On Thursday I'll be installing kyb-gr2's with my HR's, powerslot rotors,
and hawk brake pads.

I've got about 54K on my baby and I 'm wondering if it's time to bleed the brake fluid and replace?

Should I wait?


The guy doing all the installs suggests I wait and says it is not really necessary at this point in time.

Although I trust this guy....I'd like to get some feedback and second/third/fourth opinions from my fellow .orgers before proceeding.

Thanks all.....

 

No need to bleed unless you have fluid leak out or get bubbles. Maybe after many years you could bleed but the fluid lasts quite a while.

 

I recommend you replace your brake fluid every two years. Brake fluid absorbs water and makes for a spongy pedal feel and corrodes brake parts.

 

Yes, I read somewhere that 25K miles is a good cutoff point for brake fluid. Brake fluid will still work when it's old and nasty, but the internals of the brake system can corrode, and the fluid will boil much easier due to the absorbed water lowering the boiling point. I just flushed my fluid this past weekend, and noticed a difference already (had 41K mi on the old fluid).

 

is replacing the break fluid easy as bleeding the break and close it and refill it?
or anything else involved?

 

Yeah, you bleed the brakes (stopping periodically to refill to ensure that the master cylinder does NOT go dry) until you see new, fresh fluid coming through.

 

Bleeding the brakes doesn't take very long so why not do it? Changing all the fluid obviously takes time and is IMHO not worth it unless you want to go with a higher DOT rating.

 

Unless I'm mistaken, changing the fluid is literally as easy as bleeding the brakes... basically you just keep bleeding the brakes while adding new fluid to the master cylinder reservoir until the new fluid comes out the bleeder screw/hose.

 

I agree its the same kind of effort, it just takes a lot longer (as I said). My understanding for why you bleed brakes is to prevent contaminants from entering into the system. Since there shouldn't be any contaminants in the middle of the fluid lines, it doesn't make sense to bleed them. The only way I could see this making sense was if you wanted to change from DOT 3 to 4 or 5. The higher DOT values are less susceptible to temperature and would reduce (not eliminate) fading.

 

what is the normal DOT rating does the car come in? if it comes with 3... do you recommand increasing it 5?

 

My understanding is that DOT5 is NOT to be used for anything other than race/track situations where you change the fluid often. I believe DOT5 (silicone-based) brake fluid is NOT hydroscopic, meaning it doesn't absorb water (so water, which eventually WILL get in the lines over time, will corrode the brake system, and will boil/vaporlock under heavy braking very very easily, thus causing temporary failure of the brake system)

Normal specs call for DOT3 I think. Use DOT4 since it's easily available, is fully compatible with DOT3, but demands a higher boiling point... use fluids that exceed DOT4 if you can afford it, but if it exceeds or meets DOT5, make sure it is NOT silicone-based and is fully compatible with DOT3/DOT4 brake systems.
I'm sure there's a site out there somewhere that details all this and more a little better

 

Don't waste your time bleeding. If you need bleeding you will know it.

However, chances are at 54K your baby is 2.5-3 years old. (so says your profile too!) This means that the fluid has had time to absorb some moisture, rubber breathes. This means that effectively the boiling point of the fluid is lowered. At worse what happens is that at around 100 degrees celcius, 110-120-130-140, the water starts to boil out.

Water you say. a mere uncompressible liquid you laugh? Well when water becomes steam it is reduced to a measly gas. This gas acts just like air in the line and makes it spongy.

You can check the forum for other posts regarding Silicon (DOT 5?) vs. other types of fluid (DOT 3?). Silicon does not absorb water but does not hold up well to abuse. DOT 3 hold up well to abuse (heat) but absorbs water.

 

I recommend you replace your brake fluid every 2 1/2 years or so

 

I believe what spirilis said is true.

Check one of the myths at http://www.stoptech.com/whitepapers/...otors_myth.htm

 

Some good advice above. I got a BMW motorcycle and it calls for yearly brake fluid change. When I do it I am amazed at the dirty fluid that comes out. This can corrode every thing including the expensive ABS unit. I personally wouldnt go past 2 years 50K miles. Check out Caster oil GT it is dot 3&4 compatable.

I use a mityvac unit and the optional (included in some kits) catch canister. $40-60 but it is well worth it. So basically it is pump the handle and keep sucking out the fluid, keep the master cylinder from sucking air which is rough to get out. Bleed in the conventional manner. once you get clear fluid at all points. Remember bleed screws are little guys and too much mustle will break them.
Do not drive at all until you are sure you have a firm pedal. Modern ABS brake systems can be tricky to bleed. My cycle is ABS and it has a nipple on the unit.

 

Oh and most important!!! Brake fluid can ruin your paint. Take an old shower curtain and cover up the fender etc.

 

I think my vacuum pump is a Mityvac unit (hand pump w/ gauge and canister), it was $25 at Autozone

 

DOT 3 AND DOT 4 brake fluids are ether based and are hygroscopic in nature - i.e. they absorb water vapor. As the braking system in not quite airtight, a significant amount of water can be absorbed from the atmosphere in the course of a year. A 3% water content in brake fluid drops the boiling point as much as 170 degrees F. Brake fluid should be completely replaced annually.


I bleed my brakes every 2 years or so... but recently when installing my stock brakes back on I bled em again.

 

I just replaced my brake fluid three weeks ago using a Mighty Vac pump and cannister. Are you supposed to keep the cap on your master cylinder fully tightened or loose when bleeding? I kept the cap on, but didn't tighten it down after every refill during the bleeding process. Just curious.

 

thanks for all the info guys...one more thing....is there a certain brake fluid that you guys recommend?

 

There are some expensive high-performance fluids like Motul (http://www.motul.com/uk/produits/index.html) you can use, in fact Motul boasts good performance even while wet... so that'll be great for high performance braking systems. I wasn't going all-out when I flushed my brakes, so I used Valvoline SynPower brake fluid (from Autozone, roughly $5/canister). I'd definitely go with a DOT4-compatible fluid, since they're easily available at Walmart, Autozone and other shops, and offer higher boiling points.