Brake booster vacuum line question

[Pablo M]

1972 2002tii

I’m refreshing the brake system at the moment: new calipers, wheel cylinders, pads and shoes, drums and rotors, stainless steel brake lines, reservoir and related lines. 
 

Noticed this condition on brake booster vacuum line. What’s going on and do I need to replace booster, MC, or both? I hadn’t planned on replacing them as I’m on a budget 😁.

 

 

1972 2002tii

I’m refreshing the brake system at the moment: new calipers, wheel cylinders, pads and shoes, drums and rotors, stainless steel brake lines, reservoir and related lines. 
 

Noticed this condition on brake booster vacuum line. What’s going on and do I need to replace booster, MC, or both? Or replace the hose? The current hose appears to have an integral metal coiled wires under the black and is poking out in places.
I hadn’t planned on replacing any of them though as I’m on a budget 😁.

 

 

[visionaut]

Looks like you'll need a new metal-lined booster vac hose (they're lined to not collapse under vacuum). And maybe a new one-way check valve too, while you're in there.

 

Maybe new clamps too.  Shouldn't break the bank...

Edited January 1, 2023 by visionaut

[TobyB]

LOOKS like the car went to the beach.

 

Scrub it off really well, and see what it looks like

after THAT!

 

If that's brake fluid coming out of the booster line, then yeah,

you'll need a new main cylinder, and to vacuum all the fluid outa the booster.

 

You can put new seals in the main, and see what happens-

often, the bore will clean up well enough that supple new rubber

works just fine with it.

 

t

 

[Mike Self]

+ 1 on Toby's suggestion to clean the hose thoroughly--M/C housing too to see where the fluid is coming from.   Your hose may be perfectly OK as they're designed to withstand brake fluid.   Those booster hoses are pretty sturdy and last a long time.  The hose material is sold by the meter by the usual sources.  Be sure to get the proper stuff--ordinary hose (like heater hose or the like) won't work.

 

The primary place those hoses fail is the short section that goes between the check valve and the manifold.  It's clipped to a bracket on the OEM air cleaner and is unnaturally and sharply curved, eventually failing at the bend.  E21s have a similar hose that's molded in a curve to eliminate that tension of bending a stiff, straight hose.  Makes a good replacement for the original item; looks like BMW used the 02's hose as a lesson-learned and improved it on the E21.

 

mike