Hi

I have an 89' F250 and I am having trouble with my brakes.

Previously, I could not get the air out of the rear brakes, so I swapped a master out of my parts truck ( did not know if it was good or not ) and put in a new brake hose connecting the steel line along the frame rail to the two steel lines mounted on the rear axle.

Before I did the swap I got nothing but air out of the back brakes, and now I have bled all out the air out of the entire system (hopefully I bled the ABS modulator right, as there was no special procedure in my Haynes manual as there is only one bleed screw on it) but i still have virtually no brakes.

When I pump the pedal with the engine off, the pedal gets harder as it should but I can hear a "squishing" noise that ceases as I pump faster. When I put my foot down slowly the pedal slowly falls almost to the floor before showing slightly more resistance.

So I need to know if this master that I swapped in could also be bad? And could it be the culprit of the "squishy" noise which I heard before I did the swap?

Also, with the engine on the pedal practicall falls on its own until it is almost to the floor before I have brakes.

Thanks for any help, it is greatly appreciated!!

 

remove the lines from the mc and have someone pump the brakes and see if a good flow comes out,also did you bleed the mc first before bleeding at the wheels?

 

From my experience, its a possibility the new master can be bad. Did you get the air out of it when you switched it over? Bench bleeding. Does the rest of the brake system look good? (calipers, wheel cylinders, lines?) There is an order for this truck also. I want to say its the farthest from the master cylinder to the closest but I could be wrong. I cannot find my paperwork at the moment (I have a huge pile of info on my truck that the haynes isnt useful for). Maybe someone else knows though.

[edit] I guess Neal beat me to it. He has the right idea too!

 

I took the master out of the other truck (which was still full of fluid) plugged the holes and then installed it into the truck that i am working on. I did not bench bleed it because I assumed that bleeding the brakes normalling would get rid of the air that would enter where the lines were disconnected, because the resevoir was full of fluid.

So is my next step unhooking the lines and just seeing if fluid comes out evenly from both holes?

Thanks for the advice

 

If the master cylinder is bad there will be lots of bubbles in it when you push the brake pedal. Also there will be fluid around the rod.

 

YEah,bleed the master for all you know if could have air in it.