eggnumber41679

Hi, all -- I just picked up a 1984-86 Peugeot PY10-FC in what seemed to be pristine condition. This morning I raised the seat a few cm and began tightening the bolt that secures the seatpost bracket, and I guess I torqued it too much because the bracket BROKE. There's a vertical crack, straight-through, that's left about a 1cm x 1cm piece hanging on one end of the bolt. I'm not sure what kind of metal was used to make the bracket, but the cross-section looks like plastic, although the surface feels like metal.

What are my options in fixing this? Can it be welded together, or is the whole frame a wash now?

Here's an image of the technical specifications sheet from the 1985 Peugeot catalogue:
https://www.cyclespeugeot.com/images/...ications_1.jpg

Any help would be very appreciated!

Chombi

A pic of the damged part would help us understand what happened better to give you our opinions.
Repair can get tricky if the part is bonded/glued to the frame tubes.

Chombi
84 Peugeot PSV

eggnumber41679

Went to my LBS, and they determined the lug is aluminum.

scbvideoboy

That sucks! Was that the proper bolt and nut?

miamijim

No, that was not the proper nut/bolt. I'd like to see before pics of the frame/bicycle if you have them


Sorry, but you have 4 options....

1. Find evidence that there was prior damage and return. The improper bolt leads me to believe something wasn't right

2. Find an internaly expanding seat post. Not sure how safe it woud be on a carbon frame.

3. Try to have it repaired.

4. Find a new frame

5. Maybe Vitus can repair it?

eggnumber41679

Yes, it's not the proper bolt. Unfortunately this was a Craigslist find, so I can't return it. Wouldn't even if I could. The Dura-Ace components themselves are in such good condition that I could get back what I paid for the bike.

I'd like to fix this if it's possible and economical. I've sent a query to Calfee, and am waiting for a response.

Here's an additional photos.

miamijim

A local welder may be able to help you out. Mybe weld it from the inside and outside them fille down the inside to make it smooth?

eggnumber41679

I was told at my LBS that welding might not be a good idea because the lug is made of aluminum. Does that make sense? Would you know why or why not?

Thanks again, all.

mudboy

Welding will heat the lug and you run the risk of having the lug-tubing adhesive soften or weaken.

Personally, I think it's toast. You might be able to get a BMX seat collar to work.

Grim

It needs to be tig welded. There is a putty material that can be put on the surrounding metal to absorb the heat.

It is a matter of finding somebody that knows what they are doing.

scbvideoboy

Nova cycle supply sell alum and steel seat collars in different diameters. If it can't be repaired professionally or too $$$, not sure if you cut off the retaining bolt collar and use one of these seat collars to fit over the lug and clamp it together.

Looks like a lot of repair work to heat the bond out and remove the lugs and replace it, likely need a special jig for all that.

But once the alum is cracked it will continue and eventually the whole lug will fail. Someone had the wrong seatpost or just doesn't know how to treat bolts going into aluminum

Chombi

Aluminum CAN be welded with the proper equipment. I think they can build up the aluminum if pieces did fall out from that gap and the built up area can be ground back down to shape as needed. The problem is, that lug/pinch clamp piece is all bonded to the the top and seat tubes. That's a lot of specialized work you have to have done because of this. It's going to be questionable if the frame can still be repaired without spending over what it's worth. Unless you find a specialist repair shop that can do it or somehow have Peugeot fix it, that frame is toast.
What was the original owner thinking when he put that primitive looking binder bolt on the bike??!
I suspect he had seatpost slippage problems and mounted that humungous looking nut on there so he could really torque down on it....thus the cracked seat lug...... Caveman technology applied on a poor Peugeot....

84 Peugeot PSV

Batman_3000

I had that exact same fracture occur on a vitus 979 frame. The reason ? The seatpost was stuck, so I used a little block of hardwood and a mallet to try and open up the brackets a very small amount, and one of them cracked vertically (broke) on retightening after height ajustment. The solution was to strip off all of the parts and give the frame away.

Your main worry may be: "If I get the broken one welded back together, how do I know the other one is not going to fail too ?"

Alloys become brittle with age. So I'd tend to agree on principle with the people who say have it all ground flat and use a MTB collar. But then I'm not a qualified engineer or metal specialist, so even that would require some expert advice. Actually, it doesn't even seem possible given the shape of that glued on lug.

This is general issue with all those Vitus glued up bikes. They haven't aged well at all, and the seatpost binder issue is a big worry.

Viva el good ole steel.

scbvideoboy

yeah second look at that lug, there doesn't seem to be any extension for a seat collar clamp to fit onto...what dura ace group? Are you wanting to keep the dura ace or sell the group?

Grand Bois

Alloys become brittle with age?

Chombi

Yes, some alloys do break down with age. The magnesuim alloy wheels in some classic sportcars are changed out for safety for this reason. My uncle owns a 1965 Cobra roadster and he just changed out the Halibrand alloy (I think they are magnesium alloy) wheels on it for this very reason. They are said to have some sort of internal breakdown that occurs that some call as "rot".

eggnumber41679

Thanks all for your advice. It's sounding like the problem might be fixable, but even if it is the frame's beyond totalled. I'm hating life right now.

The component set is all Dura-Ace 7400, which is 6-7 speed, I believe? The rear cassette is 6-speed. The downtube shifters are friction for the big ring and index for the rear. Everything is in asonishingly immaculate condition. The rims are Mavic MA-2 laced to DA hubs. I swear to god this thing rides like heaven. I think I'll probably be selling the group off and... weep over the frame. Anyone interested in the group?

Bikedued

That can either make them leak air, or self destruct, or both. Neither of which are desirable on any car
that goes over 15mph,,,,BD

Grim

Except that Aluminum in particular 6061 that most frames are made of is not one of those alloys. 6061 is VERY stable. It can corrode from, electrolysis. It can have fatigue from flexing but it doesn't degrade without a mechanical catalyst (flex from loading and bending). If it did then our military and commercial airlines wouldn't be flying planes built in the 50's and 60's.

https://en.wikipedia.org/wiki/6061_aluminium_alloy

Panthers007

I think this is a bit better:

unworthy1

I'd check with these guys in Canada since they are the only qualified and experienced Vitus (and other) frame repair service I know of:
https://www.guywires.com/salestuff/vitusparts.htm
If they tell you to junk it...it may well be toast. I've had some critical aluminum alloy parts crack-repaired by a really expert TiG welder who specialized in just this sort of thing for alloy auto and motorcycle wheels (where your life can be at stake). If such a welder won't do it, it's because it can't be repaired with certainty so as to guarantee strength...you wouldn't want to ride it even if it might look OK.

Grand Bois

Thank you.

eggnumber41679

Thanks. I put in an inquiry with these guys, and hopefully they can help. They claim they can fix a problem like this:



Which... is not quite the same, but makes me optimistic. =)

PDXaero

I think a repair would be possible, maybe not cost feasible, but it could save a wonderful frame so don't give up yet. After all, at least it wasnt the carbon that broke.

Amani576

And if you decide to junk it. Get the carbon tubes out somehow and find a creative use for them. Heck, you could probably use the lugs as napkin rings or something. Recycle what you can, those materials don't break down all that well naturally.
-Gene-