Tight Brakes with History

[DeuceIsLoose]

Hi Gents,

I've been researching the brake issue threads and can't figure this out so I thought I'd ask for input. I may or may not have a problem.

Here's the history:
Buckner Transport picked up my truck from Kennesaw GA about 4 weeks ago (they did an awesome job). After about 70 miles the brakes totally locked up on them. They let them cool down and then found a Semi service station and backed off the slackers and put some air lube in the system. After that they worked fine all 550 miles here. When I got the truck, I'd say the brakes were medium tightness and the pedal went about half-way down.

Current situation:
I bought another truck here in Louisiana and checked it out before I recover it tomorrow. It needed it's brakes bled. So I took the MC cap off the one I had here at home (from Kennesaw) and fit the pressure bleeder fittings on it so I could quickly switch out the caps and bleed the MC on the one I'm about to recover. I put some saron wrap over the MC to keep junk out of it and let it sit overnight and most of a day without a cap--only wrap on it.

When I got back home, I put the cap back on the one here (from Kennesaw) and took it out for a test drive for other issues. Now the brakes are very tight and the pedal maybe only goes down 85% of the way. It's almost like it bled itself overnight with the cap off. I've got a 400 mile drive in front of me to the farm and I'm concerned she might repeat history and lock up on me again. I've been on two other drives with her for about 15 miles and no problems yet, but I thought I'd ask for some input.

Any thoughts?

Thanks guys, I've put a couple threads up here lately and all the advice has been lifesaving.

Also, there's a pic, because everyone loves pics.

Donnie

 

[jwaller]

sticky air pack

 

[gimpyrobb]

I agree, sounds like an airpack issue.

 

[wsucougarx]

x3 airpack issues

 

[jimm1009]

venting issue

Also remember that the vent on the master cylinder needs to be free flowing air in both directions.
You can't install the vent for an axle or transmission in the master cylinder cap and have it work properly because the vent is supposed to be one-way valve (for the gearboxes and axles).
I purchased an extra one for my master cylinder while I was replacing all of them on my truck. I took the cap off, removed the rubber seal and spring, and reinstalled the cap. This allows the air to flow in both directions as required while the fluid level fluctuates as the pedal & plunger moved.
Jim

 

[DeuceIsLoose]

How do airpacks go bad? What exactly in them fails? Can you rebuild them or is it a replace issue?

Thanks--I'm trying to learn.

 

[jwaller]

ebay has rebuild kits everyday. very easy to do.

 

[WillWagner]

Could just need a lube. There is a 1/4 NPT plug in the rear of the air pak. Drain the air, remove the plug and give it a teaspoon on Marvel Mystery Oil and then give it a try.

 

[DeuceIsLoose]

Thanks Will and Jwaller. I'll give that a try.

Donnie

 

[OldGoat]

Could just need a lube. There is a 1/4 NPT plug in the rear of the air pak. Drain the air, remove the plug and give it a teaspoon on Marvel Mystery Oil and then give it a try.

I would try that first before the air pack.