Just got a '92 W250 from my late Uncle. The brakes aren't exactly good (what's new, right?). The pedal has a lot of travel but eventually firms up at the bottom of the stroke. When you first go to hit, the brakes, as soon as you touch the pedal the pedal almost drops by itself - it's really weird feeling.

When you push the pedal down, the Brake and ABS lights come on but if you tap the brake pedal the lights go out until the next time that you hit the brakes.

Is this a bad dump valve?

 

It could be a bad dump valve. It could also be the rear brakes way of adjustment from the self adjusters not working.

 

Before you go spending tons of time, money and effort ripping out, replacing or retrofitting anything, get the truck up on stands, adjust the rear brakes to where they're close as can be to the drums without scraping, then properly bleed the brakes. The rear cylinders on these trucks are notorious for seeping air, especially when the shoes are out of adjustment. Make sure the reservoir stays full during the bleeding process.

Every time I've experienced brake or master cyl issues, it's always come back to the rear wheel cylinders sucking air into the system

 

My RWAL was a crash looking for a place to happen from the time I bought the truck(1996)

 

All good suggestions.

Make sure the brakes are in good mechanical condition- no leaks. Nobody almost nobody bleeds the rear brakes properly (RWAL ). Do it right and your problem will vanish.
The big upgrade is all the 350 stuff will fit. Change to Chevy 1 ton brake cylinders, and the 12X3 inch dodge 350 shoes and it will be much better stopping. They made a poor choice and used some really small rear cylinders on the D/W 250's.

 

The one wheel was way out of adjustment. I adjusted it and bled the brakes (including the rwal valve) and it all works perfect.

 

Good deal!

 

 

 

 

HAHAHAHA!!! I love the 3 Stooges!! Good call TMan!

 

Add me to that list.

 

I have a confession...

I've been watching and enjoying the 3 stooges for over 45 years.


I'm so ashamed...

 

There's no shame in Stooges T-man!!

 

I'm like a chimp in a zoo exhibit. Throw a banana in front of him and my and they smile. Turn on the stooges, and I imitate the chimp.


Eh, I don't throw my own poop, or drink my own wizz, but I think you get the idea...