Bicycle Mechanics - broken frame

I have what I think is a 1983 Trek 620, which I bought from a friend about 1986. I love this bike and put on about 5,000 miles a year, mostly commuting in Chicago. This morning both seat stays cracked where they are welded to the seat tube. Is this repairable? If so, any idea where I can get it done (in or near Chicago or northern suburbs) and how much it would cost?

Very likely. But you might want to post in the framebuilder's forum, with pictures, since they would have a good idea of what you will need.

I assume the frame is brazed, not welded and it should be a fairly straightforward repair for a frame builder. However, the cost is uncertain and you will need at least a partial repaint. Whether the frame is worth repairing is up to you.

Call Lickton's or Chicagoland in Chicago as they should be able to supply the names of some local frame builders.

Yes, it's easily repairable but not necessarily cheap. RRB Cycles (http://rrbcyclesusa.com/) is one place to get an estimate.

Didn't these frames come with lifetime warrenty? But that is for the original purchaser.

Didn't these frames come with lifetime warrenty? But that is for the original purchaser.
Hmmm..... that's a possibility if the friend the OP bought it from has his original proof of purchase and would make the warranty claim for him.

Ninety miles west of you is one of the best shops around for this kind of work. Visit Yellow Jersey (http://www.yellowjersey.org) in Madison, WI. They'll tell you what it'll cost and you can make a fix or replace decision, and if you choose to have the job done they'll turn it around pretty quickly. Best not to try to gt an estimate over the phone, toss the bike in a car and make the drive.

IF both stays went at the same time and they are definetly cracked apart instead of just pulling the stays out of the BB lug then I would suspect that the cause of the damage is internal rusting. Over that many years of regular riding water could easily have rusted away enough of the metal that the stays just got too thin and finally let go on you. If that is the case you will be able to gauge the amount of rust when you strip the parts out of the frame for any subsequent repair. At that point if the tubes seem very rusty and crusty on the inside around the BB area I suggest that it would be easier to just give the frame a Viking warrior's funeral and go frame shopping. On the other hand if the silver brazing joints just let go and the tubes slipped out of the BB lug then it would be an easy fix. You'd clearly see the brazed portion of the ends if this is the case versus a crack.

Buying a decent older mid grade CrMo frame that is in good shape would be FAR cheaper than having the tubes replaced. Or if it is purely that the brazed joints slipped out of the BB lug then you're still in for a lot of trouble since you still need to strip all the bits off the frame in that area and remove the paint before the joints can be brazed or silver soldered back together.

The 620 was a really nice touring frame IIRC, so if it isn't too rusty then brazing the seatstays back onto the seat lug should be a piece of cake and well worth the trouble. But the cracking may be an indication of a much more serious problem. A framebuilder would know, and Yellow Jersey is capable of fixing just about any steel frame ( may not like the cost, depending on what's needed).

Blind guesses without pictures.

174595174594

That's the lug that broke. Personally I prefer lugs that attaches to the back of the seat-tube rather than on the sides for this reason. Not terribly difficult to repair. Any competent frame-builder can braze that back together pretty easily. I'd say $50-100 for something that basic.

It's the Plug in the end of the seat stay, that forms that logo faced piece, its a cast piece,
sleeves inside a squared off end of the seat stay tube.

a framebuilder can heat the seat stay up and pull the broken one. replace it with a plain one , no Trek Logo,
grind, or file off the tip part that is still attached to the seat lug.

and braze up the new ones

Or they could just fillet braze back on what is there for a lot easier fix.

I don't know why but I was thinking CHAIN stays when I typed my previous post. I guess I've got "frame dislexia" and read "chain" where you clearly put in "seat" :D

Yeah, this would be an easy fix for any frame guy or even any decent welder with some brazing experience. Fillet brazing the stay ends back into place would add maybe an oz of brass or, more likely, silver solder to the weight of the frame. The biggest bit of trouble will be giving the area a good "down to raw metal" cleaning to prep it. And of course the paint for quite a few inches on either side will need to go.

Silver solder won't build up a fillet, but a wad of brass would work as a practical fix ,
replacing the plug tip would be a cleaner finished job, look almost as new, just no Logo.

http://www.os2.dhs.org/~john/stay-end-fail.jpg
That's the lug that broke.


It's the Plug in the end of the seat stay, that forms that logo faced piece, its a cast piece, sleeves inside a squared off end of the seat stay tube.

No, it's not the lug, and no, it's not a one piece plug. The stay ends were cut at an angle, and a flat plate stamped with the TREK name brazed over the end. Then the stays were brazed onto the sides of the seat lug.

This type of failure is usually a result of not having enough brass under the stay. When I brazed stays on I tried to fill the area beneath the stay as full as possible without spilling over onto the seat tube.

That said, an easy fix for this would be to chop the stays off flat and use a plug such as described by feitsbob:
http://www.os2.dhs.org/~john/seat-stay-plugs.jpg

Silver solder won't build up a fillet, but a wad of brass would work as a practical fix ,
replacing the plug tip would be a cleaner finished job, look almost as new, just no Logo.

Well you could always get them engraved first:
http://www.os2.dhs.org/~john/trek-plug-1.jpg

N.B. these were samples made by Andrew Hague in Wales and never actually used on production frames.

No, it's not the lug, and no, it's not a one piece plug. The stay ends were cut at an angle, and a flat plate stamped with the TREK name brazed over the end. Then the stays were brazed onto the sides of the seat lug.Thanks for the info. Was this the result of the bean-counter department dictating production methods?

Acutally with all the various silver solder and silver brazing products covering such a range there are some nice silver solders that will fillet out such a repair very nicely while not having to get quite as high a temperature as needed for all out brazing. That's where a good welder or frame guy that knows his brazing alloys front back and sideways would be a great advantage.

27 years and 120,000 miles is a pretty good run. I'd get it fixed.

Thanks for the info. Was this the result of the bean-counter department dictating production methods?
No, it's a traditional means of finishing off seat stays.

un broken, #17 is that piece having been heated till the brass remelted, the brass when hot flows into the gap between the ID of the tube,
and that part of the cast top piece that still has some brass on it..

No what you show, JDT is a cast piece , just like BB shells and lugs ,

If you were to order several hundred pairs of those pieces they would put Your name on it ..

Cutting the hollow tube at an angle, then capping it with a piece of steel sheet would be available in a hand made frame , When I did my DIY

un broken, #17 is that piece having been heated till the brass remelted, the brass when hot flows into the gap between the ID of the tube, and that part of the cast top piece that still has some brass on it..

No what you show, JDT is a cast piece , just like BB shells and lugs ,
Most of them are not cast, but machined from steel rod stock. The "TREK" marked ones I posted above were samples, brazed into a prototype frame (thus the brass residue). I found the frame cut up and in the scrap bin, so I pulled the plugs out and took them home. :eek: