Fuel Pump Flange Stud

[mcrenshaw]

The bike is a '97 R1100R. I changed the fuel filter. While tightening the six flange bolts one of the studs twisted off. No doubt a bone headed operator error that. See the attached photo. The question is how to make the repair. My initial though is to drill it out, insert a bolt of the correct size and use some JB Weld on the inside of the tank to effect a permanent mount. Currently the gasoline has been drained and the tank is under a fan to dry thoroughly and evacuate all of the fumes. Is there a more effective way to repair this stud?

 

[pauls1150]

Don't know if there's a better way, but I will confirm that JB Weld does adhere well to the tank material.

 

[toooldtocare]

Just a though, but you could use a rivnut. Install it using some sealer before you set it into place to make a gas proof seal, then use a screw through it to hold the pump on, also using sealer on the threads, not lock-tight, but a gas proof sealer on open end rivnuts, or use a closed end rivnut. http://www.rivet-nut.com/Rivnut_Fasteners.asp and http://www.aimfasteners.com/rivnut.html#.Ua3s_uDArIo

Edit, rivnuts are often used on bicycles and a bike shop may be able to install one for you. The tools to put them are simple, some of them not much more than a screw and nut to pull the rivnut forward and compress it into place. They work much like a pop rivet.

 

[gsaddict]

Carefully grind flush, removing a minimum of material
Bore out and tap M5
Thread a SS M5 screw in from behind with a #10 x 1/16" nylon washer under the head.
Use red Loctite on the threads and let set.
Be sure to use a "used" locknut that has the lock plastic threads already cut in in on that stud.

Note: If you can't source M5, 10-32unf is very close.

 

[mcrenshaw]

GSAddict, the bore and tap with M5 was exactly what I tried to do. Because of the location of the broken stud at the top of the tank tunnel, I could not get a purchase on the hole with the tap handle. That is to say I could fit the tap, but could devise no way to turn it and tap the threads. I have a small adjustable wrench but even that didn't work after trying for quite a while.

Ended up shimming the new bolt from the inside with a couple of washers then setting it in place with JB Weld. After six hours of setting it seems firmly in place but I'll let it firm up overnight. As most handwork goes I did not get it positioned in exactly the same place and I had to open the bolt hole in the flange just a skosh. The flange now drops in place the way it should. I'm now confident that the new o-ring will effect a good seal from fuel leaks and that I will be able to tighten all the nuts correctly. That said, I think a little touch of anti-seize on all the studs will help.

Thanks for everyone's comments! -Mike

 

[gsaddict]

GSAddict, the bore and tap with M5 was exactly what I tried to do. Because of the location of the broken stud at the top of the tank tunnel, I could not get a purchase on the hole with the tap handle. That is to say I could fit the tap, but could devise no way to turn it and tap the threads. I have a small adjustable wrench but even that didn't work after trying for quite a while.

Ended up shimming the new bolt from the inside with a couple of washers then setting it in place with JB Weld. After six hours of setting it seems firmly in place but I'll let it firm up overnight. As most handwork goes I did not get it positioned in exactly the same place and I had to open the bolt hole in the flange just a skosh. The flange now drops in place the way it should. I'm now confident that the new o-ring will effect a good seal from fuel leaks and that I will be able to tighten all the nuts correctly. That said, I think a little touch of anti-seize on all the studs will help.

Thanks for everyone's comments! -Mike

I would drill and tap with a 90 degree reversible drill.
Glad it worked out for you