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I have a brake pedal that seems to be depressing further than it used too.  There are no external leaks and the reservoir is still full?  I think my "original" booster is leaking vacuum.  Braking action is still good. Can anyone help me confirm/troubleshoot?  Can you direct me to a vendor for a plug and play replacement?



Last edited by George P
Original Post

Hi TC...  What you will find is that the lever, cables, and interface to the brakes are all independent from the hydraulic brakes, but the mechanism for compressing the pads is a mechanical part of the stock calipers.

So it's not "completely separate", only about 85% separate....

In this picture you can see the eccentric lever that the cable pulls on to compress the pads mechanically....  (of course this was before my brakes were cleaned and refurbulated…..)


MC_and_Rear_Caliper 002



Images (2)
  • Brake_Teardown_Day_1_03-26-13_008
  • MC_and_Rear_Caliper 002
Last edited by George P
tomcat posted:

I think you misunderstood my question.  How do I troubleshoot/diagnose/confirm what my failure mode is?

...To check Booster Chamber for a Leak. Attach Vacuum Gauge to Intake Manifold, Start Engine and Let Idle. Record Gauge Reading. From the Manifold, Pinch-Off the Vacuum Hose Leading to the Brake Booster. Note the Vacuum Gauge Reading. If there is NO Change, There is No Leak. If the Reading Rises, Even So Slightly...You Have a Leak! To Confirm...Release the 'Pinch' and Witness the Reading FALL, Momentarily (Vacuuming the Hose Out). If the gauge reading does Not Rise Back to the Previous High, there Is a Leak This Procedure will Also, check the Entire Length of that Hose, For Leaks. Or Pinch the Hose Off AT The Booster, to Check Only the Booster.


Last edited by marlinjack

I did this: Removed one line at the master and installed a plug . Test pedal for travel. Removed second line at master and plugged. Tested pedal, should be rock solid. Reconnected first line disconnected then tested pedal.

I had air trapped in the rear lines so plug and tested it first. Bet you'll see an improvement. I had to buy (about $60.00) a Motive Products power bleeder to get it out. Nothing, and I mean nothing else worked.

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