Grease your barcons too!
#1
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Grease your barcons too!
Granted, there are enough threads reminding us to grease our seatposts, stems, and aluminum BB's, but here's another one more likely to be overlooked:

I just extracted this disaster from the bars from a mistreated 1976 Schwinn Voyageur II. The steel removal bolt had bonded itself to the barcon shell, requiring destructive removal of the barcon body.

Once the aluminum body was removed, the steel expander wedge was visible, which revealed something else: Two of the three plates on the wedge had bonded themselves to the aluminum walls of the bar. It required a couple of taps with a punch to break free.

This brings up two interesting points: Barcons - at least, the Suntour ratcheting design - have two points wherein they must be greased to prevent bonding; the barcon body, where the threaded cone is fitted (AL to steel), and the steel wedge plates against the aluminum bar itself.
I believe this would also apply to most of the other designs out there, though greasing locations might differ slightly - case in point, Simplex's cone is on a spinning shaft, Suntour's is fixed.
The bar was secured in a Park fork jig for the job.
-Kurt

I just extracted this disaster from the bars from a mistreated 1976 Schwinn Voyageur II. The steel removal bolt had bonded itself to the barcon shell, requiring destructive removal of the barcon body.

Once the aluminum body was removed, the steel expander wedge was visible, which revealed something else: Two of the three plates on the wedge had bonded themselves to the aluminum walls of the bar. It required a couple of taps with a punch to break free.

This brings up two interesting points: Barcons - at least, the Suntour ratcheting design - have two points wherein they must be greased to prevent bonding; the barcon body, where the threaded cone is fitted (AL to steel), and the steel wedge plates against the aluminum bar itself.
I believe this would also apply to most of the other designs out there, though greasing locations might differ slightly - case in point, Simplex's cone is on a spinning shaft, Suntour's is fixed.
The bar was secured in a Park fork jig for the job.
-Kurt
#4
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-Kurt
#6
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-Kurt
Last edited by cudak888; 12-24-09 at 08:07 PM.
#7
Oh yeah... some of the worse bonding you can have is by oxidation of aluminum parts in close contact with each other (like in this case)... Worse than a steel frame with an aluminum seatpost stuck in it. My mantra it to disassemble,clean, lube and reassemble everything every three years (and annually for the bikes that I ride in rain/snow/road salt)
#8
#9
I am going to have to do some destruction to a set of Suntour bar cons myself shortly. The shifter parts came off fine, but both expander bolts have been stripped out. So the expanders are stuck in the bars and have a set of Dura Ace non-aero brake levers trapped as well. I don't want to do it, but am going to have to.
#10
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#11
I don't have any of those (and that 110-120 is a way too tall order for the 70s era); the closest I have in my parts box is an 80s 100mm SR Custom. If that fits the bill, let me know and it's yours.
#12
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Bikes: 1990 Trek 1420 - 1978 Raleigh Professional - 1973 Schwinn Collegiate - 1974 Schwinn Suburban
I hear ya Kurt.... and for those of use with kickstands, grease those puppys too!
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#13
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Greasing them is a good idea, I've come across a few really stuck pairs.
But something you may want to try before destroying the shifters is to drill a tiny hole in the end of the handle bar above the expander just big enough to fit the tube from the can of PB Blaster or Liquid Wrench. If you get lucky the hole will line up with a slot in the expander and you can really fill it with the penetrating fluid, but even if not it should allow enough in to usually work. Let it soak at least over night, and maybe use some heat if really stubborn. It's worked for me on some that were really bonded in.
But if it's a common shifter like a Suntour and you just want to get on with it, then I see nothing wrong with using the big drill.
But something you may want to try before destroying the shifters is to drill a tiny hole in the end of the handle bar above the expander just big enough to fit the tube from the can of PB Blaster or Liquid Wrench. If you get lucky the hole will line up with a slot in the expander and you can really fill it with the penetrating fluid, but even if not it should allow enough in to usually work. Let it soak at least over night, and maybe use some heat if really stubborn. It's worked for me on some that were really bonded in.
But if it's a common shifter like a Suntour and you just want to get on with it, then I see nothing wrong with using the big drill.
#14
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The lever body and the threaded cone were (and remain - in pieces) fused together permanently. As with some seatposts, some bits are simply far too stuck to salvage.
-Kurt
#15
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-Kurt
#16
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Bikes: Fuji S-12s, Trek Navigator 200, Dahon Vitesse D7, Raleigh Sprite Touring ('70's)
I managed to destroy one of these early on in my C&V 'career' by simply not knowing that they are in essence a left hand thread product. I saved it by drilling out a small bolt to replace it, but man, what a pain.
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