pipefitter Posted April 3, 2015 Report Share Posted April 3, 2015 I have a 1973 datsun pl 620 that was converted to 4 wheel drive.The front end is a dana 25 off a jeep,my problem is i put front disc brake kit on it but the master cylinder can not give the volme of fluid i nneed resulting a spongy peddle.I think if I can find a master cylinder off a disc brake car it might work but I am alittle lost as what to do at this point any suggestions will be appreciated. Thanks 1 Quote Link to comment
]2eDeYe Posted April 3, 2015 Report Share Posted April 3, 2015 My 4x4 uses a 15/16 Z car master cylinder from a 1980 (I think) ZX and stops well. 1 Quote Link to comment
ggzilla Posted April 3, 2015 Report Share Posted April 3, 2015 The disc brake master does not have particularly big reservoirs. Too low volume won't cause a spongy pedal. But it will cause you to have to press the pedal twice. Spongy pedal is caused by air in the lines, or perhaps by weak brake hoses. To get rid of a long pedal travel, fit a larger diameter master cylinder. 620 factory disc brakes use a 13/16 master. The ZX master is for all-disc brakes (front and rear). 1 Quote Link to comment
pipefitter Posted April 4, 2015 Author Report Share Posted April 4, 2015 thanks guys,I will check into the ZX master cylinder 1 Quote Link to comment
pipefitter Posted April 18, 2015 Author Report Share Posted April 18, 2015 hey I got the 1980 zx master cylinder but where the master bolts to the vacuum booster the master doesnt fit into the aluminum adapter so do I change those also,thanks for the help. Quote Link to comment
ggzilla Posted April 19, 2015 Report Share Posted April 19, 2015 U need a factory 620 disc brake master (1978-1979) Or maybe someone changed the brakes to a non 620 booster. Quote Link to comment
]2eDeYe Posted April 19, 2015 Report Share Posted April 19, 2015 Need a pic of the booster Quote Link to comment
pipefitter Posted April 19, 2015 Author Report Share Posted April 19, 2015 Need a pic of the booster Quote Link to comment
pipefitter Posted April 19, 2015 Author Report Share Posted April 19, 2015 As soon as I figure out how to post a picture I will,all I know is that is a factory bendix 5 inch booster an they make a 6 inch and 7 inch,but I think a7 inch would hit the clutch master cylinder Quote Link to comment
pipefitter Posted April 19, 2015 Author Report Share Posted April 19, 2015 Need a pic of the booster Quote Link to comment
]2eDeYe Posted April 20, 2015 Report Share Posted April 20, 2015 Looks like you just need to change out the aluminum adapter. Should be easy to come by at the junkyard. Quote Link to comment
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