Urgent ques: Rubber Brake lines
 

Hey guys. Doing work on the 280S and I need help.

Neither my father nor I have the knowledge of this and we need to know if there's usually a ball bearing or something acting as a valve in a rubber brake line...not steel.

I had to change out a steel line and we're able to bleed all lines but one. It seems to be clogged cuz I cant get the wire that I'm cleaning it with all the way through.

Could it also be like a mini mini strainer/filter or something?

None of the above make sense but its all we can think of.

That or it's completely clogged.

Your help = AWESOME.

Answer
 

NEVER poke wire through the rubber brake flex hose, it damages the inner hose ply.

There is no ball or valve in the rubber brake flex hose = any blockage indicates a junk hose that MUST be replaced.


Here is all the data you need on brake hoses..

Brake:
http://www.peachparts.com/shopforum/showthread.php?t=142411



Have a great day.

Ordered new hoses. Thanks.

It is possible for a piece of the inner rubber lining in a brake hose to pull away and act as a "flap" valve. This can happen in older brake hoses and result in either pressure not getting to a caliper or pressure not being released from an engaged caliper - depending on how the lining peels away. That is one reason why all rubber brake hoses should be replaced on older cars as a normal safety item. One long-time Mercedes mechanic said he found the O.E. hoses on benzes were good for 20, or so, years. Many have been left on much longer than that w/o trouble but should be replaced. Think about all that flexing going on over the years.

The main reason brake hoses do not release after pedal application is they are constricted from swelling inside. When one applies the brake ,the Master has a great enough pressure force to flow thru the constriction, but when released , the only force to return/release the calipers is Residual pressure ..much less than pedal pressure...resulting in a hanging brake pad.
An easy test for this condition is to jack each wheel , apply the pedal force , and then hand turn that wheel..if wheel is locked [or excessive drag]. open bleeder ..if the wheel then frees , you have a bad hose. if it doesn't , you have stuck caliper.

Nice trick, Arthur.....