Brake pedal maxed out

[dirtyfingernails]

I drove the duece to work today. On the way back home, I noticed that brake pedal was hard as a rock--no give at all! Even the brake lights were permanently engaged! I released the pressure from my air tanks and it's the same! What gives? Rubber hoses seem to be intact with no depressions. Thanks for any help that could be offered.
Steve

 

[Westech]

sounds like time to take it apart and see what stuck. I would get a rebuild kit and have at it.

 

[clinto]

break a bleeder screw open and make sure not to be in the path of the brake fluid

 

[sermis]

Mine did the same a while back after I got the truck. There was trash in the bottom of the master cylinder from the PO. Took it off and inspected. It looked to be NOS or rebuild. Clleaned it out and have not had problems with it.

 

[bottleworks]

If you open the trailer air line valve, does the pedal return to normal?

 

[dirtyfingernails]

Opened the trailer line--no air. Opened the bleeder valve on the airpack and fluid streamed out--I could hear the brakes releasing at the same time. I guess my air pack is toast. Are these difficult to rebuild. The one on there looks brand new.

 

[sermis]

When mine did the same thing I opend the air valved on the rear and it did not release. I was thinking the air pack also. Turned out to be the master. The trash in it cloged the holes so the piston would not allow the fluid to release.

 

[dirtyfingernails]

Sermis,
I think the master is okay because after bleeding the pedal is perfect--about 2 inches of depression before brake engagement. However, after charging the system with air, it pushes back again. I drove it after bleeding and it's working okay now. But, the pedal is sure near the top and TIGHT! Although it's this tight it is still currently releasing. How much pedal play is normal when the system is charged with air??

 

[BEASTMASTER]

mine did the same thing in the 4th of july parade , took the master cylinder apart cleaned it, and put it back together , been fine since.

 

[poppop]

I have had this same problem with a couple farm trucks. The return hole in the master cylinder was pluged. On another truck The master cylinder was replaced and had this problem. Something was a little different and I had to adjust the pedal rod. It was holding the cup in just a little and covering the return hole.

 

[m-35tom]

right pp, check the m/c pushrod adj. if cracking the bleeder on the pack releases the brakes, the fluid is not going back to the main m/c, the one on the pedal. all the pack does is push on the second m/c which is part of the pack. with no air the fluid from the main m/c pushes the piston in the second m/c so it has un boosted brakes. with air, the main m/c pushes a air regulator on the side of the pack that puts air to the pack air cylinder and that pushes the second m/c. the problem almost certainly revolves around the main m/c.

 

[JohnnyReb]

Are you bleeding it with someone pressing the pedal?
When you bled it and it improved then it sounded like an air in the lines problem. Before making adjustments or rebuilds, I would bleed the brakes the old fashioned way first: Get on the bleed valve and have a person press the pedal; before it goes to the floor, close the bleed valve then have the person on the brake release it....then repeat the procedure three or four times. MOST IMPORTANT is not to release the brake pedal before closing the valve. May require three people with one relaying the messages.....just a simple test before wenching.........

 

[JohnnyReb]

I kept an old jeep on the road for a long time using this procedure.

However, you still have air getting in the lines, so this won't fix the problem...just diagnose it...

 

[JohnnyReb]

Are you bleeding it with someone pressing the pedal?
When you bled it and it improved then it sounded like an air in the lines problem. Before making adjustments or rebuilds, I would bleed the brakes the old fashioned way first: Get on the bleed valve and have a person press the pedal; before it goes to the floor, close the bleed valve then have the person on the brake release it....then repeat the procedure three or four times. MOST IMPORTANT is not to release the brake pedal before closing the valve. May require three people with one relaying the messages.....just a simple test before wenching.........

Now that I re-read my post....should be wrenching......wenching is a whole different sport!!

 

[Recovry4x4]

Steve, knowing the problems you had with the brakes, I'd say someone got under there and cranked the pedal adjustment to get a better pedal just like they adjusted the shoes all the way out. That hole mentioned in a previous post is called a compensating port and if blocked, will do exactly what your brakes are doing. Check that and I bet you find your problem If that doesn't work start thinking about rebuilding the master cylinder. Call me if you need help.

 

[Rocco]

Mine did the same thing.
I opened up both bleeders on the front
and i heard the brake shoes release
and then it was fine but i have a feeling its going to happen again soon,
so im going to check out the MC.

 

[dirtyfingernails]

Popop, Kenny, Where is the return hole (compensating port) you speak of. Do I need to pull the master cylinder or is this an adjustment of the push rod? Thanks.
Steve

 

[Recovry4x4]

You may not be able to see the compensating port. Check to see if there is free play in the pedal. Do this from underneath. The push rod should not be resting against the piston at all. There is also supposed to be a spring holding it off, check for that as well.

 

[poppop]

The port is in the bottom of the MC close yo the end where the pushrod is. I don't think you will be able to see it. If you rebuild the MC you can see it through the bore. Run a wire through it to be sure it is open.

 

[aboonski]

Kenny!!! I am reading all of the posts in this area because I still have to fix my brake system that has similar if not identical problems. I'll probably start with cracking open the bleed valve on the air pack first to see if it releases the brakes then I'll go from there. By the way I did talk to Matt at Green Gem and he is working out a trade-in of the turbo with me. I am going to make a trip up to see him sometime next week. We were up in Jacksonville on Tuesdy to see my 22 year old son off for the AF but spent the whole day at the MEPS center waiting for the processing mess to finish up. My finace wanted to leave for home once the boy left for the airport so my plans to go up to visit Matt had to be postponed. Women run the show you know!