This up coming weekend i will be changing my brake booster, after i bleed the brakes, how much brake fluid will i need to put back into my car, and is there a certain type that i need to put in there? thanks :cheers:

 

I would take the opportunity to flush the whole system with methylated spirits, and fill with DOT 5 silicone fluid.

(now watch the sparks fly!)

 

Before I started, I would buy some Speed Bleeder Screws Fom Mid America, p/n 602-707 @ $14.99. Or probably at parts stores.
That way "you", have more control over brake jobs.
Just my 2c.
tony


[Modified by oldace84, 1:06 PM 8/26/2003]

 

I just flushed mine and refilled with Syn and it took about a quart...but I bled them until there was no color left and then some.

 

Now is the time to do a flush of the entire system. Use a turkey baster to suck out the old fluid from the MC reservoir and fill with clean fluid. Bleed each wheel until the fluid comes out clean and no bubbles. You will need about 3 pints to a quart of fluid. I usually by 4 pint cans so I don't have to mess with a quart jug.

For street use, just get a good DOT3 fluid. I use Castrol LMA in my 92 and for my 87 autocross car, I use the Ford HD fluid.

Speedbleeders are a good idea if you intend to bleed brakes a lot, typically after autocross or track day events. For the street, they probably are not really necessary but they sure make the job easy!.

As far as DOT5 silicone fluid, the factory service manual says DO NOT USE IT!! Silicone fluid is not compatible with ABS systems. Silicone fluid will cause cavitation in the ABS pump and cause foaming of the fluid. Braking hard from high speed and having DOT5 in the system may very well cause you to have a really bad day! Nobody I have ever asked about DOT5 fluid and ABS has ever said it's OK to use.

 

I use ATE Super Blue and it comes in two different colors (blue and gold). I rotate the colors on my flushes and always know when I've gotten the old fluid out of the system. I road race with this fluid and can attest to it's being able to hold up to extreme temperatures.

Mike

 

:iagree: :thumbs:

 

Nobody I have ever asked THAT HAS USED IT has ever said its not OK to use.

First I will send out a challenge- anyone here on the forum had a bad experience with DOT 5?

Next tell me why not DOT 5, and we will devise some experiments to prove or disprove your concerns. I am prepared to be wrong on this one, but not just from hearsay and myths and legends.

Cavitation and foaming you say, how about I whisk some up in a jar with an electric drill? would that be a fair test? DOT5 vs Dot 5.1?
(5.1 is the best synthetic "normal" brake fluid). I have not done this test, but it could be an interesting thing to do , don't you think?

Have to start collecting jamjars :D

(Told you the sparks would fly!) :D :D :)

 

I think a discussion like this really belong in the "Autocrossing and Roadracing" forum. I'm sure there are some very experienced people that know specifics about the good/bad of DOT5 fliud in ABS-equipped cars. DOT5.1 synthetic is enough of a different animal that it could very well be useable in ABS systems. The watchword here being "synthetic" as opposed to "silicone".

My highly trusted and very experienced brake specialist agrees about not using silicone DOT5 fluid in ABS cars. Other people I know who do a lot of track events agree on not using silicone fluid. And the factory GM service manual clearly states that silicone fluid should not be used in ABS-equipped Vettes.

I, for one, would not really want to take part in a "real-world" experiment where I would drive my Vette at high speeds such as on a road course where I would expect ABS braking to be used. The thought of repeatedly doing 140 down a long straight into a hairpin turn with silicone fluid in the brake system is not a pretty one. In a street car where the ABS system may seldom be used, one may be able to gat away with silicone fluid. But why take the risk? Even if it works fine for 99% of the time, that 1% at some point may cost you vehicle damage or your life (or someone else's!).

Stirring up just about any fluid with an electric blender will cause foaming. Open containers will easily let air mix with the fluid. Even thought there should be no air inside a brake system, the ABS pump will cavitate and foam the silicone fluid. Not a good thing in a system that depends on a liquid form to make it work.

 

:cuss I wasn't going to say anything. However...people that intentionally post mis-information or misinformed rhetoric "to watch the sparks fly" about something safety related like brakes are dangerous at best. This is especially true relative to the inexperienced who, in their enthusiasm, treat much of what they read as gospel.

Here's a quote from the Performance Friction website (a respected brake pad and brake fluid manufacturer):

"Silicone DOT 5 is not compatible with the ABS hydraulic control unit because it doesn't lubricate the ABS pump like glycol based fluid. Silicone is slightly more compressible than glycol fluid. It has a higher wet boiling point because it doesn't absorb moisture like glycol fluid. This lack of moisture absorption causes problems when water gets in the brake system. Instead of mixing with the brake fluid (so it can be flushed out easily), the moisture gets trapped at low points in the system and causes rust. "

Not enough? Here's a quote from Wilwood, another respected manufacturer:

Wilwood does not recommend using DOT 5 fluid in any racing applications. DOT 5 fluid is not hygroscopic, so as moisture enters the system, it is not absorbed by the fluid, and results in beads of moisture moving through the brake line, collecting in the calipers. It is not uncommon to have caliper temperatures exceed 200° F, and at 212° F, this collected moisture will boil causing vapor lock and system failure. Additionally, DOT 5 fluid is highly compressible due to aeration and foaming under normal braking conditions, providing a spongy brake feel . DOT 5 fluid is best suited for show car applications where its anti-corrosion and paint friendly characteristics are important.

Do a search on all the major brake fluid manufacturers and you'll see the same thing. Call LPE or Rippie or any of the other respected tuners and they'll tell you the same thing.

 

I stand corrected.

So brake fluid manufacturers recommend fluid that needs changing every year or so, but don't recommend a fluid that doesnt need changing. Thats convinced me.

Having said that, as far as I know, the automotive industry is the only industry still using glycol based fluids in hydraulic systems. The military use silicone in helicopters and land vehicles. Jumbo jets and other aircraft use silicone. Many cars (and Harley Davison Motorcycles) use silicone. To suggest that I am dangerous at best, to consider silicone is a bit strong. Hell, I even use it myself in one of my cars, and no problems yet.

I was expecting some flames for expressing the possibility of an unfashionable point of view, but hey I'm a big boy now :D

If you do change to silicone however, I would recommend changing all seals and flushing the lines, as glycol contamination does cause problems. It is the size of the job to change, new seals etc that prevents me from using it it my Corvette. I use therefore DOT 5.1 synthetic

As pointed out , these are brakes - make your own decision.


[Modified by britvette, 12:32 PM 8/27/2003]


[Modified by britvette, 3:33 PM 8/27/2003]

 

Um, I like the ATE Super Blue, as stated, comes in two colors, super blue and super yellow, when I flush the system I can tell the old stuff is gone. My local BMW dealer has it along with the good gear lube.

Eric
no VAT jokes today....

 

thank heaven for that Eric - I haven't stopped laughing at the last one yet. :rofl: