stewmeat

Hey Framebuilders,

i am not sure if this is the right sub to post in but i just bought a used 1987 schwinn tempo and noticed a crack in the paint on the downtube that connects to the bottom bracket lug.

https://i.imgur.com/SGPf8Gr.jpg

is this a crack in paint or a crack in the tube. if it is a crack in the tube, will it be an easy fix? the imgur link will provide a higher resolution photo. thanks much guys.

CliffordK

That is the seat tube and not the down tube.

On the right side of the photo (rear of the bike), the crack appears to extend through the brass joint filler, so I would be very concerned that the joint would be in the process of failing.

If it is actually the joint and not the tubing, it is quite possible that it could be repaired quite cheaply by a good frame builder. See if there are any local to you.

unterhausen

I never thought that was an easy repair, depends on how little filler there is in the joint. Does it go all the way around? I don't know how these were constructed, it might not be a problem at all. I would look at it from the inside before I panicked

stewmeat

Ah yes, it is the seat tube, i had a brainfart. I wasnt sure if it was a shadow caused by the light i shined on the brass filler area but i will take it to a framebuilder by me to get it checked out. Thank you very much for your reply.

stewmeat

I have not yet taken out the crank to inspect the inside but the line goes around the entire part where the seat tube connects to to lug. I didnt notice it at first but it seems that the previous owner applied white touch up paint to that section. I will inspect it thoroughly once i take out the crank. Thanks for the help.

pwyg

It looks to me like a break if it does not crossover to the casting you are lucky and it is a easy repair. if you take hammer and punch to the center area and hit it and the tube pushes away from the casting it is cracked, if you want to really want to see if it is broken. On the other hand if you ride it and it breaks more and cracks into the casting the frame will not be worth repairing. To repair you need to cut out seat tube, carefully grind out remaining tube from both the seat lug and bottom bracket shell and slide in new tube and silver braze it in. I say silver braze as most failures are due to the high temperature the frames are originally built with and it is not good for the tubes and lugs to go through more than one high temperature cycle.
Paul

Andrew R Stewart 

Remove the BB. Place a long wood shaft in shell. Try to flex shell up and down while looking at "crack" if the tube is cracked you'll likely see some light through the expanding crack (a small flashlight stuck in the seat tube will provide the light source).

Or clean the inside of the seat tube well then apply a thick lube to that inside surface where the crack would be. Ride the bike. Do you see anl lube seeping out through the crack?

Given that the crack seems to shift it's path and go up the shoreline, where there's usually a thin layer of filler, makes me think the filler has failed. This is seen every so often from poor pre brazing prep or a cold brazing job. Andy.

Cyclist0094

I'm with Andy on the failed filler, If it were the seat tube the crack is usually above the lug. Judging from the white seat tube, the stamped steel BB shell and Columbus tubing sticker I'm going to take a wild guess this is a 70's Atala.

fietsbob

a Re brazing the Joint and repainting what was a Low cost used bike buy, that 1987 schwinn tempo

will be rather expensive , when done by a Professional, Maybe just ride it till it fails completely and buy something else..

It is almost 30 years old .. may have come through a Japanese OEM company making them for the Brand.

stewmeat

Thank you very much Paul, I am most likely taking it to a framebuilder around here soon to have them assess the the situation. I was hoping it wouldn't be a such a big ordeal as i love the color of the bike.

Y

stewmeat

Thanks for the tip Andy! I was thinking of shining a light through the BB and see if there are light leaks, but i will try the wood method as well.

Y

stewmeat

Hi Velonomad, yeah i am goign to take their advice, however the bike is an 87 schwinn tempo with Columbus Tenax tubing.

stewmeat

Hi fietsbob,

I may be wrong, but it was probably made by panasonic. I am afraid to ride it till it breaks, i don't want a failure like that on the road. however a part of me still believes that there is life in it if i can get it fixed, as long as it remains structurally sound.

Y

pwyg

Just make sure they are going to grind out the old and not burn it out. nor would i recommend trying to re-braze. I typically do these repairs for about 150.00 for the repair only including the new tube. The repaint is another thing.
Paul

stewmeat

i read that you can possibly tig weld to fix it. is that a possibility?

fietsbob

I recommend at least scrape away the paint, to uncover the brass that is used to braze it together ..


30 years of use could have made the joint fatigue .. (unless it sat un used most of those decades,)

Cyclist0094

Schwinn Tempo. Ha I missed that one by two miles

unterhausen

you can't tig over brazing.

If Panasonic made it, the problem is probably that the brazing material didn't make it all the way to the edge of the bb shell socket. I'm going to say that the fact that it has gone all the way around and not moved vertically is evidence that it's fine, and you should just stop the rust
This rests on my assumption that it was ring brazed from the inside, not the outside

stewmeat

Thanks again unterhausen! I remove some of the paint to further assess the situation and i had a damp towel to wipe away the dust and dirt; a little water got into the crack without knowing and eventually i noticed very very small droplets of red. at first i thought my bike was bleeding...haha... but it appears to be rust. i tried replicate that again by dabbing a little water in that, and put pressure on the pedal, more very small rusty droplets came up. I know i shouldn't put water but i thought the seat tube was a goner anyways, but it seems that it could be bad brazing because the water only came up in the same spots. Now i think the crack was crack in the paint that came from rust. I will get it checked out prefessionally, but how bad is internal rust at the location?

Thanks again!

unterhausen

you probably should stop the rust one way or another. I would still go inside the bb shell and look to see if it is completely brazed

saltydogcyclist

Anybody know the current status of this OP frame? I just found a similar situation on a 1989 Schwinn Voyageur. Same tubing and same braze fail. Seat tube has no sign of cracking. I'm deliberating my options.

unterhausen

I think your frame has a much more serious failure, since the shell seems to be cracked

stewmeat

I had it checked by a local frame builder and they said that it looks like the braze is giving away between the seat tube and bottom bracket. at that point, it may fail. i am holding onto the frame and one day fixing it up. however, saltydog's frame seems to be cracking from the down tube portion of the BB and i have no knowledge of the stress coming from that area. i'd be safe and not ride it.

saltydogcyclist

Thanks for reply Stewmeat. I will visit a frame builder as well and make a decision regarding a fix. I will post result within my other post. Such a pitty. Thought I had my retro gravel bike secured.