no brake lights.....now no brakes

[Biggles]

So I checked my lights.....I had no brake lights. I trouble shot the wiring and got the brake lights to come on by unplugging the brake light switch on the front of the air pack and jumping the plug. I assumed that meant I needed a new brake light switch. I ordered that. installed it today when I went to check my brake lights. not only do they still not work now I have no brakes. What have I done? did I allow an air bubble into my air pack when I swapped the switches out and now I need to bleed? The pedal just sinks to the floor and no lights or brakes.
Help!

 

[hoop]

My switch is not on the air pack.
It is on MC.
If it is on the front of the MC, that is fluid side. If on the side that is air side.

Edit
I am wrong.....It is on the air pack..I guess I have done enough thinking for one day.

 

[Biggles]

it's on the front of the air pack fluid side.....I think

 

[ranchand]

The switch should be on the air pack. Find someone with a power bleeder Much easier than yelling at your wife

 

[Biggles]

so if the switch is on the front of the air pack (the fluid side?) and I swapped it out I need to bleed the brakes? I was hoping I wouldn't have to bleed them but I do already have a power bleeder so I guess I've got a reason to use it now.

 

[ranchand]

Oh yes you must bleed them thoroughly

 

[whyme]

bleed the air pack and u will prob notice an immediate improvement but there will still be air in the system so yes... bleed away!

 

[Biggles]

That's what I was afraid of. Thanks!

 

[Biggles]

would air in the fluid side of the air pack cause the switch to not activate? I still don't have any brake lights. I assume I need pressure in there to cause the switch to close and turn on the lights right? Or do I STILL have something else wrong with my brake lights?

 

[RAYZER]

Air in the system,no pressure ,no brake lights !

 

[Jake0147]

Indeed, the switch is a pressure activated switch. It doesn't care if you want to stop, it only cares if the brake system was capable of building and maintaining an adequate pressure.

There are two styles of switches. The older style should have been upgraded, but it's out there. It is a fluid pressure switch. If you removed the switch and fluid came out of the hole, then it's an older switch and bleeding is necessary.
If it's the newer style switch, it's activated by the air assist pressure. There would have been no fluid leakage of any kind when changing this switch.

That said, no pedal is no pedal and the immediate concern is why. If the fluid leakage during the switch change is not conclusive (I can't see why it wouldn't be but you never know...), start with the basics.

First, you need a sealed and contained system.
Fluid level?
Look for visible leaks at any of the wheel ends?
Look for visible leaks along the frame?
Second, you need to fill it with a non-compressible liquid (brake fluid) which includes removing any pockets of air (compressible) trapped within that non-compressible fluid.
See the power bleeder suggestion above for sure. Otherwise, the standard brake bleeding routine applies, except that you would start with the airpack bleeder, and then begin with the farthest wheel from the master and working closer.

 

[Biggles]

Indeed, the switch is a pressure activated switch. It doesn't care if you want to stop, it only cares if the brake system was capable of building and maintaining an adequate pressure.

There are two styles of switches. The older style should have been upgraded, but it's out there. It is a fluid pressure switch. If you removed the switch and fluid came out of the hole, then it's an older switch and bleeding is necessary.
If it's the newer style switch, it's activated by the air assist pressure. There would have been no fluid leakage of any kind when changing this switch.

That said, no pedal is no pedal and the immediate concern is why. If the fluid leakage during the switch change is not conclusive (I can't see why it wouldn't be but you never know...), start with the basics.

First, you need a sealed and contained system.
Fluid level?
Look for visible leaks at any of the wheel ends?
Look for visible leaks along the frame?
Second, you need to fill it with a non-compressible liquid (brake fluid) which includes removing any pockets of air (compressible) trapped within that non-compressible fluid.
See the power bleeder suggestion above for sure. Otherwise, the standard brake bleeding routine applies, except that you would start with the airpack bleeder, and then begin with the farthest wheel from the master and working closer.

Ok, I do have the older style switch, I bleed the brakes using my power bleeder. it went well I did get air out of it especially at the air pack bleeder. Now my brake lights work but I still don't have brakes. I can pump the pedal up until it is rock hard I can hear air hissing I have the proper amount of brake fluid in it and no apparent leaks. If I hit the pedal after it's been sitting it still mushes to the floor, and no brakes. if I keep screwing with it the pedal gets harder and harder until I can't push it at all. still no brakes. Is this a problem with the air pack? Do I need ot add oil to it? is the air assist not assisting?

 

[redjordan]

did you ever get this resolved, I am at about the same point as you.

 

[Biggles]

no, I took apart the air pack and checked it out everything seemed ok, possibly the small double piston deal between the hydraulic and air side sticking intermittently. I put the truck back together re-bled the brakes and it worked for a bit then my pedal dropped all the way to the floor with no resistance. So now I'm thinking the piston in the master cylinder is stuck down, either that or my brake fluid got out somehow. there is no leaks so I'm thinking that it could have gotten into the air system. I haven't checked to see if I have fluid int he master cylinder still. basically I have determined that I didn't have them bleed well enough the first time and now I have one of tow problems either my piston int he master cylinder is stuck or I don't have any fluid in it. I'll post when I get a chance to figure that out.

 

[redjordan]

I bled the **** out of everything starting with the air pack, then the farthest corner. I have brakes now