Another ABS and parking brake light problem

[Codyt123]

Hey guys, I am new to the forum but have been reading the threads for quite a while now. So I have a '94 7.3 turbo IDI with a sidewinder kit on it. I have tried everything I can think of or have read on this forum trying to get my ABS and parking brake light to stop coming on. I have replaced my front calipers and pads, rear brake shoes, cylinders, turned my drums, brake booster and master cylinder, vacuum pump put out good vacuum, checked my rear RABS sensor, bleed brakes and RABS unit under the cab and yet, these lights still come on after a short drive. Hitting the brake pedal seams to set the lights off and my pedal gets stiff and the truck hard to stop. My flashcode read code 16 which didn't tell me much of anything other than the problem shouldn't occur.. Anybody have any suggestions?

 

[Clb]

Fwiw
To help the search database...
My 93 will fire it once in a while then it goes out, aint found the issue yet, all conections good, -50k, no rust, me thinks bad dash crap...

 

[Codyt123]

Fwiw
To help the search database...
My 93 will fire it once in a while then it goes out, aint found the issue yet, all conections good, -50k, no rust, me thinks bad dash crap...

Yeah, the only thing I can think to try is reading the flash code once the truck is running and the fault has happened. Since the lights reset once I turn the key off and don't come back on until down the road when using the brakes, is it possible that the system check is missing the problem because it has been reset resulting in flash code 16?

 

[Thewespaul]

Check it with the problem active, whatever it is its not storing a code. With the brakes getting stiff I would say you are losing brake boost, a vacuum pump, line or brake booster issue.

 

[Codyt123]

Check it with the problem active, whatever it is its not storing a code. With the brakes getting stiff I would say you are losing brake boost, a vacuum pump, line or brake booster issue.

Ill try reading it with the code active tonight after work. I Just replaced the brake booster and master cylinder thinking that would help but no luck, vacuum pump held a consistent 25in. The only time vacuum dropped pretty low is after really fast braking but it built right back up when I stopped tapping the pedal. The only thing that I did notice was that my vacuum slowly bleeds off once I turn the truck off.

 

[Thewespaul]

If it bleeds off you have a leak.

 

[fordbuilt]

It sounds to me like your problem with the brake light is going to be air in the system. Your f/r bias switch is detecting more fluid movement in either the front or rear. About the only way to get all the air out of that system is going to be to pressure bleed it or open the bleeder on the antilock brake system. I believe that unit uses a tone ring on the back rear axle inside the differential. That would indicate you only have rear anti-lock brakes. I’m assuming you changed the sensor on the top of the differential going into the housing to pick up the tone ring. If not, I would start there after you have removed all the air from the system. If air is inside the antilock brake system, it may throw both of these lights on. Good luck hope this helps.