stripped bolts at oil line - what to do?

[Druegeme]

I noticed slight oil leaks at the connections of the chrome oil lines on right side of the bike going from oil pump to oil tank accross the transfer case. The leaks are at no 13 and 18.

I checked the bolts and they turned loosely not able to tighten. Took the oil lines off (I have the oil drained right now as I am about to work on the clutch) and saw that the o-rings are intact but quite hard almost brittle.

And the threads in the engine case where the two M6 allen bolts go are stripped.

I assume it was leaking due to orings old, and someone kept tightening the bolts in an attempt to stop the leak but stripped the threads.

So, what is the right thing to do? I have ordered fresh oem orings and consider putting helicoils in there. What do you guys think?

[Shores]

Would it be possible to tap the holes to the next larger size bolt or would it be better to use helicoils?

[Druegeme]

good question. it would have to be M7 though as M8 would be too big in the tight space and flange mount. Not sure really.

[Shores]

Or go to the next size SAE.

[Shores]

If you went to the next size and the heads were too big, you could just have the heads turned down to the size of your original bolts so they still fit the flange.

[Druegeme]

I like the SAE idea. 1/4 = 6.3mm. With the original thread M6 that could work. Just tap to 1/4 and get new bolts.. hmm!

[Shores]

I like the SAE idea. 1/4 = 6.3mm. With the original thread M6 that could work. Just tap to 1/4 and get new bolts.. hmm!

Davej had that suggestion on another recent thread. Pick his brain for details.

[brianmac]

Can't use helicoils?

[Druegeme]

I could use helicoils. I was looking for opinions if that is a good idea or any alternatives.

[davej]

another thing you can try is to clean up the stripped thread with a tap then buy the next size longer bolt to get to un-used threads that are deeper in the threaded hole. You will have to cut the length of the longer bolt so it don't bottom out but leave it longer than the original bolt. Assemble it and screw the bolt all they way in until it bottoms out to see how much needs to be cut off then cut off a couple extra threads so it don't bottom out before sealed.

[Druegeme]

Thanks. Not much extra length to go with so I'm going with the helicoils I think. Not much torque required on those 7.2footpounds so it should be ok. Unless I break a tap and it gets stuck in the hole that would be worst case so I'll be careful and keep it oiled

[roadiemort]

1/4 turn forward 1/2 turn back, repeat, use a bottoming tap if possible.

[Ratl]

What Roadiemort said and keep it oiled.

[roadiemort]

https://www.cnccookbook.com/different-types-thread-taps-complete-guide-choosing/

[brianmac]

Keep it oiled?

[roadiemort]

Paraffin wax works well with aluminum drilling and tapping and grinding, discs don't load up with aluminum.

[Lug Nut]

Keep it oiled?

While tapping hole...

[Druegeme]

ok thanks guys waiting for my new orings meanwhile practicing tapping threads on some old aluminium parts

[Druegeme]

I ended up using longer M6 bolts, 22mm and 25mm instead of the 19mm stock. The 25mm was slightly too long but Instead of cutting it I used a thick washer. (one thread on the case is slightly deeper)

Everything is snug and I was able to torque it to spec 10NM.

It was interesting comparing the new and old orings. The texture had completely changed from soft to hard.

Thanks to everybody who chimed in here, really appreciate ideas in a tricky situation. It paid off to go slow and think this througj before jumping the gun.