Brake fluid change?

[garyemunson]

Does anyone here actually follow Ford's recommendation to replace brake fluid every 2 years in an F53 chassis? For decades I've been using synthetic fluid and changing every 4 years. At that interval, the fluid is just beginning to change to an orange color. I doubt at 2 years you'd see any change. I've followed the 4 year time in all my vehicles for many years and have never had to replace a caliper/wheel cylinder/master cylinder/ ABS module. Different mfgs are all over the place with change intervals, our Caddy even calls for 10 years! I'd NEVER leave fluid in a vehicle that long. Any thoughts?

[opnspaces]

I don't know about that. Every master cylinder I've ever encountered has had a rubber membrane between the cap and the brake fluid.

[liborko]

Brake fluid must be exposed to atmospheric PRESSURE for the brakes to work properly. Most brake fluid reservoirs have a tiny hole in the cap for that purpose. Except GM vehicles. Every GM vehicle I ever owned had rubber membrane separating brake fluid from atmospheric MOISTURE thus GM does not insist on regular brake fluid changes. How ever there is nothing wrong with changing it every two years.

[ajriding]

You are correct, brake fluid is not petroleum like most everything in the world. DOT3 and 4 fluids are made from a glycol-ether … Dot 5 from something else.
Synthetic suggest it is synthesized, but like synthetic oil, it is not. Not sure what the synthetic denotation means, but it doesnt really matter.

Fluid will absorb some water. If the brake fluid exceeds 212F then that water can turn to steam, and when you release the brake pedal and try again that steam might have pushed a lot of fluid into the resivoir, displaced by steam, and when you go to push the brakes this steam easily compresses and then there is not enough pressure to push the actual brake pads to slow down…

More likely they will get spongy and feel soft, but still stop the vehicle.
Seems like changing would be prudent, but I defer to old mechanics that laugh at this even for RVs.
Use low gear. For diesels exhaust brakes are great (for any manual shift trans exhaust brakes will work fine).

In conclusion, someone needs to keep money flowing to the mechanics

[DFord]

Doug, you mean to say you've never heard of someone riding their bakes a little too much going down a mountain and heated them up so much it cause the water in the brake fluid to boil which made the brakes useless? I've heard those stories for years. Around where I live with heavy dew the normal every morning thing, my brake fluid turns dark as it absorbs moisture pretty rapidly. I should change it yearly but I'm not that good at keeping up with it and I don't have any trips over the mountains planned - plus I come down mountains as slow as I go up them. Yes, brake fluid has an affinity for moisture and fluid reservoirs are not air tight so there's no way to prevent it from becoming contaminated unless you move to a very low humidity area in the dessert.

[ktmrfs]

dougrainer wrote:
HOW does moisture get to a Brake system?????? Just removing the reservoir to check fluid level is NOT going to introduce moisture(humidity) to contaminate the system. The OEM recommendations (IMO) are CYA for them. A Motorhome would be a 10 year flush and replacement. Automobile--Never. How many people out there have had an actual first hand knowledge of a Brake Failure problem/accident that was determined to be a failure to flush their Brake fluid? In 50 years of driving and 40 years in the RV service, I have never heard of such a problem on Motorhomes or Auto's. Doug

newer vehicle reservoir is more moisture resistant than those of the 1960's, but by no means are imune to water introduction. Water molecules are very small, smaller than oxygen, Nitrogen and most other gases. As a result water can and does penetrate many plastics and through reservoir caps.

As for failures on vehicles I've worked on, (but not maintained by me) back when rear brakes were drums, water in the fluid was often the cause of rear wheel cylinder failures which was pretty common on higher mileage vehicles that hadn't had brakes flushed. On mine, never had a rear wheel cylinder failure, but I flushed lines every year.

[road-runner]

My feeling is that changing the fluid helps prevent maintenance jobs down the road, like master cylinder failures, wheel/caliper cylinder failures, and rusted hard lines. I have a 25 year old car that has had none of these failures. Without brake fluid changes I believe I would have seen them happen. If you never keep a vehicle past its 10th birthday, I suspect you're just handing off the future failures to the next owner.

[dougrainer]

otrfun wrote:
We siphon (with a vacuum brake bleeder) all the brake fluid out of the reservoir every year or two on all our vehicles, then refill it with new synthetic brake fluid. Takes about 12-16 oz. to refill the cars and 32 oz. for our Ram 3500. Literally takes all of 2-3 minutes to do. Can't say there's some dramatic improvement in braking, but it's nice to see the fluid clear with so little effort and cost. Still do the occasional brake bleed. When we do, the brake fluid is significantly clearer vs. how it normally looks when we don't do the siphon and fill.

This does NOT make any sense. What about the fluid in your Lines and calipers that is OLD? If you do anything it would be to flush and bleed the complete system. Not the occasional bleed. Doug

[dougrainer]

HOW does moisture get to a Brake system?????? Just removing the reservoir to check fluid level is NOT going to introduce moisture(humidity) to contaminate the system. The OEM recommendations (IMO) are CYA for them. A Motorhome would be a 10 year flush and replacement. Automobile--Never. How many people out there have had an actual first hand knowledge of a Brake Failure problem/accident that was determined to be a failure to flush their Brake fluid? In 50 years of driving and 40 years in the RV service, I have never heard of such a problem on Motorhomes or Auto's. Doug

[wolfe10]

opnspaces wrote:
I put changing brake fluid right up in the same category as injector flushing and the 3000 mile oil change. I view all three as nothing more than an add on money grab for the service writer.

Sorry, but if one is discussing a HEAVY vehicle with hydraulic brakes, that statement is dangerous.

Agree, hard to boil brake fluid in a PU, but different for a 20,000 pound plus motorhome with a toad!

[opnspaces]

I put changing brake fluid right up in the same category as injector flushing and the 3000 mile oil change. I view all three as nothing more than an add on money grab for the service writer.

[otrfun]

We siphon (with a vacuum brake bleeder) all the brake fluid out of the reservoir every year or two on all our vehicles, then refill it with new synthetic brake fluid. Takes about 12-16 oz. to refill the cars and 32 oz. for our Ram 3500. Literally takes all of 2-3 minutes to do. Can't say there's some dramatic improvement in braking, but it's nice to see the fluid clear with so little effort and cost. Still do the occasional brake bleed. When we do, the brake fluid is significantly clearer vs. how it normally looks when we don't do the siphon and fill.

[allen8106]

I've never changed the brake fluid in any vehicle I've owned in 45 years of owning cars/trucks and have never had an issue that I'm aware of.

[RLS7201]

ajriding wrote:
There is no such thing as synthetic oils. Synthetic motor oil is just higher quality petroleum. Syn brake fluid is just a higher number. It all comes from oil. The higher number fluids usually can take higher temps, so maybe the "synthetic" is a better choice for a heavy vehicle, but not all brake systems are meant for just any fluid you pick out.

You can never change brake fluid if you prefer. As vehicles started to get better and last longer and need less maintenance then we started seeing things like "change brake fluid" or "rotate light bulbs" .

Yes, some water particles might get in the brake fluid and have an effect, but you can run the life of the vehicle and never change the fluid, it will still work. Do change your brake pads and do use high quality pads for a motorhome. Cheap pads are the wrong choice.

All brake fluids are technically "synthetic" in that they are man made and do not contain a petroleum base.

[Dave_H_M]

dang aj, I was hesitant to say that.

I never have changed any brake fluid in the last 10 plus years.

I never had any consequences in modern day vehicles. hammered my last TV down the road 160K miles and 13 yeas with nary a problem with the fluid. :h

[ajriding]

There is no such thing as synthetic oils. Synthetic motor oil is just higher quality petroleum. Syn brake fluid is just a higher number. It all comes from oil. The higher number fluids usually can take higher temps, so maybe the "synthetic" is a better choice for a heavy vehicle, but not all brake systems are meant for just any fluid you pick out.

You can never change brake fluid if you prefer. As vehicles started to get better and last longer and need less maintenance then we started seeing things like "change brake fluid" or "rotate light bulbs" .

Yes, some water particles might get in the brake fluid and have an effect, but you can run the life of the vehicle and never change the fluid, it will still work. Do change your brake pads and do use high quality pads for a motorhome. Cheap pads are the wrong choice.