brake bleeding

[junia]

I need to make sure I'm doing this right because this is the second time I'm bleeding the brakes and the breaks work for a while but then they get spongy after a day.  When I bleed my brakes I have a friend pump my brakes a bout 4 or 5 times until they get hard to push down and then I open the bleeder valve and then close it before the pedal gets all the way to the bottom.  I do that a few times on each brake until I do all four.  Maybe I'm doing something wrong that maybe someone could correct me.  Also,  if anyone is wondering I make sure that I don't run out of brake fluid in the master cylinder.  How does that oneman bleeder work??

[camppain]

have your friend pump the pedal up 4 5 times then have him hold the pedal to the floor. then open the bleeder screw. then repeat this on both sides till you feel the pedal stiffin up.

one man bleeder work off of vacuum you'll need a compressoor to hook it up to they just suck the braqke fluid and air out when the blleedr screw is open.

[HippoSleek]

What camppain said basically.  One guy in the car (D), the other at the caliper ©.  One guy pushes the pedal, the other opens bleed nipple (as little as possible!  There should be resistance in the pedal.).  When it gets to the floor, close the nipple.  Use a basic brake bleeding kit from a parts house (plastic tube and a catch bottle).  Here's the script:
D - "Pushing"
C - "open"
D - "Floor"
C - "closed"

Do this several times until you have a firm pedal and there are no air bubbles coming out of the nipple.  Start at the caliper farthest away from the M/C and move toward it (RR, LR, FR, FL)  Keep an eye on the M/C.  When you are done on a corner make sure you tighten up the nipple or air WILL get back in.

Also, in addition to the one man system that uses vacuum, you can get "Speedbleeders."  They are specially made nipples that have check valves built in so you can just loosen, go pump your self, then tighten.  I've heard mostly good reviews about them from people who bleed their brakes as often as I buy gas (i.e., full blown track cars).

[wizdom98117]

I've tried to bleed the brakes myself using the bleeding kit (tube&catch bottle), but still I get a VERY spongy brake pedal.

I think the problem is that when I bled the brakes the first time the master cylinder ran out of fluid before I got the chance to fill it up again. So, I'm assuming that there's a lot of air bubbles caught in the system. But, when I bleed from the Rear Right brake I don't get any air bubbles. Should I move onto the next brake (Rear Left), then continue to the Front Right and Left??

What do I do? I've already been through 3 bottles of brake fluid. My friend will come over tonight to help me bleed the system, any suggestions??

Your help appreciated.

[240Stilo]

This should be archived if it isn't already in there.

[240 2NR]

It should already be archived, at least a post that was mostly mine and hippo's used to be in the FAQ.

I think you found your problem. If you let air in to the MC you have to get out all the fluid between that air pocket and the bleeder. If you only get a few pumps before tightening it you just move the bubble closer to the caliper, but have not solved the problem. When I changed my MC I was pumping out what looked like otherwise good fluid for a while before I hit the big air bubble from the MC. No reason not to waste a little extra fluid to insure it was done right when a whole liter only costs about $5 and they're so vital to your safety.

Make sure when you flush the fluid that you keep pumping until you see fresh fluid coming through the line which is the other reason for the clear tubing.

[holisticbeatz]

Did you notice any drop in the brake fluid level when you bled it for a second time. Quite possibly, there might be a leak in your brake lines causing air to get into your system.

[mrmephistopheles]

go look in archive for my braking faq. i discuss how to properly bleed your brakes.

[Speedy240]

First of all have you ever had your rotors turned and if you have how many times. They could be under spec and could be causing you to have a soft peddel. The only way to have this checked out is to take off the rotor and get them miked either autozone or a brake shop will do it.

Also if you are bleeding the brakes be sure to always check the master cylinder and make sure it is full becuase if you let it get low there will be more air pumped into the system than there was before.

Your master cylinder could be bad Check the seals for leakage or damage. Apply and hold brake pedal look for bubbles or fluid swirl at compensating port in reservoir.

BREAK CHECK "we do it right! well sometimes"

[240 2NR]

Originally posted by Speedy240
First of all have you ever had your rotors turned and if you have how many times. They could be under spec and could be causing you to have a soft peddel. The only way to have this checked out is to take off the rotor and get them miked either autozone or a brake shop will do it.

The tolerance between new and at the limit rotors is like 2 or 3mm. There's far less increase in the pedal travel due to rotor wear compared to the 1/4" per side (almost .5" total) that the pads can wear down while within spec.

Adjusting the pedal travel before engagement (actual braking force applied) is very easy and I wrote a short write up about it.

The master cylinder could be on it's way out as well. Any leaking or evidence of stripped paint directly underneath where the MC mounts to the brake booster?

Brake FAQ

Pedal firmness adjustment