Series 3 Gearbox breather

TheMegaMan · Jan 2, 2021

So nearly finished by S3 rebuild, but realised I'd forgotten to refit the remote breather banjo to the gearbox.

Due to significant incompetence on my part (and a twisted breather pipe that acted like a spring), I've lost the banjo bolt 'somewhere' on my gravel driveway. Consider it lost for good.

Looked at the parts book for a replacement, I see part 22G1941 shown, but it's a local breather valve, not the remote banjo/plastic pipe arrangement I have. I'd like to keep the remote version, if possible, as I may well go deep wading!

However, the V8 gearbox seems to have a banjo-type arrangement, with part 595478.

My question is, does the V8 banjo bolt fit in the I4 gearbox breather hole? And is it also the same thread as the breathers on the axles?
And am I correct in assuming there is just the single port on the gearbox, or is there also a breather on the transfer box that I've not found? The V8 gearbox seems to have two ports...

Flossie · Jan 2, 2021

I know the LT77 use BSP threads, 1/4" I think, you can use a cheap pushfit elbow and 6mm nylon pipe if so.

TheMegaMan · Jan 2, 2021

Flossie said:
I know the LT77 use BSP threads, 1/4" I think, you can use a cheap pushfit elbow and 6mm nylon pipe if so.

I bought a remote breather kit for the axles a while ago, and I think that had 1/4" push-fit connectors as you describe, but they are too small for both my axle breathers and the gearbox.

I think these are more like 5/16" diameter, but don't know what the thread is, and it might even be M8...or more likely, mine is imperial but the banjos I can see on ebay are M8, given they seem to suggest they are for newer Defenders and Discos, rather than series.

Thanks for the suggestion, but I don't think it's what I have on my Rover axles or gearbox breather.

Flossie · Jan 2, 2021

Coiler axles are 1/8" BSP so they would be too small if your box is same as LT77 at 1/4".

Flossie · Jan 2, 2021

Wadeing bellhousing plug on a LT77 and maybe r380 is 1/4".
I you've got one of them to try for fit in your box?

TheMegaMan · Jan 2, 2021

FYI, the remote breather pipe I have is something like this:

https://www.ebay.co.uk/itm/363080402411

I've also been looking around to see if I can determine what gearbox model I have. I'm 99% sure it's not an LT77. I've found many S3 4 cylinder gearboxes that look like mine, but none seem to say what model they are...and curiously, none have a breather where mine is. So I'm now wondering whether this was something added by a previous owner, and it's completely non-standard. It wouldn't surprise me, as it had a few other mods to assist with wading (home-made snorkel, etc).

Thank for your offer, @Flossie, but it hardly seems worth the effort getting one to me to try. I've just ordered a 595478, so will see if it fits when it arrives. If not, I'll have to comb the gravel on my driveway and find the damn think that flew out of the cab!

rob1miles · Jan 3, 2021

If you get a nylon 1/4 BSP elbow it will probably fit and if the thread is a bit wrong it won't damage the box while you search for the right one. I lost a thumbscrew on our gravel drive - if fell from the dash through a gap in the floor and turned up 18 months later when I looked down and saw it plain as day despite searching for ages.

jamesmartin · Jan 3, 2021

TheMegaMan said:
FYI, the remote breather pipe I have is something like this:

https://www.ebay.co.uk/itm/363080402411

I've also been looking around to see if I can determine what gearbox model I have. I'm 99% sure it's not an LT77. I've found many S3 4 cylinder gearboxes that look like mine, but none seem to say what model they are...and curiously, none have a breather where mine is. So I'm now wondering whether this was something added by a previous owner, and it's completely non-standard. It wouldn't surprise me, as it had a few other mods to assist with wading (home-made snorkel, etc).

Thank for your offer, @Flossie, but it hardly seems worth the effort getting one to me to try. I've just ordered a 595478, so will see if it fits when it arrives. If not, I'll have to comb the gravel on my driveway and find the damn think that flew out of the cab!

is it 4 speed and all ali

TheMegaMan · Jan 3, 2021

Ah, I think I have an LT76. I'll try an elbow for size tomorrow, but I'm not hopeful. Got a bit of tape over the hole at the moment!

I've done my entire rebuild over gravel. Not the best of places, but I didn't really have a lot of choice. I've dropped lost of nuts, etc, over the months, but found nearly everything else. But this one just flew and I've really no idea where to start looking. And it was old and tarnished, so it won't even sparkle in the daylight.

TheMegaMan · Jan 3, 2021

Definitely a 4-speed. I think it's ali, but not actually checked. Looks like this https://www.picclickimg.com/d/l400/...nd-Rover-Series-Iia-Series-Iii-4-Cylinder.jpg and the breather is in the middle of the cover plate on the far right if the image.

jamesmartin · Jan 3, 2021

TheMegaMan said:
Ah, I think I have an LT76. I'll try an elbow for size tomorrow, but I'm not hopeful. Got a bit of tape over the hole at the moment!

I've done my entire rebuild over gravel. Not the best of places, but I didn't really have a lot of choice. I've dropped lost of nuts, etc, over the months, but found nearly everything else. But this one just flew and I've really no idea where to start looking. And it was old and tarnished, so it won't even sparkle in the daylight.

thats std series box and never had remote breathers, just little holes on the square tin top plate and circular plate further forward

TheMegaMan · Jan 3, 2021

jamesmartin said:
thats std series box and never had remote breathers, just little holes on the square tin top plate and circular plate further forward

OK, in that case, it must indeed have been a PO modification. I was beginning to get that impression from googling gearbox images, although puzzled why the parts book shows 22G1941....although looking at it again now, it's not quite the same place as hole in mine - mine is more central.

So fingers crossed the PO used a V8 gearbox breather pipe/banjo, as that seems to be what I've ordered!

Colthebrummie · Jan 3, 2021

Go over your gravel with a magnet.

Col

Blackburn · Jan 3, 2021

Likely 1/8 BSPP thread.
Nominal Size (inches) Major Diameter (inches)
1/8 8.8 mm

rob1miles · Jan 3, 2021

I have to work over gravel, I have a very large magnet on a piece of string that I drag around when I drop something. Pity it wont do the SS nuts and washers I keep dropping.
I also have an old 1960s plastic kitchen mat, kind of woven plastic tubes, horrible thing but great for working on as its stiff enough to slide underneath and oil runs through it.

TheMegaMan · Jan 3, 2021

You're right...I really should get on and just find it. I just don't really know where it went or how far. I'll dig out a magnet, and hope the bolt isn't brass. It would be a lot easier if I didn't have a Land Rover parked over it...

I do have a bit of carpet I lay down when I'm working under a car and likely to drop stuff, but on this occasion, I was working inside and didn't think I'd need it. Unfortunately, the floor wasn't fitted...

Nice idea about using something plastic/oil immune, though. 60's furnishings do have a use!

TheMegaMan · Jan 4, 2021

Tried dragging a magnet around under the Landy as well as I could but didn't 'catch' anything.

Checked the size of the hole, and found a 3/8" UNF and M10 bolt both seem to fit. The 3/8 is a little looser than the M10, so I'm guessing it's actually tapped to M10, and the plate is thin enough that for the few threads through it, the imperial bolt thread also fits.

Is it plausible that the V8 gearbox breather is M10? Or would M10 have been used on Defender/Disco gearbox breathers?

Looking on ebay at M10 banjo bolts, most seem to be either aluminium or stainless...so maybe that's why the magnet didn't find it. I'll search again once I've managed to move the Landy out of the way.

TheMegaMan · Jan 4, 2021

Oh, and this is where it fits...the bolt checking the thread...

TheMegaMan · Jan 5, 2021

Sorry to drag on with this thread (pun intended), but I'm really confused.

Part 595478 turned up today...but it doesn't fit. Thread is too fine.

It looks like it's 3/8"/10mm diameter, but 28tpi (0.91mm pitch). What kind of size is this? As far as I can tell, UNC would be 16tpi, and UNF 24tpi. Tables seem to suggest it might be ISO Inch, 28UN. A bit niche?

When I was trying bolts in it, 10mm x 1.5mm pitch fitted, and 3/8" UNF (24tpi=1.06mm pitch) fitted, but the bolt that arrived with a 0.91mm pitch doesn't. It's presumably very marginal that the 1.06mm pitch bolt fitted, probably because 3/8" is a little loose in a M10 hole.

I can't see any M10 x 1.5mm banjo bolts, so I hope an M10 x 1.25mm pitch will fit. Most seem to be 1.00m pitch, but experience suggests that is probably going to be too fine, again.

Can anyone see anything obviously wrong with my thinking, here? It's damn annoying!

TheMegaMan · Jan 5, 2021

Scrub that...I've found an M10 x 1.5mm banjo bolt on the Think Automotive web site, so I've ordered one of those, too. Something *must* fit!

Series 3 Gearbox breather

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