Jabsco twist and lock issue sorted. Need a screw!

[lustyd]

Well, Jabsco call these screws self tapping screws, but no doubt you know better.

Definitely self tappers, when you buy the pump housing there is no thread in the plastic and they're a bugger to screw in the first time. Most don't buy just the pump housing though, it's cheaper to buy the full unit.

 

[lustyd]

On the manual loo it's the same screw that's used into the collar around the joker valve .. #31, 6 off in the parts list.

I just installed one and uninstalled another and these are definitely different screws in at least some manual toilets. From memory the joker assembly ones were longer. I can't remember whether it was the old loo or the new loo but would make sense that they standardised over time.

 

[Tranona]

Well, Jabsco call these screws self tapping screws, but no doubt you know better.

They may well do - I am not responsible for the display of their ignorance. Just look at the picture and compare with a proper self tapper. Then buy a new base unit and note the thread already moulded in together with the notch to take the first part of the thread and the plain end to the screw. A self tapper cuts its own thread into the correct size plain pilot hole. Very different.

 

[lustyd]

I did buy a base, it didn't have any thread cut at all

 

[Tranona]

OK I am obviously out of date because last time I did this job (many years ago) there were threads in base.

Apologies to Jabsco as well!

 

[Martin_J]

And I still can't recall if I have two different lengths of those (two different thread height) screws in my toilet spares box on board...

Is there a name for screws with the two different height threads alternating?

They look very much like threads in a masonry screw :/

 

[NormanS]

They get manky because it's a seawater flush not entirely sealed from the outlet side, it's not a lack of cleaning. Also, the plastic degrades over time in UV so will begin to yellow.
Again though, what you perceive to be engineering and design improvements go against the design principals they have in place. Any fool can engineer a CNC machined aluminium pump with set screws holding it together. It takes a real pro to create a design that's cheap, doesn't leak, widely available parts, and good enough to be bought by the mass market with some profit margin left. I don't think it's the perfect design, but given we don't see better designs that are even remotely as popular that should tell you all you need to know about whether the design can be improved while maintaining a business.

I can assure you that on my boat, the outside of the base of the pump is entirely sealed from seawater. You must have a leak. My toilets are in their own compartments (loos), so the amount of exposure to UV light must be negligible. If of course you choose to install your toilet out on deck.......

 

[pcatterall]

Thanks all! quite interesting in the end and good to see that some other owners need training in how to fit a screw! I guess that I will try a bodge fix and if it goes pear shaped I would buy the base
( didn't spot that it could be had as a seperate item) That said my current bodge might outlast me!

 

[Martin_J]

It's when the end of the screw pokes out through the hull that you realise you've gone too long :/

 

[lustyd]

I can assure you that on my boat, the outside of the base of the pump is entirely sealed from seawater. You must have a leak. My toilets are in their own compartments (loos), so the amount of exposure to UV light must be negligible. If of course you choose to install your toilet out on deck.......

The inside isn’t sealed from seawater unless you have a freshwater flush.

 

[Laysula]

Would be nice if I could buy replacement stickers for the top of the pump.

 

[lustyd]

Would be nice if I could buy replacement stickers for the top of the pump.

Seal Assembly includes them Jabsco Seal Assy -3000 Series

 

[smithy]

I fitted a helicoil into the plastic base, working well for a few years.

 

[davidmh]

When I refit screws such as this I normally check the fit of the screw in the base before I refit the pump unit, I do it by hand and you can feel how tight or loose it is. When I refit the pump I put in screws in with my fingers to make sure it is going into the hole properly and then finish off with a hand screwdriver. Powered screwdrivers are the work of the devil.
David MH

 

[lustyd]

Powered screwdrivers are the work of the devil

Bad ones are, and certainly when people use drills. Electric impact drivers on the other hand are a gift from the gods and in the right hands a very delicate tool which can prevent over torquing which, in the case of a Jabsco loo, will snap the plastic tube off that you're screwing into!

 

[Laysula]

Seal Assembly includes them Jabsco Seal Assy -3000 Series

That's just one sticker out of two and I don't need the seal assembly. At £8.95 plus post they can whistle.

 

[Dellquay13]

It's when the end of the screw pokes out through the hull that you realise you've gone too long :/

Early on in my boating life I discovered how little void there was under the sole of a Fletcher Arrow 14 with its very shallow V hull when screwing down a loose helm seat, but only when there were two bounces when the protruding screws snapped off as it slid down the rollers off the trailer into Salcome harbour

 

[tico]

Technical term for this type of screw is a 'PT Screw' if my memory serves