Weird brake issues

[MattHarrell]

Occasionally, after it's rained outside, the brakes on the truck are overly responsive. I can't tell whether it's the front disks or rear drums. What usually happens is that the first couple of times I use them, even lightly, they react as if I've slammed on the brakes. It rained yesterday and this morning as I was driving through the neighborhood I hit them lightly a couple of times and heard one of the wheels lock up entirely. I think it was one wheel only. After doing it twice they then started to behave normally.

So, can anyone tell me what's going on? They behave fine most of the time and recover quickly after doing this. The RABS light is not coming on at all. The slide pins on the front brakes were lubricated relatively recently. And it doesn't seem to happen while it's raining - only when it's been sitting overnight after raining.

 

[Howard]

My guess would be rear wants a service. Possibly sticking shoe after parking brake use. Give them a treat and clean them up.

 

[MattHarrell]

Well I do use the parking brake almost all the time. I think I used it last night.

Would it make sense that it would only happen when water was on there? I'll pull apart the drums and see if I can see anything

 

[Howard]

Possible slight corrosion. Wet of damp weather may cause the shoe to stick to the drum. I've had similar with other cars.

 

[DeRocha]

My vote is on surface rust. Your rotors are bare steel and will flash rust when exposed to any moisture. This rust is normal and removed the first few times you apply the breaks.