Brake Problems

got the truck used, was told brake lines were replaced and the brakes just needed to be bled. bled brakes, found a leak due to a missing washer. replaced washer and bled the truck again but still didn’t work. felt great break pressure till I turned on the truck, then the pedal went to the floor again. So next I replaced the master cylinder, bled the master cylinder, re-bled the brakes, same conclusion. good pressure then it disappears after the we turn on the truck. no cruise control. any suggestions?

When you ask a question about a vehicle, think as if you’re going to the parts store for parts.

The counter person at the parts store can’t help you unless they know the year, make, and model of the vehicle.


Also, what order did you bleed the system in?

Sounds like maybe the power brake booster has failed. Is it vacuum operated or is it a power steering pump powered brake booster?

Yeah, year, model, miles, engine would help a lot here.

I don’t recall encountering washers in brake hydraulics. Where did you find a missing washer?

When you press on the pedal and don’t get a firm response it is either air or a leak. You just have to step by step isolate where the problem is. Can you narrow it down between the front and back?

Brake lines replaced, do you mean the steel brake lines or the rubber brake hoses? I ask because the only washers that I can think of are the gaskets for the hoses where they attach to the calipers. There are two washers, one on each side of the fitting that the banjo bolt goes through.

Are you finding any new leaks? Does the fluid level go down in the master cylinder? Did you repeat the bleed procedure after starting up the truck? If so, was there air in the system?

Me: I need wiper blades for my 87 Nissan Pick Up.
Counterman: Automatic or Manual?

I hear ya @Keith;

I think it my old Rangers, that when I’d ask for any part under the hood they had to know the wheel base?

And why every repair starts out with “remove the positive battery cable…”.

I agree that the only washer I can think of is the copper crush washers, but that should have made such a leak impossible to miss at purchase.


LOL, Keith, that joke made my day. It’s so true.