How easy it is to disconnect existing hydraulic brake lever and plug in another lever

[echappist]

I guess the real question is, "is this a rather technical job best left to the pros?"

I have a MTB for which i may want to convert into a road-ish set up (currently has Avid hydraulic brake levers). Also have another bike currently set up with 105 for which i may want to install Di2.

On caliper systems, i'd just take out the cable from the housing, swap the brake lever (or shifter), and I'm good to go. I'd imagine the process to be more difficult, if actual hydraulic line work (e.g. bleeding of the line) is required. Anyone cares to enlighten me on this?

Thanks,

[jtakeda]

For starters let’s assume the hydraulic cable hoses are compatible with your shifter AND the correct length.

If that’s the case above and it were me.
I’d fill the bleed funnel with a little fluid, disconnect the shifter end
cut the olive and barb off—install a new olive and barb
Re-attach and push some new fluid in from the caliper end(push out the air you introduced into the shifter side)

You should see some bubbles come up in your bleed funnel and once that’s done voila.

PS—id also turn your freestroke screw all the way down in the beginning

[benb]

If you're talking about using a Shimano/Campy/SRAM hydraulic brake integrated shifter with your current MTB calipers & discs that's probably a really hard job and might not end well.

The master/slave piston sizes need to match up and a bunch of other stuff. I would not necessarily expect it all to work right even if you got it all setup and bled it well and all the hoses matched up correctly. You might have not enough power or too much power or modulation that is all screwed up.

I'm not sure that's what you are talking about though?

[echappist]

For starters let’s assume the hydraulic cable hoses are compatible with your shifter AND the correct length.

If that’s the case above and it were me.
I’d fill the bleed funnel with a little fluid, disconnect the shifter end
cut the olive and barb off—install a new olive and barb
Re-attach and push some new fluid in from the caliper end(push out the air you introduced into the shifter side)

You should see some bubbles come up in your bleed funnel and once that’s done voila.

PS—id also turn your freestroke screw all the way down in the beginning

Good lord; you are obviously way more skilled at this than I am. It's like me listening to a talk on relativity...


If you're talking about using a Shimano/Campy/SRAM hydraulic brake integrated shifter with your current MTB calipers & discs that's probably a really hard job and might not end well.

The master/slave piston sizes need to match up and a bunch of other stuff. I would not necessarily expect it all to work right even if you got it all setup and bled it well and all the hoses matched up correctly. You might have not enough power or too much power or modulation that is all screwed up.

I'm not sure that's what you are talking about though?


Yep, that was part of the motivation. The cylinders on MTB hydraulic levers are ginormous, and i'd like to be able to run levers that are more "road-sized". It doesn't even need to be an integrated shifter, just smaller levers that I can swap out when i'm in the mood for doing longer distance trail rides


THe other is more of straight swap of DI2 8070 with Shimano 105 (this one is more of a one and done job)

[NHAero]

Two thoughts:
- Since I run my brakes Euro-style, I've bought a used bike on occasion with hydro and switched the hoses side to side without incident or bleeding, being careful to not lose fluid.
- FWIW, I have two bikes with Shimano RS685 hydro shifters and XT hydro calipers and they work together fine. Don't know if later gen road hydro shifters and MTB calipers are compatible, but these are.

[thermalattorney]

For your 105 disc system that you're looking to upgrade to Di2, your brakes and hoses are compatible BUT you'll need to have the correct nut at the lever. Unfortunately this nut is sold with the hose sets, not the levers.

Provided you have the correct nut and you can afford to lose and inch of hose length, you might be able to shorten the line without losing too much fluid *if* you do it with the hose vertically when cutting. You'll still need a bleed funnel and fluid to top it off and tap the bubbles out, but it's possible to do this without resorting to a full bleed.

That said, full bleeds on Shimano are easy. It could be years before you need to bleed again, so it's something worth getting right.

As for your MTB setup with Avid brakes, all bets are off. It's unlikely those brakes are compatible with any drop levers.

Good luck!

[vqdriver]

I guess the real question is, "is this a rather technical job best left to the pros?"


not terribly technical if you've worked on hydro before, but even if done right, mixing and matching hydro is a crapshoot.
i'd take it by the lbs

[bikinchris]

I do it often without having to bleed the brake, but I get paid to do it.

Whit proper technique and setup, It's not very hard, but it does take practice.

[Gummee]

Y'all are missing an important key bit of info in the OP:

Avid/SRAM brakes = DOT fluid
Shimano brakes = mineral oil.

No way. No how. Period.

IF we were talking about Shimano to Shimano road to mtn lever swaps? Sure. Things work fine pretty well across the board.

Ditto with Avid/SRAM to Avid/SRAM

Things get a little more interesting when going from TRP to Shimano, etc

M

[echappist]

in other words, i really ought to leave this to the pros

dammit, caliper brakes were never this hard to deal with...

[bikinchris]

Y'all are missing an important key bit of info in the OP:

Avid/SRAM brakes = DOT fluid
Shimano brakes = mineral oil.

No way. No how. Period.

IF we were talking about Shimano to Shimano road to mtn lever swaps? Sure. Things work fine pretty well across the board.

Ditto with Avid/SRAM to Avid/SRAM

Things get a little more interesting when going from TRP to Shimano, etc

M

Oops, I didn't read through. Abort, abort.

[Ronsonic]

Two thoughts:
- Since I run my brakes Euro-style, I've bought a used bike on occasion with hydro and switched the hoses side to side without incident or bleeding, being careful to not lose fluid.

Same here except every time I try that the hose get flicked one way or another and splashes out contents.

[Gummee]

Oops, I didn't read through. Abort, abort.

OP: Switch to Shimano brakes and your problems pretty well go away if you want to swap back and forth from road to mtn and back. Bleeding Shimano brakes is just about 'bang two rocks together' simple.

Actually, switching to Shimano brakes makes pretty much all your braking problems go away. SRAM brakes suck out loud to work on. The fluid is toxic. The fluid eats paint. etc etc etc

M

[Jaybee]

OP: Switch to Shimano brakes and your problems pretty well go away if you want to swap back and forth from road to mtn and back. Bleeding Shimano brakes is just about 'bang two rocks together' simple.

Actually, switching to Shimano brakes makes pretty much all your braking problems go away. SRAM brakes suck out loud to work on. The fluid is toxic. The fluid eats paint. etc etc etc

M

I agree with all this. Shimano w the mineral oil is the way to go, especially for the application described. In SRAMs defense, I will say that the Guide RSC brakes that came on my bike are superior in feel, modulation and power to the XT and XTR brakes on my other bikes - but I'm not looking forward to the day I have to bleed them.

TRP is also developing some sort of quick-connect for hydro hoses, but I'm not sure of it's status. More here. (https://bikepacking.com/bikes/rodeo-labs-traildonkey-3-sea-otter/)