I've had brakes go out because of water in the fluid not fun...even if that never happened I change every fluid before some would say it "needs" to be. this avoids supplementary issues from just running fluid that is tired/ has contaminants present from wear.

 

Do you need a scan tool to bleed/flush the brakes? I'm not familiar with bleeding the ABS system.

 

You only need a scan tool to bleed the brakes if the HCU has been replaced. Then you follow the ABS bleed procedure, otherwise it is the simple 4 corner brake bleed procedure.

 

That is correct,👍🏁

 

The entire brake fluid thing has gotten crazy in the USA.

Going back a few decades, during on-going discussions within SAE we discussed the issue but also noted that many did not follow the procedure that was laid out in the owner's manuals, and at times people put petroleum-based products into the master cylinder to keep it up. Also, there were discussions about how to warn owners that the brake pads were wearing out. The initial focus was using the mechanical "squealers" that attached to the pads, but that was ineffective. Also during the '90s there were instances of pickup trucks losing their brakes due to fluid boil. It happened on other vehicles too, but the disc/drum pickup trucks with their front bias were really bad.

At the end of the day, the SAE committees came up with a compromise, and like all compromises, everyone left the table unhappy.

Because of the lack of maintenance, to address the brake fluid boil the adaptation of phenolic pistons to insulate the fluid from the brake pads was universally adopted across all weight classes and vehicle manufacturers. Our company came up with an insulating layer that went between the friction material and steelback. That was incorporated into the early '99-04 brake pads, and initially, even the front pads had a stainless steel heat shield that was added by the caliper manufacturer.

There also were rubber compound changes to the brake hoses and M/C diaphragm to make them more resistant to air transfer. And there were additive packages to improve the life of brake fluid.

To address the pad wear-out warning, a float sensor was incorporated in all master cylinders. That proves to be a very ineffective solution as you can have individual foundation brakes wear out pads due to movement failures or in the aftermarket a change in the wear balance due to friction material formulation changes that let the front or rear brakes wear out first. The volume change in the master is supposed to account for all pads in a combined manner. It doesn't work well when you have one foundation brake on a corner go steelback to the rotor as many of us have. No wear-out warning light.

So the check-off list rids us of needing to do the periodic maintenance of brake fluid. They didn't follow this in Europe, European vehicles still have the schedule in the owner's manual, along with the need for DOT 4 in most cases. In about 3-4 years DOT 3 and 4 end up at the same boiling point.

Or does it. It certainly took the obligation out of the manufacturer's hands and allowed everyone to improve their JD Powers score for maintenance, which actually was the first blood.

Brake fluid turns dark due to water and copper absorbtion. Where does the copper come from? The brazing of the tubes from the flat stock into a tube. It's better at this then it was, but by about 6 years it's where you don't really want it, the additives for anti-corrosion have worn out depending on temp exposure. But the SAE guess was that brakes wore out around 30-40k miles, people would put on new calipers, brake fluid would be changed, and maintenance solved.

So we might not have the same worry about fluid boil that we used to, unless you have over-extended the original design load, changed to a more metallic brake pad, or have issues of hysteresis from slide pins, pistons hanging, or pads rusting in the brackets.

But although you can get away with it, I wouldn't be one to wipe my hands and say "no problem here" based on the owner's manual, it certainly didn't have the best practice in mind.

The Europeans, BMW, VW, Audi ... the guys that run the alps, sort of normal driving but with a trailer, every 2 years or 20-30k miles, DOT 4. But what do they know ......

 

TooManyToys,

Are you down near Seaside or further south, near Wildwood? I grew up in Passaic County, so was just curious.

-- Dave

 

Near Asbury Park.

 

Thanks! I thought that was the case but wanted to confirm.

 

I too bleed the system every few years.

I use
https://www.harborfreight.com/brake-...der-92924.html

takes me about an hour from start to finish to do all corners.

Although I know noone who bleeds their brakes. I have seen brake fluid in cars that is as dark as crude oil

 

How does that work? Are you pulling a vacuum with the trigger bottle? What is the other bottle used for?

 

I used this kit recently on two vehicles where i had to replace the rear calipers; including the superduty. It makes brake bleeding a 1-person job. The other bottle is the reservoir for clean fluid and it sits on top of the master cylinder so that you don't have to keep topping off the master cylinder reservoir with clean fluid. With the old 2-person brake bleed you run the risk of damaging rubber seals in the master cylinder when the pedal stroke by your assistant exceed the normal range of motion. I have to add that my kit had trouble pulling fluid to the rear brakes without me giving a little push on the brake pedal; still a 1-person job. My front brakes did not need the pedal assist because the vacuum unit is closer to the master cylinder. Overall I give the kit two thumbs up.

 

Thanks David. Looks like I will have to add this kit to my wish list.

 

... or forscan.. which is free.

 

DOT3 and DOT 4 can be mixed, no problem at all. For the small difference in price use DOT4. Has a higher boiling point.

 

Tests have shown that fluid does deteriorate. In areas with high humidity it will also contain more moisture. These 2 combined will be the cause of a failure sooner or later, but usually much later.
Now as far as performance go I do like to flush them every couple years. They still work good enough but I'd like it to be 100%. If it was a difficult job or an expensive job I might not do it that often but it's SO easy to do and costs SO little in fluid. Plus I clean and lube the slide pins at the same time. Never have issues w brakes.