Arrrgghhhh…. so near and yet so far……

I’ve nearly got my Sonder Frontier frame built up, just needed a new rear brake hose, which arrived this morning.

Turns out you can’t just swap the banjo from one hose to another with XT brakes, and as far as I can tell the hose has to be threaded into the internal routing from the top of the downturn so I can’t use a Shimano hose.

Can I use the standard Uberbike banjo on an M8000 caliper or do I need a specific banjo that just fits these brakes?

Was really hoping to get the bike up and working this weekend but looks like it’s going to be another week on the workstand. ☹️

Why do you have to go top down?

Unless its specific to that bike we always route our rear brakes from the caliper up to the top. That way at the worst it’s a barb and olive to replace

Because there’s just a large void behind the exit panel in front of the bottom bracket and I can’t see any way of threading the hose through to the small entry/exit point at the head tube end.

Cheers Tracey, unfortunately I can’t see how to do that on this frame thou as the cover is very small at the BB end and it looks like a large space begins it. Can’t see where the hose needs to go.

Would be a lot easier for me if I could just replace the banjo.

OK, don’t know if this is going to work, but this is what I can see from the BB end

Oh god, why is it so hard to post photos on here these days?

There are two types of olives for Shimano hoses, make sure you get the correct one. Two sizes of hose.

Thread it one way then thread it back if you thinks thats easier. (Needs 2 hoses)
Reverb barb is the go-to tool for this.

Carbon frames are great in that popping the fork off gives great access to upper downtube cable ports. This probably only has small pressure relief holes in the head tube though.

Otherwise, threading the hose up from the BB port then using a torch and a pick to pull the end out will work. My alloy scale had ports like this.

All sorts of other tricks are out there. I remember reading about using a vacuum to suck a great through.

Cheers BearBlack. I think I’ll have to see if there’s enough space at the HT end to pull the hose with some tape wrapped around it in that case and tape the ends together.

Not over happy at having to spend even more money to fix something that never used to be a problem though. This frame build is beginning to get more expensive than a fully built Frontier would have cost.

I’ve had this a few times and come up with a solution that works for me on a couple of different frames. If you already have a hose in there, as you pull the old hose out, tape a bit of string to the brake lever end of the hose (use very sticky tape like gorilla tape and make sure the string is central with the tape) and tie the string to the bars so it doesn’t pull through. Then tape the new hose to the end of the string at the BB end and carefully push/pull the hose through using the string as a guide. If you don’t have a hose in there thread one through front the top as you describe above and then follow the steps above.

@muggomagic cheers for the suggestion, might try that.
I did wonder about threading an old gear or brake inner from the top down and sliding the brake hose over it so it guides the hose back up to the top, if that makes any sense (sorry, under the influence of Mud City Stout at the moment, so it might not)

Thanks for the help and suggestions folks.

Inner may work if it only needs gentle guidance to get it out. Another option is a small screw in the end and attach thread (trim the hose after doing this).

Cheers, that sounds promising.