Bentley doesn't tell you if you're supposed to have the car on while bleeding. I am assuming that you have to have the car off when bleeding the brakes manually. Can anyone please confirm? Thank you.

Yes, the vehicle does not have to be running in order to bleed the brakes.

Wouldn't it be easier to have your system on to bleed the system? I am not talking about turning your engine on, but giving brake boosters power when you bleed? What do you think?

If the engine isn't on, you won't have power to your brake booster, since most brake boosters get their power from the engine vacuum. For the 735, I am not sure.

Yes, pumping the pedal can get exhausting without the booster (or so my assistants say), but when was the last time you did some hard quad thrusts at the gym? I'd prefer not to have the engine shaking around when I'm trying to pour brake fluid in the resivoir, but thats just me.

Even if you have a hydraulic booster, there's no power going to the brakes unless the engine is running (your power steering doesn't work in the ACC position, does it?).

Do it without the car running, it's easier to tell when you've pumped up the pedal enough to loosen the bleed screw (usually 4 or 5 pumps), and you won't build up so much pressure that the fluid shoots out at you like a water cannon.

Bently doesn't say anything about it. This is why I am asking.

not sure about the 7 but i would think it is similar as for the 3 series. for the e36 the bleeding instructions are as follows. (car is off)

open the first bleeder valve on the caliper and pump the break paddle all the way to the floor and back 10 times, then hold the break paddle on the floor for the duration of the bleeding procedure. I use a pressure bleeder.

bleed all 4 corners, remove power bleeder and let the break paddle go. pump a few times to make sure you got all the air out. top of reservoir.

For something like this, I'd say to just give it a try and get back to us. I don't think anyone turns their cars on for bleeding brakes, but I can't think why it would be a problem to do it. Honestly, I'm kind of curious about it. Give it a shot and let us know.

Car off

Start from the wheel furthest from the master cylinder put the box end around the bleeder then the hose, have your assistant pump the pedal about 4 or 5 times, the pedal will get hard, they MUST hold it down and tell you they are holding it then you can break open the valve, the pedal will goto the floor but they must still hold it, let it flow for a few seconds then tighten it back up, tell them when its tighten back up and have them pump again, do it until you dont see anymore bubbles then move onto the next wheel working your way up towards the master cylinder.

Never let the resevoir get so low to wear your sucking in air, check it and refill it every now and then, Make sure they dont let go off the pedal with the valve open or they will suck in air.

Car off

Start from the wheel furthest from the master cylinder put the box end around the bleeder then the hose, have your assistant pump the pedal about 4 or 5 times, the pedal will get hard, they MUST hold it down and tell you they are holding it then you can break open the valve, the pedal will goto the floor but they must still hold it, let it flow for a few seconds then tighten it back up, tell them when its tighten back up and have them pump again, do it until you dont see anymore bubbles then move onto the next wheel working your way up towards the master cylinder.

Never let the resevoir get so low to wear your sucking in air, check it and refill it every now and then, Make sure they dont let go off the pedal with the valve open or they will suck in air.
+1

don't be pumping the pedal with the valve open like everyone else is saying!

+1

don't be pumping the pedal with the valve open like everyone else is saying!

Word, one of the guys above me said open the valve then pump the pedal, thats something you sure as hell don't want to do, that'll suck air into the system and you will have to get that air out.

Also bleeding the brakes manually (as opposed to using a pressure bleeder) can be hard on the master cylinder. If the master is old, don't use full pedal strokes at first, go about halfway down, and be sure to go slowly.

Some cars need to be running when the brakes are bled to keep air from getting trapped in the abs system, but I don't know about your car.

If you have a car with the electronic boost and nitrogen cylinder, or one that takes its boost from the engine pump, like a 633 or similar, you should have the ignition on or the engine running.
If you have a car with a manual brake system, or vacumn boost, it is not necessary.

Even with a hydraulic booster, it's not necessary to have the engine running. There will be enough pressure from pressing the brake pedal manually to bleed the brakes. And no air bubbles will spontaneously appear in your ABS module from bleeding them without the car running.

Just leave the car off, pump the pedal 4 or 5 times, hold the pedal, open the bleeder, close the bleeder and then repeat. Go right rear, left rear, right front, left front.

I bled the system manually, and it worked out well.