Brake Bleed Blues

[PedalUma]

I have recently had to do brake bleeds on things such as gigantic cargo bikes and eTrikes. It is such a pain. This is where you can share your pain and pick up useful real world tips from others. One eTrike took two hours to get all the bubbles out.
I just purchased these large 200 ml syringes to help. I do not care if I waste a little fluid. I want all the bubbles out fast.

Here is a starting place video from Park Tool.

 

[fooferdoggie]

are you taking the caliper off so the line is as closer to vertical as possible

 

[PedalUma]

Yes, the caliper comes off with the pads off, and the caliper is on or over cardboard away from the rotor. Pull the old dark junk oil down until you hit fresh oil from the top dispenser added reservoir or syringe. Dispose of the burnt junk. Then go the other way with fresh oil so no bubbles appear at the top. I am making it sound easier than it is. For the rear drop the callipers and put the front wheel up on a milk crate, so the bubbles want to migrate up. It is not taking the caliper off, it is lowering it down while still attached to the hose. This way there are no S-curves like under a kitchen sink that can trap air. When the fresh oil has no bubbles up top cap the top, like a pipette with the plug, install the bottom plug and clean everything before installing the pads. A block is required to prevent the pistons from popping out.

 

[PedalUma]

Bleeding a bike can be such a mess. Get cardboard under it. @Aushiker, It was about 14 years-ago-working a 9 to 5 selling wine;
when I was at a picnic table eating a tuna sandwich from home with two ladies from work at lunch, I explained that I could not work on things with rubber gloves, I had to really feel what I was doing. They laughed and laughed, even more at me. They were thinking about condoms. Mineral oil on the hands is nasty. I would still rather feel what I was doing. Who wants a raincoat in the shower? In the west of one island I love you can be in the rainbow mist and ride the waves in and out with your toes sticking up. The waves and air at 82 degrees as you view the rainbow and gliders an and an observatory on a mountain. Iti is exactly between a baja like desert an a jungle.

 

[speedub.nate]

I just sold my analog cargo bike but before doing so stripped off the Avid Mechanicals and installed new Magura hydros. Good riddance.

The electrified cargo I'm building now was the donor of those Maguras, and I'm treating it to a set of Paul mechanicals.

I don't "hate" hate hydros, but I much prefer the simplicity of cable pull. I hadn't even thought about trying to get a long, heavy cargo bike at the correct angle for a proper bleed! Yeesh.

 

[Gordon71]

My solution was to buy hydraulic calipers for my rover that worked by the original cables. No bleeding needed and they work great.

 

[stompandgo]

I prefer doing a dual syringe bleed over a lever bleed with a cup. I've found that once the majority of the easy air is removed, using one syringe to pull and the other to push helps get the last of the air out.

 

[JGcycle]

I prefer doing a dual syringe bleed over a lever bleed with a cup. I've found that once the majority of the easy air is removed, using one syringe to pull and the other to push helps get the last of the air out.

Any chance that you could post a step by step tutorial on this method?

 

[PedalUma]

I prefer doing a dual syringe bleed over a lever bleed with a cup.

Me too. Having both pressure and suction really works to force it through.
I fantasize about using DOT 5. It is used in race cars and is super stable. I just don't know how it will impact seals. It is supposed to inert.

I'm treating it to a set of Paul mechanicals.

Really good mechanicals are really good. Just tighten the inside pad after a big ride until it touches and then back off a quarter turn.