Planning on bleeding/refilling brake fluid with a Motive power bleeder when I change over to track pads for an upcoming HPDE. Was looking at the FSM for which order to bleed each corner and I noticed this (see bold text):

Bleeding Brake System NFS0000A CAUTION:
While bleeding, pay attention to master cylinder fluid level.
1. Before working, turn the ignition switch OFF and disconnect the connectors of ABS actuator and control unit or battery negative terminal.
2. Connect a vinyl tube to the rear right bleed valve.
3. Fully depress brake pedal 4 to 5 times.
4. With the brake pedal depressed, loosen the bleed valve to let the air out, and then tighten it immediately.
5. Repeat steps 3, 4 until no more air comes out.
6. Tighten the bleed valve to the specified torque. Refer to BR-27, "Components" (Front) and BR-40, "Com- ponents" (Rear).
7. In steps 2 to 6 below, with the master cylinder reservoir tank filled at least half way, bleed air from the front left, rear left, and front right tires, in that order.

Anyone know why this is necessary?

 

It's a blanket statement…basic precautionary step to preventing damage to your system if the odd chance something goes wrong…required…maybe, mandatory…probably not…

but if **** hits the fan, don't say they didnt warn you...

 

Never unplugged it yet, bleed many Z's.

 

That's kind of what I figured.

The wheel order seems odd too. Always heard work from the farthest corner from the master cylinder to the closest which would be 1) R rear, 2) Left rear, 3) R front 4) L front.

FSM says:

2. Connect a vinyl tube to the rear right bleed valve.
7. In steps 2 to 6 below, with the master cylinder reservoir tank filled at least half way, bleed air from the front left, rear left, and front right tires, in that order.

No big deal, and I'll follow the FSM but would have been nicer if I could jack up the rear and do both rears then jack up the front and do both fronts...don't think I can get to bleed valve with RPF1s on it.

Of course if you jack high enough from the rear jack point you can get front and back off the ground at once (think NASCAR). Not sure if the jack point is sturdy enough for this but I've done it a good bit with no problems.

 

No need for the order if you never run it dry. Also avoid running the master dry if possible , it is a Pita to get the air out

 

The motive power bleeder is fantastic, I used it when I did my conversion to Brembos, and I bled my brakes in one shot with a perfect pedal. As recommended, do not drain the master cylinder, a friend had the hardest time bleeding his ABS pump after all the fluid accidentally drained out of a dropped brake line. I think the last thing that he did that worked was bleeding it with the key on.

One thing I will suggest is have some good towels and lay them in the engine bay to prevent any spills, I found it to be a bit messy to get the cap off.

 

Good tip about the towels. My car is far from a show car but underneath the hood it still looks showroom!

Another question: Is it possible to bleed the clutch system? I'm sure the answer is yes but my understanding is that the slave cylinder is in the bell housing. So is there a bleed valve somewhere else to bleed the clutch system? It has fresh fluid in it now, but it is not a 'racing' fluid like ATE or anything and I have had clutch issues on the track before.