Hello everyone. I have a 90 F250 4x4. I recently replaced the rear brakes, drums, and wheel cylinders on both sides. Now I'm attempting to bleed the abomination from hell know as brakes. I've bleed RR, RL, RABS, FL, and FR...several times!!! I've tried using the hand pump vacuum systems, I've the one person method in which you put the tube in the bottle, I've tried the two person method with one pumping the brakes and one opening and closing the bleed screw, I've tried yelling at it, I've tried cussing at it, and finally I've tried punching it. I need help. (In more ways than one. Ha-ha!!) I'm feeling defeated. Why is something so simple causing me so many problems??

The brakes had great pressure before I decided to "fix" them. The best I can get is a spongy pedal that ultimately goes to the floor.

 

Did you replace your master cylinder? If so did you bench bleed it? If not are you sure it is o.k.? Does your pedal sink to the floor eventually or are you able to force it to the floor? If it sinks slowly with constant pressure applied, and you aren't leaking fluid anywhere you have an internal leak most likely in the master since your proportioning valve should keep pressure on the pedal if it is a wheel cylinder.

Good luck and let us know what happens.

Mac.

 

I feel your pain! I bled the brakes on my '93 F250 more times than I could count using all the methods that you mentioned and never could get a good pedal. I finally took it to a mechanic and told him not to call me until the pedal felt good! I don't know what he did different than me but he got them bled good somehow. It cost me a hundred bucks but that was alot better than me setting the truck on fire which was gonna be my next step! LOL

 

Mac, I didn't replace my master cylinder and I can force the pedal to the floor. I can hear it compressing and It takes quite a bit of pressure, but it ultimately goes to the floor. I don't think have any leaks because my reservoir stays at the same level. Plus, everything was find before I did the back brakes.

LSO, this has driven me nuts! Ha-ha!! I've gotten so doggone aggregated with it. My buddy has this contraption that he's rigged up with an air compressor. I guess I'll give that a shot unless anyone else has any suggestions.

 

Chris is your brake fluid milky or bubbly anywhere? An internal leak won't use any fluid from the reservoir because it is just pushing past a piston somewhere and not exiting in the form of a leak on the ground. If you get milky or bubbly fluid from one wheel, there is still air in that line somewhere. I have used the vacuum pump method with much success before on both my trucks, but it took a while.

 

Here's something for you to try: (this is also a one-man job)

-Get a 1 liter bottle and cut a hole in the cap just big enough for the hose from the vacuum bleeder to fit in.
-Put the hose all the way to the bottom of the bottle, so it's almost touching the bottom
-Put the other end of the hose onto the bleeder with the correct rubber adapter, and crack the bleeder open
-Make sure bottle is at least 4"-5" HIGHER than the bleeder, with the cap facing up like it would naturally sit
-Cycle the brakes a few times
-Fill reservoir, repeat as necessary

This was a technique shown to me by a friend, and I'll never use another technique. This way, the fluid is forced at an upward angle towards the top of the bottle. Any air that comes out from the brake cylinder will come to the top of the fluid. All the fluid will sit in the hose (it will make it into the bottle if you pump long enough). The main point behind this method is physics: air is less dense than water, therefore it will travel to the highest point it can in the system. Fluid will stay low, and be sucked back into the system when you let off the brake. The air will not, because it will continue to travel towards the bottle (highest point).

 

I have learned that if I ever bleed brakes or otherwise have to push the brake pedal outside it's normal range, the master cylinder will most likely need to be changed. Over a few years, corrosion builds up inside the bore outside the normal piston travel. When the piston is forced into this corroded area, it gets cut up and fails pretty soon after.
As a general rule, if I'm doing that sort of brake work and the fluid is black, it gets a new master cylinder. It's under $30 for these trucks.
Also, vacuum bleeding is awesome.

 

Hey guys! This is some really good information and I'm very thankful! I'm heading out of town tomorrow, but when I get back I'm going to try the raised bottle suggestion. It really makes perfect sense, so I think it's worth a shot. If that does work out for me I've already made plans to borrow my buddy's fancy vacuum bleeder.

Thanks again guys. I'll let you all know how it works out.

 

I feel for you man, as my last truck had the same issue. Replaced master cylinder and the problem did not go away. The factory manual has the proper bleeding procedure, and if I remember correctly then you have to bleed your RABS(in left frame rail, about mid ships)first, followed by right rear, left front and then left rear right front. Important! If you use any type of vacuum device then you must remove the bleeder screw first and wrap the threads with teflon tape. Be careful that you not block the bleeder hole. Other wise you just suck air through the coarse thread of the bleeder screw. Most important!Never run your brake reservoir down past half full, otherwise ( and I have seen this) you will introduce air into the system at the master cylinder and that it gets really difficult to get a hard pedal.
So did I ever get a nice and firm pedal on my old truck? No!
And I never figured out what the problem was. Makes for great calf muscles on the left leg though
My other truck on the other hand has great brakes (all stock). I just replaced fluid and flushed whole brake system. Took thirty minutes with the wheels off. By myself with small hand held vacuum pump and two cup catch container (ala Mighty-Vac).

 

Rear brakes not adjusted properly will cause a spongy pedal also.

 

Ive seen bad brake hoses give a soft pedal because they swell and contract.

 

^^^^That. Whenever I have difficulties with bleeding ANY brake system it's usually the master cylinder. Replace it and bam, all the sudden there's pressure.

 

Don't know if it'd solve your problem, but I bought this guy to bleed my brakes a couple years ago and it makes any job SUPER easy. Takes longer for the air compressor to come up to pressure than it does to bleed.

Brake Fluid Bleeder

Mike

 

Cool, HF has their version of a Motive Bleeder! I'm going to have to pick that one up, thanks Mike!

 

When I purchased my truck in august I had to replace everything on the rear also. drums, springs, wheel cylinder ect... So I bought the harbor freight pneumatic bleeder, but I don't think my air compressor can keep up with it. Still don't have great brakes, but I haven't bled the RABS either, didn't even know about it. So I just learned something else from you guys!