Brake pedal is hitting the floor

POWIEG

MEMBER
1986 JEEP CJ7
6 CYL
4WD
MANUAL
130,000 MILES

Hi,

New to the forum. I just purchased the vehicle listed above, this is my second one. Manual, 4 speeds, power steering. I have had it about a month now. Has been driving nicely for its age and mileage. Today, I noticed the brake pedal was soft in the morning and by the afternoon, was to the floor. I am assuming based on what I read that it could be the master cylinder? I opened the hood and do see fluid in the engine below where the cylinder is.
At this time, I do not feel that I would be able to repair this myself. I don't know. But my main question is would it be safe for me to drive it to my mechanic station which is about 2 miles from me?
Thanks for any feedback.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,876 POSTS

Hi,

I wouldn't recommend driving it if the brake pedal goes to the floor.

Are you sure it's the master cylinder? Are there any leaks under the vehicle? For example, a steel brake line can rust and leak as well as other components (wheel cylinders, calipers, rubber brake hoses) and so on.

The master cylinder is easy to replace on this one. Here are the directions:

1986 Jeep Truck CJ-7 L6-258 4.2L VIN C 2-bbl
Master Cylinder Replacement
Vehicle Brakes and Traction Control Hydraulic System Brake Master Cylinder Service and Repair Procedures Master Cylinder Replacement
MASTER CYLINDER REPLACEMENT
1. Disconnect brake lines from master cylinder. Cap lines and master cylinder ports.
2. On models with manual brakes, disconnect master cylinder pushrod at brake pedal.
3. On all models, remove nuts or bolts attaching master cylinder to dash panel or brake booster and remove master cylinder.
4. Install in the reverse order of removal and bleed the brake system.

Here is a link that is how to replace one in general. It is more detailed than the manual's directions I attached.

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

If you want to do it yourself, let me know. I can help you through it. Also, make sure there are no leaks under the vehicle. Check the backs of tires, along the frame and so on.

Take care,
Joe