Front Derailleur adjustment screws...

[Aussie Steve]

Shimano 105 front derailleur, the two small grub screws that you use for adjustment...mine are totally seized.
Cannot budge them. Bike shop tried, could not move them.
I even tried leaving a drop of lube on top of each screw overnight, but think about it...how can any liquid seep down past the head? A normal drink bottle laying in the fridge on its side, doesn't leak....

Can anybody offer any suggestions...don't want to pay for new Derailleur ($75 australian)

 

[gclark8]

Take the FD off the bike and try some CRC from the other side. If that fails, drill the screws out and re-tap new threads. I have a 5mm tap.

 

[Aussie Steve]

hey gclark- thanks for the tip! yesterday I took the FD off the bike...because it's the kind that's mounted on a brazed-on fitting on the seat tube, was real real easy for a numb-skull like me...one minute with a 5 mm allen key and she's off...
you know how aluminium and steel, "weld" together (or at least steel expands differently to Aluminium) I am pretty sure the FD body is Al, and the grub screws are stainless? could this be the reason they're stuck?
What drill bit should I use to drill out the grub screws...

 

[gclark8]

I would not say without seeing it. Depends on which side is best to drill from, this is delicate work. I have the Stainless Steel bolt shop just a short walk over the line from me.

 

[jlance83]

Now that youve taken it off, why dont you try soaking it kero overnight or something. Fill up a container with kero and dunk in there.

Does anyone think that would help?

 

[Aussie Steve]

I will buy a new FD in case I bugger up the job. I reckon I could mount the FD in a vice (with 2 pieces of wood to avoid scratching the assembly) and the drilling shouldn't be too hard, it is a phillips head, so the drill bit will sit right in the centre and shouldn't travel ...
I will be very careful !!!!

 

[wooliferkins]

Mineral hydraulic oil is good it has flat molecules. Have soaked out aircraft wing attachment bolts with this, they've been in longer with more vibration and stress.

I will buy a new FD in case I bugger up the job. I reckon I could mount the FD in a vice (with 2 pieces of wood to avoid scratching the assembly) and the drilling shouldn't be too hard, it is a phillips head, so the drill bit will sit right in the centre and shouldn't travel ...
I will be very careful !!!!

 

[gclark8]

Mineral hydraulic oil is good it has flat molecules. Have soaked out aircraft wing attachment bolts with this, they've been in longer with more vibration and stress.

I would agree, find a Citroen owner and beg a few ml of LHM.

 

[alfeng]

Shimano 105 front derailleur, the two small grub screws that you use for adjustment...mine are totally seized.
Cannot budge them. Bike shop tried, could not move them.
I even tried leaving a drop of lube on top of each screw overnight, but think about it...how can any liquid seep down past the head? A normal drink bottle laying in the fridge on its side, doesn't leak....

Can anybody offer any suggestions...don't want to pay for new Derailleur ($75 australian)

I had a couple of front derailleurs which were neglected and whose adjusting screws were ALSO unmovable ...

Penetrating oil and/or WD-40 (a penetrating oil, of sorts) AND a lot of patience (waiting ... just waiting & re-trying), and you may be able to salvage the front derailleur (or, other components in the future).