Desertdawg

This is in my 93 crewcab dually...
First I drained the old burnt DOT3 out, Then I poured in the DOT5 (synth.) brake fluid, I kept pumping and refilling the system until I was getting almost perfectly clear DOT5 out of the bleeders. (I know that this is wrong, but I had to try)...
Now the peddle goes to the floor every once in awhile, the rest of the time it feels almost normal (but not quiet).

So now I need to start over, What is the method of cleaning out the system, without removing and diassembling the calipers and master cylinder to get all of the old crap out of it. I know that I saw someone post it somewhere on the forum on how to do this.
What did you use to dry it out with???

mrvette

being as it's a '93 you probably have ABS, and if so, ABS is NOT compatible with DOT 5 fluid....you have to use the old crap....
you may have a problem now, I"m not sure, about changing back again....but I'd just do the reverse of what you just did, and try it again....
something about that rapid pumping action of the ABS that foams the DOT5 fluids....

GENE

Matt Gruber

simply replace every part in the brake system.

Tom454

I agree with GENE...

DOT5 is not supposed to be used with ABS... that limits its use in Vettes up to 1982?

Anyhow, they say ABS causes air bubbles to form in DOT5, so it's a no-no.

Brian Madderom

You cannot use DOT5 in any A.B.S. system! The DOT5 and DOT3 IS NOT MIXABLE, you have to make sure all of the DOT5 is out of the system. You should flush the system with denatured-alcohol and let the system breathe for an hour to make sure it evaporates. That will get all the DOT5 out of the system. Then if you want to upgrade you can use DOT4 but NOT DOT5! :eek:

Desertdawg

I had already disabled the anti-lock setup (just pulled the fuse), It was only the rear brakes anyway.

If I can use DOT5 with the anti-locks disabled, then will the Den. alcohol work the same way. Another words just flush, let breath, then refill with DOT5.

I really want to use the DOT5, because I keep burning the DOT3 and 4, towing my fifth wheel. The last time I replaced it I flushed almost a gallon of DOT3 through the system before bleeding. It turned black, and the pedal went mushy within 3 months...
And I was real careful to not cook them this last time.
I have even gone to the expense of switching to phenolic pistons to reduce the heat from the calipers...

HELP! :sad:

jpread

I've always understood the only time to make a change to dot 5 is when you are replacing all brake components.
I don't think the rubber parts react very well to dot 5 if they have already been exposed to Dot 3.
From your post, it sounds like what I had heard may be correct I'm afraid.

Desertdawg

TTT for one more try
Read my second post above...

dman535

Desertdawg,

I would check and make sure that your trailer brakes are properly adjusted and operating correctly. You might also want to source one of those ifra-red thermo guns that can measure the temperature of your brakes, I don't think that you are generating enough heat to char the brake fluid. If you indeed are you might want to consider some duct work to provide additional air cooling to the brakes.I would also reccomend that you cosider changing your brake fluid to ATE Super Blue Brake Fluid. I run it in my BMW and it works very well. Below are a few links that should help you out.

http://www.evici.com/load/?fluids7.htm
http://www.shotimes.com/SHO3brakefluid.html

Good Luck !