It was a pulsing type of feel. It pulsed about 3 time in rapid succession both times. I felt it on the brake pedal. I just finished coming back from the store and tried to make it happen again but I got nothing. I hope this was specific enough. I'm racking my brain trying to make sense of this without over thinking it. I forgot to mention, niether the ABS light nor the check engine light are on.

 

That's what the ABS should feel like when it engages. Do you have ABS ... not just RWAL? If just RWAL, then it's something else. The RWAL feels like the brake pedal sinks a bit and some braking goes away.

 

I only have RWAL. I'm sure of that now. anything off the top of your head that it might be? I'm going to drive it around town for a couple of days to see under what conditions it happens, if it ever does again. I'll post back then.

 

Thinking ...

 

check your rear wheel seals or the adjustment of your rear brakes the oil on the pads can make them grab. my truck that I have locks up the rear brakes every once and a while, but my abs isnt working if yours is doing this it would engage your abs. I have not had time to look into what is causing mine to do this but past experiences has me thinking my seals are bad. just a thought

 

RWAL doesn't pulse ... it's just a preset pressure dump.

 

DANG IT!!! It happened again. The weird thing is that it's sporadic. I know a lot of jokes are to come after saying this, but it feels like my brake pedal is farting, but it doesn't effect my braking. Could it be the master cylinder? Oh also, I noticed that my pedal is starting to bottom out. however I still feel good pedal resistance. I hope I get chance this weekend to do the wheel cylinder mod. It'll give me a chance to check everything out. Thanks to everyone for posting threads. Hey, by the way, TMS Bill, I noticed you have a 1/2 ton like me. when you did the cylinder upgrade, did you use the GM 1 ton dually or just the regular GM 1 ton?

 

1 ton dually ... I always figure that, if it's worth doing, it's worth overdoing.

Just how low is your pedal?

 

so the brake pedal feels good. Don't get me wrong, it feels firm. but when I'm parked, I have the habit of seeing how far I can push the pedal in every once in a while. and this time when I did it, I felt the same firm pressure all the way threw until it couldn't go any more. but when I'm driving, it's still the same as always. it doesn't bottom out. still no visible leaks...

 

Does your Mater Cylinder support you Dually wheel cylinders? I'm getting ready to do that upgrade this weekend.