O rings

[Welderpaul]

Found 1 out of 2 apron oil leaks. There's two o rings, O ring 0216 24 (RM) has been taken out at some time in history and the other o ring is a bit flat and past it.
I've been loosing the ends of my fingers with a selection box of various o rings trying to get them to fit.
The o rings fit over the shaft fine, and look to match the one that is there, but when I gently try putting the shaft back in the hole it just scalps the o rings and makes me swear.
I've oiled the o rings and being careful putting them back in... i know the script on how to fit them.
It doesn't help that there is a snap ring groove machined right on the lip of the sleeve.

Harrison M300...what is the actual size of the o rings that should be in there - there's nothing that seems to refer Harrison's code to a standard O ring size. It's evidently a common problem though.

 

[brightspark]

cant answer the size but theres metric and imperial sizes I have both sets. even then some gear uses thinner ones that aren't in either . sprayguns is an example and welding torches

 

[armalites]

One of the problem is when you have the selection boxes you think you are all set, in many case you are but there are variations available in every dimension. Some applications make allowances for streching a smaller seal for a tight fit.

I feel your pain, it can be a nightmare, fortunately some parts listings list dimensions and when you compare to what you have they don't even look the same. My Volvo doesn't have a dip stick but it has a service port/dipstick. The O-ring has a chunk out of it and it is quite thick cross section for it's diameter. I've ordered 3-4 of the most likely sizes and I still can't find the right one. I can buy a new plastic dipstick buy they are about £30. Volvo parts tend to be ok-ish but this is a bit of plastic with an O-ring and you can't buy the O-ring on it's own.

These people are very good
https://www.polymax.co.uk/o-rings/

 

[grim_d]

I always find that the selection boxes o-rings are very thick compared to anything I want to use them for so they don't fit, as you are experiencing.

I would measure the old one as careful as you can as well as the grooves and contact a supplier, "oringeverything" on eBay has always been very helpful for me.

Other option, make the groove a smidge deeper?

 

[gordon stephenson]

Welder Paul, have you tried wrapping 0.002 shim around the "o" rings to get them past the snap-ring groove?

 

[Seadog]

If you can find an O-ring in a selection, that fits, you're a very lucky man. I've had minimal success. But my drawers of odd O-rings and fibre washers have come up trumps on many an occasion.

Definitely use a shim if there's enough room. It's a bit of a design flaw, really.

Unless there was a factory circlip with straight sides that was used to blank the groove.

 

[armalites]

cutting an old lemonade bottle up and using it as a guide can work

 

[Seadog]

Is the diameter constant the whole length, or does it enlarge a little above the circlip groove?

 

[brewdexta]

I had a similar problem on my Colchester chipmaster, either too thin and leaked or too fat and wouldn't fit. I sorted it by buying in-between standard sizes from Poly max https://www.polymax.co.uk/o-rings/ they seem to have a huge range. I only needed two but had to buy 20 I believe but it worked and stopped the leak, here's the original thread https://www.mig-welding.co.uk/forum...ter-lathe-adjustment.39115/page-2#post-453308

 

[pressbrake1]

Those o ring kits are rubbish, I’ve had two sets for twenty years without using them up!
I have a proper set I got from fpe hydraulic seals, try them

 

[scottmk1]

21.6mm x 2.4mm and 13.6mm x 2.4mm if you can wait a couple of weeks I'll post you some

 

[Agroshield]

If you put '0136 24 o ring' into Google, you get results, as do you with 'RM0136-24'. It is a standard O-ring code.

It is always worth trying this as a first port of call.

 

[Welderpaul]

If you put '0136 24 o ring' into Google, you get results, as do you with 'RM0136-24'. It is a standard O-ring code.

It is always worth trying this as a first port of call.

Indeed!! I googled this ref, but added 'Harrison M300' thinking it was a part number specific to them, as all their other part numbers are, and it was lost in the search results.

I have some 13.6 x 2.4mm o rings in the set but they are, as i now know, hugely oversized. The OD of the metal shaft is a tight fit in the socket (Loud pop when its pulled out type fit) so i couldn't use anything to guide it in - i tried using a sliver of beer can and it just jammed up.

I've ordered some decent quality o rings from a hydraulic supplier and it will be interesting to see how they differ in size.

O ring set now in the bottom of the wheely bin.

The other leak was a bit easier to find..

Thanks fellas, always appreciated!

 

[Agroshield]

Google is sometimes a fickle mistress. Sometimes you can put in too much and you do not get the results you want; sometimes you put in too little and the stuff you want is lost in the dross.

In the Colchester manuals I have seen, they have different 'styles' of part numbers. One style is for machine-specific parts; the other style is for what they call standard components. They list the standard components at the back of the manual.

You can sort of see it in the part diagram you show: the RM O-rings are standard; the ENOTS whatever they are are probably standard; the CB circlip is standard. The knob whose number is not shown may be standard. If you can identify the two styles, it can help find stuff.

It is also worth seeing if there are any alternative manuals to the one you have (older or newer printings), including for machines that may share parts.

 

[8ob]

If you drop an o ring into the circlip groove and grease it the piston will pass over the groove without damaging the new seals. pick it out with a bent scriber once the piston has gone past.

Bob