Shimano 105 lever problems…. No bite point!

So last week, a few big rides on the gravel bike and the front and rear brakes were working fine.

Took the it out today. Rode up a nice long 800m climb and found on he way down that the front brake wasn’t working.

Pads still have some live left in them, but I’m in the middle of Friuli and there aren’t any bike shops near by.

Have bled the brake from the bottom up (as I (annoyingly) don’t have a funnel for these), but with no results. The lever is pulling all the way to the bar and the pads are not engaging.

Bleed block in place. Pushing fluids from the bottom to the top.

The pistons have very little movement when the lever is pulled.

I’ve also noticed that there’s brake oil seeping out of a side port when I pull on the lever.

Help!

How are you bleeding without a funnel? Where is the excess oil going and how are you going to bleed the lever?

Got lots of paper towels!

But…. I think I’ve managed to do it just before it got dark. Think there was air trapped in the caliper or lever. Now feels solid.

Will attempt a ride again tomorrow.

Shimano levers are a sod to do without a funnel. It can be done in a pinch but with a funnel it’s a 30 second job.

Yeah… An adapter is now on my buy list… Just need to find an address to send it to.

I’ve also noticed that there’s brake oil seeping out of a side port when I pull on the lever.

Sounds like you’ve already found the problem I’d say.

The diaphragm on that STI displaces itself to avoid overpressure which is most likely the weeping you can see from the port.

Sometimes you can reposition the diaphragm and it reseals,  sometimes you can’t. You’ll need a T8 torx and the diaphragm is available as a spare.

When pushing the pads back, you need to open the bleed port slightly to avoid the master cylinder overpressurising.

I had this on some Ultegra STI’s and couldn’t get a firm lever without changing the diaphragm no matter how many times I repositioned it and/or bled the brake.