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Hi, I've bled many a system before but I'm just a little unsure on the double master cylinder system on the e12. What's the best way to go about bleeding these as mine has had all the lines etc blown out and new seals etc etc as well as the master cyclised replaced.
Thanks
Arron

Coincidentally, my 633 system is being contrary.

I have a good pressure bleeder. After rebuilding all of the calipers and replacing the flex brake lines the front calipers bled out just fine.

The rears not so great. Removed one caliper to check all the passages clear and assembled correctly. The line going into the caliper flows freely. The pads on both calipers are out against the rotors. Still, after repeated attempts using the pressure bleeder the flow from the bleeder fitting isn't exactly a gusher. I've opened the fitting, kept the tubing submerged in the jar of fluid and pumped the pedal to increase the flow.

The best so far is a soft pedal that stops the car, but not high enough on the stroke, or with the normal firmness to trust a test drive.

If the reservoir is full, I thought the system had some kind of self bleeding capacity. My next step is to enlist a foot on the pedal to bleed the system the old fashioned way: open-pump-close, etc.

I usually use a power bleeder, but I have found that something about the master cylinder design does seem to require a little old-fashioned bleeding with a friend at the peddle to get all the air out. Maybe it's that extra chamber as you mentioned that might get bypassed with a power bleed.

I'm going to go out on a limb here and guess that OP is dealing with a RHD car, which I believe had a funky set-up with two separate master cylinders. I believe bleeding for that system is covered in the Haynes manual, if you can get your hands on that.

If I've guessed wrong and OP is just talking about the more "normal" dual-circuit master cylinder, then bleeding should just follow the normal procedure of starting with the wheel farthest from the master and moving progressively closer. Bleeders, pumping, they all work in the end with enough patience and attention to detail.

Best of luck!

Ken

Yeah it's a right hand drive dual cylinder set-up, never seen it before but doesn't seem too challenging. I've not got a Haynes manual so ill have to invest in one if it gives me any grief.

I have the same quirky RHD twin booster setup.

I bled them successfully recently, I started by bleeding at the boosters (idk if this is the correct terminology?) then as Ken mentioned, the furthest wheel from them.

Yeah seems the most logical way to do it, the 2 cylinders at the front have been done its just a matter of furthest brake etc, cheers for letting me know

I thought there was a self bleeding feature somewhere within a hypothetical pedal firmness. Guess not.

Did a foot pump routine to get a nice firm pedal in the normal place, high up on the stroke. No bubbles in either rear caliper bleed tube.

Put it all back together, fired it up and the drat pedal was back to half way down the stroke and mushy. It stops, but obviously the system ain't right.

I'm getting tired of jacking, jack stands, wheels off, fiddle futsing around.

T. Hanson, you have hijacked OP's thread but if you are trying to get away without bleeding the front calipers (even if you hadn't opened them on this go-around), then you are inviting the need to jack, re-jack, fiddle-fust, and whatever other frustration words you want to use.

KenB

My apology for horning in on OP brake question, not thinking brake bleeding wasn't generic. Or just not thinking.