Bicycle Mechanics - Is Dura-Ace (7800) shifter repairable ?

I think it is a 7800, bought it in '04. What happens is when I up-shift (go from large cog to smaller cog) it does not shift. This only seems to happen when I am in the largest cog, but I'm not sure of that. I'll press the lever and -nothing, no click, no movement. I do it a few times and it works and keeps working (I often move several cogs at once. I would take it apart and see how it works, and what piece is failing and then either buy or make the part (if I can - I have a machine shop) but... I don't know it it is possible or advisable to do that (take it apart). Any words of wisdom out there?

Shimano STI brifters are not servicable. Shimano does not sell repair parts or publish a repair manual. There are a few guys who claim they have repaired various versions of STI's but there is no commercial service for this I know about. If you decide to go inside one, you are pretty much on your own.

The usual "fix" is to hose out the mechanism with copious quantities of WD-40 to wash out the accumulated crud and old lube and then lube them with light oil like TriFlow. This will often get them working again. Otherwise they have to be replaced.

Campy's Ergo brifters are servicable and both parts, instructions and commercial rebuilding services are available. Shimano has none of the above.

Campy's Ergo brifters are servicable and both parts instructions and commercial rebuilding services are available. Shimano has none of the above.

The small parts were discontinued for the Ultrashift (third generation) levers and were never available for Powershift or Escape levers. Replacement assemblies consisting of everything but the brake blade, hood, and mounting hardware are available for about $100 although that's a far cry than the $5-$10 you'd spend to replace the parts which usually broke or wore out in first and second generation levers.

First generation small parts (apart from the G-springs and left G-spring carrier which are common to second generation levers) have also been discontinued.

Symptoms OP describes indicate the usual gummy grease issue.

Symptoms OP describes indicate the usual gummy grease issue.


+1
Shoot your shifters full of WD40. If that doesn't fix the problem try new cables and cable housings. Lubricating the part or the cable that runs through the short housing at the rear deralleur may also help.
You probably do not need new shifters.

My Shimano 600s act the same way. I try to upshift the rear and it just does nothing, you have to try it several times. Same for the front. If I try to shift down to the small ring or micro-adust it, it wont move. I have shot it with WD40 to fix it before, and it works for a while.

The small parts were discontinued for the Ultrashift (third generation) levers and were never available for Powershift or Escape levers. Replacement assemblies consisting of everything but the brake blade, hood, and mounting hardware are available for about $100 although that's a far cry than the $5-$10 you'd spend to replace the parts which usually broke or wore out in first and second generation levers.

First generation small parts (apart from the G-springs and left G-spring carrier which are common to second generation levers) have also been discontinued.
Hmmm, my two sets are Record and Chorus 10-speed 2006 vintage, pre both QS and Escapement. Are the normal replacement/rebuild parts still available for these or do I have to hope for NOS finds?

Sounds like Campy is following the Shimano business model.

Make sure that the cable is not breaking. They break inside the lever. 7800 levers break cables pretty quick.

To check, shift to the large cog, apply the right brake lever, and shine a flashlight in the cable insertion hole. If the cable does not look perfectly smooth and shiny, its got broken strands.

Hmmm, my two sets are Record and Chorus 10-speed 2006 vintage, pre both QS and Escapement. Are the normal replacement/rebuild parts still available for these or do I have to hope for NOS finds?

Those are second generation levers for which parts are still available.

You want to keep right G-springs and G-spring carriers on hand. The G-springs are wear items that are convenient to have around; and G-spring carriers seem to make it through a couple pairs of springs before failing due to fatigue.

I'd also keep right front lever return and thumb lever return springs because you don't want to be scavenging for NOS parts if you break yours after Campagnolo discontinues them (I bought the last two first generation right front lever return springs from Loose Screws).

Left G-springs and G-spring carrier might be a good idea but my left shifter still feels like new after 15 years.