How can I flush my brake system of DOT 3 fluid so that I can use DOT 5. I undertand the two can't mix.

air blow the lines clear at various connections. However, seals on wheel and master cylinders, and calipers that have been used with DOT 3 must be replaced.

what is the purpose of going to DOT 5? is it a better consintratin and does it work better?


aaron

I used a homemade pressure bleeder and just ran Dot 5 Silicone fluid through until it came out good and purple. I had a new master cylinder and calipers on the front so it was pretty empty. It has worked fine for years.

The benefit to Dot 5 is that it does not absorb moisture and rust your brake components from the inside and it does not eat off paint if you spill it. There are also some drawbacks since it may be harder to bleed.

ok thanks


aaron

I wouldn't be too quick to change to dot 5 silicone fluid from dot 3. As stated above, silicone fluid holds tiny air bubbles moreso than dot 3 and is much harder to bleed all the air out. Also, dot 5 is very slippery and will get past the seals in your master cylinder more easily. Soon after I changed to dot 5 fluid in my daily driver caddilac, the master cylinder went. So I bought a new one. I lasted no more than a year when it too allowed the fluid to sneak past its seals. I changed back to dot 3 and drove the car for years with no problems. IMO dot 5 is needed for cars that are rarely driven because the metal bores in the master or calipers or drum cylinders will rust fast if not used. I use dot 5 in my corvette for that reason. But in all cars I drive regularily I still use dot 3, and just flush it out every few years when I'm changing shoes or pads.

I agree, I wouldn't change to DOT5.There's no advantage to it if you maintain your current brake system...

change it if you want. This rumor about bleeding the brakes of air is an old wives' tale. But you must use new rear wheel cylinders or it will leak.

Take it fo rwhat it's worth. I've been a professional for 14 years, DOT5 is difficult to bleed and has no real world advantage UNLESS you have a race car or trailer queen. FO&D DOT3 is real good. Flush the system well with some of that and call it good.

I agree with Dennis. DOT5 is more trouble than it's worth.