Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 New 3W bevel box leak

A plugged vent can apparently blow the seal. I have been lucky, that is the only point that does not seem to leak, yet...

Pinion seal leaked from day one. Oil tank cap weeped continually until I vented the tank. And then there is the oil I have spilled...

Hello everyone!

Back to this subject. MMC replied to my dealer here in Madrid about my "classic" oil seal leak at the front of the bevel box. Here's their reply:

"You will have to cut through the steel bracket over the propshaft to enable you to remove the propshaft. (After the repair, you must weld the bracket back together.) You will have to replace the nose cone oil seal. Make a mark on the nut, flange and bevel box pinion. Undo the nut and remember to count the number of turns out. Replace the seal. Fit the flange in the same position. Refit the nut and remember to count the number of turns back on. They must be the same. (Please note that the front pinion nut has a backwards thread!)."

I've seen the videos from Phil Bleazey about how to replace it and all the possible documents. But I want to be 100% sure that I order the proper Viton best O-ring instead of letting them put acheap standard one back.

Can you please confirm to me where through internet exactly and which reference is the good one to buy?

Thanks!!!

The seal specification that you require should be 55x42x8mm R23 Viton double lip rotary shaft oil seal with gaiter spring. Have a look at the face of the seal to confirm this is the correct size as there is a possibility that another size could be used as well. This information is on the first page of the Alternative Parts List that is available via the MTWC website or the "M3W resources" sticky at the top of this forum list. You should be able to get this seal from a local supplier as it is a standard size but they are available from a company such as Bearing King in the UK if not, they cost about £12.

As you are a member of the MTWC you have full access to all the past Bulletin articles through the "Linked Bulletin Articles" https://www.mtwc.co.uk/news-post/ . There is an article about doing this job dated March 2020. The MMC instructions are OK but I would suggest bolting the propshaft bracket rather than welding it as it will be easier to remove the propshaft another time. Also they make no mention of the need to put some silicon sealant on the splines of the input shaft to prevent oil leaking down them. The retaining nut is a lefthand thread. You will need to fabricate a gag to hold the flange when removing the LH thread nut, see photo in the article.

Thanks Ian. Useful as always! I did revise all this documentation and I'm planning to supervise the works at our dealer's workshop. The mechanic I talked to today was more than happy when I offered my help and more instructions than the simple ones of MMC email.

To make sure again: I'm about to buy this one: https://www.bearing-king.co.uk/bear...-shaft-oil-seal-with-garter-spring/15744 It's the correct one isn't it? Here locally I'm not finding it, so I prefer to go to a sure source as Bearing King UK.

By the way: is it mandatory to remove the prop shaft? I thought it was splined at front and would slide forward enough allowing to take the bevel box out, won't it?

Shall we loose the rear wheel to release the tension of the drive belt?

Thanks again and sorry for my insistence... but as the dealer's garage here has less information than I do, I better be sure of what it has to be done and how...

You don't need to take the bevel box out. The cutting of the bracket facilitates moving the prop shaft aside, not taking it out, this then gives you access to remove the retaining nut, propshaft drive flange and oil seal carrier. You can then remove the seal from the carrier and then reassemble.

Is it better to work this with the bevel box mounted? I thought it was muh better / easier to remove it and you don't need then to cut the bracket.

There is not a lot to choose in either method, I actually did mine out of the car as I was fitting the Bleazey bevel box mount at the time. If you are not keen on cutting the bracket then take the bevel box out.

Agree with what Rog G says about the propshaft. I have done this job with the bevel box in situ and out of the car, I think it is easier in the car fitted as it is anchored down properly, although a little tighter for access. It's a lot of unnecessary work to remove the bevel box just to replace the seal. If you cut both of the metal brackets the propshaft can be removed to give you good access to the pinion nut, no need to disturb the rear wheel or drive belt. Just drill the brackets either side of the cuts and bolt a joining plate over the bracket cuts. It will be there for the next time the propshaft needs removing and just as strong to retain the propshaft in the event of failure.

The Viton seal you have the link for is the correct one.

Don't forget that the pinion nut is a LH thread!

I've not had any leaks, but recently completed the upgrade to the Bleazey BB mounts. Highly recommended. I would do both at the same time. Perhaps typical M3W job, they tend to expand in scope.

So here are my last thoughts...

My 3-Wheeler tends to go right when I don’t have both hands on the wheel. So, I believe I have to check the wheels alignment.

If it happens that the rear wheel is the cause of this deviation, and consequently I have to align it, it means I have to loose the rear wheel. Then removing the bevel box is not such a big deal as I’ll be able to release the belt.

If not, then I’ll do the change of the bevel box’s oil seal with it mounted in the car, cutting the brackets. And as you suggest, I'll bolt small plates better that asking the guys at the workshop to reweld them.