Re-sealing worn o-ring?

[dishman]

I appreciate this might be classed as an appliance issue, but it is more about sealing a worn o-ring.

I have a bosch dishwasher that has a leak.

It looks like it is from a worn o-ring seal that the diverter motor cog slots into. You can just see the tiny sliver of a rubber o-ring. I can't think the leak can stem from any other seal. I don't remember losing a washer or anything when I repaired the mechanism.



However, it seems like this o-ring fits into a groove, and it is tiny, and probably not meant to be replaced. I probably disturbed it when i fixed the diverter valve actuator.
It has drip leaked since....and only just got round to trying to fix it.

The drip actually stops once the dishwasher heats up.

But.....assuming the o-ring replacement possibility is very low (i would probably do more damage trying to get it out) would a high tack plumbers paste work if I coated the shaft and the o-ring in it?

I have read that Molykote 111 might be the best stuff for this and will resist any washout. Are there any other pastes or seals that might work in this situation? Or might be better? Or is there a better solution?

Dishwasher otherwise works perfect, and is around 25 years old.....I'm not giving up on it now....

 

[jj4091]

Not really into dishwashers, but if you want to keep it going is there a sub assembly you can replace can't really tell from your pic what that is. If it's a diverter valve try googling your model number to see if there is a seal or kit or the assy.

 

[steven lee]

Molykote 111 is the right stuff for this. It is a silicone grease so it is safe on the rubber and it will not wash out or dry up the way normal plumbers paste would. Smear it on the shaft and the o-ring, run a couple of hot cycles and check it. Fair play keeping a 25 year old machine going.

 

[Deluks]

Inspect the O-ring with a magnifying glass for any tears or nicks, bear in mind that rubber can harden/shrink/expand over time, so it might not fit as it used to.

If it needs removing, a safety pin can be used to hook it out. If Bosch can't provide a replacement (unlikely) then a specialist bearing/O-ring supplier might have one (try Orbic)

Clean away the existing grease and any debris, and regrease with your moly stuff.

 

[dishman]

Ok, I might just try that Moly stuff and see how it goes.

Just checking there was not a better solution I was missing.

If that moly stuff is better than normal plumbers paste, I think I'll give it a go.
To be fair it's not that much more expensive, but did not want to buy something when a generic paste would be the same. But, it does seem to have a good reputation for being used in this scenario.

If it fails, a hunt for an o-ring may commence.

Out of interest, the diverter mechanism on this is the similar (nearly identical) to those found in boiler diverter valves. Is that cog shaft similar to that found in a boiler diverter mechanism? Wondering if the o-ring might be a source able part via a boiler spare or something.

 

[endecotp]

In my experience, the difficulty with replacing worn O-rings is working out what size they were before they became worn.

See if you can get an assortment pack. What is the approximate size?

 

[dishman]

I'm not removing it to find out....yet.

But the internal diameter of that hole is 2.5mm, so assuming that o-ring is sitting in a groove, and some is meant to protrude, I imagine the external diameter is about 3mm.

 

[Johntheo5]

A standard 2.5mm ID O ring has, I think, a minimum CS of 0.5mm which gives a OD of, 2.5+(0.5x2), 3.5mm.

 

[dishman]

Seems the o-ring is not what i thought.....

Whilst prodding and taking a measurement, I realised that that gray doughnut was actually soft rubber. It is a chunky doughnut o-ring, not just the slim black part.



Looks like I need to work out if this is available as a spare....

 

[jj4091]

Try typing you model number into the Ranson spares search page. I have always found them very helpfulin getting parts for old machines if you can't find them on the site you might need to ring them or send them your pics. They often have excellent exploded views of appliances

Bosch Dishwasher Seals & Gaskets - Page 3

Find genuine Bosch Dishwasher Seals & Gaskets spare parts and accessories.

www.ransomspares.co.uk