The back reservoir is for the front and the front reservoir is for the back. Since 80percent of your stopping power is in the front brakes you need to activate them slightly before the back breaks to keep the car under control. SO, when you push on the pedal, the piston moves to allow fluid from the back reservoir to flow first. The fluid is then routed to a metering valve to ensure both sides are activated evenly and to the rear.
front front - rear rear.
the rear is usually smaller and closer to the brake booster
You bleed the rear brakes the same way you bleed the front brakes. If you can't get brake fluid to come out the rear bleeders you may have a faulty master cylinder or the master was allowed to empty out the reservoir that feeds the rear and now it is air bound. Removing the master cylinder and bench bleeding the master may be what you need to do and don't let the reservoir go dry!
. If you have the 4-port master cylinder, the bottom ports go to the rear brakes & the upper side ports go to the front brakes.
The reservoir with the lesser fluid capacity is for the rear brakes since the front calipar pistons require more fluid therefore they require the larger of the two.
Just in front of the driver's position inside the engine compartment is a big round thing, with a fluid reservoir on top. This is the master cylinder for the brakes, and the reservoir is for the brake fluid.
Master cylinder possible but could also be wheel cylinder problems or warped rotors
On the firewall, in front of the booster, on top of the master cylinder.
The clutch master cylinder is fed through a hose from the brake master cylinder reservoir. It is located on the firewall under the hood directly in front of the steering wheel, under the wiper motor.
Generally the front brakes of an average type braking system stops approx. 60% or more as opposed to the rear brakes wich attribute to 30-40% of the total braking power on said vehicle, that is why typically the front brake master cylinder reservoir compatment contains twice the amount of fluid in it as the rear brake master cylinder fluid fill compartment.
Bad master cylinder.
The brake reservoir is on top of the brake master cylinder. It's under the hood, on the firewall in front of the driver. The vacuum boost is the big round thing and the master cylinder is right in front of it. Slide the wire retainer to the side and the top of the reservoir will come off.