Morris Minor Owners Club

My 1275 engine, the oil drain plug threads are stripped. I was changing oil, and the plug was seized. I finally got it to move but it won't unscrew, it's just spinning. Oil isn't leaking, but now I don't know what to do.
Thanks in advance.

bloodyank wrote: ↑Sat Jun 22, 2024 1:06 am My 1275 engine, the oil drain plug threads are stripped. I was changing oil, and the plug was seized. I finally got it to move but it won't unscrew, it's just spinning. Oil isn't leaking, but now I don't know what to do.
Thanks in advance.

it's just spinning. Oil isn't leaking Leaking (or not) is irrelevant.

I don't know what to do Repair or replace, before using the car.

That’s helpful -not-
As the plug is spinning it’s obviously not gripping to be able to remove it, pulling as you turn is also impractical. Even if you do remove it, a repair is difficult.Looks like your best bet is to find another sump.

Unfortunately, the 1098 and 1275 sumps are not interchangeable because the 1275 has bigger bearings. A second hand 1098 sump is easy to find but I suspect that it is not so easy to find a sump for a 1275. Since you are in the USA we must remember that parts may be more scarce than they are in the UK.

I happen to have a 1098 sump on the table right now. I am assuming that the design of the oil drain is the same. As you can see in the pictures, the drain plug thread is in a collar or neck piece of metal that is brazed on to the pressed steel sump (the sump body itself is much too thin to be threaded). It looks like there is enough metal in the collar piece that it could be drilled out and tapped for the next size up thread. That next size up might be metric. Or if that cannot be done, an engineering workshop might be able to remove the old collar and braze on a new one.

I would drop the sump from the car (this will be very messy if you haven't been able to drain the oil) and take the sump to an engineering workshop. The drain plug may have to be bashed out with a drift from the inside (if the thread has gone there will be hardly any metal holding it in). Then they can decide what is the next size up to tap for a new drain plug.

It's a nuisance for you but don't panic. This can be fixed.


Stephen

Drill a hole through the centre of the drain plug so as to drain oil before removing the sump.
Less messy even if you have to leave it overnight to drain, then remove the sump as per Stephens advice.

I have just looked at the spare 1275cc Midget/Sprite sump I have and which at some time in the past has suffered from the same problem
To overcome the stripped thread the previous owner cut a small section out of a 'A' Series sump and brazed it over the failed sump plug.
It seems to have worked ok.
The threads are all the same for the 'A' Series sumps 1/2" UNF.
An engineering workshop should be able to remove the damaged plug and re-thread back to 1/2" UNF.
The head size of sump plug is 3/4" Across the Flats (AF).
The Morris Marina 1275cc sump will fit the 1275cc Midget/Sprite engine but the strengthening plate between sump and bell housing will have to be removed.
I thought I was going to have the same problem as above with the Marina sump I have as I could not get the drain plug to undo. I managed it in the end but it was a close shave to stripping the thread.

Bill_qaz wrote: ↑Sat Jun 22, 2024 9:37 am Drill a hole through the centre of the drain plug so as to drain oil before removing the sump.
Less messy even if you have to leave it overnight to drain, then remove the sump as per Stephens advice.

I very rarely remove oil drain plugs on engines. Pumping or vacuum removal through the dip stick hole is less messy.

I’ve had a manual vacuum pump like this for over 25 years. Still in use.

https://youtu.be/ZLQROKWizb4?si=La0Ryrfi7xMMzJZb

I have a couple of cheap oil pumps like these, but have only used them for transferring diesel fuel.

https://youtu.be/7ztrkUQ_QyE?si=_JZ6gzzdsQk14yoK

Both methods have advantages over draining oil from sump,plugs.

That means the repair (it’s probably the sump threads, but could be just the plug) is a relatively simple matter.

Replacement of the sump is obviously not one of the options I would choose. Other people may do it that way, but I wouldn’t.

In my opinion and experience draining hot oil from a sump via a sump plug is much better as it helps to remove/flush any crud from the bottom of the sump.
Even better if a magnetic sump plug is fitted.

+1

philthehill wrote: ↑Sat Jun 22, 2024 12:31 pm In my opinion and experience draining hot oil from a sump via a sump plug is much better as it helps to remove/flush any crud from the bottom of the sump.
Even better if a magnetic sump plug is fitted.

I absolutely agree with old cars like the Minor but not on some modern cars. My Audi S3 has a composite material sump and is very easily damaged. Even the dealers use a pump to drain the oil on that so I do too. It’s certainly much less messy.

Stephen

Well yes, however we are all about Minors here but regarding modern stuff some haven’t got a dip stick !! Apparently dealerships rotate the vehicle 180degrees and let the oil drain from the filler cap. It’s quite a sight !

https://youtu.be/gDE76uJ4ZvQ?t=1025

——- well the dipstick bit is a fact !

In some cars the dipstick is often found sitting behind the steering wheel

One trick I've used in similar situations is to insert the end of a screwdriver between the turning bung and the sump itself as a wedge while turning the bung.
The wedge pushes the bung out and the bung should then catch the threads that are left and come all the way out.

It may be that the threads on the bung are worse than on the sump...you never know.

Good luck.