brake bleeding problem
 

My car is a 88 190 2.3-16, i have recently fitted new rear offside brake pipes (flexi and copper) along with a new caliper, ive now come to bleed the brake but seem to be getting no-where, here are my observations:
The fluid in the master cylinder doesnt seem to be going down after maybe 20 mins of bleeding,
When the bleed valve is opened, a small amount of air will come out it,

Is there a special proceedure on this car? or somthing im missing as i spent over an hour last night on the back to no avail,

any help greatfully recieved

Are you using suction, pressure, or someone holding the pedal down while you open the valve? Check here for bleeding techniques.

Are you saying you replaced the brake line with copper? This is a no-no. The copper can't handle the pressures used for braking and would certainly fail after a while. Only tubes specially made for brake lines can be used. These tubes are called Bundy tubing.

Q: The technique im using is some1 holding the pedal down while i open the valve, (never really had any problems using this way before on other cars,

Kestas: Yeah its proper brake pipes that were made up by a local car parts shop.

Are you having your helpe pump the brake pedal a few times before opening the bleed valve to build pressure in the system?

yhliem: Yeah, the pedal is pumped between 5-10 times before each bleed,

You've probably bled the rear part of the resevoir dry and the fluid level in the front chamber is not going down. You may have your car on a slight incline with the nose down. Fill the resevoir full full full and check it often. It does not take much fluid to bleed lines.

glenmore
1991 300CE

glenmore: hi, i think you may be right with this one, cos i wasnt sure if the resevoir had different chambers, but the car is inclined at the rear, ill go home and try it again, cheers

Been there. Has to be very full to spill over into the rear chamber, even without incline. Helps to clean the outside of the reservoir so that you can see the level of the rear chamber.

Thank God for this board! I replaced my rear calipers, and could not get them bled right to save my life. That is, until I searched this board, and found out that I needed to fill the reservoir up to the very BRIM, so that it would trickle back into the back of the reservoir.

Boy, I felt like an idiot... 20+ years of working on American cars did NOT prepare me for some of the little things I run into on my 190e!

Rear Brake Bleeding Problems
 

Yes very important to fill to the brim so fluid covers this small air vent in order to fill the rear chamber. It is not easy to visually see whether the rear chamber is full or not. Before doing this I actually had the master cylinder totally reconditioned and then still could not get the rear to bleed.

Imagine- This post was 3 years old, and it is still around to help someone. What an amazing resource.

Been there, done that...
 

I know the pain of the 16v fluid resevoir all to well. It looks full, it seems full, you might even be adding fluid to it, BUT, unless the sucker it to the top and more to spill over into the back compartment, you aint bleeding nuthin' but air baby! My dad and I bled the lines dry trying to bleed the system of air before I got in there with a good light and a magnifying glass and realized the front compartment was full and the secret rear compartment was bone dry. Sneaky Germans! I am sure it serves some other purpose other than confusing DIY guys like us, but, I will not soon forget that mistake and aggrivation of knowing how to bleed brakes and still not getting anywhere. After the rear was full and kept full all four lines bleed in no time easy peasy.
Silly Rabbit.