13 replies to this topic

[Hilly703]

1991 Rover Cooper S

After draining my oil to change my gear shaft selector seal I very carefully put my sump plug back in. I made sure not to ratchet it in too quickly ect... But it doesn't seem to be getting tight so I am thinking I have stripped the threads on the sump casing.
The plug was stupidly tight to undo so perhaps the threads were knackered when I took the plug out?

Basically what's the best fix? Do I lift the engine to remove the sump and re-drill, tap and helicoil the hole or is it worth trying to PRC/locktite the plug in the hole and hope for no leaks?

Not very keen on the idea do putting a helicoil into the sump with it on the car because of swarf in the sump ect...

Help?

[AlexMozza]

You could try cleaning the thread out with a thread file or chaser first. Or a thicker washer so that when it tightens up it might be on a better bit of thread.

[minisilverbullet]

There is a tapered replacement plug! I am not sure how reliable this is.

[pickuptruck1994]

Use a timesert think thats how its spelt, i have done one on a bmw sump bung hole and just grease the drill bit and tap used to catch the filenings then flush half a litre of oil through it to wash it all out.

[dklawson]

If you don't want to install a HeliCoil since you are worried about swarf, the Time-Sert will have the same issue.  Both require tapping the sump.  Really... all options do apart from fitting a rubber bung.

 

Mechanically, a thread insert of your choice (HeliCoil or Time-Sert) are your best options.  As pickuptruck1994 said, pack the drill bit and tap with grease and it will collect the swarf if you work carefully.  The biggest issue with either is that you need to keep the drill and tap perpendicular with the surface of the boss where the sealing washer sits.

[Shep76S]

Not the perfect answer but, how about some ptfe plumbers tape on the plug.
I have used this in the past.

[Hilly703]

Thanks everyone for your help, I'll try packing it with another washer as a short term fix then I think I'll lift the engine over the winter and make a proper job with a helicoil insert. I'm not keen on using the tapered replacement plug as I don't want to risk cracking the case.

[Hilly703]

Not the perfect answer but, how about some ptfe plumbers tape on the plug.
I have used this in the past.

A classic mini specialist I spoke to on the phone yesterday suggested this as a short term solution too. Perhaps I'll stick some of that round it too as well as an extra washer.

[Shep76S]

From memory I ran a mini like this for a couple of years.
I think a lot of people forget lefty loosey, righty tighty when they are upside down and laying on their backs.

Edited by Shep76S, 02 August 2014 - 09:34 AM.

[sledgehammer]

I was wonder if dowty washers could help 

 

http://www.ebay.co.u...=item2ed415b25d

 

they seal with less torque on the bolt than a copper washer

 

I use them at work on hydraulic rams etc , they can almost be loose - but still seal against high pressure

 

used with some PTFE tape they could help while you find a more permanent cure

Edited by sledgehammer, 02 August 2014 - 09:48 AM.

[Gremlin]

Not the perfect answer but, how about some ptfe plumbers tape on the plug.
I have used this in the past.

A classic mini specialist I spoke to on the phone yesterday suggested this as a short term solution too. Perhaps I'll stick some of that round it too as well as an extra washer.

An extra washer wont help, if anything it'll be a hinderance as you'll have to clamp enough to get another face to seal, as above, for temporary only, try a dowty washer and some ptfe tape

[dklawson]

In post #1 Hilly703 said that the drain plug did not seem to be getting any tighter.  That says the threads are gone so unfortunately additional or different washers are not going to fix this.  The tapered drain plug is not a great option... as mentioned above, they put stress on the sump casting and that can make things worse.

 

Were I looking for a DIY fix that did not involve tapping the sump, I would go to an industrial supplier and get a couple of items.

Remove the drain plug from the car.  Look in the sump to inspect what is left of its tapped hole.  If I remember correctly the sump is tapped at least 6mm (if not more) beyond the length of the drain plug.  Take the drain plug to the industrial supplier and ask for a 5/8 UNC bolt LONGER than the drain plug.  Ask for a dowty seal to fit the bolt (or a hydraulic hose sealing washer for G3/8 fittings).  Visit the DIY center on the way home and see if they have any cylindrical bar magnets and some epoxy glue.

 

At home, thread your new regular bolt in the drain.  Determine how much you need to cut off its length so it can fully thread into the remaining tapped hole.  Cut off the excess length.  Drill the center of the threaded end and glue a small magnet in place.  Allow the epoxy to cure then fit the dowty washer to the bolt and tighten it in the sump.  You do not need a lot of torque to make the dowty washer seal.  This can be a permanent solution if necessary... just go easy on the torque.  

[Captain Mainwaring]

In post #1 Hilly703 said that the drain plug did not seem to be getting any tighter.  That says the threads are gone so unfortunately additional or different washers are not going to fix this.  The tapered drain plug is not a great option... as mentioned above, they put stress on the sump casting and that can make things worse.

 

Were I looking for a DIY fix that did not involve tapping the sump, I would go to an industrial supplier and get a couple of items.

Remove the drain plug from the car.  Look in the sump to inspect what is left of its tapped hole.  If I remember correctly the sump is tapped at least 6mm (if not more) beyond the length of the drain plug.  Take the drain plug to the industrial supplier and ask for a 5/8 UNC bolt LONGER than the drain plug.  Ask for a dowty seal to fit the bolt (or a hydraulic hose sealing washer for G3/8 fittings).  Visit the DIY center on the way home and see if they have any cylindrical bar magnets and some epoxy glue.

 

At home, thread your new regular bolt in the drain.  Determine how much you need to cut off its length so it can fully thread into the remaining tapped hole.  Cut off the excess length.  Drill the center of the threaded end and glue a small magnet in place.  Allow the epoxy to cure then fit the dowty washer to the bolt and tighten it in the sump.  You do not need a lot of torque to make the dowty washer seal.  This can be a permanent solution if necessary... just go easy on the torque.

 

 

A fine answer, the only trouble is the bugger dropping out later. 

 

Personally I'd tap it out to the next clear metric sump plug size and pour the old engine oil back through the engine to flush it out. If you'r careful whilst tapping there will be little if any swarf left near the hole, a vacuum and a flush with old oil will do the trick - 

[dklawson]

When you tighten a drain plug with the bonded metal/rubber (dowty) seal you feel the rubber compress and then a solid stop when the metal surfaces come into contact.  You don't need much more torque than the metal to metal contact.  The compressed rubber does a very good job of keeping things from moving.  I would not worry about the homemade long-body plug dropping out when a bonded metal/rubber seal is used.  I would not use the homemade plug with metal crush washers.