Brake Bleeding Question

[Monark192]

I can get a nice stream of fluid from either front brake but the rears do nothing when the bleed valve is backed off and the pedal pushed. Can there be an airlock in the system somewhere?

 

[jlaird]

For sure, bleed the longest line first, passanger rear I expect, and just do it again and again and again.

 

[tony barnhill]

[ QUOTE ]
Can there be an airlock in the system somewhere?

[/ QUOTE ]

Yes, simon, you could have lots of air in there - do as Jack suggested: start with the wheel farthest from the masdter cylinder & get it to flow first.

 

[Monark192]

I have a feeling that the "again and again and again" could wear out my wife's pedal pushing patience. Sounds like time to visit the neighbor, extra beer in hand.....

 

[jlaird]

Oh yea, sometimes 20 times or more.

 

[tony barnhill]

Get an empty beer can (you can handle that part)...fill it halfway full of brake fluid..stich a hose down in it & attach the other end to the opened bleeder...fill the master cylinder with fluid & get inside & pump...no air can get back into the system...as fluid leaves the cylinder add more...when the can overflows, call the wife.

 

[vping]

[ QUOTE ]
Get an empty beer can (you can handle that part)...fill it halfway full of brake fluid..stich a hose down in it & attach the other end to the opened bleeder...fill the master cylinder with fluid & get inside & pump...no air can get back into the system...as fluid leaves the cylinder add more...when the can overflows, call the wife.

[/ QUOTE ]

I did this with my son. It took awhile and there was some whining but then victory!

 

[philman]

did you bleed the master cylinder before going back to the wheel cylinder?

 

[Monark192]

er........... nope!

How do you do that??

 

[philman]

i used a mityvac unit. it's the only time i've got it to work. i rebuilt the master cylinder for my tr7 (the same as a later mgb master cylinder). I could bleed the front brakes at the wheel, but not the rear. I tried for at least half an hour pumping the pedal with a bleeder hose attached at the rear wheel cylinder with no effect. I took the brake line for the rear brakes off at the proportioning valve and bled from the master cylinder, then i reconnected the brake line and was able to bleed from the rear cylinders. there are other ways to bleed the master cylinder, all should work.

 

[Steve_S]

Are you sure the brake pipe isn't smashed on the rear axle? It's a very common problem. Just a thought.

 

[Kimberly]

How old is the flex line for the rear brakes?

 

[Guinn]

I'm not about to go out in the cccold to check, but it seems to me that the driver's side (left side) rear wheel is the farthest from the master cylinder - if you trace the tubing. I believe the single flex tube diverts just above the rear axle, on the right side.

See Moss pg 57 or VB pg 146 which show diagrams.

Do bleed as suggested: farthest wheel first.

Guinn


Guinn

 

[PAUL161]

I know this might sound goofy to some, but I fill my systems the same as I fill Aircraft brake systems. From the bleed valve back. Usually takes all the air with it. Works great on clutch systems too. You just have to watch that the MC reservoir doesn't overflow. Oh, and no pestering the wife to pump the pedal. /ubbthreads/images/graemlins/jester.gif PJ

 

[LLAngus]

Check the Tool forum to see how to make an inexpensive pressure bleeder. It works.
/ubbthreads/images/graemlins/lol.gif /ubbthreads/images/graemlins/hammer.gif

 

[jlaird]

Paul, think I like that idea. Gota consider it some.

 

[kennypinkerton]

I've got my garden sprayer, and am slowly working on making one of those.

 

[maynard]

Check the brake lines. Often on Bs, if the car is towed backwards (which may have happened before you got the car) the tow hooks crimp the lines.

 

[kennypinkerton]

Yes, sometimes flatbed towing will pinch the metal lines going across the rear axle.

 

[Monark192]

Metal lines look good and the flex hose is ok. I was starting on the drives side rear as it seemed furthest from the master as the brake fluid flows.