Jabsco Head O Ring Exact Size ?

[peghall]

If you're asking me to recommend more durable toilets, what I recommend depends on where in the world you are. 'Cuz shipping, currency exchange rates etc can price ANY product that may be a great choice in one country out of sensible reach somewhere else.

So if you'll tell me where you are, I'll try to make affordable suggestions.

[Jd1]

Originally Posted by peghall

So if you'll tell me where you are, I'll try to make affordable suggestions.

Victoria, BC, Canada

Thanks!

[peghall]

Originally Posted by Jd1

Victoria, BC, Canada Thanks!

Which makes U.S. heads affordable... There are two US mfrs left who still mfr in the US...W-C is gone, Jabsco is now doing all its mfr'g in Mexico with parts made it China and other offshore sources. Groco only makes manual toilets--the Model K is a very expensive ($700+) bronze "throne"...the HF is an affordable compact that's a lot more durable than a Jabsco.

Raritan makes a full line of manual and electric macerating toilets. Their PHII has been rated the best in its class for more than 30 years. The PHC uses the PHII pump, but puts it on a compact base to fit in a tighter space. Both are available as a "conversion" which consists of the pump and base, allowing you to re-use your existing bowl seat and lid. Keep the PHII/PHC well lubricated and put a rebuild kit (about $60) in it every 5-6 years and it'll give you trouble free service for at least 20 years. If you shop hard you can find the PHC conversion for under $300...which in the long run is considerably less than spending +/- $100 every couple of years to replace a Jabsco pump. PHC - Raritan Engineering HopCar, who's a regular poster in this forum, is a marine store owner who offers VERY competitive prices to forum members...I suggest you ask him for a quote.

[MC2019]

Yes the seal at the plunger would be a wiper type seal, not an oring. Oring's are not used in dynamic/moving part situations only static non moving part situations.

Mechanical Engineer with over 30 years of experience ......

[Sailmonkey]

Originally Posted by mackconsult

Yes the seal at the plunger would be a wiper type seal, not an oring. Oring's are not used in dynamic/moving part situations only static non moving part situations.

Mechanical Engineer with over 30 years of experience ......

Except for those times that orings are used in dynamic seals...........like in the raritan head pump. In a high pressure application you're correct, but in a low pressure application, where extrusion is not a concern, you're wrong.


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[Jd1]

As a followup and hopefully of help for future cruisers finding this thread:
The o-ring (and it was in fact an o-ring) fit perfectly. Alas, I do not believe this was my problem. One thing I did not mention was that my head spits back at me when there is air in the system. This is easily circumvented by going slow on the pump at the beginning but it's a nuisance. I now believe that the flapper valve at the bottom of the pump is defective. I also found a 'spare' part in the pump head - a little toothed ring that holds on a weight on the valve sheet in the head of the pump. I suspect that this causes air to be allowed in where/when it isn't supposed to be.
An interesting development of things for sure and I now know a whole lot more about the head pump
I am not yet clear on what to do next I do have a full spares kit on hand so I might just replace those two seals (and the joker valve just because it's already apart). Chances are that I will replace the head with the Raritan as recommended by Peggie once I have used up my spare parts for this head.

[a64pilot]

Originally Posted by mackconsult

Yes the seal at the plunger would be a wiper type seal, not an oring. Oring's are not used in dynamic/moving part situations only static non moving part situations.

Mechanical Engineer with over 30 years of experience ......

All the hydraulic cylinders in my Backhoe used O rings to seal the hydraulic fluid and of course that is continually moving, The cylinder had a wiper seal at the end to wipe off dirt, and the O rings had white plastic rings on either side of them, but the O ring was in fact doing the sealing

[peghall]

I suggest you investigate the cost of replacing the pump vs. rebuilding it. A few years ago, ITT spun Jabsco off to a company called Xylem Flow Control who manufactures in 3 countries: the UK, Mexico and China. All their products sold in the western hemisphere are made in Mexico, but since you're in Malaysia, you MIGHT be able to find an affordable "made in China" replacement pump locally. Worth checking into IMO.

You might also check Australian sources...Jabsco seems to be one of the more affordable choices there. Not sure whether theirs are made in China or shipped from Xylem's UK plant...but if they are made in the UK, they seem to be a bit higher quality than those made in Mexico and China.

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
http://www.amazon.com/New-Get-Rid-Bo...dp/1892399784/

[MC2019]

for the question about oring material for those that kind find service kits stick with EPDM or Viton ....

[Obiwan II]

Oring sizes:

I was looking for o-ring sizes with a google search and found nothing so I've purchased
a kit, measured the o-rings and posted them here.

Jabsco 29120-3000 from 2007.

Jabsco item 30 piston o-ring: ID 34.25 x 5.1CS
Jabsco item 9 access plug o-ring: ID 38.0 x 2.0
Jabsco item 18 o-ring OD 52.5 x 2.3
Jabsco item 10 base seal: OD 73, ID 60.2, thickness, 4.8mm
base seal is a flat rubber washer , not an o-ring

the piston rod seal, item 18, is not an o-ring however its possible to glue one in place, in the cap, that should fuction just fine , roughly 20mm OD X 8mm ID at a guess.

[eerkes]

Thought I'd mention something I did when my piston o-ring needed replacing. It was no longer making a seal, likely due to age and wear. I didn't have a new one yet wanted to go sailing so looked for a temporary fix. I found a similar sized o-ring at a hardware store but one whose cross area was much smaller (downright skinny). I removed the old o-ring from the piston and installed the new skinny o-ring in its place and then reinstalled the old fat o-ring on top of the skinny o-ring. The skinny o-ring pushed the old o-ring out enough to make a good seal. Not sure how long this will work but certainly long enough to go sailing for a few days.

[pandw]

Jabsco 29044-3000 seal = IIRC 3/4" x 5/16"

Now you "just" have to source that...