My brakes are locking and I fishtail whenever it's wet outside.

Dear Car Talk

Dear Car Talk | Apr 01, 2001

Dear Tom and Ray:

I love my 2000 Ford F150 XL Short Bed Regular Cab pickup. My heart swells every time I look at it, but there is one problem that concerns me greatly. Every time the truck gets wet -- even slightly -- and I use the brakes, they tend to lock up and the truck skids or fishtails a bit. This can happen while driving through rain, first thing in the morning or even after washing the truck. These brakes are very sensitive to the slightest bit of moisture. The lockup happens for only a few seconds, but even in that short period of time, the loss of control is very disconcerting. If I touch the brakes a few times before I actually need them, the problem is averted. I've driven the truck about 8,000 miles so far, and I haven't asked the dealership about this yet. Do you guys have any idea what's causing this? -- Christopher

RAY: Yeah, it's your brakes.

TOM: Very helpful, Dick Tracy.

RAY: OK, it's your drum brakes, which come standard on the rear wheels of the base version of this truck. This is a funny phenomenon. Usually when drum brakes get wet, they get slippery and don't stop the car. But when drum brakes get just a little bit wet, they grab and lock up.

TOM: Why? We don't know, but this is a classic case of moist drum brakes. Your symptoms are textbook! The moisture in the air overnight can even be enough to cause this to happen.

RAY: But you also have antilock brakes (ABS) on the rear wheels of this truck (they're also standard on the base model). And ABS is supposed to sense wheel lockup as it happens and release and reapply the brakes rapidly to prevent skidding.

TOM: So there are several possibilities here. One is that your ABS system isn't doing squat. (That's the technical term for it.)

RAY: A second possibility is that the mechanical portion of your braking system is malfunctioning, preventing the ABS from releasing the drum brakes quickly enough. It might be a case of drums, contaminated with brake fluid, that need to be cleaned, or it might be that your brakes are adjusted too tightly.

TOM: But the third and most likely possibility is that, since you bought the cheapest possible version of this truck and you got only REAR ABS, the ABS is working fine, and this is as good as it gets.

RAY: That's why we advise against rear-only ABS. The way four-wheel ABS works is by comparing the speeds of all the wheels, and if one's going slower than the other three, the ABS assumes that wheel is locking up, and it corrects it. But if the ABS is only comparing the rear wheels to each other, and both rear wheels happen to lock up, the ABS thinks everything is fine, and you skid.

TOM: In any case, I'd definitely head over to your Ford dealer and ask a mechanic to check out your brake system. If he tells you that it's working as well as it possibly can (which is what I'm afraid he'll tell you), then ask him why Ford sold you a truck with this stupid, inadequate, rear-only ABS on it (and note that Ford has eliminated rear-only ABS for the 2001 model year).

RAY: And if he can't help you, putting some weight in the back of the truck might make a big difference. So try filling the bed with 500 pounds of manure ... or a mother-in-law or two. Good luck, Christopher.

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