I took apart the breather on my car this week, just out of idle curiosity as I've never opened one up before really, but I'm guessing it's been on my car since it was new and I've suspected it's not been in tip top condition for a while...
It fills up with emulsion almost weekly, no idea why as the car gets thrashed over a fairly long distance twice a day.
I ground around the lip halfway down the breather to release the two halves...
With the top removed you're left with this bit. It's pressed into a rubber gasket and the bottom half of the breather. Gently prising it out with a screwdriver revealed this rubber one-way valve...
In this breather the rubber had perished and there was 1/3rd of the rubber broken away completely, obviously this should have (and I dare say *will*) be what consigns this breather to the dustbin. Only once I'd got this far did I really check how much they are new. This, perhaps, I should have done first. Then followed an hour long search of the farm for a bit of thin rubber to match the broken valve. I eventually found a suitable bit of rubber and cut it into a circle using the broken one as a template. I secured it to the three original securing holes (originally it had three rubber pegs, but these were also buggered) with three pop rivets.
The bottom part of the breather also has a different type of one-way valve built into it, it's a piece of rubber tube with slots cut into it, which sleeves over a metal pipe with perforated holes behind the rubber slots. Air can come up from the crankcase through the metal pipe and out through the rubber slots, but the slots will close up and seal if air tries to go the other way. I didn't have any rubber tube and having already come unstuck having to hunt for a bit of rubber sheet for the other valve (I used a mudflap off me 2CV, BTW) I elected not to try and replace it and I cleaned up up as best I could and left it. It wasn't broken like the other one.
Then I welded the two halves back together (minus the rubber gasket, I'm not sure how critical it was, but I assume becaue the breather originally fitted together with a rolled seam it needed a gasket, it's welded now, and therefore sealed) You're best off cleaning it right up and fusing it with a TIG welder, but you're welcome to MIG it like I did, it just doesn't look very nice. It's important not to put too much heat into it because you'll bollocks the rubber you just replaced again. Don't bother gas welding it or brazing it, the rubber is almost immediately behind the bit you're welding, and the heat will shag it.
Then I stuck it back on the engine. Does it work? I do not know, but I hope so, I can't see why with all the oil residue and mayo and shite removed, and that broken rubber one-way valve replaced, it shouldn't at least be an improvement on what I had. The worst case scenario is that I need to buy a new one, and I'd have had to do that anyway, so it was worth a try. I'll report back when I've finally finished putting this cocking engine back together...
don't think so
