2nd Gen Non-Engine/Transmission Truck stops, but only when brake pedal goes all the way to the floor

[JStangeland]

I tried searching the archives but didn't really find anything related to my symptoms.

My 98 work truck will stop, but the pedal goes all the way to the floor and the braking only happens at the end of the travel. I looked under the hood and noticed the fluid was low and I topped it off, but it didn't solve the problem. I drove around and used the brakes but the fluid level hasn't dropped at all. The brake and ABS lights are lit up on the dash. How would I go about troubleshooting this?

--I don't know that this would be relevant, but I had to get pushed off a bridge yesterday due to a fuel leak, and I had to use the brakes without the engine running and this morning when I went to drive the truck I had the problem.

I appreciate any clues you guys might offer about where to start looking!

 

[B.G. Smith]

I'll start the rumble. Can you tell if all four wheels have brakes now? Get someone to depress the pedal and see if you have brake fluid pressure at a bleeder screw on a front and rear wheel. How low was the fluid when you added? My guess is that for some reason when you used the brakes without the engine running the proportioning valve shut the front brakes off and you only have rear wheel brakes now and they need adjusting. bg

 

[fest3er]

Like my '98, does your truck have rear wheel anti-lock (not 4 wheel)? This sounds very much like ABS engaged and never disengaged. On my '98, when ABS engages, I can hold the pedal to the floor and get only a small percentage of normal braking power, as though the rear brakes are completely eliminated and the front brakes are reduced 75%.

• Verify the speedo has no intermittent operation (works at some speeds, doesn't work at others).
• Verify that the ABS receives vehicle speed sensor (VSS) signal at all speeds.
• Verify that the rear proportioning valve mechanism is OK (but this may not be related to the problem).

 

[wcjp]

I'd start by inspecting the brake lines. Are they expanding/defective? On my 96', I replaced the defective passenger front brake line with braided stainless steel. This caused erratic braking. Had to replace the other lines too. Braided Stainless Steel has zero give.

 

[JR]

How low was your fluid? You could very well have introduced air into the system if the MC went empty. I would try bleeding just to eliminate the possibility before you really start tearing into anything.

 

[mwilson]

How low was your fluid? You could very well have introduced air into the system if the MC went empty. I would try bleeding just to eliminate the possibility before you really start tearing into anything.

X2...Start with the basics.

Mike.

 

[DMather]

Air.

Quick test. Pump the brake pedal a few times and note whether it goes down less each time. If it does you have air in a line.