720 Jason Posted October 11, 2015 Report Share Posted October 11, 2015 tried several times to bleed brakes, but after removing the brake line in several spots we realized new mastercylinder was not pushing fluid past the cab. seems the new MC is for a 1980 240/ 280zx motor. hoping to find a rebuild kit for the cleaned up old MC. (so tired of crawling around on the ground.) Any advice would be greatly appriciated. -jason Quote Link to comment
datzenmike Posted October 11, 2015 Report Share Posted October 11, 2015 Your 720 should use a 13/16" master. Just go to an auto supply store and tell them what truck you have. Quote Link to comment
720 Jason Posted October 11, 2015 Author Report Share Posted October 11, 2015 ok, just looked to make sure, and they're both (old and new) 15/16. does that explain why i'm not getting fluid to the rear? Can I really just use any MC w/ proper brake line outlets and 13/15 bore?! what if I've got the wrong booster too? Quote Link to comment
flatcat19 Posted October 11, 2015 Report Share Posted October 11, 2015 Adjust your pedal pushrod length. Quote Link to comment
720 Jason Posted October 11, 2015 Author Report Share Posted October 11, 2015 ok, i think the old booster is ok, but can i just turn around and install that new 13/16 MC. they'd be compatible? and one more stupid question, whats that measurment represent? the hole for booster? b/c both 15/16 MC's had different length "flanges" that insert to booster. so confusing. and the atuo suppy people arn't as helpfull as one might think Quote Link to comment
flatcat19 Posted October 11, 2015 Report Share Posted October 11, 2015 Did you bench bleed the MC before installing it? 1 Quote Link to comment
720 Jason Posted October 11, 2015 Author Report Share Posted October 11, 2015 pedel push rod that engages the booster? so if i replace both the MC and booster, I may need to also adjust the push rod? Quote Link to comment
720 Jason Posted October 11, 2015 Author Report Share Posted October 11, 2015 yes, bench bled Mc Quote Link to comment
flatcat19 Posted October 11, 2015 Report Share Posted October 11, 2015 pedel push rod that engages the booster? so if i replace both the MC and booster, I may need to also adjust the push rod? Derp. You have a booster. As long as you haven't messed with anything on the pedal side of things you should be fine-and not have to mess with it. My Datsun does not have a booster. That's why I went there automatically. 1 Quote Link to comment
datzenmike Posted October 11, 2015 Report Share Posted October 11, 2015 ok, i think the old booster is ok, but can i just turn around and install that new 13/16 MC. they'd be compatible? and one more stupid question, whats that measurment represent? the hole for booster? b/c both 15/16 MC's had different length "flanges" that insert to booster. so confusing. and the atuo suppy people arn't as helpfull as one might think It's a 720 so yes the original or new 13/16" master has to be compatible. The 13/16" is the bore size inside the booster. Larger calipers need more brake fluid to move them so most old Datsun cars are only 3/4". Your 720 will have larger calipers on the front and wheel cylinders on the back and so will need a slightly larger master cylinder. Obviously the zx with a 15/16" master uses even larger brakes. The early ('79-'81) 15/16 280zx master will fit the 720 booster because the bolt pattern is vertical. The '82-'82 280zx master has a horizontal mount bolt pattern and won't. Just get the 720 master... or rebuild kit and you're good. Quote Link to comment
720 Jason Posted October 11, 2015 Author Report Share Posted October 11, 2015 thats great! thank you. got some solid help from ya'll when I had to rebuild carburater. great pictures... thanks again Quote Link to comment
flatcat19 Posted October 11, 2015 Report Share Posted October 11, 2015 Remember...even new parts fail right out of the box. Quote Link to comment
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