UKC

I think there might be a slight leak in the master cylinder of my Tektro Auriga Comp brakes. There are some replacement seals available online and a master cylinder kit, as well as the whole lever assembly for £30. I’m tempted by the lazy solution of getting the whole lever assembly but I’d like to strip the thing down really to find the problem. I can’t find any online instructions on how to strip the lever down and replace the seals - has anyone done this or similar please?

Out of interest, what's your evidence for the leak being in the master cylinder?

I had an odd one a few years ago where my front brake hose developed a pin hole leak about 1/2 way down the side of the forks - took me a while to find that one.

Failing that, I just take things apart carefully and take lots of photos of where each part goes and which way round.

Failing that, I just take things apart carefully and take lots of photos of where each part goes and which way round. <trying not to get brake fluid or oil on my camera/phone> (from experience)

I still need to be sure, but I think there were signs of oil around the lever / reservoir. Could have been left over from a messy bleed so I'll check before I try replacing anything.

Trouble is, I can't even see how to start! Nothing obvious to undo.

Yes, despite best efforts that stuff seems to get everywhere. Still, I suppose there are worse fluids to be covered in.

I've recently had the same thing with a Shimano lever. Oil clearly leaking from around where the lever operates the cylinder/reservoir. While I'm sure it's just a seal, the effort and cost of repairing drove me to the easy way out and i bought a new lever. Not proud, but like you, discovered it wasn't really self-serviceable

I haven't ever seen or used these brakes, but a common system is to have the piston held simply by a circlip. So if you take the lever off it may become obvious, although in the diagram of the lever I can find the lever pivot appears to be push fit and therefore maybe a pain to remove. You may still struggle as the clips  are small and access is difficult.

Thanks. Even if I could get the lever off, access to the end of the piston looks tricky. The option of a whole new lever assembly is looking attractive.

I’ve just had a look at a diagram online and the lever axle is held in place by a grub screw. They might have covered it over with a rubber bung or similar.

Sorry, missed your reply. Thanks - I’ll have look. 

No problem. You need to wind the reach adjust all the way in to expose the screw.