When bleeding brakes - engine on?

Does the engine need to be running when bleeding the brakes? If not I can do this in my garage (rain or shine), otherwise outside.

Any thoughts/recommendations/suggestions? Also, is there any easy way to bleed the master cylinder - pretty sure I got air in there when changing out the calipers yesterday?

Thanks as always.

Brian.

You do not have to run the engine when bleeding the brakes. As a matter of fact it is probably best not to run it. YOu can do it inside or outside depending on the weather. But you can do it inside rain or shine. As far as bleeding the master cylinder, you will need a bleeder kit and then you will need to remove the brake lines to apply the bleeder. Pump the brakes with the bleeder installed until you have no more bubbles in the fluid. Reinstall the brake lines and then bleed the brakes on all four wheels starting with the wheel the furthest from the master cylinder and work your way around. Make sure you keep the master cylinder full at all times or you will need to do the job all over again.

Do not run the engine when bleeding the brakes. This can be done inside or outside, makes no difference. However, when bleeding the Master Cylinder, you will need a bleeder kit. I bought mine at Autozone. Disconnect the brake lines and connect them directly up to the kit assembly connectors. Finally, pump the brakes until you have no air bubbles. You must keep brake fluid in the master cylinder while doing all four wheels. Good luck!!!!!

Consider this a two person job. The previous posts are clear on how. If you really think you have air in the MC then bleed it first using the bleeder kit. Next do each wheel starting with the right rear, then left-rear, then right-front, then left front. Do one at a time. Open bleeder, have friend push pedal to floor (do not release) then tighten bleeder. Repeat until no bubbles in the bleeder line. Be careful not to get brake fluid on paint. It will strip it. Good luck, take your time, it will work fine.

Thanks to your advice, got the brakes working great! Once I got the calipers on the correct side of the vehicle, bleeding the brakes was no problem...long story but no harm done.

Brian.

When I tried the traditional method described above the pedal was soft and fading with engine running. I went through two quarts of fluid to make sure all the air was out. Called the local shop and he told me it should be done under pressure with a machine (to force out any air) and a scan tool to open and close the ABS system to ensure fresh fluid gets in there also. I took it over and watched them do it and that was the procedure the tech used. Charged $90 total.