Deuce brakes LOCKED UP

I was getting my deuce ready today for the trip tomorrow up to MD for the Steelsoldiers breakfast. Maddawg308 was going to be at my house at 7am & I wanted to make sure everything was good to go today, so I could hop in & go tomorrow.

WELL.....

I worked on it doing misc things (checking lights, airing up tires, checking fluids), then I drove around my front field. When I was about to leave to go get diesel, I had to turn around (3 point turn) and when I stepped on the brake it felt like I slammed on them. The truck stopped instantly & the brake petal was all the way up & would not go down. I got out, looked underneath, got back in & tried to brake. This time it went down 1/4 inch. The truck would not move. I let it sit 5 minutes & got in & backed into its parking spot.....touched the brakes, they locked up & the petal is all the way up again.

Needless to say, my plans tomorrow are now shot. No breakfast for me. I was looking forward to meeting the Maryland SS members too.....I guess that will have to wait until the next meet now.

Is my master cylinder screwed up?

If not, what else?

Thanks!

Sounds like air pac..open the emergency service and supply on the back of the truck if the pedal isn't rock hard and the truck moves that is your problem..! Happened to me a couple of times . And you can move the truck and stop it. Just will have manual brakes so drive easy testing.

My M543A2 did it once and i drove it 20 miles with the air bleeding off on the service and emergency suppply.

didn't we just cover this exact scenario with someone from florida ???? public opinion thinks it's the MC

While the air pack could cause this, and I would try draining the air first,....


My truck locked the brakes once. It too had a pedal with no free play at all. My problem was a loose jamb nut on the master cylinder push rod that had allowed the push rod to lengthen over time. In effect, the brakes were never fully releasing.

If dumping the air doesn't help, take a look at the push rod and be sure it has 1/2" free play. (at the pedal)

I thought someone else had this same problem and was advised to check the airpack, something about giving it some lubrication .

There is a ton of info regarding brakes locking up. Here is my problem and solution. I also have had the brakes lock up. It took a couple of pumps but the pedal was all the way up and rock hard...brakes locked up.
I bled a back wheel cylinder and fluid shot out and the brakes let go.
Long story short, I found the small return hole in the M.C. was clogged and wouldn't let the fluid return to the resevoir. After replacing the M.C. problem solved...I even saved the old M.C. by cleaning out the return hole.
My airpack was fine.

BEASTMASTER said:

didn't we just cover this exact scenario with someone from florida ???? public opinion thinks it's the MC

Click to expand...

Either OR?..?

And yes it was covered.

I have had a problem with the pedal pushing back. I hit the brake and the pedal turns to stone. Anyone had this happen before?

I have just started experiencing some brake issues when my truck is loaded and am trying to stop (it is also very cold outside.... 25 to -15 F).
As I am downshifting and preparing to stop, I step on the brake and it feels normal.
I step on the brake again and it gets a little harder (I'm assuming its the air assist helping to put more pressure on the brakes).
by the third or fourth time I step on the brake it has only an inch or so of play and very little stopping power that I can sense..... kinda the opposite of the brakes locking up you guys are talking about, but I figure connected somehow...