Cap Keeps coming off.


New Member
The upper spar keeps coming loose from the cap that connects it to the lower spar. The holes on the spar have elongated and broken open. I am thinking of cutting the spar and drilling new holes. Has anyone done this before? Is there a better solution .
I can suggest two solutions: Rotate the spar 90 degrees and drill new holes.
Or, better yet, reverse the spar and drill the holes in what used to be the top end.

There should be no reason for the cap to come off, it is there to protect the spar end and give it a finished look. The spars are joined by Interlocking Eyebolts (P/N 79044). If these are the problem or the holes in the spar are worn, get a new set of eye bolts and do as Pete suggests, swap ends and redrill for the new bolts. The eye bolt holes are located 1/4" from the end of the spar with out a cap in place. When you swap ends also replace the cap(s) and pins. Cap w/o eye (lower) is P/N 43106, Cap w/eye (upper) is P/N 79030, Pins are P/N 79513. Some people also put a bit of sealant (3M 4200/5200 or epoxy) on the inside of the boom where the cap fits. You can find a close up of how things are suppose to look in both the Rigging Manual (photo) and Parts Locator (drawing). Both documents are available on the Vanguard website ( as pfd documents. Good luck.
I found that my cap end moved a bit after being held in place with 5200 (sail tie end). the pins mention by jJohn are probably a good idea. The only problem with shortening the tube is that the wear marks made by the many plastic sail holders will be exposed and may be considered unsightly.
Kino, Al,
The pins work well. Placing one on the opposite side from the eye on the cap will help keep the cap tight. These pins are small and tapered. Drill a hole equal to the small end and drive the pin flush with the surface and you are done. No sealant on the pin is needed. You will have to look close to find them. Remove the pin by driving them in thru the spar tube with a small punch or nail. They will probably be captured in the cap, just pull them out of the cap (like pulling teeth). An alternative method, not quite as nice visually, is to use aluminum pop rivits. 1/8" diameter x 1/4" long work well. Put a little dab of sealant on the rivit before insertion will help seal the hole.