Bleeding brake master cylinder - ABS type

[ajb902]

SHi All,
First post here but gained lots of information from the site. I have a 2004 d22 with the yd25 engine (which has blown up on me once but been rebuilt).

I recently gave it a body lift and whilst I had the tub off the back I cleaned and painted the chassis with wurth stone guard. Couple of the hydraulic brake pipes were rotten so I changed them.

I am now having serious trouble bleeding the secondary piston in the master cylinder. I can't even get any brake fluid to pump out of the piston. It appears as if it isn't getting brake fluid out of the reservoir.

If I fill the piston (from the outlet) as the pedal is being released then I can get fluid into the piston and it comes out at high pressure when the pedal is depressed, but it never refills from the reservoir side.

Can anyone shed any light on this for me? I've struggled for a while with it and even taken it apart and all looks in order so I am stumped!

It is the ABS type and is the master cylinder with the screw in the side which limits the Pistons travel.

Any help will be greatly appreciated. Thanks....

 

[ajb902]

Here is a picture of the cylinder with the components out. It's the cylinder with th "S" on it in the picture which I am having trouble getting any brake fluid out of.

I apologize for the picture being upside down but I can't for the life of me get it the right way round!

 

[dilmah]

try a vacuum bleeder if you have access to compressed air

 

[vicszd30]

Howdy fella,, ya poor bugger. Brakes huh!

Now that you have that apart you know you'll need to put a seal kit through it don't you

Not sure about your model and unfortunately the latest model brakes that I've worked on is an '03- but you need to hire/buy a brake vacuum bleeder !
The lines on these utes are a shite to me and I have never had any luck bleeding the nav's with the peddle alone, Vac first then peddle -for "me" was the only way!
You can use it on the master cylinder also and it make bleeding that a breeze ...
Cheers Vic

 

[jonney]

you should be able to manually bleed the master cylinder without any dramas, how about you replace all piston rubbers and re assemble then prior to fitting the cylinder back , fill the resovour with fluid and very lightly pump the pistion in and out a couple of times then leave the cylinder sit in its upright position for a good hour and repeat this light pump once again then re fit the cylinder to booster. connect all back together and start the engine then bleed the cyclinder whilst the engine is running, [ the booster supplies vacume / pressure ] when the cylinder has been bled you then need to bleed the following brake lines at abs unit then at wheel cylinders [ fronts only may work.] try this.

 

[ajb902]

Thank you all very much for the suggestions, they are things I haven't tried. Looking at the mechanism though i can't see how fluid can get into the cylinder without a vacuum as it needs to get past the rubber grommet in the piston.

Sadly I'm not with my wheels at the moment as I have been sent overseas for work but will report back on my success or failure when I get back to the car.

Once again, thanks for the suggestions.

 

[ajb902]

I've got back car and am still having no luck, even with a vacuum. I've taken the master cylinder apart again to have a better look. The rubber grommet in the secondary piston just doesn't seem to be able to move enough to allow fluid past. The grommet takes up the whole width of the small orifice, so even if it moves fwd it never creates a gap. Could the grommet have expanded over time or change it shape? I have attached some pictures to help my explanation....

 

[jonney]

didn,t you put in new parts on this m/ cylinder ? if the rear lines were pershed i would say the internal rubbers in the cylinder wouldn,t be in great nick. start from scratch and fit new rubbers etc to re build the cylinder.