U Joint Boot Question

[Jruby38]

I install a new U joint and used my old boot. I see the back is on good but I have a little gap on the front by the engine output.  Does the front fit flush to the block?  Any pics, I do not have any way of comparing to another Valk.  I think a little silicone seal is in order to keep any water or dust out. Last U joint went 100k any still seems ok, so I won't be back in there soon.

[sandy]

When reusing the old boot, it forms a "fit" and if you have a gap, it needs to be rotated to find the old "fit" position. New ones are symetrical.

[Ricky-D]

There is a lip on the inside circumference of the boot that is meant to fit into the corresponding groove on the case.

For two reasons.

A better sealing and a better more secure retention of the boot in the proper position.

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[Jruby38]

Does the boot shrink with age like me, and will a new one be longer?