Brakes pull and fade when wet?

It's getting scary to drive when wet. My brakes work very good when the roads are dry. When it is raining and under heavy braking, the brakes pull, usually to the left, and fade to the point when I lose braking power and can no longer lock them up if I try. I upraded to a ZJ booster and master cylinder about 2 years ago. Brake Fluid, Calipers, pads, shoes, drums, wheel cylinders, hard lines, and soft lines have all been replaced in the last year or two. I just vacuum bled them twice and feel no difference. HELP!

92psychoxj said:

It's getting scary to drive when wet. My brakes work very good when the roads are dry. When it is raining and under heavy braking, the brakes pull, usually to the left, and fade to the point when I lose braking power and can no longer lock them up if I try. I upraded to a ZJ booster and master cylinder about 2 years ago. Brake Fluid, Calipers, pads, shoes, drums, wheel cylinders, hard lines, and soft lines have all been replaced in the last year or two. I just vacuum bled them twice and feel no difference. HELP!

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Are you running semi-metalic pads? If so they don't have the same braking characteristics as OEM pads, but last a lot longer. I'd replace the pads with OEM (NAPA) and file the friction surfaces (with a fine tooth flat file) of the calipers to knuckle and coat them with a high temp synthetic grease made for disc brakes. One of your calipers may not be releasing. I've got more than one bad rebuilt calipers.

To test for a dragging caliper I drive around the block and brake hard several times then drag the brakes to heat them up, then jack up both front wheels and turn them by hand. The amount it takes to turn them should be about the same. If one is more difficult to turn then you probably have a bad caliper or bad flexible brake line that swells and acts like you're braking. I see that you replaced yours but getting defective parts isn't unusual. Stainless steel braided lines will prevent the lines from losing their firmness.

Wet brakes lose a lot of the stopping power. When going through water or a car wash I always drag the brakes for a short while to heat them up and evaporate the water.

I'd also pull the drums and check to see if you have a leaking wheel cylinder(s) and adjust the shoes and parking brake. If your rear brakes are good you should be able to stop the vehicle just using the parking brake, can you?

I just did a complete rear brake job and increased my stopping power by at least 25%, even though there was plenty of shoe material left before I did it. The parking brake's ability to stop the vehicle and/or hold it while in gear at idle is a good indicator of the condition of the rear brakes.

The pads are semi-metallic. The are Duralast Gold (not the Cmax ones), from Auto Zone.

I looked at the Napa OEM pads online and all I saw was semi-metallic. I thought the original pads from the factory were semi-metallic?

92psychoxj said:

I looked at the Napa OEM pads online and all I saw was semi-metallic. I thought the original pads from the factory were semi-metallic?

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You may be right. When I replaced mine I went to O'Reillys and had them pull their super duper shoes ($40) and their brand ($20) and had them set both side by side on the counter. Their brand didn't have the metal flakes in the shoes material or the pin pressed in the shoes, it came loose vs the expensive ones which had the pin already pressed in.

If everything is set up right the semi-metalic ones should work fine and last longer, but I went with the less expensive ones because rear shoes tend to last forever.