bleeding brakes - hose in jar under fluid?

I've read in a non-XJ book that when bleeding brakes the end of the hose in the catch jar must be underneath some fluid at all times. Is this really necessary?

 

I think its so you can tell when all the air is out. It could be so you don't suck any air back into the system but I have never been able to seal the threads on the bleeder screws to get a positive seal so you can leave the screws open. They do make bleeder screws with check valves for one person bleeding.

MN

 

It's primarily so you don't suck air back up into the system. NOT 100% critical as long as air bubbles don't travel back up the tube. They CAN'T if the end is submerged.

 

Seal the threads somewhat with anti-seize goop and just barely crack it open, 1/4 turn.

 

Or wrap it with teflon tape.

 

Replace the bleed nipple with a SpeedBleeder one -- you won't be sorry.

Basically it's got a spring loaded ball valve inside it, so when you've loosened it you can pull the lever and fluid can escape, but as soon as pressure stops the valve closes so no air can get back into the system.

Solves the whole need to keep the end under fluid, or to keep opening/closing the bleed nipple.

That or you could go buy a vacuum bleeder - that solves the issue too...

 

Where'd you get your speed bleeders?

 

Used a vacuum bleeder. Was uber easy. Autoparts store.

 

I must be inept (the echoing chorus of laughter will surely follow that statement), I've always had to follow a vacuum flush/bleed with the time tested manual method (which means finding a willing volunteer in the case of my car). I cannot get a hard lever without the manual follow-up

 

Any bike shop will sell you SpeedBleeders - they're about $15 a pair
A couple of people make them, but you want the M8x1.25 size.

 

I did the manual follow up, but for an entire new front brake system (rebuilt MC and calipers, new lines) pumping (even with a speedbleed) would I think be futile at this.

So how did I open and close while squeezing. (only once or twice needed after using the vac). Box end wrench on bleeder, then hose. (Kinda holds the wrench in place. SQueez. Foot operates wrench. Open close (not much rotation between open and close). Repeat 2 or three times. Done Switch sides.

 

Ahhh yes - this is a good point of note, you cannot fill a NEW line with a speedbleeder nipple on - it just won't work.
If you just replace the nipple then bleed the system, no problem.
But if the system has been drained, you'll need to figure a way to get the whole thing mostly full of new fluid BEFORE adding the speedbleeder. Manual method, vacuum method, or a syringe pushing fluid through -- it's got to have fluid in it before the speedbleeder works.