How to Bleed Brakes?
INF3RN0666
06-13-2004, 07:05 PM
Hi, I have looked at many sites on how to bleed brakes but I am still confused on one thing. My brakes were bad before, but after I blead them, they're horrible. I automatically assumed that the engine has to be on while bleeding the brakes, but non of the articles I read indicated if it should be on or off.
Should the engine be off when bleeding the brakes?
What difference does it make if it's on while bleeding?
Should the engine be off when bleeding the brakes?
What difference does it make if it's on while bleeding?
MagicRat
06-13-2004, 07:23 PM
If you have a buddy step on the brake pedal when you open the bleeder screw, it does not matter whether the engine is on or off.
Engine off is safer. You are under the car and you do not want to get run over.
However, engine on means much less pedal effort for the buddy. This is handy if its your girlfriend/wife helping you, instead of your 230 lb beer- drinking buddy.
Engine off is safer. You are under the car and you do not want to get run over.
However, engine on means much less pedal effort for the buddy. This is handy if its your girlfriend/wife helping you, instead of your 230 lb beer- drinking buddy.
INF3RN0666
06-13-2004, 08:37 PM
Ummm really? I was using a stick kuz I have no friends :P. But why is it that my brakes are worse now. Now the car doesn't even stop! I might as well not have a brake pedal, rotors, calipers, and save some weight/gas!
MagicRat
06-13-2004, 10:14 PM
:eek7:
A stick?
Get a friend/parent/hooker and bleed them properly. Keep the engine off.
Start with the rear right wheel.
Have your buddy stomp on the brake pedal HARD 5 timers quickly then hold the pedal down. You open up the bleeder screw, just a quarter to half turn is enough. (Caution, fliud will really spray out). The brake pedal should sink to the floor. Make sure your buddy holds the pedal on the floor while you close the bleeder screw. Then your buddy can release the brake pedal.
Repeat this about 4 to 6 timers for that right rear wheel, (but the other 3 wheels will only need 3 or 4 repeats.
Then do the left rear, right front and left front. Make sure the master cylinder stays full.
If you are on your own, it it possible to gravity bleed the brakes, by opening up the screws and letting the fluid dribble out, one wheel at a time for 10 minute or so, or until the dribble is a steady stream, and there is no more air. However, the first method is better at getting rid of all the air.
A stick?
Get a friend/parent/hooker and bleed them properly. Keep the engine off.
Start with the rear right wheel.
Have your buddy stomp on the brake pedal HARD 5 timers quickly then hold the pedal down. You open up the bleeder screw, just a quarter to half turn is enough. (Caution, fliud will really spray out). The brake pedal should sink to the floor. Make sure your buddy holds the pedal on the floor while you close the bleeder screw. Then your buddy can release the brake pedal.
Repeat this about 4 to 6 timers for that right rear wheel, (but the other 3 wheels will only need 3 or 4 repeats.
Then do the left rear, right front and left front. Make sure the master cylinder stays full.
If you are on your own, it it possible to gravity bleed the brakes, by opening up the screws and letting the fluid dribble out, one wheel at a time for 10 minute or so, or until the dribble is a steady stream, and there is no more air. However, the first method is better at getting rid of all the air.
public
06-14-2004, 04:01 AM
Leave the motor off. Spend $30 bucks and get a hand operated vacuum pump. You plug the hose on to the bleeder and with the Master Cyclinder cover loose you squeeze the handle and it pulls the fluid thru. And you wont have to bother anyone to help you. Good Luck.
INF3RN0666
06-14-2004, 06:44 AM
I've heard of a method where the helper slowly pushes the brake pedal. When he starts pushing it, I open the bleed valve and when the pedal is on the ground, I release the valve.
Doc Fantastico
06-14-2004, 07:23 AM
what we did was this first get the car ready then attache a small ruber hose to the bleeder valve open it up and keep the end of it submeged in brake fluid... that way no air can get into your brake lines...
timberdoodle
06-14-2004, 08:39 PM
see the idea is to not have any air in your brake lines, which is probably why your brakes are failing you now. THe act of having someone pump the brakes before you open the bleeder is to build up pressure so that the fluid comes out nicely, and the pressure pushes out the air. You repeat the process until there are no air bubbles coming out of the line. You need to submerge the line in fluid, because if you dont then air will obviously get up inside the line, and it would seem that the job never ends. I have speed bleeders which work very well, you only need one person but be wary of the master cylinder running out of fluid in any case.
MagicRat
06-14-2004, 11:57 PM
what we did was this first get the car ready then attache a small ruber hose to the bleeder valve open it up and keep the end of it submeged in brake fluid... that way no air can get into your brake lines...
Air can still sneak in past the threads of the loosened bleeder screw, when the brake pedal is released. The bleeder screw must be closed when the pedal is released, every time.
Air can still sneak in past the threads of the loosened bleeder screw, when the brake pedal is released. The bleeder screw must be closed when the pedal is released, every time.
Moppie
06-15-2004, 01:05 AM
A very nice explanation MagicRat
Iv been bleeding brakes in everything from race cars to road cars for years, and thats exactly how I was taught to do it, and its exactly how I do it.
The only thing I would add is, for those living with RHD cars, or with cars where with a remote master cylinder: Always start with the wheel furtherest away from the master cylinder, and work towards it.
Also be aware that some newer cars have remote bleerers after the master cylinder, or on the master cylinder, but before a wheel, or the propotioning valve.
And of course if you have ABS then don't touch it with out proffesional advice, as some of the system is kept under very high pressure.
Iv been bleeding brakes in everything from race cars to road cars for years, and thats exactly how I was taught to do it, and its exactly how I do it.
The only thing I would add is, for those living with RHD cars, or with cars where with a remote master cylinder: Always start with the wheel furtherest away from the master cylinder, and work towards it.
Also be aware that some newer cars have remote bleerers after the master cylinder, or on the master cylinder, but before a wheel, or the propotioning valve.
And of course if you have ABS then don't touch it with out proffesional advice, as some of the system is kept under very high pressure.
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