ABS/ Brake light Question

[Doubeleive]

This is my son's truck. I told him last evening we'll need to get by Oreilly and have them plug into the OBDII and pull the codes.

I can't recall, but do the lights have to be on at that time? Or will the scan pull stored codes as well? I ask because ithe lights have been off since yesterday morning

I am going to give you 2nd opinion on that.
it depends.....
generally speaking the "brake" light will only come on under certain conditions. 1. the parking brake is set, or there is a fault with the sensor 2. the fluid level is low (or it thinks it is low i.e. bad fluid level sensor). 3 the proportioning valve is stuck. 4. a fault in the ecbm. the 4th one is where it gets tricky if it ls loose solder then each time the key is cycled it passes self testing until you hit a bump or whatever vibration causes it to loose contact inside and fail ABS (making both brake & abs illuminate) until it passes again. when that happens any stored code can or may disappear and will not come back until it trips again then disappears again when the key cycled so it would be wise to scan it while the brake light is on. ABS also self test's each time and will function basically the same there may not be a stored code.
If you get the "brake" light alone with no ABS light then it is one of the first three I mentioned above.
If you get a ABS light only and no "brake" light, then it's most likely a abs sensor fault or bad hub (causing erratic data) which is much easier to pin down.

***it's also possible if air got in the abs module it could be a problem as well, but you really need to get whatever codes it gives when the lights are illuminated in my opinion. I wrestled with this stuff before.

 

[Blk00ss]

I am going to give you 2nd opinion on that.
it depends.....
generally speaking the "brake" light will only come on under certain conditions. 1. the parking brake is set, or there is a fault with the sensor 2. the fluid level is low (or it thinks it is low i.e. bad fluid level sensor). 3 the proportioning valve is stuck. 4. a fault in the ecbm. the 4th one is where it gets tricky if it ls loose solder then each time the key is cycled it passes self testing until you hit a bump or whatever vibration causes it to loose contact inside and fail ABS (making both brake & abs illuminate) until it passes again. when that happens any stored code can or may disappear and will not come back until it trips again then disappears again when the key cycled so it would be wise to scan it while the brake light is on. ABS also self test's each time and will function basically the same there may not be a stored code.
If you get the "brake" light alone with no ABS light then it is one of the first three I mentioned above.
If you get a ABS light only and no "brake" light, then it's most likely a abs sensor fault or bad hub (causing erratic data) which is much easier to pin down.

***it's also possible if air got in the abs module it could be a problem as well, but you really need to get whatever codes it gives when the lights are illuminated in my opinion. I wrestled with this stuff before.

With regards to air in the system...We did get air in the system when I did pads. As mentioned, I had a mishap with the front left. My C clamp got stuck inside the piston (I got lazy and didn't use an old pad or piece of wood like I normally do). When I backed the c clamp off, it pulled the piston quite a ways out. Once I got the c clamp "unstuck", I was able to press the piston back in, but as I was doing so, it spit fluid out from around the rubber seal. I completed the job, but our pedal felt odd. So the next day I bled the front left only. It pushed a good amount of air out, and the pedal has felt great since, and the brakes perform better than they ever have. But... I'm wondering if I should go back and bleed all 4 corners. Keep in mind too, we have no leaks. I say this because I fully expected it to leak after seeing how far I pulled the piston out during that process. But now I'm wondering if maybe we didn't get all the air out and it took a couple of weeks for it to catch up with us, and now the system "senses" it. But I dod find it odd the light seems intermittent. He drove home yesterday and to school this morning...no light

 

[OR VietVet]

If pedal feels "great" and not too much travel, I would guess that is not it.

 

[treehan77]

$20 says it’s the ABS module. Resolder the connections and good to go. Ive done this 3x, on mine and two friends trucks.

 

[Blk00ss]

$20 says it’s the ABS module. Resolder the connections and good to go. Ive done this 3x, on mine and two friends trucks.

$20 says it’s the ABS module. Resolder the connections and good to go. Ive done this 3x, on mine and two friends trucks.

This is what I'm leaning towards. It hasn't come back on in 2 days. Its all over the place.

I can't solder worth a crap. If I were to buy a reman, does it require a re-flash?

And, it looks like a pain to remove (blindly). Is that the only way it comes out?

 

[treehan77]

This is what I'm leaning towards. It hasn't come back on in 2 days. Its all over the place.

I can't solder worth a crap. If I were to buy a reman, does it require a re-flash?

And, it looks like a pain to remove (blindly). Is that the only way it comes out?

It’s not too hard to remove- IF the screws aren’t corroded. I used a small right angle ratchet, it’s a small torx bit iirc. Very easy since mine is rust free.

 

[MassHoe04]

When you said: "Once I got the c clamp "unstuck", I was able to press the piston back in, but as I was doing so, it spit fluid out from around the rubber seal."

That concerns me... I don't think I could really trust that the piston would not leak by again.
It leaked when used the clamp to push the piston in. Possible it could squirt out when braking under much higher pressure?

It may not be leaking now, but I just don't get a warm and fuzzy on that one.

 

[OR VietVet]

No, never, which I thought was odd.

But...I've done hundreds of brake jobs. I've done a few on this specific vehicle. I simply changed pads front/ rear.

I did have at driver front a mishap with one of the pistons and it leaked some fluid out of the rubber surround as I was pressing it back in. But we have no leaks, no loss of fluid and after we bled them, the brakes work better than they ever have. And no lights directly after that mishap. These lights just started coming on this past weekend

Like @MassHoe04 noticed, I should have reacted to this before. There is a square cut seal around the outside of the piston that holds back fluid and there is the dust boot that keeps debris from entering in there to try and keep the outer surface of the piston clean from that debris. If you had brake fluid come out of that dust boot, you have a leaking square cut seal. That leak was caused by either cocking the piston in the housing or there is corrosion/crud built up on the outer surface of the piston and the fluid is leaking past that and the surface of the square cut seal. The pair of calipers should be replaced for safety sake. I used to rebuild them all day long but you can get quality reman calipers or new for a fair price. You may not have leaks now, but IMO and in @MassHoe04's opinion, you will have a leak eventually and that is a safety problem.

 

[MassHoe04]

Just a side note from my own recent experiences with my brakes...

I did rear pads and rotors. Simple enough. Did dozens over the years. Not rocket science... Anyway, a PO had run pads on the rig for so long the pads just wore down to the metal backing plates on the pads. You know, that familiar sound that sounds like grinding rocks on metal when you hit the brakes...

So, time for new rotors and pads in the back. I compress the pistons to make room for the fat new pads. They go in with the C-clamp. Not that easy, but they do go in. Great! Everything is in and done.

Go for test run to seat the pads on the new rotors. A few easy stops and all seemed good.

Then, my night and new brakes all just went to heck...

Driving on a straight-away at 40 mph. Come to a stop light and smell that nose-burning, stomach-flipping smell. Please, don't tell me that stink is me!

In my rear view mirror, I see clouds of white smoke billowing out from the wheel wells on both sides!

Both calipers locked up totally. Locked the new pads on so tight, the pads were smoking and the new rotors were glowing bright red in the night. Short distance to home, so I make a run for it. Rotor were so hot, they were making that clinking noise that you might hear from a hot stainless steel exhaust as it cools down.

Best I can figure was the caliper cylinders rusted or corroded behind the pistons because the pistons really just kept moving out, but never making it back to the inside starting point (as it would when new fat pads would force them to).

When I forced them in, I did not damage seals, but the pistons did get jammed up on the corrosion that built up behind them over the years.

I ended up having to replace calipers.

Pads were not damaged, so I scuffed them up and reinstalled.
Rotors did have a little pedal pulse, but I did not have funds for another set after dropping in new calipers on both sides.

P.S.: Finally ended up with new premium coated rotors to fix parking brake issue (posted a few days ago). got rid of the wobbly ones...

 

[OR VietVet]

@MassHoe04, the crud had built up on the surface of the caliper pistons and when they were collapsed to make room for the pads they damaged the square cut seal surface. The square cut seal is designed to twist in the lip bore, where it is mounted inside that caliper bore, and it will twist when you apply pressure and the piston moves and when you release the brake pedal, that twist is supposed to pull the piston back and allow for the pads to move back and have rotor surface clearance. Your piston crud and seal age combined to cause that problem.

Did the brake pedal fade and float to floor as well? thankfully you replaced fluid with the new calipers, it was over heated during that fiasco. When brake pads get that hot, you are lucky the friction material even held to the backing plate after all that heat. Did the rear brakes make noise after that? I would expect the overheated rotors to cause a noise.