Flushing the brake system
Thread Starter
Instructor
Joined: Sep 2002
Posts: 137
Likes: 0
From: Toa Baja Puerto Rico
Flushing the brake system
I'm about to install speed bleeders on my 87 Coupe. The brake fluid is a nasty shade of dark brown so I am going to flush it all out and put in DOT 4 fluid. A friend of mine suggested that I buy a couple jars of alcohol and after getting the old fluid out, put alcohol in the reservoir and flush the system with alcohol before adding the DOT 4 fluid. He claims the system will be a lot cleaner. Anyone done that? Is it safe for the system? I already had brake failure due to fluid contamination and want a clean system before adding the DOT 4.
Drifting
Joined: Oct 2005
Posts: 1,729
Likes: 62
From: South Lyon MI
From what I remember I thinkk you can go to dot 4 but thats all you will be able to use after that without hurting the seals and other componets. You may want to look into the wilwood dot 3's as an alternative. I don't think I have ever heard anything bad about dot 4 but it does kind of narrow your options after you start using it. good luck
Al
Al
Melting Slicks
Joined: Jun 2004
Posts: 3,253
Likes: 2
From: Castro Valley CA
Valvoline Synpower brake fluid or Castrol LMA flushed thru the system is all you need. I have no direct knowledge, but I would save the alcohol for your cotton swabs. Just flush an extra bottle of BRAKE FLUID thru the system, it is so easy to do with Speedbleeders.
Race Director
Joined: Jul 2004
Posts: 16,795
Likes: 62
From: Lake Havasu City, AZ
Valvoline Synpower is DOT 3 & DOT 4.
I buy it by the quart for under $5 at our local grocery chain. I'm sure you can get it even cheaper at Walmart.
At that price why take the chance of contamination?
I buy it by the quart for under $5 at our local grocery chain. I'm sure you can get it even cheaper at Walmart.
At that price why take the chance of contamination?
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Never use alcohol to clean the system.
All you should have to do is to suck the old fluid out of the master cylinder reservoir and refill it. Then bleed the brakes with the speed bleeders.
The ABS pump and the lines running to and from the M/C will still have dirty fluid in there but because the ABS does a self-test at each start-up with the car moving through 3-4MPH, this fluid will eventually clean itself out. You may seen the fluid in the reservoir get a bit dirty, but after a couple weeks, just suck that fluid out and refill.
Depending on how you drive the car, a good DOT3 fluid or DOT4 is all you need. DOT3 is fine for typical street and highway use and will even work for autocross. Good DOT3 fluids are Castrol LMA, Ford Motorsports HD fluid or Valvoline. A quart is more than enough to flush the system.
A true DOT4 is not really needed unless you take part in track days or HPDE events. DOT4 fluids have a much higher wet boiling point and they tend to be more costly than DOT3 fliuds. The higher the WET boiling point the better; most DOT3 fluids have wet boiling points up to around 350 degrees.
All you should have to do is to suck the old fluid out of the master cylinder reservoir and refill it. Then bleed the brakes with the speed bleeders.The ABS pump and the lines running to and from the M/C will still have dirty fluid in there but because the ABS does a self-test at each start-up with the car moving through 3-4MPH, this fluid will eventually clean itself out. You may seen the fluid in the reservoir get a bit dirty, but after a couple weeks, just suck that fluid out and refill.
Depending on how you drive the car, a good DOT3 fluid or DOT4 is all you need. DOT3 is fine for typical street and highway use and will even work for autocross. Good DOT3 fluids are Castrol LMA, Ford Motorsports HD fluid or Valvoline. A quart is more than enough to flush the system.
A true DOT4 is not really needed unless you take part in track days or HPDE events. DOT4 fluids have a much higher wet boiling point and they tend to be more costly than DOT3 fliuds. The higher the WET boiling point the better; most DOT3 fluids have wet boiling points up to around 350 degrees.
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