I have a 1996 K3500 that I got off a service company. They changed out the brake fluid to DOT5. I have anti-lock brakes. Is it OK to have DOT5 in these??? Someone said I should only use at most DOT4 because DOT5 will foam in the lines. http://www.dieselplace.com/forum/smileys/Geek.gif

This is not good! Dot 5 is a silicone base. ABS brakes pump the fluid and silicone will foam and give a spongy break.


More important. Many Dot 3 & 4 brake system parts are not compatable with Dot 5 and will soften or corrode.


Another reason manufacturers like the DOT 3 and 4 fluids is that it is hydroscopic and holds water. At first you may think this is a bad thing. But it keeps the water in suspension and it does not settle in low spots and cause rust and corrosion in the brake system. Whereas with DOT 5 the water will puddle in the low spots. (Hum? one for the emulsify-demulsify diesel fuel additive affectionatos to think abouthttp://www.dieselplace.com/forum/smileys/Ermm.gif).


Because it holds water, it should be changed every 2 years.Edited by: JohnnyO

Good info JohnnyO. But how does one go about changing the brake fluid? That, and power steering, are the only fluids I don't change regularly. http://www.dieselplace.com/forum/smileys/Unhappy.gif

Here's the easiest way to change the brake fluid, and have all the air out when your are done. I would start by emptying out most of the fluid in the master cylinder first, so you are not pushing more DOT 5 through the system. Then use this bleeder to push all the old fluid out, and new fluid in.
http://www.motiveproducts.com/Power%20Bleeder.JPG


http://www.motiveproducts.com/index.htm

http://www.dieselplace.com/forum/smileys/Ermm.gif Seems strange that the pipline service company would run something like DOT5 in their brakes if it is soo bad. Should I run DOT4 then? Isnt that synthetic?

The reason I ask is that it gets to -60F below here at times and synthetic seems to be the thing to use to make sure all the parts work.

Maybe it was really DOT5.1 Reading the page below seems to indicate it is OK. Hmmmm.

http://www.synlube.com/brake.htm

Hi Jim Wilson -


Regarding your question on how to change the fluid. I wrote something up on brake fluids and how to change the fluid.


I posted it under:


HD & 3500 Trucks
Brake System & Fluid MaintenanceEdited by: JohnnyO

Whoa, that's quite the post! Thanks...