...bleeding tip.
So, on both my 320i and the 325, I wound up either replacing the master cylinder or pulling and reinstalling.
If I've vacuum bled both systems and the pedal still requires a 1/3 of pedal length before engaging well, do I need to bench bleed those puppies?
Before I r&r'd the master on the 320, pedal was firm at first push, engaging right at the top of the stroke. It was the radical change that made me think it's time for a bench bleed.
And, forgive the stupid question, but why couldn't it be done "in car"?
Have you tried a pressure bleeder? That seems to be thR best choice in my experience.
I like gravity bleeding myself. As an added bonus, no special tools are required.
And I think you can bench bleed a master in the car. It just makes a mess. Use the brake line fitting at the master as a bleed screw, crack it open with a rag around it to release the fluid/pressure.
Can you adjust the free play on the master? Not sure if this is something you would necessarily have to do. Does the pedal pump up?
You can bench bleed on the car; I do it with every master cylinder I've installed. What I did was go to the parts store and buy some generic brake lines that fit the master cylinder threads and bend/cut them to make a loop that feeds back into the fluid reservoir. I've got a set made for 77-79, 88-91, 96-00 Civics, and the S2000. After you've finished pumping all the air out, it's pretty easy to just quickly reattach the hard lines with a minimum inclusion of air.
sobe_death wrote:
You can bench bleed on the car; I do it with every master cylinder I've installed. What I did was go to the parts store and buy some generic brake lines that fit the master cylinder threads and bend/cut them to make a loop that feeds back into the fluid reservoir. I've got a set made for 77-79, 88-91, 96-00 Civics, and the S2000. After you've finished pumping all the air out, it's pretty easy to just quickly reattach the hard lines with a minimum inclusion of air.
That is and awesome idea! I can't believe I never heard or thought of that before. I'll definitely try that when I install the master cyl on my E30 in a couple of weeks.
Ranger50 wrote:
Keith Tanner wrote:
I like gravity bleeding myself. As an added bonus, no special tools are required.
+1.
+2.
I am assuming that just because you bench bled the MCs.. you also bled the air out of the lines and slaves?
mad_machine wrote:
Ranger50 wrote:
Keith Tanner wrote:
I like gravity bleeding myself. As an added bonus, no special tools are required.
+1.
+2.
I am assuming that just because you bench bled the MCs.. you also bled the air out of the lines and slaves?
I did not bench bleed the MCs - vacuum bled the lines on both, but had monkey'd with the MC on the 320 (remove debris from the booster) and replaced the MC on the 325.
I may try the gravity bleed, but I do like the idea of getting the brake lines to feedback the MC.
It would appear that I have step 1and step 2 to do on thing 1 and thing 2....
I can change a master cylinder, caliper, or wheel cylinder and never open a second bleeder, unless the system got air in it before I saw the car.
NEVER EVER EVER push air into a brake system unless you enjoy having electrodes attatched to your testes. It ruins your life. If you are installing a master, bleed it on the bench, until there are no bubbles coming back up into the reservoir. If you've blown a caliper, cylinder or line, top up the master and let it gravity bleed before you take it apart. Then gravity bleed. If you must bleed using the master, always use short strokes. Never push the pedal farther down than it would normally travel.
NEVER EVER EVER PUSH AIR INTO A BRAKE SYSTEM. EVER.
Well, ok, maybe not never, but really, really seldom.
I have had great success with the "loop the lines back to the reservoir" method noted earlier.
Most good parts store M/Cs come with plastic fittings and hose to do exactly this. I always bolt them up to the car then bench bleed them in-chassis.
Speaking of bench bleeding, is this necessary in a car where all the connections (inlets and outlets) are on top of the MC? I would think that the air would come out in normal bleeding this way, but I have a pedal that starts working half way down right now.
