[fordem]

I'm sure someone here knows the answer to this question - the transfer case breather on an SJ413 case - how is it fitted? Screwed in? Press fit?

My research shows that the same part number breather is used on the Gen4 Jimnys and I'm considering extended breathers, there is not a lot of room to get the old fitting out unless I drop the case, so, I'd like to make sure I have all the bits I need on hand for when I start. I already know what's needed for the differentials, and the manual transmission already has an extended breather.

[Beery]

Press fit. They'll wiggle out with some pliers or whatever if needed.

I think I cut the nub off the end of the bung so it was flush, then drilled and tapped for a 90° fitting to accept 6mm fuel line. There might be some pics way back in my build thread from when I fitted the first set of reduction gears.

[fordem]

Thanks - would you, by any chance, recall the size of the existing hole, or what you drilled it out to? I'll go take a look at the build thread and hopefully the pics didn't get lost in the photobucket "kidnap/ransom" saga.

[Gwagensteve]

If you mean the existing hole in the steel insert, that’s about 5mm. (From memory, I’ve never sized it)
With the insert removed the bore of the aluminium case is the correct size for tapping with a 1/4” BSP tap.

[fordem]

Thanks Steve - I think I'm going to follow Beery's approach - he removed the existing fitting, shortened it and then drilled & tapped it 1/8" BSP before re-installing - I'll order one, cut, drill & tap and then remove & replace, which I think will be possible without having to remove the case. To get enough room to drill & tap to 1/4" BSP will require removal.

[Gwagensteve]

Yes, agreed that approach avoids dropping swarf into the case.

[fordem]

Steve - what's your take on greasing the tap to catch the swarf as you tap the hole?

This is not for the transfer case breather but the axles - the existing breather tube is supposedly a 9mm ID and can be tapped 1/8" BSP without redrilling (the correct drill size is 8.8mm)? The folks who have done it before me have greased the tap and then changed the diff oils after.

Beery did something similar (tap to 1/8" BSP), but I think he had the centers out of his axles when he did it.

[Gwagensteve]

I have experimented with this- last time I tapped a diff breather to 1/8” BSP I greased the tap and then checked how much swarf was left in the axle after tapping. I’ve always done it to a bare housing but did wonder about how much debris actually made it into the housing.

I’ll be taking the centre out every time.

[fordem]

Gotcha - thanks...

[fordem]

If there's anyone else who comes across this discussion - another suggestion that I came across to permit tapping "in situ" is to fit an air chuck to the fill port and pressurize the housing to 4 or 5 psi and allow the air to blow out of the breather as you tap. At this point in time I'm undecided, I plan to tap another fitting to see how much swarf is generated before I go near the axles - I do have "spare" fill & drain plugs from a GV axle that should fit the Jimny axles if I choose to go that route.