Brake Problem

[Lobell]

Hi all, I just posted in "ask a tech" about my brake issue. Figured maybe someone in here had the same problem as me though so I'll give a quick synopsys. If anyone has any clues please feel free to let me know. Thanks!!!!

 

I never noticed a problem while driving the truck but here is what I have found out since they told me about it. When the truck is off and you press on the brake pedal it stops about halfway down and you can't press it anymore. When the truck is started up and in park, you press the brake and it goes half way down without a problem then gets a little harder to press but keeps going. After you pass the 1/2 way mark though you can hear what sounds like air comming from the footwell or infront of the firewall. After 3/4 the noise gets louder untill the brake is completly to the floor.

 

When you are driving on the road the brake are very responsive. If you press them the brakes hard about 1/2 way down the tires will lock so the brakes seem to be at least working. I didnt even notice any issues as the truck drive and stops fine.

 

Also to note, we have a Brake-Force brake controler on the truck for towning an inclosed car trailor. I dont think this would cause the problem but maybe? Brake-Force Link

 

Thanks again!!

 

Brian

 

PS - I just went out and did a quick test with someone else pressing the brake while I listened in the engine bay. I took a picture of the hose that the noise was coming out (the hose vibrated with pedal pressed). It seems to be going to the engine/power steering pump? When the pedal is pressed down all the way it makes a sucking noise and then when released its fine.

 

[asilverblazer]

It sounds normal to me, but I could be not understanding it correctly.

[Lobell]

It sounds normal to me, but I could be not understanding it correctly.

 

When I went to the DMV in New Jersey they said that the pedal should only go down 1/2 of the way and then stop due to brake pressure. When the truck is in park and the motor is off the bake does stop under normal brake pressure 1/2 way down, but when the motor is running and the truck is in park, it goes 1/2 way and then starts making a "sucking" or "air" noise and continues to go down further until it is all the way down to the floor. The sound does get louder as the pedal goes from 3/4 down to 4/4 (on the floor).

 

Thanks again!!!

[Kodiak450]

Vacuum fitting leaking? Usually when you hear a sucking air noise, I would assume there is a vacuum line leaking somehwere. Bad valve maybe? How's the fluid level? Master cylinder sealed properly? (Cap secure? Gasket still good?) No small holes in master cylinder, maybe in cap? Some things that come to mind. I'm not a mechanic, but with brakes locking up would seem like a master cylinder failure somewhere. Something to do with the Hydraulics.

[Kodiak450]

I was just looking at the pictures again. I noticed the reserve tank has had brake fluid on it and dirt stuck to it. Was that from you topping off tank and some fluid over spilled and you didn't bother to clean it up? Reason I ask, the gasket could be bad and letting out some fluid and air in.

[Billy-Jean]

same thing happened to me, i had to change the master cylinder

[Shaners]

The power steering pump runs the brake booster too. My pump went bad and I almost wrecked because I not only lost power steering but power brakes too!!! Thank goodness I was only in the driveway!