Brake cylinder reservoirs

[tom231]

Good day everyone!  On my Series 1 240Z, new to me.

The smaller brake fluid reservoir is almost empty, ie...which I have read is for the disc brakes.  Am I able just to fill that reservoir, with number 3 fluid, and then I am ready to go?

The front, which I believe is for the drum brake, is full.

thanks for the help!    Tom

 

[SteveJ]

Which Master Cylinder do you have?

Early

Later

If you have the early master cylinder, the front reservoir is for the disc brakes (front), and the rear reservoir is for the drum brakes (rear).

If you have the later master cylinder, the front reservoir is for the rear brakes, and the rear reservoir is for the front brakes.

Note: Some early cars have been modified to use the later master cylinder due to the lack of availability of rebuild master cylinders. You'll need to look at the path of the brake lines to verify.

If the reservoir is low for the rear brakes, I would inspect the wheel cylinders and brake lines for signs of leakage.

[tom231]

SteveJ-Thanks for the reply and pics.  Looks like I have the early master cylinder.  So the smaller reservoir is for the disc brakes, ie...larger for the drums?

I will have a mechanic check out the items you mentioned above.  Would it be OK to go ahead and fill that reservoir?  If so, do I use the DOT 3 fluid?

thanks again SteveJ!    Tom

PS-What a GREAT FORUM!!!

[SteveJ]

Tom,

As I said before, for the EARLY MC, the front reservoir is for the front brakes (disc brakes), and the rear reservoir is for the rear brakes (drum brakes). 

The only risk about adding DOT 3 fluid is if a previous owner used DOT 4 or DOT 5 fluid, and that is unlikely if the car was not set up for track use.

There is one other possible explanation for the loss of brake fluid from the rear reservoir. It could be leaking into the brake booster.

Finally, do not just go by the size of the reservoir. They can be swapped. Look on the driver's side of the MC. You should see F and R cast in the body of the MC.

[tom231]

Thanks again SteveJ!!   Tom