Front brakes won't bleed, even with vac! - Page 3 - PeachParts Mercedes-Benz Forum

toomany MBZ · #31 03-21-2011, 09:16 AM

I would think one of those reverse bleeders may be okay if you have new fluid to begin with and still have air in the lines. Use one of those Motive power bleeders, which will push all the old fluid out of the lines and through the calipers, a one person operation.

vstech · #32 03-21-2011, 09:19 AM

I agree with the idea of the reverse bleeders, but the use is troubling... fills the MC with dirty old fluid, or forces you to suck it out as you push air/fluid/water/rust into it... ya can't start clean like you can with a motive style power bleeder...

lutzTD · #33 03-21-2011, 09:20 AM

Ive always done it the shade tree mechanic way. about 2 ft of clear hose and a jar or water bottle. Fill the jar with a little fluid, put the line on the bleader and the other end in the fluid in the jar, just barely crack the bleeder, then slowly pump the brakes. The fluid in the jar keeps it from sucking air, just watch the clear line until the bubbles are gone and the clean fluid shows up. just never push the pedal to the floor. It has always worked perfect for me. I made a pressure bleeder for my clutch but I end up doing brakes the old way

vstech · #34 03-21-2011, 09:22 AM

Quote:

Originally Posted by lutzTD

Ive always done it the shade tree mechanic way. about 2 ft of clear hose and a jar or water bottle. Fill the jar with a little fluid, put the line on the bleader and the other end in the fluid in the jar, just barely crack the bleeder, then slowly pump the brakes. The fluid in the jar keeps it from sucking air, just watch the clear line until the bubbles are gone and the clean fluid shows up. just never push the pedal to the floor. It has always worked perfect for me.

it is possible for this to work... just not likely.
the bleeder screws will always allow a bit of air in each time you release the pedal.

lutzTD · #35 03-21-2011, 11:02 AM

Quote:

Originally Posted by vstech

it is possible for this to work... just not likely.
the bleeder screws will always allow a bit of air in each time you release the pedal.

has worked for me for the 27 so years Ive been a shade tree mechanic.

vstech · #36 03-21-2011, 11:24 AM

like I said, it can work.
you should try using a power motive style bleeder. it's SOOOOOO simple and sure.
you may be doing things that the average DIY would not do. also, you have no way of knowing for SURE it's working for you. so, really it's not a good idea to recommend a method that is known to fail, just because you have successfully done it.
I'd be willing to bet 10.00 that your brakes have some air in them. get some CLEAR hose and connect to the bleeders, with a wrench already on them, have someone step on the brake, and YOU slowly open the bleeder while watching the clear hose... I bet you see a bubble escape.
it's virtually assured your method will allow some air past the bleeder threads into the caliper.

leathermang · #37 03-21-2011, 02:56 PM

Quote:

Originally Posted by lutzTD

has worked for me for the 27 so years Ive been a shade tree mechanic.

Because something has worked for you... potentially due to specifics of your situation ( in this case the tolerance in the bleeder threads ,etc)

DOES NOT MEAN THAT IS A GOOD THING TO RECOMMEND TO OTHERS... PARTICULAR IN A SITUATION WHERE ALL LEVELS OF MECHANICAL SKILLS ARE REPRESENTED AND YOU HAVE NO WAY OF EVALUATING THOSE LEVELS... AND THIRD PARTIES LATER ARE GOING TO BE READING YOUR RECOMMENDATIONS...

VStech is giving you the straight dope here... as am I... both personal experience AND THE PHYSICS REASONS for what we recommend...

"it is possible for this to work... just not likely.
the bleeder screws will always allow a bit of air in each time you release the pedal."--VStech

lutzTD · #38 03-21-2011, 03:09 PM

Quote:

Originally Posted by leathermang

Because something has worked for you... potentially due to specifics of your situation ( in this case the tolerance in the bleeder threads ,etc)

DOES NOT MEAN THAT IS A GOOD THING TO RECOMMEND TO OTHERS... PARTICULAR IN A SITUATION WHERE ALL LEVELS OF MECHANICAL SKILLS ARE REPRESENTED AND YOU HAVE NO WAY OF EVALUATING THOSE LEVELS... AND THIRD PARTIES LATER ARE GOING TO BE READING YOUR RECOMMENDATIONS...

VStech is giving you the straight dope here... as am I... both personal experience AND THE PHYSICS REASONS for what we recommend...

"it is possible for this to work... just not likely.
the bleeder screws will always allow a bit of air in each time you release the pedal."--VStech

readers have the choice to read yours and my experience and decide. no reason to yell. Look at the factory specified procedure for bleeding the clutch. In that process they have TWO bleed screws open and connected to the brake system. with the clear tube you will see on the next pump if you pulled in air

leathermang · #39 03-21-2011, 03:33 PM

Quote:

Originally Posted by lutzTD

readers have the choice to read yours and my experience and decide. no reason to yell. Look at the factory specified procedure for bleeding the clutch. In that process they have TWO bleed screws open and connected to the brake system. with the clear tube you will see on the next pump if you pulled in air

Instead of saying " I recommend this method because it worked for me for 27 years " ..

WHY DO YOU NOT TELL ME AND VSTECH WHAT IS WRONG WITH OUR DESCRIPTION OF THE PHYSICS OF THE SITUATION ?

We are talking BRAKES.... not clutches.... there is a little difference in the potential for DEATH between them.... Stay on the question at hand.. bleeding the brakes.. and address the PHYSICS... that is where the boys get separated from the men in forums like this. Step up to the ( CORRECT) plate and do yourself proud !

vstech · #40 03-21-2011, 04:27 PM

Also you will not see air seeping in past threads .

compu_85 · #41 03-21-2011, 05:07 PM

Quote:

Originally Posted by toomany MBZ

. Use one of those Motive power bleeders, which will push all the old fluid out of the lines and through the calipers, a one person operation.

To the OP: The cost of this tool is worth every penny. I used mine last night to do the fluid on a friends new to him Passat. After taking the wheels off it took perhaps 15 min to bleed two big bottles of fluid through the system. Did the clutch too. The fluid which came out was black black black, probably hadn't been changed in at least 10 years. You want that OUT of the system, not being pushed back into it.

Gravity bleeding just doesn't develop the flow rates needed to purge junk from the system.

-J

Cr from Texas · #42 03-21-2011, 05:15 PM

Quote:

Originally Posted by vstech

it is possible for this to work... just not likely.
the bleeder screws will always allow a bit of air in each time you release the pedal.

That's my expereince too, but I've only been at it about 55 years. Checked with Dad who's 90 and a retired professional mechanic - his experience also. We both use the two person method. I think he put me on the pedal at about age 6. My granddaughter age 7 helped me with this the last time I bled brakes - good bonding experience.

I can also confirm the validity of the physics.

Quirky Mercy · #43 03-21-2011, 09:34 PM

I am not looking to ruffle feathers, just a helpfull suggestion when you have no help. I agree that pedal bleeding is best, but the method I suggested works if done right like lutzTD stated. I use this method even with a helper it keeps all the fluid off the cement.

leathermang · #44 03-21-2011, 10:21 PM

Quote:

Originally Posted by Quirky Mercy

I am not looking to ruffle feathers, just a helpfull suggestion when you have no help. I agree that pedal bleeding is best, but the method I suggested works if done right like lutzTD stated. I use this method even with a helper it keeps all the fluid off the cement.

How old are you ?

lutzTD · #45 03-22-2011, 08:36 AM

Quote:

Originally Posted by leathermang

Instead of saying " I recommend this method because it worked for me for 27 years " ..

WHY DO YOU NOT TELL ME AND VSTECH WHAT IS WRONG WITH OUR DESCRIPTION OF THE PHYSICS OF THE SITUATION ?

We are talking BRAKES.... not clutches.... there is a little difference in the potential for DEATH between them.... Stay on the question at hand.. bleeding the brakes.. and address the PHYSICS... that is where the boys get separated from the men in forums like this. Step up to the ( CORRECT) plate and do yourself proud !

DISCLAIMER: follow the FSM for all maintainance procedures, use this method at your own risk.

first off, I NEVER said you guys were wrong. I have done two man bleeding in the past and it is of course the recommended method if you have a help, which most times I do not

second, your "physics" are just mentioning physics without explaination, I do agree vacuum bleeding does not work becuase it introduces negative pressure to draw air through the thread because it is a constant negative pressure and the not momentary negative pressure as a jar bleed is

my description was just add a line to your scenerio, the line is full of fluid. You pressureize the system not vacuum. the pedal release draws fluid from the easiest source which is the fluid in the line, most of the pedal release is refilling the master cylinder bore from the reservior, it seems to me the threads get fluid pushed in them when you pump and it is harder to draw that than what is in the tube. IF you do draw air in the threads then the next pump will show a bubble. if you cant get the bubbles out of the line with a few consecutive pumps then you know its not right. I would then tighten the bleed screw slightly and do it again. when you can flow clean fluid with no bubbles you are done. Also, if you still want to use the two man bleed at the end, this method will allow you to get the majority of the fluid changed and the air out very quickly

DISCLAIMER: follow the FSM for all maintainance procedures, use this method at your own risk.

if you dont feel like making your own, here are several kits to one man bleed, they basically do the same thing. you can also get one at Advance or NAPA or Pep Boys

http://www.google.com/#q=one+man+bleeder&hl=en&prmd=ivns&source=univ&tbs=shop:1&tbo=u&sa=X&ei=W5mITZPfDo-2twfBu8ToDQ&sqi=2&ved=0CB4QrQQ&bav=on.2,or.r_gc.r_pw.&fp=1528e66fe9bc4f15