Just replaced everything for the front brakes except the the booster and vacuum lines. I don't think that it's the vacuum check valve. I did find some tiny leaks on the new lines corrected them and now it's worse, drive to store bleed brakes drive bleed and repeat sooooo tired of it and yep back on the bus for work. Damn it

Your right caliper is hanging up(stuck) either from a stuck piston from dirt rust etc . It could also be a brake pad is unable to move on the pins.

Could also be a kinked brake line allowing pressure when applied to force through but taking forever to release at all.

I have all metal to steel braided lines x3. I will check caliper piston, but I don't think so calipers are brand new. I didn't have an issue with the pins, how ever I have been crossing a lot of road construction could have gotten something in there. Truck was at an idle, stepped on the brake pedal and the engine was cutting out, booster?

the old vw's used to that, what happened was that the rubber brake hose would look fine on the outside, but be rotted and swollen up on the inside.

so foot pressure pushed fluid into the caliper, but the swollen up hose blocked the fluid from getting back out again, so the caliper stayed closed.

o.k., i just saw your post where you already replaced the rubber lines.

The piston seal is tapered. it's on the piston upside down.

Anything is possible, its brand new caliper (re-man), but would be my stupid luck. I will check out the anatomy of a brake caliper and see whats up.

Hi Wyoming9, I took your advice about the stuck piston, the only thing I did was take some brake clean to but with that said three things happened this week end : the weather got cooler, the piston got sprayed with cleaner and the truck was parked for 24 hours. Today I drove it every where and it didn't even try to lock up. The pedal built pressure at start up and remained the same the entire time. Instead of building pressure until the pedal was stopped above the gas pedal by about a half inch and would not budge until release pressure off of the hydraulic system. I will pull the caliper off and check the movement of the pads on the pins. You have always had solid advice, thank you

I will go over every inch of the lines and look for a kink Wyoming but all of my brake lines as far as I know are full metal to steel braided then directly to wheel or load bearing hub in the back. But I will pick that system apart. I suspect a blockage could be a possibility but I am trying to figure out how and where it got in and so on... This truck has definitely sent me to school without the books...lol I think it's a two year Toyota degree.

I had this problem. It was my pushrod length (on the booster) was adjusted too far out and applying light constant pressure to the master cylinder.

I just learned that I needed to do that, I have been racking my brain. I hope this is the case, much cheaper than the booster. But I am prepared to replace that too. I have never done brake work before had no idea what needed to be done just did it.

I have gotten faulty parts from the part stores several times. I did have a booster to apply the brakes just driving down the road. The higher the rpm the more it would apply the brakes.

When the brake locks up and hopefully you are at the house, raise the front end and see if it is still stuck. If so I would suspect the caliper, then the booster, then the master cylinder in that order if it was me.