Cannot bleed the brake on my 87 300sdl
 

The brake on my 300SDL project car always feel mushy. Tried to bleed the right rear brake and now nothing works. I loosen the bleeding nipple and connected a hose it, asked a friend to pump the brake while I watched the brake fluid coming out into a bag. Some fluid and air came out then NOTHING afterward. The fluid reservoir does not go down and the brake now goes all the way to the floor. Removed the caliper with the brake line dangling, pumped the brake, still nothing come out and reservoir does not go down.

Tried to do it with engine running and still nothing. I have bled brakes before but not with a car with ABS. Did I do something wrong? Why there is no fluid coming out even with the caliper removed, I would expect at least some would come out due to gravity.

Any help is appreciated.

Cars with ABS tend to need more pressure to force fluid through if you're using a power bleeder, so I would take that to mean that gravity alone isn't enough (although I have never tried).

You are closing the bleed nipple when the pedal is on the upstroke, right?

I am not using a power/pressure bleeder. I loosen the nipple, asked my friend to pump and hold, then I tighten the nipple then repeat the cycle. It works for a while with some fluid and air coming out then NOTHING. No matter what we did with the pedal, there is nothing coming out. I remove the caliper and still nothing coming out when pumping the pedal.

the resovoir has two chambers, one for the front and rear. the rear is probably empty. its hard to tell so look from both sides.

How to look? How to fill the rear chamber?

just look at all sides of the resovoir. I think you have to look at the side facing the engine. if you put your hood up all the way this is easier. to fill you just let the fluid flow over the chamber wall. i jiggled the resovoir a little bit.

I was told by someone that bleeding the brakes with the car running gives more pressure and makes it easier. Is this true?:confused:

Well with the car running the vacuum assist will be working so you won't have to press on the pedal as hard, but I don't think it would make it any easier.

Make sure both chambers are full by filling the resivour a bit past the full line, then try again. If you still do not get any fluid when pumping you may have master cylinder issues.

Thanks for all your help. I fill the reservoir to the brim, put the caliper back in and it is kind of working now, at least it is back to what it was. I can bleed the RR brake and fluid come out. Will work on it later this week.

are the brakes just mushy, or does the pedal keep going all the way to the floor slowly after the car is stopped, running, and in gear?? If the pedal keeps going, I"d suggest you get a master cylinder or the rebuild kit. Brakes aren't something to cheap out on......
If they're just mushy, but the pedal doesn't keep going, you probably need to re-bleed the whole system and keep the resivour full this time.....

mushy brakes
 

You will need to pressure bleed them ....
http://faculty.ccp.edu/faculty/dreed/Campingart/jettatech/bleeder/index.htm
http://www.brakebleeders.com/
http://www.bmw-m.net/TechProc/bleeder.htm

Pressure bleeders are nice, but the two-person old way works just as well. If the car is older the only thing to watch out for is not to press the pedal down too far or it will encounter grooves in the MC which could damage the internal seals. IMHO pressure bleeders are an unneccessary expense, though some people swear by them.

On the other hand, avoid vacuum bleeders, they never get a solid seal around the bleeder nipple, and if you have a manual one (like a mityvac) you'll be pumping like crazy.

" the two-person old way works just as well."

You will be there a Loooong Time!!

"could damage the internal seals"
The number one reason to use a pressure bleeder!!

OK lets do the math

Master cyl $231.66

Home made brake bleeder $30.00

A savings of $200.00

Thats a good reason $$

You won't damage the MC doing this procedure unless you're careless with the bleeding. Get a good helper and you're all set--just a personal preference.