Stripped sump plug thread

[johnetype]

If you want to fit a 3/4 UNF sump plug as the repair for a stripped 5/8 UNF one, this is a better option than the Terry's Jag one listed above as it has a magnet to collect swarf and comes with a Dowty washer which will give you a good seal without having to tighten it up so tight you risk stripping the thread again.

https://www.ebay.com/itm/Magnetic-Oil-S ... 51953c058a

[Steve Marshall]

I just bought the oversized one from Coolcats. It is 18TPI but 1/16th inch larger than standard (so 11/16ths) with a taper and slots to allow it to self tap the existing thread more deeply. About £10 + £10 postage.
I am not sure about the state of my existing thread, it just didn't feel right when I tightened it up to stop it weeping. Fearing the worst when I do an oil change.
I was worried about not having a plan B if it all went horribly wrong!
The nice thing is he included a surprise universal 5/8ths free expanding rubber emergency get you home sump plug for free.

Steve

[Steve Marshall]

Amazing value on eBay 252571370222 114pc Oil Pan Thread Repair Kit Sump Gearbox Drain Plug Tool Set

6 taps of different sizes and 36 plugs!

All metric I suppose, but still!

[Freddie116]

Just to wrap up this thread, I did the job this morning. I drilled it out with a 16.25mm hss bit (went into the baffle inside which was an error but got all the swarf out I hope) and then tapped a new thread with a 5/8 UNF 18, inserted the helicoil and then the old 5/8 sump plug went in like a treat. I made sure to run some old oil back through to wash out the swarf before fitting the helicoil so it could run out of the tapped hole. I greased the tap as well to get the swarf to stick to it. Hope helpful to anyone else who might be attempting!

[Steve Marshall]

I inherited a sump plug hole which had been stripped, upsized to 18mm and then stripped again.

I really didn't want to take the sump off (impossible inside my garage, and a tow truck to get it anywhere else) so I got a reduced shank 18.5mm drill bit and bored the opening out in situ with a right-angled drill - having radically shortened the bit. Then I taper tapped the hole to 20mm x 1.5mm.

Luckily the previous owners had left a few 5/8" threads in situ, so I only drilled and plug tapped up to that reduction.

There were a lot of small pieces of alloy swarf, but I think I picked them all up (I hope) with a toothbrush covered in grease.

The whole was then deep enough to accept an alloy 20mm plug (magnetic) intended for a Porsche, and I was either lucky or skilful enough to get the thread perfectly square, so it works well. I used a 20mm copper hollow crush washer.

Before refilling with fresh oil, and changing the filter, I flushed the sump through with all of the old oil

So far so good.

[John37]

This is a bit late but a common repair for this in the 70's was to screw in a taper BSP plug with ptfe tape. I've never gone that route myself having needed to. That guarantees my sump plug will strip at the next oil change.

[Paul bow]

Hi. If your near Coventry then I had Rob Beere put in a time cert, better than a helicoil and I can confirm i have had the plug out 4 times with no problems..
Pukka job