How important is it to "Replace Brake Fluid after 2

[RedShift]

Just went through the Clymer manual to see what I should do at the next service interval, and was reminded that brake fluid should be replaced.

I know it can pick up moisture and suspect it then becomes acidic.  It should be clear and through the sight glass it still is.

Doesn't my car's brake system have the same general type of fluid?  How come no one replaces a car's brake fluid?  Is it because of the rubber tubing that deliveres the GS500's stopping power?

Just curious as I pine for the snow to go and the grass to grow again...

[Cal Price]

I just checked the owners manual, Maintenance schedule.

It does say change the fluid, dot4, every two years. Hoses every 4 years as well. It does seem a bit excessive at first glance but then brakes are brakes !

[The Buddha]

Cars aleo you're supposed to change it 2 or 3 years. Its listed in the 60 or 75K mile service. On a bike also I believe that 2 years is a bit excessive, however as the fluid begins to turn browish it has got enough water in it to mess up things pretty bad, especially if you live in a humid place. My vulcan ended up having brakes that refused to release one day ... anyway I'd swap it for dot 5 and run it for 5 years cos it doesn't take water on. BTW you do have to swap the entire fluild ... as in remove all of it, and replace it with dot 5. BTW swapping lines ... if you do that dot 5 is a good time to do that.
Cool.
Srinath.

[RedShift]

... anyway I'd swap it for dot 5 and run it for 5 years cos it doesn't take water on. BTW you do have to swap the entire fluild ... as in remove all of it, and replace it with dot 5. BTW swapping lines ... if you do that dot 5 is a good time to do that.
Cool.
Srinath.

DOT 5 eh?  Never heard of it 'til now.  Hey, research    -- something to do before Spring.

So far I have two votes for "excessive" unless there's some tinge of brown to the fluid.  I've never cracked the seal on either reservoir.  Anyone else have any opinions on doing what the manual asks versus what seems otherwise reasonable?

[The Buddha]

Dot 5 is blueish and silicone based, not petroleum, amongst its advantages are ...
1. Does not take on water.
2. Lubricates the seals etc in the bleeding pumps.
3. Does not eat paint so spills and leaks no problem.
4. Is that cool blue color, easier to see level etc in reservoir.
5. It can sit in an opened bottle for years, and can be in your brake system for 5 years without any hassle.

Disadvantages ...
1. Will not mix with 3 or 4 or even 5.1 ... so you need to get rid of it all and flush your system and fully bleed the air.
2. has slightly lower boiling point than 5.1 ... so racers prefer that.
3. Its pricey ... almost $7 for a pint.
4. Harder to find, bike stores or speciality auto parts places, though in my area autozones or advance auto parts have them ... due to the large number of ricers in this town I presume.

OK so you must look at it this way ... I am the famous El cheapo conquistador OK ... I dont use oil that costs more than 75 cents, I dont spend more for a brand name, and really I do all my bike parts shopping at walmart or the scrap yard. I believe this is worth it. You do need a bleeding pump in all honesty but you need that even with 3, 4, 5.1 unless you want to leave some of the old fluid in there.
Cool.
Srinath.

[cummuterguy]

I highly recomend you DON'T switch to DOT5, most people I have dealt with who have tried that in their cars have had nothing but problems (I'm an auto mechanic by day)

Flushing with dot4 is a good idea, it's quite easy to do.

quick easy way  to do it.

1. unscrew your master cyl cap (clean it first so as not to get grime or dust into the cylinder)

2. using some type of suction tool, (turkey baster or even that blue 'snot sucker' they have for infants will work) remove as much of the old fluid in there as you can.

3. refill the cylinder with new fluid, leave the cap off for now.

4. with your bottle of fluid right there with you, open the bleed valve on your caliper, if you have some tubing to allow the fluid to flow into a jar,great use it to keep your floor clean, but if not,it's water soluable.
DON'T PUMP THE HANDLE!!  gravity will let the fluid flow out without air coming back into the system. DON'T WALK AWAY OR GET DISTRACTED WHILE YOU FLUID IS DRAINING!  if your master goes empty, you'll have to bleed the whole system.

5. watch the level very closely in the master, top it off often, before it gets more than 3/4 empty, but let it drain at least 3 times the amount that would normally be in the system.

6. close the bleeder valve, top off the level one last time in the master, and re-install the cap.

7. you're done, clean up any spills quickly, brake fluid eats paint!!

[se7enty7]

as long as you can completely clean out the system you're fine with dot5.


YOU MUST NOT MIX IT.




this is near impossible to do with a car... but with a bike it's much easier

[The Buddha]

I have seen a lot of ricer cars that have all new SS braided brake lines and maybe different discs and even different calipers ... and they all use DOT5. The thing is I believe if you are swapping a line out ... by that point you already have put in so much air in the system you'll have to get rid of might as well do the whole fluid and hence dot 5 is an ideal choice.
Cool.
Srinath.

[cummuterguy]

true, it is probably easier on a bike, but with our gs being so easy to work on, I don't think it's very beneficial to switch.

plus, if ones does end up mixing by accident, a spongy pedal and really poor stopping distance will be the result....   not the best thing on a bike

maybe if an the system was going to be torn apart anyway, i'd consider it... like after replacing the master and lines or something.

also, they make 'litmus' tests for brake fluid, (dot 3 or 4) that make it easier to determine if a flush is needed, vs. just looking at color

a company named 'fascar' makes ones I use at my shop

[Michael]

So far I have two votes for "excessive" unless there's some tinge of brown to the fluid.  I've never cracked the seal on either reservoir.  Anyone else have any opinions on doing what the manual asks versus what seems otherwise reasonable?

It's the brakes!  Why risk it when brake fluid is cheap and the flush is quick and easy to do.  
It's kinda like the advice that you should change your helmet every five years.  That may be excessive too, but who'd risk it.

[RedShift]

... It's the brakes!  Why risk it when brake fluid is cheap and the flush is quick and easy to do.  
It's kinda like the advice that you should change your helmet every five years.  That may be excessive too, but who'd risk it.

Michael, your point is well taken.  Here I sit in -4F, roads covered with that white stuff, and the bike is sitting not 50 feet away in the garage waiting for spring.  It isn't that difficult to flush the lines and replace the fluid, but somehow I never seem to get motivated.  Dag nabbit, I should take on this and more maintenance challenges.

Perhaps my priorities are screwed up.  Time to find a copy of Zen and the Art of Motorcycle Maintenance (Robert Pirsig) and rebalance.

Thanks for pointing out this question's other side.

Roy...

[scratch]

Stopping is kinda important. We spend so much time on the "go" stuff (exhaust systems) that we overlook the required importance of "stopping".

[Roadstergal]

Silicone is indeed non-hygroscopic, unlike glycol-based fluids.  Silicone brake fluid also has a lower boiling point than good DOT4 or DOT5.1 glycol-based fluid, and gives a mushier pedal feel.  It's mostly used in applications where replacing it is a pain or where they're pretty sure the owners of the vehicle won't be doing performance driving and are unlikely to care enough about the internals to do the service (it comes in Harleys from the factory).

I use DOT4 and replace every year; it's not much stuff and not much of a pain to do.  Be sure to recycle the fluid at your local hazardous waste dropoff point.  It's not miscible with used oil for recycling purposes; I've heard of some auto parts stores that dump brake fluid in with the oil, but you're not supposed to do that.

[RedShift]

I highly recomend you DON'T switch to DOT5, most people I have dealt with who have tried that in their cars have had nothing but problems (I'm an auto mechanic by day)

Flushing with dot4 is a good idea, it's quite easy to do.

quick easy way  to do it.

1. ... 2. ... 3. ... 4. ... 5. ... 6. ... 7. ...!!

Gee, CommuterGuy, if it's that simple, why are we quibbling?  The only problem is to dispose of it properly.  I think you have me convinced.  

[Eric_in_OR]

Wow, that was easy! While the front brake went quickly, I got impatient on the rear, and started doing some of the loosen / pump / tighten procedure discussed in the Haynes. Even so, I was able to put 4-reservoirs worth of DOT4 through and be done with the whole project in a half hour. Unfortunately, I then felt the need to go look at the automobile's brake fluid color, and discovered that they were in far far worse need of a flushing!

[scottpA_GS]

And you brought back a 3YO Thread to tell us that?