Brake Trouble

[goosefoot33]

Hey gents, I've been poking around here on the forums for a few days to find a solution to my braking problem but haven't found one yet. My problem is a very soft pedal.
When I press on the brake pedal, it will go all the way to the floor with little foot pressure. It will grab lightly about halfway down, and once it hits the floor it grabs a little bit more and will stop the truck eventually.
If I pump the pedal three or four times, the pedal becomes hard and will bite right down about 1/3 of the way down (right where it needs to be).
I just replaced the master cylinder (bought it new from Napa and bench bled it), and then had the brake fluid flushed and brakes adjusted by Firestone. E-brake works excellent.
If I jam on the brakes in a panic stop, occasionally the left pad grabs and jerks the truck to the left slightly.
I replaced the leaky brake booster about three years ago, after which it sat in dry storage for about a year and a half.
The truck is a 1986 F-250 6.9L w/ 31,000 miles (not a typo... it was a Florida fire truck in its past life)
Any help would be greatly appreciated!!

[cdnsarguy]

First do the vacuum test on my photo link..... find both parts. Usually a pedal dropping as you say could be the M/C....... try pumping the pedal fast twice. Does the pedal stay at a higher position...... Remember the vacuum pump will loose all/most vacuum after 3-4 pumps. Check for vacuum leaks....... especially under the juice tin on the right fender.

Does the proportioning valve light come on when the hard pull left happens.

[goosefoot33]

I'll have to try the vacuum testing this weekend if I have time to do that. No light comes on when it pulls to the left... there's not too many lights to illuminate in the cab. I don't even know if that would be in with the lights above the gauge cluster??
I took it back to the shop that flushed the brake fluid after I installed the master cylinder because they were a little aggressive on "adjusting" the brakes and my rear brakes were sticking. The drums got so hot you couldn't even touch them for a second.
They performed another brake fluid flush because I also complained that the fluid was dirty. Well they discovered I have a bad e-brake cable and that should be replaced. I'll be doing that myself this weekend hopefully.
When I took it out for a test drive, the pedal seemed to respond faster when I do a "panic" stop. They not only grabbed sooner, but they grabbed a little harder than they did before. Now it only takes pumping the pedal two times before they get the right amount of bite, instead of having to pump then 3- 4 times... I'm not too sure what this means...
One last thing to note is that the bleeder screw on the front left caliper is frozen, so to bleed the brakes all they did was remove the hose... should I roll the dice, buy a new caliper, do ANOTHER fluid flush and then see where I'm at??
I really appreciate the help gents!

[rmr]

Sometimes you can get a small pipe wrench on the bleeder and get it out,
the real small size, I'm thinking they are 6"??
But you will need to put a new bleeder in if the pipe wrench does manage to chew it out of there.

[cdnsarguy]

If you are pumping the brakes and they feel better after a few strokes then either the rear brakes are out off adjustment or the master cyl is fubar.

[Fordpowerstroke350]

How did they manage to bleed calipher by removing hose without getting air in the system. Best bet is to replace calipher and rebleed. If still had dirty fluid then flush was not complete. Would find me another shop

[jameslester2]

I have a similar problem, I just replaced the brake booster and the master cylinder, my brakes seem to be working better. I bleed the brakes and, the master cylinder has enough fluid in it, however the brake indicator light cycles on and off. I believe that the vacum pump is fine, i replaced that about a year and a half ago and if that go's bad the brakes would be hard, to my understanding? Im fairely sure that my indicator light does not have a short or anything, because prior to me having to replace my master cylinder and brake booster it started comming on and my brakes started acting up. When I brake hard the truck seems to pull towards the right, just trying to get some ideas on where i should go from here, is it most likely a brake line issue or a frozen calipar, thanks for any help

Oh yea its a 85 f250 6.9L

[Rick_Hipp]

Goose & James, do a vacuum test as Pete advised. Brake hoses to the calipers may need to be replaced as they deteriorate internally, causing the pulling to one side or the other (not letting fluid pass properly).
James, the light comes on when the emergency brake is applied, air in system, low vacuum, or the sensor switch is defective. Sensor is round thingy with boot & vacuum line on passenger fender. Rarely go out but I had to replace one. I've learned that rebuilt VPumps do not last anywhere near as long as Ford Factory pumps. I get mine on eBay.
Thanks to member Coolball

Rick

[goosefoot33]

Over the past week or so I've discovered a few things that might be contributing to my issues. I found out that the brake booster I installed ~3 years ago is for a truck UNDER 8500GVW, while mine is over 8500GVW. This might explain my need to enlarge the holes on the mounting flange of the master cylinder to make it flush to the booster.
I also managed to loosen the frozen bleeder screw on the front drivers side caliper that Firestone couldn't get loose. Fluid came out right away, no air, and the fluid was pretty clean. I bled a little out and then tightened it back up.
Lastly, I found out a cable inside one of the drums is broken, which is causing the e-brake to lock up on that side. Coincidentally (or not so much), it started locking up after I had the brakes serviced and cylinder changed out in the same drum at Firestone. Here are the pictures:

http://img.photobucket.com/albums/v4...CIMG1322-1.jpg
^^Passenger side cable, works fine

http://img.photobucket.com/albums/v4...m/CIMG1324.jpg
^^The other end of the cable, attached to the adjuster.

http://img.photobucket.com/albums/v4...m/CIMG1328.jpg
^^Broken cable on drivers side

http://img.photobucket.com/albums/v4...m/CIMG1331.jpg
^^No connection on adjuster

Needless to say, I probably will NOT be going back to Firestone any time soon...

[Excavator]

If you cant get that bleeder out, try this. IT WORKS

Loosen the hose banjo bolt on the caliper.
Now take off master cyl cover
tap on brake pedal once and let off.
Now just wait half hour and fill master cyl as required.
It will self bleed.
Repeat if you feel you have too, then just tighten uo banjo bolt
And now I see that you did get bleeder to come loose but remember my tip

[Tat-Tude Dually]

damn goose those brakes look like they have been under water all their life!


I myself had to replace my rear brakes on my dually this weekend because the rear wheel seal went out and man what a mess that was And I also had to replace vacuum pump as well this weekend