Need advice to repair a broken V-brake boss post!

I recently bought a cheap used 2009 Trek 7.2 FX hybrid on CL for a good price. I added some spare MTB parts and now it feels like a mountain bike with heavy, but smooth road wheels. Perfect for commuting and casual road riding. The front V brake was a cheap replacement and howled when I test rode it, but I thought I'd just replace it. No biggie, right? But when I removed the old brake I was disappointed to find that one of the brake boss posts was sheared off. Trek tells me the posts are welded on, so it can't be replaced. I know that I should buy a new fork, but I'm determined to make this work without spending any significant money. I've just been riding it using my rear brake only, so I just need it to be decent and safe.

The new brake doesn't have much to grab without the brake post. It's inserted just under half an inch into the remaining boss. So the best I could do for now was find a longer bolt that reached all the way through the brake and threaded into the boss about 1/2 - 3/4 of an inch. It locks down pretty tight, but obviously it doesn't have a solid post to rest on. The front brake works quietly and effectively for light stops, but if I do any hard emergency braking tests, it howls loudly, even though it's holding strong enough to make me go OTB when I was leaning too far forward. I'm pretty sure it's howling due to the missing post. I found a product online called the Problem Solver Cantilever Repair Kit, which also used a longer bolt, but it included a cylinder spacer that goes around that bolt to presumably mimic the missing post. All the close up pictures are below. What do you guys think? Will it hold? Where can I get a metal spacer that would do the same thing, and would it even serve any purpose? Would it stop the howling? Any help you guys can provide would be greatly appreciated. Thanks.

 

Brass or aluminum tubing from a hobby supply store? Not sure about wall thickness, but maybe multiple sections of concentric tubes using increasing diameters?

http://www.hobby-lobby.com/tubing_music_wire_403_ctg.htm

 

are you absolutely sure that the stud is not screwed in place? sometimes those cs folks dont have the right answers.

personally, that seems like a dangerous solution. may i suggest a new fork, you should be able to get one below 50 bucks off ebay.

 

I'm going with bing! on this one. My guess is that it's threaded into the boss on that fork. Get some vice grips on it and try to unthread it. If you have access to a small butane torch, heat it up to free any loctite then try to remove it. Worst case you need to replace the already unuseable fork, best case, take the stud to the lbs for a replacement. Meanwhile, I'll check my bike tool box, I may have one laying around!

 

It doesn't appear as though the stud is threaded since there aren't any flats (that I can see). Considering the ramifications of the brake breaking off and stopping your front wheel precipitously, you might consider having a stud welded on or using some type of caliper brake.

 

I'm with the others: threaded seems a MUCH more reasonable method of fabricating that part of the frame. Take the other side apart and see if it lends a clue.

If it is indeed welded in place, I would turn a bushing to the correct dimensions, as you described in the repair kit. Steel would be an appropriate material for this. The remainder of the original post should be filed flat and square. Use a LONG bolt that engages all of the remaining threads. Grade 8 would be nice.

 

Another vote for threaded. The boss seems to be threaded into the painted post.

 

definately 2 pieces of metal going on there there. appears the stud is threaded in and locked into place via loctite with a counter sunk flange. I have some easy-outs at work that would make removal a 5minute process... PM sent.

 

Slightly different approach. There is a hole at the bottom of the tube where it meets the fork. Can you mount a non-cantilever brake to that hole?

 

Thanks for all the feedback everyone. Here's my response to all the comments:

Redwoods, Rusty - Thanks for the link. I'll keep that in mind, but right now I'm not even sure how a tube spacer (bushing?) would help unless it was perfectly snug to the bolt or threaded on the inside. That would be the easiest solution if I could find that. Yes, a longer bolt might help too. There is plenty of threads left in the boss to go deeper.

Bing, Fosl, UPSed - I originally thought I could unscrew the post out too, but as you can see there aren't any flat spots to grab with a wrench. I do agree that CS anywhere can be very unreliable, so I'm not ruling out that it can be unthreaded. Welding on a post is a possibility, I guess, but that's probably my 2nd or 3rd preference.

UR2KLOS - Sorry, I don't get what you mean. There is a small opening between the painted boss and where it meets the fork, but not sure what I can do with it.

eatsrice - Thanks so much for the offer to try and remove! I may take you up on that offer. Will call you later.

STR rocks!

 

If you find it is threaded, i have some i have removed from a '98 RS Sid that you can test fit for replacement. Or, i have a Salsa Cromoto fork you could replace it with. Only problem with the fork is that its disc only and the steerer is only 6 7/8".

 

you can pick up a garage sale bike for ten bones and steal the parts.

 

Yeah, a used MTB fork can be had for 10-20 bucks. A new one for 40.

 

And if you do get to remove the post, the part is called a brake stud and is easily available at most shops. They can break due to age.

 

The 2 blades of the fork are welded to the steerer tube. There is a hole around 1/2 and inch from the bottom of the steerer tube. Side pull brakes have a mounting bolt that is in that position. I don't know if the hole is big enough though.

 

http://www.bike-accessories-compone...oy-bmx-bicycle-brake-front-or-rear-black.html

 

Bing - When you get a chance, could you link where I can get a new $40 MTB fork? I have larger road wheels, so would it need to be a 29er fork? Also, I'm guessing it would be wide to fit MTB tires, which might look odd with my skinny road tires. Thanks.

UR2KLOS, sxc70 - There is a hole at the base of the steerer tube, so this is an option if I can't fix the post. Thanks because I never would have thought of it.

Strobe - Thanks for the offer. Will contact you if I go in that direction.

 

Ding, ding, ding: we have a winner. Bing gets the prize. Homer is not the first one to torque off a brake post. Next lesson: Torque and it's application

 

Take your pick from bikewagon. http://www.bikewagon.com/catalogsearch/result/index/?brand=128&dir=desc&order=relevance&q=fork

Am not sure but if you want one for skinny tires, I think its the 700c. Bikewagon also sells the same forks on ebay around 45 shipped.

On eBay, the Mosso forks are getting good reviews. they have a cool factor to them vs. the high ten models from bikewagon. Those are at a 65 dollar price point.

http://www.ebay.com/itm/NEW-MOSSO-A...Cycling_Parts_Accessories&hash=item256ba2cbee

 

I found a 700c fork in take-off room at The Path. Think I paid less than $10 for it.