best fix for stripped oil plug hole

[kcmoto]

have been trying permatax liquid thread, but it doesnt' seem strong enough or i can't clean out the hole well enough. i'm using a brake cleaning agent to clean the hole and the oil has drained overnight so there is no dripping.

any other products out there or tips to repairing?

i want to avoid tapping if possible.

thanks for any advice!

 

[Zerotact]

you might be able to helicoil it. Or, you may be able yo find an expandable rubber plug. We used them at an oil change place since honda oil pans are aluminum. Last resort before replacinf the case is to have someone weld it closed, and then re- drill and tap it.

 

[biglou]

If the case isn't cracked around the hole, then a heli-coil or, better still, a "time-sert" will do the job. I forget which metric size it is, but my buddy's 99RM250 needed new threads and I got a hot tip that a 1/2-20 was just a shade bigger with the same thread pitch (threads per inch) as the metric threads. $3.50 for a magnetic drain plug from NAPA and he was good to go. Tapping, re-tapping or using a threaded insert isn't that big of a deal. Way better than a new case half for sure. The expandable rubber plug idea sounds pretty good, too.

 

[kcmoto]

thanks for the suggestions.

i'll check into the expandable rubber plug option. this sounds like a solution that may not involve drilling and tapping.

if rubber doesn't sound feasible after more research, any advantages of using heli-coil vs time sert? heli coil seems to grab the entire length, but the time sert only locks toward the bottom?

since oil will always be pouring through the hole, i wonder if either insert will eventually slip under mfg recommended torque.

thanks again guys!

 

[cr25096er]

if done right they seem to last a while.

 

[Zerotact]

The expandable plugs held pretty good as far a securing themselves in the hole. What it is, is a chunk of rubber with metal plates on each side, and when you turn the bolt the plates get closer, pushing the rubber out sideways.
It was definately a cheap fix for a stripped honda oil pan.

 

[RM_guy]

Tapping to the next size works good as Lou pointed out. Put grease in the flutes of the tap to catch the chips as the threads are cut.

 

[jmics19067]

I don't particurly like the rubber "freeze " plug idea too much for repeated use. Only because the repeated use can cause sealing problems down the road. Some times the helicoil can thread it self out with the bolt while unscrewing have yet to see that happen with a timesert. While all three are tight though they will hold themselves in just about perfect.
If skid plate clearance is not an issue I like the replacing a 12mm thread with the 1/2 inch thread<if that is your size> because the only real difference is only which size wrench you grab at oil change.

I also like the idea that if you use the 1/2 bolt and down the road it strips out<threads do wear especially aluminum when you dont use a torque wrench properly> you should still have plenty of meat left in the boss for a time sert or other repair.


just thoughts on looking for things way down the road.

 

[kcmoto]

Ok, this is my logic for now. I want a solution that removes the least amount of material from the crankcase.

Non drill solution
I can use the expandable plug solution, but may have to replace after X number of oil changes so the total eventual cost may be a problem. Will have to actually find the plug to determine cost.

Drill solution
tapping to the next size is still under investigation vs heli coil, timesert, or other insert solution. Under this scenario, I wonder if tapping to the next size will remove less material than using any kind of insert. If so, I would choose to tap to the next size and buy a new oil plug. If for some reason, the thread becomes stripped again, I can utilize the insert solution and use the original size oil plug.

Does the above logic sound correct? I still need to verify that tapping to the next size will indeed require less material removed so that I can utilize an insert solution in the future if necessary.

thanks for all the feedback.

 

[RM_guy]

If it is a 12 mm bolt, you can tap it to a 1/2 fine pitch thread (1/2-20) with out having to drill anything. That's the beauty of it. With an insert you would have to drill it out to thread the hole for the insert.

 

[biglou]

Let me change my above post from "1/2-13" to "1/2-20". Guess who gave me that tip? ;)

 

[kcmoto]

rm_guy, thanks for the information.

1/2-20 is a standard size? sorry, but i'm not familier with bolt sizes. according to my manual, the oil plug i have is 12x1.5(mm). so you are saying the next size up of 1/2-20 should be used instead of going the next size up in metric? in metric, i can only find 14x1.5(mm) which would require drilling and then tapping.

sorry for the many questions, but this will be my first attempt at tapping.

 

[RM_guy]

1/2-13 is the standard coarse thread size and 1/2-20 is the standard fine thread size. The finer pitch thread requires a larger pilot hole for tapping and a stripped M12 is just the ticket. You may have to call around to get the tap and bolt. I was able to pick them up at work. If you really can't get your hands on one then email me at rmguy@dirtrider.net and I will send you one.

In metric you will only be able to get a 14x1.5 which would require drilling before you could tap.

One other thing. Make sure that the replacement bolt is not any longer than the one you are replacing. When I first did this on my sons 125 I had at least made an effort to get the bolt close to the right length. Th threw it all back together and while at the track my boy complained that the tranny wouldn't shift. I thought, crap, now what did i do :confused: It turns out that the bolt was .030" longer than the stocker and it must have hit something in the tranny and prevented it from shifting. After a little grinding I was back in business.

 

[motorider200]

I used to have a yz that had a rubber stopper in it. It work great never had any problems with it and it never wore out

 

[JasonWho]

I think they are saying that you currently have a 12 mm wide bolt. They are wanting you to go to a one-half inch wide bolt, which is 12.7 mm wide.

Hope this helps,
JasonWho

 

[NO HAND]

I think it's a very good idea to go with a tap for next size bigger because that way you don't have to worry about the draining cavities that go through the thread to drain the oil from the transmission side. I had seen someone try to fix the thread on a CR with an insert and all he did was effectively blocking the drain passage from the tranny side.

 

[2smoke]

Id recommend following Lou's advice and tap up to the next size. Stripped my plug hole on the Katoom over 3 years ago. Haven't had a problem since...in fact it screws in easier than the original.