Brakes too sensitive when wet

Hi folks,

This morning I was driving in very heavy rain (and equally heavy traffic), first gear for almost one and a half hour, and every time I hit the brakes, the truck was coming to an immediate stop, much sooner than expected and with much more authority than usual.

Mind you, this is not the first time I noticed this, it is as if my brakes get really stronger when wet. Sometimes, even when I start in the morning (and I assume there is some condensation on the brakes), they seem to react much stronger than anticipated.

I would typically expect the opposite, since water usually means longer braking distances etc. But this was extreme, I mean just touching the middle pedal resulted in an abrupt stop. On one occasion, I even skidded while doing maybe 1 mph!!!

Anyone has any idea what's going on here?

Needless to say, all help will be greatly appreciated.

Rgds

I had a similar problem with my rear brakes locking up. They were spent, and my e-brake cable was sticking.

Mine do the same thing everytime it rains or after I was my jeep.

This is a very common problem, and theories abound on why it happens. Other users have reported improvement when they replaced linings, drums, springs or wheel cylinders. Backing plate wear has also been implicated. I have had it occur right after replacing the linings and springs, though. One thing that seems to contribute is if the brakes are not adjusted well. I know that this seems opposite to what you would expect, but it seems that when the brakes are not adjusted tight, the leading edge of one of the shoes will grab. In my experience it is always the left wheel that locks up. The self-adjusters on these brakes are not very well designed, and often fail or work poorly. I would start by opening the brakes up and looking for faults, particularly a broken or rusted-out self-adjuster cable, but assuming you find nothing visible, try manually adjusting them and see if there is any improvement.

I agree with Matthew. I also have suspected -- but I have not confirmed -- that the problem may be worse with organic linings, which swell when they absorb moisture. If my rear brakes will cooperate by wearing down a bit more, I plan to install semi-metallic or carbon ceramic shoes the next time and I hope that will make a difference.

Gents,

I appreciate the various ideas. What I didn't mention, is that:

1. Truck is very old (1984), but shoes and front pads were replaced about a year ago, last we checked they had plenty of life. The e-brake cables are also new.
2. About two weeks ago, I had my mechanic adjust my rear brakes, because sometimes when I brake and then let the truck roll, I hear a "thumb-thumb-thumb" noise.
3. OI think Matthew is right, I believe it was the left wheel which was blocked every time I touched the pedal.

I called my mechanic and I'll have him have a look at the brakes first thing tomorrow morning, let's see what he finds. I'll keep you all posted.

Rgds

As I read this post I was thinking "I wonder if organic pads swell (soften) with excessive moisture". Further into the thread Eagle mentioned the same thing. I don't like the organic pads. My old Grand Marquis used to grumble every now and then after replacing rotors and pads and it used to drive me crazy cuz I just had to check for metal to metal contact. Every time I checked I found plenty of meat left on the pad. I changed over to semi-metallic pads and never had the problem again.

Each make and pad manufacturer is probably different but that was my experience with them.

I just put loaded calipers on my Toyota Corolla, work fine but I don't like the sounds coming from them. I'm guessing that they are organic...not sure if you can even specify what type you want in loaded calipers???

My guess is the rears might be more of an "out of adjustment" situation allowing the shoes to cock and lock.

Good luck,
Jay in MA

Jay Welch said:

My guess is the rears might be more of an "out of adjustment" situation allowing the shoes to cock and lock.
Jay in MA

Click to expand...

Hey Jay,

I didn't know that the brake shoes could be cocked and locked. A 1911 yes, but the brake shoes???

LoL

Thanks for the tip, appreciated. The problem is, we do not have as many options as you have in US on spare parts, so we have to live with what we can get.

Rgds