some time when i put foot on brake pedal it goes all way down. I has to pump them to get them to hold.
Could it be air in the lines?
It could be a worn out master cylinder. The brake fluid may be slipping past the piston.
Could be air in the lines, or a bad master cylinder. Open the top of the master cylinder and see if the level of brake fluid is way down. If it is you might have got air in the lines. Then you have to find out where the fluid went, fix the problem and bleed all the air out of the brakes.
The truck isn’t safe to drive as it is. Filling up the master cylinder with fluid isn’t a fix, just a way to improve the situation.
If it is only sometimes I’d bet on the master cylinder.
it was , i put fluid in it .
Thank for answering my question
I’m not a mechanic, just someone who came in here to get some advice and came back to give an update.
I had a car that did the exact same thing, and it was only 6 weeks after a brake job at a chain that I will not mention but will never use again. I put my head through the windshield, totaled the car, and came close to being killed. Please do not drive it until the problem is solved, as one of the car experts said, it’s NOT safe.
I’m certain it’s the master cylinder, and if you get the brake fluid changed every 3 years from now on this kind of problem will be much less likely to happen again.