Hello, having some issues with my trusty tech 3 e4, they are probably 4 years old, little use, on 3rd set of pads and been faultless in that time, however todsy I swapped them to a new bike, internal routed, I’ve bleed the brakes lots of times and I get no bubbles, even back bled system. I do have alot of lever travel, the lever pulls in near the bar, if I then pump it a few times it firm’s up when held in, let go of lever then pull again and it’s near the bars again, the master cylinder makes a weird noise when this happens also, like a puff noise? Will a simple replacement of master cylinder piston solve this?

What you describe sounds a lot like a poor bleed. If not, then replacing master cylinder seals followed by a good bleed will do it.

If you suspect the lever, clean and dry thoroughly after the bleed then dust with talc and lie the lever off over night. If there’s a leak, it should become visible then.

Try taking the caliper off the frame when you bleed it, making sure the bleed nipple is at the highest point. There could be an air bubble trapped in the caliper.

Also make sure the pistons are pushed fully back as air can get stuck behind them. Also make sure the BPC screw is fully out. Once bled, check the caliper is correctly aligned as this will make the lever feel spongy too.

That sounds a little like a leak at the connector. I was fitting an old, old set of Tech 3s and there was a crack in the fitting at the caliper, was losing fluid as a result. Kept getting sponginess and hearing the puff sound, eventualy spotted the leak

Hello, first thanks for the replies, secondly sorry for the late reply, I don’t get on here much but wanted to update on this situation.
It was a bleed issue, the hose it routed bellow the bb, which puts this section of hose bellow the bleed nipple.

I brought a hope easy blles kit which makes things alot easier, it basically just allows the master cylinder to hold more fluid so your not constantly topping fluid up while bleeding.
I removed the rear caliper and screwed in to abit of wood down lower near the floor and then bleed it, this removed all the air and has been spot on since. Hope this will help anyone else who may come across this