View Full Version : replacing with DOT 5 brake fluid


Rob H
May 9th, 99, 11:47 AM
I have to replace the master cylinder, so I thought this was a good time to change to dot 5. I have repainted my brake booster 3 times now and it's getting old. I read Bob Tiley's post that he just bleed the 5 through without flushing out the system. I don't want to or have the time right now to take the whole system apart. I have original brakes (front disc) and all new lines, but all filled with dot 3. I wish I had done this when I put all the lines in. Any thoughts on how this will work. Bob, how much fluid did it take to flush the whole system? I have a vacuum pump, what did you use? thanks for any advice.

Gene Chas
May 9th, 99, 7:13 PM
I was going to post a similar question Rob. I need to rebuild my master (or add power)and all my wheel cylinders. The whole system hasn't been used for a while and I wanted to flush it out. Can I use a solvent such as kerosine for this or must I use the new Dot 5 /silicone fluid?

[This message has been edited by Gene Chas (edited 05-09-99).]

Bob Tiley
May 10th, 99, 10:11 AM
I flushed out less than a quart through the front and a quart through the rear brakes. The front calipers were new so there was not a lot to flush out there. I have a pressure bleeder that clamps to the top of the master cylinder and I pressurize it to 10 or 15 psi and open the bleeder screw and let it pour into a jar, then stop and refill the mstr cylinder and do it again, and again until clear purple fluid comes out.

JimC
May 10th, 99, 11:52 AM
Posted a similar question a while ago, the advice given was to flush with alcohol or DOT 5.

Gene Chas
May 10th, 99, 1:40 PM
Bob, your presuure bleeder would make my day! I spoke to a brake guy today and he definitely recommended NOT using a solvent, just the fluid to flush them out. Guys thanks for takin' the time to help.

Chris R
May 11th, 99, 7:10 PM
I just purchased all of the components to rebuild the brakes on my 66 today. My car has front discs also. I have also ordered brake lines from Classic Tube. Classic recommends using DOT 5 due to thier characteristics of resisting the elements that brake fluid goes thruogh. The place I bought my parts from told that soaking the parts in something called "denatured" alcohol should be done to clean them before using DOT 5. Im not sure if this is a good idea but another customer in the store overheard us talking and said that he did this in his 69 Buick a few years ago and hasnt had a problem yet. It is spendy at about 20 bucks a quart (DOT 5 that is), but I bought some anyway.

Hope this helps, Chris R.