Brake Issue

[DocsTruck]

Well, I haven't had many problems with my truck but today I was moving it and the brake pedal went to the floor so i parked it and checked the fluid. The truck doesn't have power brakes by the way. I took the top off of the master cylinder and found the back reservoir to be low so I added some fluid and put the top back on the master cylinder and tightened it down. I then started her up and pumped the brakes and the pedal still went to the floor. I put the truck in drive to move her a little but the brakes seemed to be locked up now. So, what could cause this? Brake fluid is full, yet the pedal goes to the floor and the brakes seem to be locked up. Thanks for any direction in fixing this issue.

[PwrWgnDrvr]

Never seen this, but the m/c piston could be stuck at the end of the bore, locking the brakes.
Loosen the brake lines at the m/c and see if fluid bleeds out and the brakes release.

[DocsTruck]

Thanks I will try that. I won't be back to where the truck is until probably next weekend. I'm wondering if it could've gotten stuck when I had the pedal hard against the floor?

[dodgeboykim]

Thanks I will try that. I won't be back to where the truck is until probably next weekend. I'm wondering if it could've gotten stuck when I had the pedal hard against the floor?

In my experience, Once pedal goes to floor the master cylinder is usually hooped due to being pushed out of normal range. My guess you will be replacing it and also looking for where fluid leaked out or some other problem.

[DocsTruck]

Thanks, I've already been looking at videos on how to rebuild the master cylinder in case that is the issue. I know I don't want to replace it with some aftermarket Chinese junk, so, I'd rather rebuild the original one if possible.
I do need to look for the leak, but I haven't seen any fluid on the tires or under the hood, but yes, I do need to spend some time and get it figured out. Maybe this is my truck's way of telling me that I need to spend some quality time with her. Lol.

[PwrWgnDrvr]

Contact John Geidl and get your m/c lined with stainless. Search the forum for his name or id powerwagonjohn.

[DocsTruck]

Quick question.
Is there a sequence for our trucks when it comes to bleeding the brakes?
I'm gonna make a brake bleeder out of some plastic tubing and a drink bottle to bleed my brakes. An old mechanic at work told me my issue may be air in the line.

At the same time, I will look for the leak that has caused this issue in the first place.

[ozzie]

rule of thumb is start with the right rear wheel,, and then the left rear, and then right front, and finish with the left front.

[DocsTruck]

Thank you.

[PwrWgnDrvr]

aint no way air in the lines will lock up your brakes!

[DocsTruck]

Yeah, I thought that sounded strange, the guy I talked with was saying it was "vapor lock", which I thought was strange.
After I look at the master cylinder and search for the leak, I'm sure I will bleed the brakes anyway. I really should go ahead and change out the brake fluid because it looked pretty nasty.

[PwrWgnDrvr]

Have u ever changed the rubber flex lines at the ft wheels and rear axle? They deteriorate internally over time and will lock the brakes also. But that won't also cause the pedal to go to the floor.
The old guy using the term "vapor lock" in conjunction with the brake system pretty much eliminates him as a knowledgeable and credible source.

[DocsTruck]

I haven't checked out anything on the truck as of yet and have never checked the rubber lines that you have mentioned.
I agree, the guy I work with seems to know everything and everybody and is usually wrong about 99% of the time. I had never heard of vapor lock when talking about brakes, that's usually a fuel issue, so, yeah he's pretty much a maroon as Buggs Bunny would say.

[sambudo]

have you had any luck with your brakes?
I have a similar problem. except my pedal went to floor and I still have fluid in reservoir.

[sambudo]

have you had any luck with your brakes?
I have a similar problem. except my pedal went to floor and I still have fluid in reservoir.

[dodgeboykim]

have you had any luck with your brakes?
I have a similar problem. except my pedal went to floor and I still have fluid in reservoir.

Sounds to me like your master cylinder is worn out.

[DocsTruck]

I was finally able to get back to our lake place where I have the truck, it had been about a month or more since the brake issue occurred. The first thing I did was to push the brake pedal and found it wasnt going to the floor anymore and was building pressure. I cranked her up and was able to move the truck, brakes were no longer locked up. Go figure? The brakes were working okay and I had pressure but the brake pedal did feel a little spongy, so I think a rebuild of the master cylinder is in the near future. I have no idea as to why the brakes were working again by the way.