HELP! Need advice on how to fix my FJ.....

[MN Made]

 

I removed the left side (as you are sitting on the bike) oil galley plug today to install a temperature sender. When I was removing the plug, I noticed little tendrils of aluminum coming out of the area between the plug and the case hole threads. Similar to what you would get when you are drilling a hole in aluminum. When I got the plug all the way out, it appeared that the aluminum threads on the plug were damaged. As best I can tell, the threads on the case are okay. However, when I try to thread the sender adapter into the hole it goes in a short way and then stops as if it is the wrong size. It doesn't seem to be cross-threading. I can't feel any burrs in the case threads, but it would follow that there is some sort of burr that removed the plug threads as it was coming out. Right?

I am trying to find an M20 X 1.5 tap or thread chaser to run into the case, but they are hard to come by - especially locally. Anyone have any experience with this or any ideas? I'm scared to put the plug in more than finger tight. Meanwhile, the bike lies dormant during riding season.

[novaraptor]

Greater minds will undoubtedly weigh in on this, but I would say that it sounds like a PO cross threaded that bolt and just forced it in. As far as I know, the best and probably only way to go is to find a good tap and die set and clean it up.

Novaraptor

[FJmonkey]

If the aluminum threads are damaged you may not get enough torque to reseal it. In many cases like this I would Heli-Coil it or something similar but I am not sure if that product will seal and it may leak. Maybe go up one thread size and get a larger plug. There is a solution, maybe Randy will tell us how he fixes this kind of problem. It won't be his first time or his last.

[MN Made]

Well, I've exhausted all of my local options for a 20mm tap. I had to order a plug and taper tap from China via Ebay. I am hoping that I can clean the threads enough to install the adapter and be good. So, here I sit. Hurry up and wait, right?

If the threads in the case are damaged, I think a helicoil may work - although there isn't a lot of wiggle room to drill a much bigger hole in the case. The top/head of the plug seals against the side of the case using a copper washer (or O-ring in the original configuration). Therefore, the torque on the plug provides the seal - not the threads as with an NPT fitting. So, having the helicoil in there shouldn't matter.

[mr blackstock]

Hello,

I recently got the idea in my head to add an oil temp guage so I could access my oil's average temp to see if I need to go and spend money on a new oil cooler etc.

I had intended on buying a plug to fit, then tapping a new thread down the middle for a temp guage.  I discovered that the thread in the casing is a different type, ie it is not metric or imperial, perhaps BCE.  I have been told it is a common thread amongst fitters and turners, plumbers, etc.  I may have been mis-informed here, but nowhere could I find anyone to help.

I got around the problem by tapping a thread into the NOS plug from Yamaha, then inserting my oil temp sender.

I bought a couple of new plugs for $12 each, plus the "O" ring




Not a lot of metal in the plug for a deep thread.



I have had nil issues so far, no leaks.

cheers, Gareth

[racerrad8]

I have had nil issues so far, no leaks.
cheers, Gareth

Keep an eye on that. Those plugs are cast aluminum and are prone to crack under the constant pressure of the taper threads of the sending unit.

That is the reason billet galley plug fitting are made.

Yamaha Main Oil Galley Adapter

Hopefully you never have any problems.

Randy - RPM

[mr blackstock]

G'day,

I was concerned about how it would go, for that reason I only torqued it a little, enough to prevent it falling out, not tight enough to crack.  Time will tell though.  I was going to copy your plug adapter, but as the plug thread is a strange type, it would have been a big hassle tracking down the right die, probably would have ended up costing me more too.

When I come shopping at your store for more than one or two things to save on postage I will be getting that adapter!  Looks a fair bit sturdier than mine!

Cheers, Gareth

[MN Made]

Ok. Got the holes cleaned up and fit the adapter - no problems. Thank goodness it was only the plug threads that were damaged. Appreciate all of the input.

[novaraptor]

  Good to hear.. Most of the time the hard part isn't doing the wrenching. It's locating and then waiting for the right tool or part.

Nova