Soft brake pedal

[Dbleeger]

My brake pedal is very soft and nearly goes to the floor before the brakes kick in. The brakes seem to work fine asides from that. My first thought was that I was low on brake fluid or I have air in my lines, so I checked the two reservoirs. The larger reservoir is filled and the smaller one is completely empty. I'll bleed the brakes next, but am hoping to get some input on this issue. I also traced the brake lines and didn't see any signs of leakage.

I'm not familiar with a dual reservoir master cylinder and am not sure if there should be any brake fluid in the smaller reservoir or what the purpose of the black liner is. What are your thoughts/explanations? I've attached a photo of the smaller reservoir.

[chevymaher]

There is your problem fill the smaller one. Check the rear brakes they probably worn out that is where the fluid went. Rubber seal keep air from getting in the system if you dont let it run dry.

[Old Barney]

I'll try to explain: the black piece still in the reservoir has to be removed as the fluid is under that black piece still there. Just pull up and out with your fingers. When reinstalling the cover and the reservoir is full put the black piece back in the cover and reinstall the cover. This soft gasket keeps the fluid in when the wheel cylindersare being pulled back in releasing the brakes. and when the brakes are applied this black soft gasket is sucked into the reservoir slightly. I would guess it could be called a diaphragm.

[Rod's Trucks]

IT also reduces the ability of the brake fluid to absorb moisture. Brake fluid is 'hydrscopic' ( I think I spelled that correctly).
That means it likes to absorb moisture. Additional moisture in the fluid reduces the boiling point, and helps promote corrosion in the piping and other components....bad juju!
That is one of the reasons to flush the brake system occasionally... to get rid of any moisture contaminated fluid.
Rod J

[AstroWill]

The fluid is below that rubber :)

[Dbleeger]

Got it! Thanks, everybody. Filled up the front reservoir and that fixed the issue. I haven't had a chance to look at the rear brake pads to see if they are worn out because of the weather, but I will once it clears up.

[AstroWill]

Congrats! Glad you got it figured out.

Would love to see more of your Tiger :)