I need to change the brake pads on my 00 Supercab and need to know whether I should change/purge the old brake fluid or leave it alone.

My truck has 110,000 miles on it and this is only the 2nd brake service.

Thanks,

 

WHen you change your pads, you should not need to do anything with your brake fluid other than making sure the reservoir does not overflow when pushing the caliper piston in so the new pads fit. Make sure the brake reservoir cap is open when you push the caliper piston in.

 

It has been suggested to change out the fluid as a regular maintanence procedure. Many sight dirt and moisture as the reason. There are lots of thresds here for methods some have used to do this. (gravity bleed, pressure bleed, ETC) I have had several high milage trucks but never did the fluid change. Of course, these trucks were in high milage service with the average yearly milage in the 50K range.

 

Like jumpingjack said, you shouldn't need to even bleed the brakes, much less change the fluid altogether. But I'm all about the preventative maintenance. For something that costs under $10 and should take less than an hour to do it yourself, changing the fluid every 30K or so (whenever you change the front pads) is cheap insurance. All you need is paper towels, a closed-end wrench, a 2' length of fuel line, the new fluid, and maybe a baster or syringe to get the bulk of the old fluid out before you start. Oh, yeah, and another person to pump the brake pedal and watch the fluid level really helps.

Remember, the brakes are the absolute most important system on your truck. Just something to think about. If you need more detailed directions, search this forum.

 

If you doubt your ability to do this, then have a qualified mechanic do it. If you get air in the ABS pump, you will need to bleed that out as well - and that can be tricky. Also, it makes no sense to change the fluid on a front brake pad change and not bleed out the rear lines too. Similar to the ABS pump, the proportioning valve (for the rear brakes) can also be a be-otch to bleed if it gets air in it.

If you do it yourself, make sure you have the reservoir filled with fresh fluid at all times...

 

I strongly recommend you flush out your brake system. Your brakes are probably the most important system in your vehicle.

Brake fluid is hydroscopic, it absorbs water. Old brake fluid must be flushed out or water absorbed by the fluid eventually causes internal rust on the disk calipers and pistons.

Changing old brake fluid helps high temperature operation because fresh (dry) brake fluid has a higher boiling point than older (wet) brake fluid. If brake fluid boils, compressible gas bubbles form, resulting in a spongy brake pedal.

Brake fluid in a brand new vehicle will boil at about 400°F for DOT 3 brake fluid, and about 446° for DOT 4 brake fluid. This is fluid with 0% water in it. In a one year-old vehicle, the fluid has about 2% water in it. This can reduce the boiling temperature of the brake fluid to about 340°F. Once the system gets to a level of about 3 1/2%, which happens after about 2 1/2 years, the fluid will boil at a temperature of about 280°F. This is below the normal operating temperature for brake fluid.

Heat is a killer to a brake system. Fresh brake fluid (especially DOT4) keeps the system in top shape.

 

Silver2000:

Very informative. I didn't know old brake fluid degrades that fast. I will pump out the old and add new Dot 4. Hopefully after 3 or 4 cycles, I will have close to new fluid in the system.

Thanks,

 

I use a vacume pump to bleed my brakes and it works great. it takes no time at all. Ford says to flush the brake fliud every 2 years.

 

The local brake guru says replace the fluid every 4 years for the reasons previously stated.

He also warned of not reseating the piston into the caliper without cracking the bleeder. "The tolerances on the ABS unit are extremely tight." He is a distributor for most major brands of ABS components.

Use a hose on the bleeder, if you are not changing fluid, to prevent air from entering the system.