Well in the spirit of 1 step forward and 2 backward..... Yesterday, I got around to rebuilding the rear master cylinder on my 06 450 Sportsman. This machine has been sort of a project as I purchased it over a year ago, low hours but plenty of neglect and it needed quite a few repairs. The rear emergency brake never worked and the master was leaking fluid. Got the master all set and re-installed, went to bleed at the caliper...no problem, got all the air out but the nipple would not tighten. Removed it completely and pieces of aluminum thread came out with it. I know they make nipple repair kits for cars and Harley's. My first thought is to use a heli coil. does anyone know the nipple thread? Looks like 1/4-28.. Any advise would be appreciated as I really hate to buy a new caliper as they are at least $175.00.

 

1/4-28 is the correct size. If the threads in the caliper are stripped and the oem size wont work,you can get a cheap zerk kit that has several different sizes that you can tap the caliper threads out to.

 

The Heli coil should work ,I never did one in that small of a diameter. $175 sure is a high price for a brake I never use ,the next option is a used rear master cylinder from Ebay.

I find the rear brake a pain because sometimes I stand on it while without knowing while riding and it causes premature rear brake pad wear.
I myself can't see a situation where back brakes only would be a handy thing to use.

 

They have helicoils in 1/4-28 but if you don't have the right bit and install tool in your tool box,costs more than to just get the next oversize fitting and tap it out plus some auto supply stores have zerks that are self tapping to repair damaged caliper threads.Never trusted helicoils,but loved how time serts work,but they're even more expensive,but haven't found one small enough for zerk repairs.

 

Thanks OPT.......give me some options.

 

You might try a good auto store.Try a new oem 1/4-28 first. If it screws in and seals you're good to go. Plus most good auto stores have self threading oversize bleeders for this very reason because people have stripped out the threads. We had these at the shop.Got them from Wurth if I remember.If that doesn't work,then the next over size and a tap.Look at this first. Thread Forming Grease Fittings, Thread Forming Zerk Fittings, Spin Drive Grease Fittings Sorry gave you the list for grease fittings! Can't find the self tapping bleeders we had at the shop.. You might try a good auto store.Plus worst case scenario,there's products like this that I'm not too crazy about.http://threadformingtaps1.sofbal.com...-8-inches.html
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Well, either skill or I got lucky........the helicoil worked well. I drill the hole .300" deep on my drill press and first tapped with the tap provided in the helicoil kit. Finished tapping with a bottoming tap. The shortest coil is 3/8" so after inserting, I cut it off with my dremel and filed it flat. The repair is certainly stronger than the soft aluminum. Thanks for all the reply's. I wanted to post the results in case others run into the same issue. $30.00 saved me $175.00 in this case. I'm sure tapping for the next larger nipple as OPT recommended would have worked well also.

 

Wondering what you'd do with the helicoil as far as the length.Sounds like you have it sorted out pretty good. Good tip for others on repair besides tapping out for a larger fitting.

 

Hello opt.......As far as the 3/8" long coil, Once it was installed, I cut it off close to flush with the caliper using my dremel and cut-off wheel. That left a small nib sticking up which I filed flush with a mill bastard file. Cleaned up really well. You'd never know it was repaired unless you looked at it closely..........at least with my crappy eyesight anyway..........lol..........

 

Reminds me of an old joke: New salesman in hardware store was offended by a customer looking for a "bastard" file. Manager told the salesman that was the name of the file. Armed with this new knowledge and ready,another customer came in looking for a file. Salesman said,"how about this bastard file here? Customer said no,I want that SOB there...