Blocked top tube internal cable routing....

Hi Gang, I just picked up a late 90's road bike, a Peugeot Competition 400, Columbus Thron tubing, so nothing remarkable but it's in good nick apart from one issue....

The top tube internal cable routing seems blocked. Initially I could see what looked like some plastic from some old cable housing stuck in there but after some careful prising with tweezers I managed to remove a two inch section of screwed up cable outer plastic, deep joy, or so I thought!

Celebrating my prowess I tried to thread a brake cable through the top tube but to my horror I found the internal routing was still blocked. It seems there was more old plastic stuck in there, so I thought sod it and got my drill out and carefully drilled out some more of the plastic.

Sadly my drill bit isn't long enough to get all the way in there, I also tried using a spoke and straightened coat hanger and tried pushing from the other end to dislodge the offending blockage but it's properly jammed in there.

The interweb hasn't provided any help, so I was wondering if any of you have experienced this problem, and how you solved it, here's hoping and thanks in advance...

p.s. I know I could use cable holders to route the brake cable externally, but I'd like to avoid that if possible, thanks.

If it ain't moving with a bit of spoke jabbing it, it probably ain't moving at all.

A drill would be the last tool I'd be reaching for to fix this problem.

Sticking a spoke from the end nearer the blockage did move it fractionally, but the spoke's not long enough to push from the far end. Yeah a drill is the way forward but my drill bits aren't long enough and the curve in the internal cable routing tube would stop me from reaching the blockage anyway. I did find a video online on how to make a long flexible drill bit but sourcing suitable bendy cable for the shaft seems tricky.... Not giving up though!

Yeah a drill is the way forward...

Don't think you quite grasped what I was saying.

if its just plastic couldnt you (carefully) melt it out with petrol or something else that will eat away at it?

If it is just plastic you could take the frmae to the local piza outlet and put it in their oven to melt the blockgae.

Ah right, see you what you're saying now... Well initially the blockage looked like it was just by the entrance of the cable exit, I could see it was just plastic and freed quite a long chunk of plastic, but the remaining blockage was only two inches down and felt/looked like plastic. As it wouldn't shift I figured drilling carefully would be fine, and I've got a compact drill. Doing that did shift more plastic, but there's clearly more further down the tube. If I can't make this flexible drill bit thing I'll just hand it over to Winston Vaz.

take the frmae to the local piza outlet and put it in their oven

The best suggestion yet...

put the drill down

Bingo! Some careful drilling, a few squirts of plus gas, a longer stiffer steel rod and some light hammering got the bastard unblocked, here's the result and one of the two offending pieces of chewed up plastic....

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The only problems I get are blocked bottom tubes

Good news! I was going to suggest greasing it then using a high pressure water jet to blast it out.. Could of made it worse though I guess :)