What to do if I have air in my brake lines?

[gobble]

I just rebuilt my calipers and made a mistake. I let fluid drain out of the lines to the point that it emptied my master cylinder and got air in the lines. I've put three bottles of Motul 600 through the system and still have a soft brake pedal. It seems like the little bubbles have stopped, but the pedal goes halfway down before it starts to be effective.

What do I need to do to get the rest of the air out? Is there a trick to working the air down to the bleeder valves? Or do I just have to keep running fluid through the system?

 

[Daria]

No real trick to getting the air bubble out. If the lines were short (like on a motorcycle) you could tap the lines and it would help move the air bubble along the line.

Buy a lot of brake fluid and start flushing if through until you notice improvements. It also helps if you spread the flushing of the brake fluid over a few days with some driving around in between (so you can allow the air to migrate on its own a little).

 

[matteni]

Be sure to follow the procedure in the manual. You basically want to bleed the farthest line from the Master cylinder first (right rear), then left rear, then right front, then left front. You need to keep filling the reserve tank and bleeding until there are no bubbled from that line - then tighten - then repeat.

Also - as you will see from the testimonials in the FAQ section of this site - get some of these http://www.speedbleeder.com/

A terrific investment and big time savor IMO.

 

[sak]

Or do I just have to keep running fluid through the system?

Thats your best bet.

 

[Larry Bastanza]

Complete bleed will do it, and it should be done anyway.

Nick,

I think you have a small contradiction in your advice though.

Follow the procedure in the book - YES

Start with the furthest and work your way closer, well NO

Since the brakes are setup in a diagonal fashion, the book states RR, LF, LR, RF as the sequence.

They have a nice picture under "brake bleeding" in the on-line manual.

HTH,
LarryB

 

[gobble]

Try this. Much better than speedbleeders.

www.motiveproducts.com

 

[matteni]

Complete bleed will do it, and it should be done anyway.

Nick,

I think you have a small contradiction in your advice though.

Follow the procedure in the book - YES

Start with the furthest and work your way closer, well NO

Since the brakes are setup in a diagonal fashion, the book states RR, LF, LR, RF as the sequence.

They have a nice picture under "brake bleeding" in the on-line manual.

HTH,
LarryB

Great catch - thank you for the correction. Next time I will look myself before quoting the manual!