Morris Minor Owners Club

Hi Folks,
Can anybody tell me which size and type of socket I need to remove the oil pressure relief valve - looks to be about 25mm.

NOTHING on a Minor is metric..... DO NOT use metric sockets or spanners.... IIRC it's 1" AF.

I guessed it would be 1" but wasn't sure if it was AF, Whitworth or Woolworth!
Many thanks Roy.

bmcecosse wrote:NOTHING on a Minor is metric..... DO NOT use metric sockets or spanners....

Not true, over the years a few nuts and bolts may well have been replaced by metric ones by a previous owner..
Also If a metric happens to fit better due to a damaged/corroded nut bolt etc I see absolutely no reason why not to use it! Again if you have a 13mm ratchet spanner, then this can come in very useful as its basically 1/2"

As far as I'm concerned, if there's no danger of rounding off a bolt head with a metric socket, for instance on low force areas such as the rocker cover bolts, then go for it. But you should really use the correct spanners.

I would say this, having packed the big ends with shimstock...

NOTHING on a Minor is metric......

Apart from all of the wheel bearings, MM engines, MM gearbox components etc. Whit headed bolts and nuts on MMs are interchangeable with 'Metric fine' sizes so cheaper metric parts may abound.

Yes - I knew that was coming - but you don't use spanners on wheel bearings....... and the MM bolts may have metric threads - but NOT metric heads. 13mm is far too loose on a 1/2" AF bolt/nut - and use of such is a major cause of rounded off fittings and skinned knuckles. Seriously - don't do it!! In extremis - it may be necessary to hammer a 12mm socket onto a badly worn 1/2" AF fitting in an attempt to remove it. It should then be thrown away - and new parts fitted.

Bought a 1" AF socket for the princely sum of £3.82 including postage - fits perfectly!

Go easy tightening it up, the head size is no indication of how much force it needs!

I use the 'woolworth' normally

Boomlander wrote:Bought a 1" AF socket for the princely sum of £3.82 including postage - fits perfectly!

Good!

General socket size rule of thumb for post MM Minors is Whitworth on the body and AF on the engine.

Only suspect Metric may have been fitted if it is a nut and bolt, eg holding front panel or sill covers on etc.

Fitted the new oil pressure relief valve today - Pig of a job trying to get the thread to catch on the securing nut while pushing on the nut at the same time against the pressure of the spring!
Finally used a small socket on the end of a socket extension to push on the dome of the nut compressing the spring and then turning the nut till the threads caught enough to hold it without springing back out again!
Took a good few tries before it was finally in, I won't be doing that job again thank the Gods!

So, how's the oil pressure now? As compared to what it was before you replaced the oil pressure relief valve?

And they say size doesnt matter as Roy says use the right tools for the job they were intended and if the nut is rounded off bin it .

katy wrote:So, how's the oil pressure now? As compared to what it was before you replaced the oil pressure relief valve?

Watch this space - Going out for a test run this Sunday

Success!!.... Found a marked increase in oil pressure - gauge reading up around 80psi at startup and even when fully warmed up still running at normal operating pressure.

Sounds good. Thanks for the comeback.

By the way, the oil pressure relief valve now uses a ball bearing instead of the bullet type plunger and seems to make a better seal.