Silicone brake fluid replacement

[Z71]

Is it necessary to periodically replace the silicone brake fluid (DOT5) in these trucks? I have not replaced mine since I bought the truck more than a decade ago. I always replace regular DOT 3 and DOT 4 brake fluids on my cars, trucks, and motorcycles every two years because it is hygroscopic (absorbs water) and causes corrosion in the brake system. DOT 5 silicone fluid is not hygroscopic. Does it deteriorate with age?

Do you need to remove the vent line on top of the master cylinder to remove the lid itself to add brake fluid if you choose to bleed to brakes and replace the fluid?

 

[dozer1]

1. By all means YES. Dot 5 needs periodic replacement.
2. I would download the TM'S for details on the bleeding procedure.

Lastly I will post 2 links that provide a wealth of information on the different types of brake fluid that you mentioned. I continue to site these 2 links when this subject comes up because I personally was trained at Motorcycle Mechanics Institute in Orlando Fl. and the information is exactly the same as I remember it from back then. You just might find that the property you mentioned for DOT 3/4 fluid (hygroscopic) is not necessarily such a swear word. Enjoy the articles. D.O.T. 5 Brake Fluid
DOT 3-4 Verses DOT 5. Which brake fluid should I use?