Author Topic: 67 master cylinder  (Read 417 times)

Jek9016

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67 master cylinder
« on: March 31, 2018, 12:41:36 PM »
My restored 67 has power brakes with an aftermarket (Bendix?) booster, drum rear disc front.  I replaced the leaking master cylinder (several times) with a replacement unit that is for front disc brakes.  However, the brakes work, but drive like there is no power assist. The power brakes worked perfect with the old master cylinder, so I have no reason to suspect the booster is failing.   I also have a proportioning valve.

Anyone have an idea how to fix this???

thx
 

z28z11

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Re: 67 master cylinder
« Reply #1 on: March 31, 2018, 03:54:33 PM »
Assuming the booster is working correctly, look at the end of the old master and determine the depth of the seat for the actuator rod (the piston end) - there are two different lengths, depending on the application/year of the setup ('69's had a shorter rod). If that matches correctly, start chasing the booster, check valve and vacuum source.

My $0.02 -

Regards,
Steve
1968 Z28 M21/U17 BRG/W
1969 Z28 X77/M20/VE3 LeMans/W
1969 L78 X66/N66 Cortez/BVT
1969 Z11 L48/M35/C60/C06

JKZ27

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Re: 67 master cylinder
« Reply #2 on: April 01, 2018, 01:04:45 AM »
And, make sure you're not losing vacuum around where the master bolts to the booster.
John
69 RS/SS Cortez Silver, L48 MC1
68 RS Ash/Ivy Gold 327EFI M20