For a project I may need to have a caliper mounted above a lever.

If it’s properly bled this should work…shouldn’t it?

Cheers

It’ll need to be very well bled. I have had brakes that work fine but if the bike travels or is stored upside down the brake takes a few pumps to get it to bite, then it’s fine again.

Does it have to be hydraulic?

So I’ll start off by saying that I’ve never had a problem bleeding brakes. Read some horror stories but all you’re doing is pushing fluid through to get air out either end.

As long as the caliper is the correct orientation i.e. bleed nipple towards the top it should be fine. All you’ll be doing is pushing fluid and air from the lever to the caliper. If they’re Shimano and you use the open cup then you may have to use a syringe instead as when you open the bleed nipple on the caliper the fluid may want to go along with gravity and come out the lever and into the cup whilst air is drawn in via the bleed nipple.

TBH, it’s more the lever being in the correct orientation that is the issue. As the bubbles will be in the top of the reservoir, and the fluid generally is pulled from the bottom. So as long as you aren’t doing extreme offroad or riding with the reservoir 90% empty, the bubbles shouldn’t be dragged into the hose. Just bleed them with the lever above the caliper and you should be fine.

Cheers all. Will experiment

Yes, as long as the reservoir is above the master cylinder, it should be fine. If it were me, I’d bleed them with totally worn pads so the system is overfilled, then lever the pads apart to force the pistons back into the caliper and force fluid back into the master cylinder reservoir. That should expel any air in the reservoir.

Another option would be to fit the master cylinder above the caliper as normal but have a second lever mounted lower down where you need it. This could be achieved with standard parts using the Shimano Inline/Sub brake levers.