Got a phone call today from a crying girlfriend.
Brakes failed in my truck and she ended up rear ending an F-250.
Luckily no damage was done to the ford and it just bent my brush guard mounts.

It feels like I have no power brakes. When you press the pedal down, it only goes down a little, as if the engine wasn't on. It was very low on brake fluid, so I filled it up, bled the brakes, and it hasn't changed. The pedal almost feels normal afterwards, but it still doesn't want to stop. It'll stop when I put all my weight on the pedal, but if anyone were to pull out in front of me it wouldn't be pretty.

Any ideas?

 

Sounds like the vacuum booster may have failed. To check the booster shut off the engine. Depress the brake pedal a few times to evacuate the booster. Apply a steady pressure to the pedal and start the engine. The pedal should fall slightly.

 

Tried it, the pedal doesn't fall.
Also, with the engine running, it sounds like an air leak when I press down on the pedal.

Where is the vacume booster located?

 

The big canister right behind the master cylinder. You mentioned hearing an air leak. You may be fortunate enough to just have a leaking check valve on the booster. It's a 90 degree plastic valve on the face of the booster (side closest to the engine) with a vacuum hose coming off of it.

Forgot to mention, sorry to hear about the accident, but apparently GF's alright, huh?

 

If the plastic check valve isn't leaking, then the diaphragm in the booster probably is and that will be much more expensive and time-consuming.

 

Would be wise to check the lines also, especially around the fuel tank.
The line is especially subject to corrosion there, and slow leaks can develop as the line corrodes, that will eat up brake fluid, but often not leave a visible puddle or even a drip, as it has to trickle down the inside of the frame rail.
As theres no way to visibly inspect that section without dropping the tank, you gotta reach up there and feel for fluid.
That happened to me a few months back, and I caught it just before it ruptured completely.

 

 

I checked all the lines, checked the check valve, nothing seems abnormal. I checked up near the fuel tank, nothing but dirt.
When I press down on the brake pedal, as I said, there is an air leak coming from the firewall. It is only able to be heard from inside the truck, under the hood my cold air intake overpowers it. I checked the vacume line running from the TB to the check valve, I can plug the line and the engine dies, so no leak there.

I'm guessing it's something inside the master cylinder. I'll probably end up pulling it and going to my local salvage yard.

Do all 94-01 Ram 1500's have the same master, or is it just 98-01?

 

That's the diaphragm in the booster you hear leaking. I would recommend reusing your current master cylinder if you replace the booster with one from a salvage yard. Are you sure you want to go that route with a safety related item?

An online search of AutoZone, O'Reilly, etc will tell you if the part numbers are different.

 

if it was shot, the pedal would go to the floor i believe. and yes this sounds like the brake booster not the master cylinder. i replaced the line that goes from intake to booster because with my blown plenum it clogged it up with sludge, there was barly any air trvel able to get through the hose....this may be something to tke into consideration...

luckily there wasnt much damage...