I am a new member to this forum and after spending a lot of time reading many many posts I bought a 99.5 F 250 4x2 powerstroke, 6 speed with 41k miles on the odometer. I just love this truck and have been doing a lot of maintainence and fluid changes over the past couple of weeks.

Well I saw the brake fluid flush post and decided to go ahead and do it which has lead me to my first crisis. Here is what happened:

Bought synthetic Valvoline DOT 3/4 brake fluid, opened the brake resevoir. Then I attached a rubber hose that fits snugly on the bleeding nipple of the passenger rear tire. Had a friend pump the brake pedal, and almost black fluid pours into the container! Kept pumping the brake pedal until the fluid runs clear, topped up the main resevoir with clean fluid, do the drivers side rear brake.

Here is where I run into trouble: I am doing the drivers side front and realize that the main resevoir is dry! So I top it up, but then when I pump the brake pedal, there is a motor noise and the pedal kind of pushes back when I press it. The ABS light goes on and I officially panic.

So I proceed to bleed both front brakes several times, now the ABS light is off, and there is less noise, but there is something wrong. I have bled each wheel several times, and there is still a mechanical pumping noise (kind of like a power steering pump) that I think is the ABS pump. I think that I have sucked some air into the ABS circuit? I definitely have sucked some air into the brake system when the main resevoir went dry.

I drove the truck around the block and the brakes do stop it good but the brake pedel kind of pushes back a little and there is that motor whining sound that feels like the ABS is kicking in.

Any help or suggestions would be greatly appriciated.

 

Is there a way to bleed the ABS motor or system?

 

Check you power steeering pump fluid. That is what provides the brake assist in our trucks. That is most likely what you are hearing.

BTW, welcome to FTE. This problem should be remedied here shortly. If all checks out well, may want to look at sticking slide caliper pins.

 

After reading your reply, I was scratching my head, because I have never heard of a connection between braking systems and p.s. pumps. I guess there is always something to learn! I really have to thank you for pointing me in the right direction.

O.k. I start up my truck and is sounds fine. While Idling, I push on the brakes hard and get power steering pump noises, just like when you turn the wheels all the way left or right when standing still.

Take it for a test drive and try braking hard several times from low to high speeds. The brakes are awesome and stop really good. The ABS works the way it is supposed to. I can feel the ABS pulsing the brakes to prevent lock up. Conclusion: Brakes are fine with no air. ABS working correctly.

Now I am thinking about the power steering pump noise and I think I know what is wrong. I think that I have damaged the pump earlier today while doing a p.s. steering fluid flush ( this was done just prior to the brake line flush).

Here is how I did the p.s. fluid flush:
1. Disconnected the return line from the cooler unit under the front bumper and ran a tube to a collection pan.
2. Started vehicle and before I was able to pour fresh fluid in the p.s. resevoir, it ran completely out and made a high pitch noise for about 10 seconds, before I was able to shut of the motor and add more fluid.
3. Filled fluid, start engine, stop engine, etc.
4. Top up p.s. fluid to correct level.

So do you think that the p.s. pump is shot since it ran for 10 sec. without any fluid?

Thanks,

 

i did my power steering flush and the noise went away pretty fast (4 minutes). good luck to you.

 

im sure you didnt hurt the pump..but it sounds like its still full of air..