Jeep owners frequently encounter a challenging situation where they struggle to push down the brake pedal. This inconvenience causes immense frustration while driving off-road or dealing with stop-and-go traffic.
If you’re experiencing difficulties pressing down on your brake pedal, there may be a few potential causes. These could include a vacuum leak, a faulty brake booster, a defective vacuum pump, or issues with the vacuum pump relay and fuse. We’ll cover each possibility and offer a solution in this article. Let’s begin.
What causes Jeep brake pedal hard to push
1. Vacuum Hose Damage / Disconnected
The brake booster vacuum hose connects the engine intake manifold to the brake booster. When the engine starts, the vacuum source pulls air from the brake booster via a vacuum hose.
The vacuum is applied to the diaphragm inside the brake booster to create the pressure differential from one side to the other and make it more comfortable to push the brake pedal.
When the brake booster vacuum hose is cracked or disconnected, you can discern the Jeep brake being hard and stiff to push.
For a brake system, you need around 16–18 inches of vacuum to operate at peak efficiency. Vacuuming less than that will result in a hard brake pedal.
How to fix
If the hose cracks, replacement costs around $50 to $100.
If you don’t know what causes vacuum leaks, repair costs vary depending on the cause of the leak.
How do we know if the vacuum hose is damaged?
Step #1: Get into the Jeep; don’t turn the key. Press the brake pedal; you will feel the brake pedal is rock hard due to air getting into the brake booster because of a vacuum leak. Because the engine is off and no vacuum source can pull the air from the brake booster.
For an adequate braking system, you will need 18 inches of vacuum.
Step #2: Turn the engine on. Press the brake pedal now; it’s easy to depress because the vacuum pump pulls air from the booster.
2. Faulty Brake Booster
Brake boosters, sometimes “vacuum verso” or “vacuum boosters,” can decrease the driver’s braking effort. The brake booster consists of booster shafts, links between the pedal and master cylinder, springs, valves that can regulate and seize the air and vacuum in the brake booster, and a diaphragm that provides separation between the air and vacuum sides.
After many years of use, the diaphragm might rupture or the check valve might leak, causing a loss of power assistance.
If the brake pedal is extremely difficult and hard to push or it takes a lot longer to stop the vehicle, these are the symptoms of a bad brake booster.
It is essential to get your vehicle to an expert mechanic before it gets worse because a sound braking system ensures your safety.
How To Fix
The replacement of the brake booster cost around $300 to $1200
The spring inside the brake servo is liable for returning the brake pedal to its normal position. If the pedal is not back, then you should replace the spring. Spring costs around $19 to $25.
how to test a brake booster
We are doing tests to check for a bad brake booster. But before testing, check the brake booster check valve.
TEST 1
Step #1: Turn the vehicle on and let it run for one or two minutes to build up pressure inside the brake booster.
Step #2: Now press and hold the brake pedal, and turn the vehicle off. If the brake booster is good, you should be able to hold the pedal for at least 30 seconds with the same amount of effort that we were using before we shut the vehicle off. For a failed brake booster, force your foot back.
TEST 2
Step #1: Let the Jeep Wrangler run for one or two minutes. So that builds up some vacuum inside the brake booster.
Step #2: Turn the vehicle off.
Step #3: Press that brake pedal three times. With a good brake booster, you should get three good breaks with an assist. For the first time, you will go down all the way; the second time, the pedal will go down a little less; and for the third time, go down less than that. So, each time you have a little bit of vacuum access.
Notice: A good brake booster can get three good brakes out with assist without vacuum access.
TEST 3
Step #1: Press the brake pedal several times and deplete all the vacuum from the brake booster.
Step #2: Now Press and hold the brake pedal with firm pressure for 15 seconds. If your foot is not moving, it means there is no leak and the master cylinder is good. If the pedal starts to creep down, it means there is a leak somewhere in the system or the seal inside the master cylinder is bad and the pressure is getting past those seals.
3. Faulty Vacuum Pump
Vacuum pumps aim to provide vacuum to several vehicle parts, such as brake boosters, etc. A vacuum pump is either mechanical or electrical. Both types have their pros and cons.
When the vacuum pump goes wrong, it cannot provide the right amount of vacuum to the braking system, making causing the Jeep brake pedal hard to push.
How to Fix
Check the vacuum pump relay and fuse.
Now use an OBD-2 scanner to check for any faulty codes related to the vacuum pump.
The cost of replacing the brake vacuum pump is approximately $600-$650.
Additional resources
https://www.repairsmith.com/blog/hard-brake-pedal/
https://www.firestonecompleteautocare.com/blog/brakes/why-is-my-brake-pedal-hard/