I have early 300zx front brakes on my 180bsss, i think the booster is a 280zx contraption (i havent seen one like this on a dato before), it came with the car but i have never been able to get the pedal to get firm...

I have taken it to mechanics and had the brakes machined and new pads on the front ( the rear is standard drums ) but after bleeding the brakes it still goes almost the floor???

When it does brake it brakes well (when its 2mm from the floor), i was told i might need to use a smaller booster, can anyone shed some light on what booster i need?

Let me know if you need further info...

Thanks

is it still the stock 180B booster in there?
the only booster I can think of thats smaller than the 180B one is the 120Y?

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1970 Datsun 1600 CA18DET - SOLD!
1970 KP510 SSS Bluebird coupe
http://www.nzdatsun.com/forums/

Hey Bloke, possibly sounds like your master cylinder is too small, same thing happened to me when i put vl turbo brakes on my 510 and didn't put the right size master cylinder on, pedal was going to the floor but still worked good before the pedal ran out of travel, most masters have their size on the side, not sure what size you need but if its standard i doubt that it would be big enough!! bill..

The booster size really doesnt affect the pedal height.Unless there is an internal fault or out of adjustment. Possibly the buffer pad in your booster has come adrift.
I Prefer to use a 7/8 dia master cyl or even 15/16.with most brakes including 300zx R32/33 .
Booters should be checked for freeplay beteen the push rod end & the M/C.
Small can boosters work ok but if you want a lighter pedal use the sunny,jap stanza type.(minor mods needed)
When fitting datto boosters lower the push rod attachment point on the brake pedal about 15/20mm so it is a straight push on the booster. This also changes the ratio. If all is done right on the brakes, then you should have a pedal right at the top of the stroke.
Then, if you wish, shorten the pushrod and adjust the pedal height closer to the floor.
Much better for heel & toe & quick driving.

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A little knowledge is a dangerous thing.
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"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

Not to keen for any firewall mods or the like, is there a standard setup that can be removed from another datto that will help my situation? (and fit behind or beside a fj inlet manifold?)


"I Prefer to use a 7/8 dia master cyl or even 15/16" Any of these standard from a datsun? (save me walking around for days with my tape measure and vernier calipers)

Just need a bit of simplified english for my simplified self.. thanks for your help guys

the 180B booster and 280ZX master cylinder ( 15/16 ) bolt into a 1600, no mods.....except that the master bleed valves hit the strut tower very slightly....so just give it a small hit with a ball pen hammer ( the strut tower ) and it will be fine.

_________________
1970 Datsun 1600 CA18DET - SOLD!
1970 KP510 SSS Bluebird coupe
http://www.nzdatsun.com/forums/

What is the diameter of the standard 120y master (theres nothing other than "AB-02" cast into the side of the master that came with my 120y booster)? 1200 master? For a disk brake rear end does anything need to be done to the master cylinder?