Okay so I need some help with my Dad's 91 D350. In the past year we've replaced: (in no particular order) both front calipers, front soft lines, shoes all around and a new brake booster since the old one went out. The brakes work like they should except for the fact that you just barley press down on the brake pedal and the wheels lockup so I'm not sure whats causing it. Any help/advise is greatly appreciated and I'll do my best to get you any additional info you might want.

Okay so I need some help with my Dad's 91 D350. In the past year we've replaced: (in no particular order) both front calipers, front soft lines, shoes all around and a new brake booster since the old one went out. The brakes work like they should except for the fact that you just barley press down on the brake pedal and the wheels lockup so I'm not sure whats causing it. Any help/advise is greatly appreciated and I'll do my best to get you any additional info you might want.

Did you replace/resurface the rotors and drums when replacing the brake pads/shoes? Also need to check and see if there is any type of adjustment on the actuator rod coming out of the booster to activate the master cylinder, it could be adjusted to close and applying to much pressure to fast.

We replaced the front rotors and the drums are good. As far as I remember there was no way to adjust the actuator rod. Another thing I forgot to mention is that the pedal has very little resistance to it.

We replaced the front rotors and the drums are good. As far as I remember there was no way to adjust the actuator rod. Another thing I forgot to mention is that the pedal has very little resistance to it.

Which brakes are locking up? Front or rear or both? Do those older dodges have the hydro boost or is it a vacuum booster?

Both front and rear lockup and its got the vacuum booster.

Is the Rear Wheel ABS system functional?

Both front and rear lockup and its got the vacuum booster.

Did you change the vacuum line or anything in the vacuum system. It sounds like the booster is doing a lot more than it should be. I'm not sure exactly how the system is setup but it sounds like there should be some kind of valving to proportion the vacuum. It sounds like you are getting more assist than you should be under light brake application. Does the brake pedal return still feel like it used to before you replaced the booster? How far does the pedal travel before the brakes lock up?

I don't even really know if the ABS is working or not but judging by the skidmarks I left in the grass I would have to guess no. Didn't change any vacuum lines or anything. There is a vacuum check valve on the booster, it came brand new on the booster, but I guess it could be bad. the brake pedal retuning seems to be normal as far as I can tell. You only have to push the pedal down maybe 1-3 inches before the brakes lockup.I can't really do anything to the truck now for a bit because my uncle took it on a trip out of state yesterday and the left lower ball joint gave out on the highway so I have to get that fixed before the truck can move again, when it happened the truck went across all 3 lanes but stopped just before it hit the median. Luckily there was no one else around them when it happened so nobody got hurt.