I have had larger version of these spicer non greasable truck slip joints do the same piston thing. Pull the Uj back and it will create a vacuum then retract or pressurise and expand. Pretty sure because of being non serviceable Spicer Life series SPL slip joints are not vented. Not really an issue with bolted flanges but a real pain when trying to remove and fit them.
Would Spirolock suit this application better then a circlip
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Interesting, I didn't know about them.
I see they're generally used on pistons, making contact on the outside. Can they also be used on the inside, as in our case?
In Europe, however, they seem impossible to find. Where can I find them in the size needed for our driveshaft?