Brake bleeding, reverse/pressure/vacuum/gravity, lever pull back or not

Here is what I do when I am bleeding a dry system.

Pistons in both calipers pushed right back and a block inserted so they can’t be pushed out.

20ml syringe with tubing attached to bleed nipple.
Fill master cylinder and either pump or use vacuum on syringe to pull fluid down. Do same on other Caliper. Pump till you get a good lever. If still struggling detach master cylinder from bar ( I attach onto an old bar) an hold so lever is highest and pump to make sure any air bubbles that may be trapped at the master banjo are released. Once you have that remove blocks and pump till pistons and pads back in to position.

Final thing make sure you have lever span on its widest setting.


Hope this helps.

 

with a dry system build pressure in the mc first by holding a thumb over the outlet hole and alternatively opening it on pressure strokes and covering it on return strokes, then hold lever in and screw in banjo and washers.

 

thats called "bench bleeding" do the same with a new master cylinder on a car/truck. I dry to use my Mityvac and thats usually all I needs to do

 

I think some of the problems are due to loads of tiny bubbles that adhere to the dry tube walls. They don't move with bleeding, but will eventually coalesce and so you can bleed them out. The old method of tying the lever back to the bar to pressurise the system overnight seems to help to move these little blighters on.

My experience is that when you first fill the system, try as you might, you can't get a decently firm feel. I've found that I need to repeat a bleed once or twice after some use before the brakes finally get a firm feel.

 

It turns into a rewarding process when you have a kick arse lever! Some things are unglamorous but the payoff is high - Its good to be gentle with the lever, dont go "mental" on it - steady pressure