Adding brake fluid to a Jeep Grand Cherokee is not necessarily a scheduled maintenance procedure. While the master cylinder reservoir should be topped off, when it gets low, it's due to other factors. Low brake pads will cause the hydraulic caliper pistons to extend outward further to allow the thinned pads to contact the rotor. This scenario sucks out more of the brake fluid (hydraulic fluid) from the master cylinder to accommodate the pistons' reach. While Jeep Grand Cherokees most often employ wear sensors on the pads to warn the driver when the pads are low, topping off the master cylinder prevents the brake fluid light from illuminating on the dash to alert the driver.
Raise the hood of the Jeep Grand Cherokee and locate the master cylinder brake fluid reservoir. It is located on the driver's side firewall at the rear of the engine compartment. (See Resources) It's a small white rectangle component with a yellow cap on it.
Inspect the amount of fluid in the master cylinder and then compare the fluid level to the full marking stamped visibly on the side of the master cylinder brake fluid reservoir.
Remove the yellow cap, if necessary, to add fluid to the master cylinder.
Add DOT 3 brake fluid to the reservoir. DOT 4 brake fluid is also acceptable, but the Jeep Grand Cherokee calls for DOT 3. Do not add DOT 5 brake fluid or any other type of fluid to the master cylinder. Petroleum-based fluids such as coolant, engine oil, power steering fluid or transmission fluid will contaminate and damage the rubber seals in the entire braking system. If you're unsure what kind of fluid is in the bottle, buy a new bottle of DOT 3 brake fluid to add to the master cylinder.
Pour the fluid into the master cylinder brake fluid reservoir until it reaches the full line stamped on the outside of the master cylinder.
Replace the cap to the master cylinder.
Have your brakes checked to make sure they're not getting too thin.
