Morris Minor Owners Club

Anyone know the prop shaft grease nipple thread size?

1/4" UNF

Thank you

Depending on their age, could also be M6.

Early engines had metric fixings, but I am not aware that any other threads were metric - can you please enlarge.

I thought this was about propshaft universal joint grease nipple thread sizes? Nothing to do with engines.
Hardy Spicer HS194 have M6 as do just about all currently available replacement UJs.
Make sure too, that the nipple is located where there is a "relief" at the end of the propshaft to accomodate a grease gun!

The grease nipple for the HS194 is M6. You will have to take my word for that.
The grease nipple on the left is M6, on the right 1/4"UNF. That was removed from an old UJ marked "Hardy Spicer" fitted to a propshaft on a 803cc Minor.

The "relief" on the propshaft can be seen. Allows full flex with a longer nipple and greasegun access.
Be careful too, measure and check that the circlips/spring retaining clips of a new UJ are the same thickness as the old. Too thick could exert an axial preload to the joint leading to premature failure.

"I thought this was about prop-shaft universal joint grease nipple thread sizes? Nothing to do with engines".
The comment was about grease nipples! - all grease nipples I have fitted to original Minor factory fitted U/J's have been 1/4" UNF.
Aftermarket non factory fitted U/J's with their associated grease nipples could be any thread.
Many after-market parts now have metric threads or instead of BSF threads UNF threads.
https://www.ujmfg.com/product/HS194.html

And not all U/Js have grease nipples fitted. Some are supplied with plugs and these need to be removed and grease nipples fitted if/when lubrication is required. Likely mostly come across with industrial items (agri PTO shafts for instance).

My original u/j's have screw plugs fitted which I replace with grease nipples when lubed although I'm not sure about the thread - just thought it would be BSF or UNF.
I thought they weren't permanently fitted for balance reasons.

Alan

Not having a grease nipple allows for greater articulation of the joint.
The HS194 universal joint is fitted to the prop-shaft(s) of a great number of different vehicles not just the Morris Minor. For example, the Morris Marina/Ital has three.

But the original question was referring to U.J. grease nipples. Therefore my comment that they could also be M6 thread in addition to 1/4" UNF.
And a picture showing the importance of retaining clip thickness and their variations. I wonder how many install circlips upside down too?
"Not having a grease nipple allows for greater articulation of the joint."
Articulation is only affected if the nipple is not fitted correctly in relation to the propshaft yoke.

[quote I wonder how many install circlips upside down too? [/quote]
There’s two ways to look at that, each way could be debated !