15/16 Brake Master Cylinders

[dscottdatsun]

I have three 15/16 master cylinders of unknown condition. I have searched high and low for rebulild kits to no avail. I took them apart to assess, clean and put one properly functioning together. I'm questioning if this is possible. It is after all brakes and safety is first when done. Are rebuilds of BMC's reliable? Does anyone know where they could be rebuilt?

[Rick-rat]

 

Rock auto, 1977 Datsun 280Z, 15/16 rebuild kits

[mklotz70]

You can also check with Ott's Friction Supply in Portland.  I bought RX7 caliper rebuild kits there when I couldn't find them online.  They can probably even do the work if you want.

[dscottdatsun]

Tried Rock Auto, you get a message their no longer available

[datzenmike]

Don't know about the '77 280z masters being 15/16", could be. The '80-'84 Maxima are 15/16"also but the masters are different bolt on pattern... kits might work

.

 

280zx '79-'81. (the '82-83 are different bolt on masters but the kits may be the same) I too had trouble years ago at NAPA. The guy searched all over and found one in a NAPA box that had artwork and printing on the box he had never seen in over 25 years of working there.

 

YES you can definitely do the rebuild yourself, I did and it's been in for 3-4 years.

 

Take note the 280zx uses rear disc brakes so if using on a rear drum car, the rear residual valves must be swapped for drum brake residual valves. It's very simple and easy to do.

[Three B's Racing]

Don't know about the '77 280z masters being 15/16", could be. The '80-'84 Maxima are 15/16"also but the masters are different bolt on pattern... kits might work

.

 

280zx '79-'81. (the '82-83 are different bolt on masters but the kits may be the same) I too had trouble years ago at NAPA. The guy searched all over and found one in a NAPA box that had artwork and printing on the box he had never seen in over 25 years of working there.

 

YES you can definitely do the rebuild yourself, I did and it's been in for 3-4 years.

 

Take note the 280zx uses rear disc brakes so if using on a rear drum car, the rear residual valves must be swapped for drum brake residual valves. It's very simple and easy to do.

280Z are 7/8" I have one in my 4wheel disk setup and residual valve for rear disks works Great!!!!

[dscottdatsun]

Mike,

 

Do you have pics of the residual valves and where they are located?  

[datzenmike]

They are in the fitting on the underside where the brake line comes out. Remove the brake line and unscrew the fitting. Inside is a small spring but watch out they all look the same.

 

Residual valve

 

 

15/16" rebuild kit

[crew521]

anyone ever use clutch master for brake master?

[datzenmike]

Not enough volume of fluid moved. Four brake cylinders vs. one slave.

 

The clutch is the same pressure to release every time. Brakes go from soft pedal to both feet pressing so hard your ass is off the seat lock 'em up pressure. Better to fit a proper brake master, after all it is the most important safety device on your vehicle.

[hosestop@msn.com]

Actually Wilwood makes a single reservoir system that pushes plenty of fluids. for four wheel disc.

[crew521]

clutch master seems to work well for brakes

[crew521]

same bore ...

[datzenmike]

I had no doubt it will work. Except it's not designed to take the pressure of a master. How many pounds to work the clutch? 25-30? That would be a very gentle stop for brake pedal.

[Dime Dave]

The clutch master is likely 5/8" bore. It will not push enough fluid and it also removes the duplex safety system from the brake system.

 

I used to own a 61 VW with a single master. When a brake line leaks the pedal goes to the floor and you have no brakes. This is why the parking brake was called an emergency brake.

[datzenmike]

I think the L512 has a single master. If you have a clutch master on I urge you to get the correct brake master for it. Find one for the later PL521 with the L16 engine. If you have to get a rebuild kit for it. Perhaps a dual master from a car and use just the front