Hi again,
I managed to replace all 4 brake hoses (lots of rusty nuts that made the task really hard), then started bleeding with the rear right wheel. Someone pumped the brake and I bled the caliper. Once I finished, noticed that front right had bled all the brake fluid out of the reservoir. When I replaced the front right brake hose, I cracked open the bleeding screw to have it ready, but left it loose somehow! I suppose I have to bleed the master cylinder now. So I need to know how to go about. And also are you supposed to do bleeding with engine running?
Thanks in advance

 

Did all bleeder screws open without breaking? If any did, you must replace the caliper.

You must bleed without the eng. running.

The reservoir must be monitored constantly to assure that the fluid level is always full. If it empties, you must start all over again.

 

Thank you Major
The blower screws are fine. Only that one was mistake not left open.
The reservoir has completeLY emptied. The master cylinder doesn't have to be blended on its own by a separate procedure?
Thanks

 

The master cyl. does not have to be bled.

 

Thanks

 

FYI I recently replaced all brake hoses on another car, and to prevent the master cylinder from draining i affixed some plastic wrap (Saran wrap) over the master cylinder opening and gently screwed the cap back on a half thread or so. This worked. (The cap is vented to allow fluid drop)

in the process I discovered a corroded bleeder screw that wasn’t functioning well, so ordered a new one. Brembo instruction for preventing master cylinder draining was to have brake pedal pressed down before opening system ... so big torque wrench jammed between pedal and driver seat. This worked too.

 

Tried to bleed the right rear caliper with no luck. The brake was pumped numerous times with the bleed screw tightened, it would just not build up any pressure whatsoever. What can I do at this stage? Thanks for your guidance.

 

You are supposed to pump the brakes until you feel resistance and leave your foot on the pedal.

Then someone must open the bleeder & looking for fluid without bubbles and the pedal will go to the floor, do not remove foot. Then the bleeder must be closed. If there is no fluid coming out of the bleeder, you must repeat the process until you do.

The reservoir must be monitored for proper fluid level.

 

Unfortunately, this is exactly what I did with the help of an assistance and the pedal never firmed up. It keeps going to the floor it doesn't matter how many time it is pumped. We repeated the process 15 times and still no resistance on the pedal. Reminder that the fluid escaped the system through a bleed screw that was accidentally left open, and the reservoir ended up dry.

 

And what does this tell me?

 

That despite repeating the instructions numerous times there's still no sign of resistance on the pedal. Not the slightest. Tried 15 times. Won't the master cylinder get damaged by this?

 

Why did you replace all of the hoses?

Did you have good braking before you replaced the hoses?

Where did you get the hoses?

 

left front hose ruptured when slammed on the brake in an almost.emergency stop
Breaking was perfect before the incident .
decided to replace all 4 hoses. Purchased all 4 directly from the merc dealer.

 

Then there must be a blockage. No pumping, remove the right rear bleeder and check it for blockage. Then see if fluid comes out of the caliper.

 

I'll let you know. Does the ABS pump bleed itself once all 4 wheels are done bleeding?

 

And what about the bleeder?

 

Instead of pedal pumping I used an oil extractor to suck the air out and it got the brake fluid flow beautifully. If there was a blockage it must have passed thru. Thank you.
On my BMW I active the ABS pump by my code reader to bleed the ABS. I don't have that Option for Merc on my code reader. So I was wondering if it's necessary to bleed the ABS pump now or not.
Thanks again for your help.

 

The answer is NO.

 

Thanks