Fixing Stripped Out Drain Plugs

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Fixing Stripped Out Drain Plugs

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Harley Davidson >> Do It Yourself Help Forum >> Engine Related >> Fixing Stripped Out Drain Plugs

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Fixing Stripped Out Drain Plugs - 1/11/2006 8:53:10 AM

HDF Tech

Posts: 14559
Joined: 5/14/2005
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Submitted by: springer_ (V Twin Forum) & http://www.bigboyzcycles.com/

There have been several posts lately about stripped out drain plugs in EVO oil pans. Today I had the opportunity to deal with this exact problem. Of course I took pictures and documented the whole fix, including some custom modifications.

I went to a local auto parts store and looked through their fix it section. I found 3 items that could work and not knowing which one would work better, I bought all 3.

On the left is a 1/2"-20 Double oversize plug
Middle is a 1/2"-20 "Piggyback Single Oversized" Plug
On the right is a 1/2"-20 Single oversized solid tapered plug

This is the Piggyback plug that we decided to use since it allows the oil to be drained without a pump. You can see the o-ring on the new drain plug. Note that there is no relief in the "seat" for the o-ring. This clearly isn't going to work.

We removed the o-ring and found that a 10mm banjo brake washer with a rubber lining fit very well. Here you can see it and the stock o-ring.

Left Side, we installed the o-ring and as soon as you tried to tighten the drain plug it just squished out. This certainly would have leaked and probably would have vibrated out. For the o-ring to work it would need a recessed step that would allow the o-ring to seal the drain plug but allow the head to seat firmly, holding the plug in place.

Right Side, you can see the Brake washer in place. It allows the drain plug head to seat tightly on the washer. The rubber lining then gets crushed between the 2 surfaces on the inside of the washer thus sealing it.

Additionally we used the solid tapered single oversized plug to start the rethreading of the oil pan. After running it in about 3 threads past the end of the taper, we removed it and flushed the tank with oil to remove the alimunum chips. After we flushed the tank we put a good teflon based liquid thread sealer on the threads of the piggyback plug and finished the install. This allowed the final plug to cut its own threads as it was installed and firmly seat itself.

Comments:

We had considered using grease to help collect the aluminum chips, but then you have to use a solvent of some sort to get the grease and chips out, like kerosene. After looking at the self taping plugs we decided that it was not going to produce aluminum chips like a regular tap would. So we decided to tap it dry. It produced more of an aluminum dust that mostly stayed in the threads of the plug. We then flushed it with oil just to have a flow over the new the threads. This washed out any of the dust left in the threads. If we had taped it for a helicoil it would have been a different story. We looked at using a heli coil first but there wasn't enough room to drill and tap it while still mounted in the bike.