Why Change Brake Fluid

[Ron & Dee]

Originally Posted by bdaball

"Old Buzzards",

I guess I fit into that catagory, but I never heard of changing or flushing brake fluid until about 2 or 3 years ago on this WH Forum, or whenever it was first decided that we all should change our brake fluid.

I think if all of the other "Old Buzzards" were honest they would say the same thing about "never heard of changing brake fluid" until just recently.

Don't get me wrong, I know there are always new ideas and new ways of doing things and I usually go along with them until proven otherwise.

I have plenty of miles on automobiles, too many to count. I have done many brake repairs myself, and also had professional repairs done, but never once heard of changing and flushing the fluid.

But don't put my in the catagory of "Ignoramus"

Ron

[DriVer]

Originally Posted by Ron & Dee

But don't put my in the catagory of "Ignoramus"

Ron at this time of the year it's what I trying to do to my neighbor Amos .. you see he's running around in a Rodolph TRNRD suit and I'm trying to ignore him!

[TandW]

I grew up working in the neighborhood Atlantic station and we also added break fluid only when a cylinder was changed out or as was more often done in those days, rebuilt. It took a long time before I came across the term "HYGROSCOPIC". It has been explained that the phenolic material that the affected brake pistons are molded from absorbs water from outside the brake system. So as the brake fluid does it's job of taking this tramp amount of moisture into suspension, it also continually loses this ability to do so. Think of the wet sponge that must be wrung out. If it were not for this hygroscopic property, brake lines would freeze from water that collects in low spots. This would not be a good thing!! Good luck!!

[DriVer]

Originally Posted by TandW

I grew up working in the neighborhood Atlantic station !!

TandW, ME TOO! In fact it's where I actually learned how to use a stick shift!! My boss's name was Thomas (Italian) and the station was up Federal Hill in Providence, RI. This was also the place where I saw my (1st) dream car (at the time) a pristine 1961 Buick Wildcat "convertible" that was fire engine red on the outside and white leather on the inside. It also had a 4-Speed floor shifter and mag wheels and as I recall it had the Wildcat 401 CID engine. Every time that car came into the station it would leave with my heart in the passenger's seat!

You know I was so young I would have paid Tom to work there. It was more fun than I can remember. A young kid with wrenches! America! What a country!

Talk about the Ghost of Christmas past! I want to thank you for allowing me to take a trip down memory lane it was swell! It's what the Holidays are all about!
■

[RustyJC]

Originally Posted by bruceh

BMW recommends brake fluid change every 4 years. Just had mine done.

For BMW motorcycles with ABS, replacement of the DOT4 brake fluid is part of the annual service requirement.

Rusty (2007 BMW K1200GT)

[bdaball]

Ah, You all are bunch of old buzzards......

Merry Christmas. May your christmas credit card purchasing memories linger for months to come! At 18%.

[George Z]

Originally Posted by bdaball

Ah, You all are bunch of old buzzards......

Merry Christmas. May your christmas credit card purchasing memories linger for months to come! At 18%.

Old yes, buzzard yes, but this one is well fed. no flying for me.

18% I think that is the old rate.

George

[max49]

[QUOTE=max49
I have a friend who is meticulous about maintenance on trucks and his own car. He has 387,000 miles on his Honda, (Accord, I think). It looks almost brand new.
I hope to remember to ask him if he changes his brake fluid.[/QUOTE]


I stand corrected, he has 390,000 miles on his Honda. I asked him if he ever changes his brake fluid. He said he just takes something like a turkey baster and sucks as much fluid out of the master cylinder as he can and fills it with new. Does this do any good?

When I asked him about bleeding the old fluid out of the lines , he said he has the shop do that when he replaces the brakes, and I forgot to ask how often that is.

Maybe changing brake fluid has gotten more important since the Phenolic pistons came about. However IMO there is another problem with the W series calipers because all calipers with phenolic pistons have not exhibited the same sticking problem. It'd be a shame that it took this long if all they have to do is make the pistons a couple of microns smaller.

So does it do any good to just replace the brake fluid from the master cylinder? That sounds easy enough.

Merry Christmas Guys!

[DriVer]

Originally Posted by max49

So does it do any good to just replace the brake fluid from the master cylinder? That sounds easy enough.

Max, This is my take on this procedure. You can put a band aid on a cut finger however absent an antibiotic, the chance for an infection in the wound exists.

Hydraulic brake system - same analogy!

Merry Christmas Max!

[Ron & Dee]

I know this must have been ask before, but here goes again

If changing and flushing the brake fluid fixes the problem, why would WH go to all of the trouble to replace the calipers?

[RustyJC]

As an outside observer who has been following this caliper sticking problem out of an engineer's technical curiosity, I'm still scratching my head over one fundamental question:

The application of phenolic pistons is nothing new or exclusive to Workhorse - because of their thermal insulating properties, they have been used quite commonly in disc brake applications. Admittedly there have been a few applications where the phenolic pistons had a sticking problem (ref. some Chrysler products in the 1970s and 1980s, C3 or C4 Corvettes [can't remember which]), but millions of cars and trucks have been on the road for years using this caliper piston material with no problems. What, in this particular application, is unique that's resulting in caliper piston sticking? The obvious suspects would be (1.) the phenolic material used is more prone to swelling and sticking, (2.) the dimensional fits used on these calipers are problematic, or (3.) something in the design of this particular braking system makes it more prone to absorb/retain moisture. Has anyone heard the identification of the specific problem since root cause failure analysis (RCFA) methodology would drive the solution from the root problem(s). Not knowing the problem or the solution makes it hard to evaluate what to expect going forward.

Just an old, broken down engineer's perspective - take it for what it's worth.

Rusty

[speed racer]

Originally Posted by Ron & Dee

I know this must have been ask before, but here goes again

If changing and flushing the brake fluid fixes the problem, why would WH go to all of the trouble to replace the calipers?

This doesn't solve the problem. It is preventive maint. They say the moisture in the brake fluid is absorbed by the caliper pistons and causes them to swell and stick. If you keep the moisture out of the system this can't happen at least in theory.

[speed racer]

Maybe changing brake fluid has gotten more important since the Phenolic pistons came about. However IMO there is another problem with the W series calipers because all calipers with phenolic pistons have not exhibited the same sticking problem. It'd be a shame that it took this long if all they have to do is make the pistons a couple of microns smaller.

So does it do any good to just replace the brake fluid from the master cylinder? That sounds easy enough.

Merry Christmas Guys![/QUOTE] "All" Workhorse W series chassis have not had this problem and more cars have had this ploblem than have been reported. I have always change the brake fluid in all my vehicles and recomend it to everyone. As a mech. I have seen what moisture in brake fluid can do to all types of brakes. The major cause of brake failure in the older and newer drum brakes is wheel cyls leaking that is caused buy rust in the wheel cylinders

[Ron & Dee]

Originally Posted by speed racer

The major cause of brake failure in the older and newer drum brakes is wheel cyls leaking that is caused buy rust in the wheel cylinders

I have honed by hand, and replaced the seals in cylinders on my older cars, but it took a long time before the pitting got severe enough to start leaking fluid.

I'm sure if the fluid had been changed at a regular interval the pitting could have been reduced and prolonged the life of the brake cylinders

Ron