Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Bevel Box Vented?

Getting familiar with the bevel box drain plug, level plug/cap and fill plug. Where is the vent or does it not have one?

The plug on the off side of the BB, about half way up (with the orange cap) is the vent.

Not having one, I can't say anything definitively, but it looks like there are various iterations of them.

Is this a vented cap or the fill up at the top?




Then oddly a side fill one but clearly with the top fill area not drilled.


Perhaps it's been commented on before, but perhaps the plug on top was the original setup but caused the boxes to get overfilled, so they switched to a side fill? Unless that hex in the box itself is the fill and that lower bolt I can see through that cut out in the mounting bracket is the actual drain.


All that said I just did a google search and came across this facebook post from G56

"Does the bevel box on your Morgan 3 Wheeler leak oil? It's worth checking the breather: if it's blocked the air inside the box will pressurise up as it heats up, blowing oil past the seals.
It's the thing with the orange plastic cap, normally on the right hand side of the bevel box: unscrew it, and check you can blow through it."

https://www.facebook.com/garage56uk/posts/484358291773523

So I guess that orange plug there is the vent?

Edit: Or what Bunny said, while I was drafting this long winded reply.

My mistake. I drained and refilled it to the level of the orange cap which is located about 1/2 up the right side. So the fill level is the hex head plug on the lower back of the box (the part that faces the rear tire)? If that is the case...That is why it began pushing oil out the orange cap.

What is the capacity (when doing it correctly)? (-:

330ml comes to mind. Drain through the big bolt on the bottom, fill through the hex nut above the drain bolt. Slightly overfill then leave it stand and the excess with drain out of the hex nut hole.

The one quart plastic jugs of gear oil have ml markings on the side, a quart is about 900 ml I think. Easy to measure that way. Put a piece of plastic tube on the tapered cap on the jug and squeeze away. I keep a spare empty jug, and add 300 ml per the marking on the side, then just empty the contents into the BB.

I guess they moved the vent to the side to make sure people couldn't grenade the thing by filling it completely to the top?

Fast Ken, if you have the equipment, you should do a video of the change, for posterity!

I concur, some people were filling to the orange vent even when on the top of the BB saying it was quieter. Always seem wrong to me to fill any sort of gearbox to the top. I asked my dealer at the first service & was told the filler/level was just above the drain. Without the NVH BB mounting it can be drained & filled from below.