Mechanics and Fixing Any Questions Answered

Further to my Silca pump question, just found this video of a guy making leather pump cups for Coleman stoves and lanterns, aka Silca pumps.
Pretty cool.
https://www.youtube.com/watch?v=_bwF6yHyUq0

Is my rear mech shot? Whenever I shift into the small ring unless I’m in the largest sprocket the derailleur won’t pick up the slack and the chain sags which means it then skips on the cassette. I’ve already tried stripping the derailleur and lubricating the cage but to no avail. Chain is 100% correct length

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Chain is 100% correct length

Is it tho

Can you show a picture of big-big to see how much the derailleur is straining?

Lubricating the cage meaning flushing the pivot where the cage meets the derailleur body? That’s usually where the problem lies.

Wd40 sprayed into the joint, then manually pivoting the derailleur cage to and fro; repeat two or three times if needed. If the cage feels easy to move and you don’t get resistance from it, then it might be shot. Might be rebuildable given it’s Campag.

Aside from a leak, is there any other reason why there would be less fluid than there should be as well as some air in my hydraulic system?

I went to ride my bike after it had sat for 2 weeks a couple of days ago. The rear lever immediately had a noticeable difference in feel; it was doing that thing where it gets progressively stiffer as you squeeze it in quick succession. Yesterday, I had a look in the lever reservoir and there was definitely less fluid than there should have been. So I attached the funnel and ‘burped’ the system to top it up and get the air out. The lever felt fine then (I think). But for some peace of mind, I took it into a shop today to have it looked at, however they reckon that if there was a leak then you’d already be able to feel a difference in the lever and the burping wouldn’t have helped. They’re going to keep it overnight to see anyway.

I’m still learning hydraulic brake stuff so just don’t know what the reason for the air and lack of fluid could be if it’s not a leak?

Fuck no, haven’t you seen the nick of my bikes?!

#rustisnotacrime.

If you move the RD on its pivots, does it actually move or is there resistance? ie. did you clean it properly? Did you put the spring pins back in the right way, giving the RD its needed spring tension?

Here it is on big big. I always size new chains using the old chain as a guide which was done using the park tool method. Over the last 2 years I’ve probably done 10,000km on this bike and fitted at least 7 chains and never had this issue before. This issue has only been happening since I fitted the last chain, I suppose there is a chance I removed one too many links (in a rush and not paying attention) but I dunno. The derailleur is super stiff to get to spring back into place. @hippy when I stripped the mech I didn’t remove any pins. I’m out and about at the mo but when I get home tonight I’ll unlink the chain and check it corresponds according to the park tool length calculator.

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How old is the derailleur? It used to be a known issue that the return spring in Campag derailleurs would lose tension and need replacing. I’ve stopped using Campag now so don’t know if it’s still an issue.

That chain length should work. It sounds like the pivots are gummed up and the spring(s) aren't strong enough to overcome this friction so your chain is stuck hanging loose. It happens when riding UK lanes full of shite every year. I've had to strip deraillers and sand corrosion off the spindles of the pivots and relube so the cage will move.

Also I don't use Campag so I'm basing this off my Shimano knowledge.

Cheers @hippy and @andyp - it’s had a hard life so I’ll give it a proper strip down. I have a super record 11 speed mech on another bike which I can swap it out for worst comes to worst

🤷‍♂️ 😎

As the light fades in my beleaguered garden I confirm that it was the derailleur and not the chain at fault. Nabbed the rear mech from my Serotta and stuck that on as a temporary fix whilst I contemplate a full strip of the especially stiff removed derailleur

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Figured. Lightly sand down corroded bushings, check the spring isn't fucked and maybe see if there's extra holes inside like Shimano so you can increase the spring tension. Lube it good (always good advice).

My 8050 di2 front mech has developed some issues. When I shift to the little ring, the chain doesn’t fully engage with the teeth of the little ring until I’ve pedalled another 1/2 revolution, and then clunks down onto the chainring. Chain and chainring aren’t worn so I think this must be an adjustment issue? It started happening after I tried to adjust the high limit to get rid of some rubbing in the big ring/small cog combo, but I’ve tried setting all the limits again and it’s still happening.

Also, potentially unrelated, but I noticed that the support bolt had worked loose, though the cage sits parallel to the chainring without it anyway because the mech is on a band-on mount.

So have you checked for any signs of fluid leaking at the caliper and the brake lever?
Take the pads out and inspect the backing plate, then chuck a bleed block in, pump the brakes and check the sides of the pistons for fluid bubbling. Roll back the hoods of the levers and see if there's any bubbles around the edges as well.

https://photos.app.goo.gl/GNvDbG1dmro6Mu4S8

Any thoughts on what product would be best to patch this with? Chipped lacquer/carbon SR crank arm. Guessing some very fine emery paper and then brushing on some lacquer? Would appreciate any thoughts/suggestions

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Wet and dry to flatten / even it out …. then rattle can lacquer or for quick and easy - nail varnish !

Remember the Di2 FD limits aren't really limits, they move the whole cage position.
I can't remember which version you're talking about but it's worth a look at the manual and adjusting each step of the way. If the support bolt isn't touching the clamp/frame or plate then it might've moved and all your adjustment will be out a bit.

Because I'm impatient and want to deliver a helpful answer, does anyone have ideas for fork straightening that don't involve a hammer (https://www.lfgss.com/comments/16939932/)?

https://www.lfgss.com/comments/16939932/

Happy to have a look and align them if they’re near SE24 at any point. No plans on heading to West or even central London. (using the specific Park Tool, which isn’t the hammer)

BikeFix just off Lamb Conduit Street.

Nice, cheers. What grade we talking, 4-600 or more like 1200?