Weird Jabsco Head Experience

[jviss]

For what it's worth:

I have a Jabsco 29090 head, vintage 1996. It works O.K. Sometimes it squeals a bit and we put some vaseline on the pump shaft and it's OK for a while. Sometimes it pumps great, other times not so great.

(I ordered a new pump assembly as a spare, as it's $16 more than a rebuild kit, and lot quicker to deploy. Plus, it's an improved version.)

Anyway, I noticed the bowl rocking, and upon investigation found that the rear two bolts were hanger bolts that had pulled out of the wood-cored fiberglass mounting surface. The fronts were through-bolted. They were also undersized at 1/4". I replaced all four with new, 5/16" bolts, fender washers, and nylock nuts. It's very solidly secured now. I also rubbed some Super Lube on the pump shaft.

Now that it's secured, the pump works great! It pumps surely and solidly, and with no noise at all. It's truly a remarkable improvement. I have no idea why.

 

[Peggie Hall HeadMistress]

Compact manual toilet only have an average lifespan of about 10 years IF they're meticulously maintained, so your toilet prob'ly had already been replaced at least once and it sounds like it was a DIY job done by a PO who used whatever he had on hand. How were you able to access the area under the head sole to use nuts?

Because that's not possible on at least 95% of boats, marine toilet mfrs design 'em to be secured using lag bolts...no nuts needed. So to guarantee a tight fit for the bolts when replacing a toilet, it's always advisable to fill the mounting bolt holes first and tap new ones, 'cuz even if replacing the toilet with a new version of the same one, the tolerances on the new bolts can vary from the originals just enough not to be a snug fit.

It's not the pump shaft that needs lubrication, it's the inside of the pump cylinder that does. Why? because lubrication protects the seals, o-rings etc that rub against the pump cylinder walls...the pump shaft doesn't rub against anything. Some of the grease you put on the shaft may migrate onto the rubber parts on it, but it's not enough to last much if any longer than veggie oil poured down the toilet. There's a very easy way to put enough grease into the pump to last at least all season, maybe even two in your neck of the woods: Remove the top of the pump (PHII owners, remove the screws that hold the pump onto the base and lift it just a bit)...stick the nozzle on the tube of SuperLube (great choice, btw) into the pump and give it a healthy squirt--about a tablespoon is enough. Put the top back on the pump, pump a few times to spread the grease all over the inside of the pump and you're good to go till next spring when you'll want to do it again as part of spring recommissioning.

--Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

 

[jviss]

On my Tartan 3800 there's a teak panel beneath the head mounting pedestal. When you remove it, there's a hole, probably 4" in diameter, so you can reach underneath.

I believe the toilet originally had hanger bolts: a lag screw thread on one ned, and a machine thread on the other. You turn the lags in, drop the toilet onto the "studs," and affix with washers and acorn nuts.

About the lube, I hear you, @Peggie Hall HeadMistress , but it just seemed to work. Jabsco has pretty good instructions for the rebuild, and the only things lubed are the rod and the cylinder bore. Your method seems like it will work, but if I do it, I may disassemble a little further and apply the grease more precisely.

 

[Peggie Hall HeadMistress]

"It just seems to work"...but for an entire season or even two? Ever wondered why a brand new toilet never seems to need any lubrication for at least the first year? That's because "my" method is the same way toilet mfrs lube every manual toilet that goes out the door (although they do it before they mount the pump onto the base. Where do you think I learned it...or do you think I just make stuff up?
But however you want to do it is ok with me...

--Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

 

[jviss]

or do you think I just make stuff up?

No, and no offense intended. I read the Jabsco manual for maintenance and rebuilding, and the only mention they make of lubrication is either pumping a bowl full of warm water with a few drops of mineral oil on dry mode; and if disassembling, "Lubricate bore of pump cylinder with petroleum jelly."

 

[Pearson 39-II]

"It just seems to work"...but for an entire season or even two? Ever wondered why a brand new toilet never seems to need any lubrication for at least the first year? That's because "my" method is the same way toilet mfrs lube every manual toilet that goes out the door (although they do it before they mount the pump onto the base. Where do you think I learned it...or do you think I just make stuff up?
But however you want to do it is ok with me...

--Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

Personally, I love to just make stuff up. You know, like jviss, experience-based stuff. I use Dow Corning DC-4 silicone grease on the pump shaft of my Jabsco periodically, like every few Florida months, and the migration you reference goes right down into the pump piston o-ring and cylinder wall and works great. I think Super-Lube is just silicone grease and some Teflon powder - maybe even better. I'll try that too - on the shaft where it lubes the shaft seal as well as the pump.

 

[Gunni]

The great thing about the Jabsco Twist-n-Lock head pump is that you need zero tools to remove the pump plunger and lube the bore of the pump. Handle unlocks and unscrews the pump top right out of the pump. It takes mere seconds to do and allows you to keep the pump properly lubed. Place a gob of SuperLube ABOVE the shaft plunger and smear some onto the plunger O-ring. Screw it back in and done. Do this when the pump begins to get stiff and you can go years only replacing the joker valve, and possibly cleaning the seat on the pump base valve gasket. Those are two fast wear parts.

 

[jviss]

The great thing about the Jabsco Twist-n-Lock head pump is that you need zero tools to remove the pump plunger and lube the bore of the pump. Handle unlocks and unscrews the pump top right out of the pump. It takes mere seconds to do and allows you to keep the pump properly lubed. Place a gob of SuperLube ABOVE the shaft plunger and smear some onto the plunger O-ring. Screw it back in and done. Do this when the pump begins to get stiff and you can go years only replacing the joker valve, and possibly cleaning the seat on the pump base valve gasket. Those are two fast wear parts.

My currently installed one predates the twist and lock model; my new, backup one is a twist and lock. That sounds like a great feature!

 

[Jackdaw]

The great thing about the Jabsco Twist-n-Lock head pump is that you need zero tools to remove the pump plunger and lube the bore of the pump. Handle unlocks and unscrews the pump top right out of the pump. It takes mere seconds to do and allows you to keep the pump properly lubed. Place a gob of SuperLube ABOVE the shaft plunger and smear some onto the plunger O-ring. Screw it back in and done. Do this when the pump begins to get stiff and you can go years only replacing the joker valve, and possibly cleaning the seat on the pump base valve gasket. Those are two fast wear parts.

Did not know that. Thanks!