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Old 11-04-2016, 09:13   #16
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Re: Rebuild question on Groco K

Quote:
Originally Posted by wsmurdoch View Post
Tell me, what am I changing when I flatten the piston rings? Am I making the ring wider, that is increasing the width of the ring thus making the outside diameter greater and the inside diameter smaller? Or, am I making the piston ring longer so that the gap disappears thus making the piston ring bigger in diameter?

Do you have any pointers or technique? I think a re-rebuild is in my future.
You are changing the OD (outside diameter) of the Delrin rings so they fit tight against the inside of the brass cylinder.

The steps I use:
1. Gently tap one side (the flat surface) of both rings to expand them slightly. And by slightly, I estimated a millimeter, but this measurment will vary with each head. I used a medium weight ball peen hammer with smooth face and placed the ring on a smooth metal dock cleat. I don't recommend using a framing hammer (too heavy) or a hammer with any sort of pattern on the face. Don't place the ring on wood (too soft) or concrete (too rough.)
2. Place both rings on the piston and insert the piston and rings into the cylinder. I used a thin, sharp blade to coax the rings into the cylinder being careful to not cut the rings.
3. Check for fit. Move the piston up and down the cylinder with your fingers. Does the piston slide easily? (Rings are still too small.) Can't move the piston up and down? (Rings are now too large.)
4. Repeat step two until the rings fit really tight, but you can still (just barely) move the piston up and down in the cylinder.
5. Remove the piston and rings and lubricate the rings with marine grease.
6. Reinstall the rings and piston inside the cylinder.

The specs for a newly built head call for .001" of clearance between the OD of the rings and the ID of the cylinder - a really, really tight fit - but most people don't carry a micrometer onboard. And the plastic rings are a challenge to measure accurately since they are flexible.

When we rebuild the head again in 6-12 months, we'll take pictures and post a complete set of color work instructions on the forum.

Let me know if you have any more questions - happy to help. (We are headed into the Sea of Cortez in three days and will be out of internet range for quite some time.)

Good luck!
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Old 11-04-2016, 09:34   #17
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Re: Rebuild question on Groco K

A couple of pics that may help.

To test the fit of the rings, I inserted the piston upside down so I had something to hold on to.
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Old 24-12-2017, 07:40   #18
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Re: Rebuild question on Groco K

I know this is an old thread but everyone says use the search function - so I did!

Had a fellow rebuild my Groco K the other day. Didn't remove the base so couldn't replace these fussy O-rings on the cylinder. It was the only thing working well so I just saved the rest of the rebuild kit.

Two questions:
1. even with a new bowl to base gasket it leaks out the sides when pumping in certain conditions, how come?
2. if Vaseline is no good, how about LanoCote on rubber surfaces?
Thanks and merry Christmas Eve!!!

PS: the guy that did the work is gone until next year.
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Old 24-12-2017, 07:55   #19
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Re: Rebuild question on Groco K

Don't use any sealant or lubricant. The two most likely reasons it leaks:

1. Bolts that mount the bowl to the base not tight enough...but more likely:

2. Bolts OVERtightened. People really crank 'em down tight trying to make sure they can't leak....but overtightening bolts (same thing applies to a joker valve, btw) will cause the rubber gasket to pucker around each bolt...causing the very problem you tried to prevent.

So if you're sure the bolts aren't loose, try backing them out just a WEE bit to see if that doesn't cure the problem.

Merry Christmas!

Peggie
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Old 24-12-2017, 08:02   #20
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Re: Rebuild question on Groco K

Two things:

1. Do not put any lube on the gasket. If you have already put lube on the gasket, clean it (dish soap) and dry it off.
2. Tighten the bolts - tight. If it is still leaking after #3 and #4 and reassembled, tighten some more.
3. Check the ceramic surface of the bowl where it fits to the base. Make sure it is level in all directions. Also, there could be something stuck to the bottom of the bowl base. If so, remove it.
4. Make sure the bronze base is smooth and clean. No small particles of old gasket, etc.

Good luck!
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Old 24-12-2017, 08:20   #21
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Re: Rebuild question on Groco K

Follow up:
We were told by Lopez Marine in La Paz, Mexico that toilets could not be imported into Mexico, citing a new rule about ceramic imports.

So, we purchased a new head while we were back in the states in May 2016 and carried it back with us in our carry on duffel bags on Alaska Airlines. Yes, an entire new Groco toilet - base, bowl, seat/lid, and lever. We divided the parts according to weight into two carry on bags, one for each of us, and each bag was still under the weight limit.

In Mexico, we got the red light in Customs and had the bags inspected. Apparently, they were looking for tobacco or alcohol, as the toilet was not a problem. I had our TIP for the boat with us, with the list of items included in case it was needed, but it wasn't. And no import fee. Just a smile and "Enjoy your stay in Mexico!"

The difference between our old head and the new one is night and day. Yes, 28 years is past the service life of a Groco head. It was time. Not a single problem with the head since installation.
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Old 24-12-2017, 10:04   #22
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Re: Rebuild question on Groco K

There's more than one Groco toilet, Sailor...the compact HF (preceded by the HC and HE), the EB (which Groco discontinued about 10 years ago) and the Model K, which is which what Flyingriki has. It's an entirely different toilet from the HF (which does only have a 9-11 year lifespan)...solid bronze with a price tag of about $1300 today and made to last at least 50 years with minimal maintenance (mainly keep it well lubricated). Groco Model K

Btw...you might want to read my reply to him directly above yours.

Merry Christmas!

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