1998 Dodge Grand Caravan even after entire brake system has been replaced why does brake pedal occasionally go down to the floor leaving auto with no brakes for a few seconds?

Answer 1

This sounds like one of four things:

1) Bad master cylinder (sticking valve).

2) Sticking ABS solenoid (or electrical short, but that's about as likely as tiny spacemen in the glovebox).

3) Contaminated brake fluid.

4) Brake fluid boiling.

If it's a bad master, you'll ned to replace it with a new unit. Rebuild master cylinders are risky.

If it's a sticking ABS solenoid, the problem should only appear very soon after either starting the engine, or an ABS stop. If it's faulty ABS operation due to an electrical short, you're going to need a professional to fix it. On the up side, you can easily pay for the repair and a new van with the money you get from selling the miniature spacemen in the glovebox on ebay.

If your brake fluid is contaminated, you can get it flushed at very little expense. If the fluid in the reservoir is black, it's likely contaminated with dye or rubber. Water contamination is more difficult to check for. Keep in mind that many shops will charge you for a flush but only change the fluid in the reservior. You can verify that the flush is completed properly by bleeding at each wheel and verifying that the fluid coming out is clear. If you have ABS, the ABS system must be separately flushed (with the pump running) which is usually not included with a generic brake fluid flush service.

If your brake fluid is boiling, the cause of brake fluid boiling should be investigated and corrected. Likely causes:

1) Driver error. Check for two-foot driving, driving with parking brake on, "riding" the brake, or "fast and furious"

2) Water in the brake fluid.

3) A brake caliper is dragging. This may only be detected when the brakes are hot (a few hard stops at high speed). Heat up you brakes, then jack up each wheel and try tu turn it by hand. For front wheel (or any wheel on AWD model) the transmission must be in neutral. For rear wheels the parking brake must be off.

4) Stuck parking brake. With the parking brake off (and trans in neutral for AWD models) the rear wheels should spin smoothly by hand when off the ground.

5) Broken drum brake return spring or seized drum brake wheel (slave) cylinder. If test shown in #4 (above) fails but no problem is found, check for missing/broken return spring or seized wheel cylinder.