Welding a Flexible Aluminum Joint

[leafman60]

I have a cracked pinch joint on the front forks of a motorcycle and I need advice on the possibility of repairing it.

The steel front axle of the wheel is attached to the fork by passing through heavy aluminum castings at the bottom of each fork leg. The bore (about 1 inch diameter) of the castings through which the axle passes are split with pinch bolts that are tightened to help secure the axle in the bore.

These pinch bolts were over tightened and cracked one of the ears that formed one side of the pinch joint. Those ears are about 1/2 in thick. Can this be welded? The resulting repaired ear would need to retain about .030 inch of flex to allow the axle to be removed and then to tighten down to secure it when the axle is re-installed.

Can an aluminum weld be made that will allow some ductility after the weld?

I have read that this is achieved by heat treating and proper selection of welding materials.

Please help.

[Ironken]

First, what kinda bike is this you're working on here? My understanding is that aluminum anneals after welding. There is alot of risk involved if the repair fails and the outcome could be tragic. Tgere are alot of forces at work on that area. If that came into my shop, I would recommend replacing the outer fork tube. Just my opinion. The layout you describe sounds like some sort of street bike, vintage or cruiser. Outer tubes are easily replaced and may require a special holding tool to hold the damper rod for disassembly. Fork seals would be a good idea at this time as well. Just my opinion though.

[leafman60]

First, what kinda bike is this you're working on here? My understanding is that aluminum anneals after welding. There is alot of risk involved if the repair fails and the outcome could be tragic. Tgere are alot of forces at work on that area. If that came into my shop, I would recommend replacing the outer fork tube. Just my opinion. The layout you describe sounds like some sort of street bike, vintage or cruiser. Outer tubes are easily replaced and may require a special holding tool to hold the damper rod for disassembly. Fork seals would be a good idea at this time as well. Just my opinion though.

Thanks. It's a Guzzi and, yes, new parts can be purchased for $1000. The crack is such that the axle remains in place and is deemed not a safety risk by the manufacturer.Used parts are virtually unobtainable. New parts would be the simple, though expensive, option but a repair would be very convenient if it is possible. I've already been told by folks in the machinist trade that the fix can be safely made.

[Ironken]

Sounds good. $1000.00 for an outer fork tube is insane. I get where you're coming from.

[H80N]

try PINWALL

Thanks. It's a Guzzi and, yes, new parts can be purchased for $1000. The crack is such that the axle remains in place and is deemed not a safety risk by the manufacturer.Used parts are virtually unobtainable. New parts would be the simple, though expensive, option but a repair would be very convenient if it is possible. I've already been told by folks in the machinist trade that the fix can be safely made.

I would try PINWALL Cycle Parts

Bet they have your bit... used... at a decent price...

http://pinwallcycle.com/

If they can't help you... then I would consider welding it... How bout some pics..??

[leafman60]

Yes, good grief. I know all about Pinwall and many other sources. Not available. My posting here is not to discuss alternative sources of parts but to discuss a method of repair. I was thinking we had some high-level aluminum welders here who could address the issues of ductility pertaining to such welds.Thanks for the good faith efforts to help, guys.

[Ironken]

There are some very skilled welders here, that's probably why you aren't getting any recommendations on the repair. We don't know what alloy was used in the casting or the configuration of the repair or your capabilities and equipment. With the limited information available the suggestions are also limited. Just pre heat the part til spit bubbles on it and puke it together with some 5356 and file it down or heap some JB weld on it and call it a day. There....a suggestion was given.

[aametalmaster]

I would try PINWALL Cycle Parts

I used to work a few miles from them...Bob

[H80N]

There are some very skilled welders here, that's probably why you aren't getting any recommendations on the repair. We don't know what alloy was used in the casting or the configuration of the repair or your capabilities and equipment. With the limited information available the suggestions are also limited. Just pre heat the part til spit bubbles on it and puke it together with some 5356 and file it down or heap some JB weld on it and call it a day. There....a suggestion was given.

Well Put....

And with the attitude displayed... I would stay 1000 miles from that job...

Welding is the simple part... the machine work... heat treat... and possible liability complicate matters considerably... especially since the OP expects clairvoiance as well.....

"Good Grief"..???...!!!.... .... Good Luck...!!

[Ironken]

Thank you H80N.

[Aeronca41]

Perhaps one of the best things about this forum is the people with wealth of knowledge that allows them to advise people what NOT to do-and a willingness to say so. My experience is limited and very dated, but this thread scared me from the start.

[FusionKing]

I have a cracked pinch joint on the front forks of a motorcycle and I need advice on the possibility of repairing it.

The steel front axle of the wheel is attached to the fork by passing through heavy aluminum castings at the bottom of each fork leg. The bore (about 1 inch diameter) of the castings through which the axle passes are split with pinch bolts that are tightened to help secure the axle in the bore.

These pinch bolts were over tightened and cracked one of the ears that formed one side of the pinch joint. Those ears are about 1/2 in thick. Can this be welded? The resulting repaired ear would need to retain about .030 inch of flex to allow the axle to be removed and then to tighten down to secure it when the axle is re-installed.

Can an aluminum weld be made that will allow some ductility after the weld?

I have read that this is achieved by heat treating and proper selection of welding materials.

Please help.

Some pictures would help
If it was the only thing that was keeping me from riding, I would weld it in a heartbeat.
I would never give advice on how to do this.
Post up some pictures and maybe we can get some real discussion going here.

[leafman60]

Hi guys. I wasn't trying to be a smart-*** earlier. I was only trying to communicate that resorting to a weld was not a first choice of action. I am very experienced with mechanical repairs and sources of used/new parts and I have already looked into that.I will try to post a picture.