Brake Question

[chillydog]

On CUCV's and other military vehicles where the military used silicone brake fluid, can you just replace a brake system component-wheel cylinder, caliper, master cylinder, brake hoses-with a factory new unit, bleed it and go on, or, do you have to disassemble the new component, wash the factory DOT 3 assembly fluid off using alcohol, and reassemble the component with silicone brake fluid? In light of the cautions against mixing DOT 3(conventional) and DOT59 silicone) that you hear, in this case-- is it really a consideration ?
What do you guys do?
Thanks!

 

[rustystud]

On CUCV's and other military vehicles where the military used silicone brake fluid, can you just replace a brake system component-wheel cylinder, caliper, master cylinder, brake hoses-with a factory new unit, bleed it and go on, or, do you have to disassemble the new component, wash the factory DOT 3 assembly fluid off using alcohol, and reassemble the component with silicone brake fluid? In light of the cautions against mixing DOT 3(conventional) and DOT59 silicone) that you hear, in this case-- is it really a consideration ?
What do you guys do?
Thanks!

Most new components have brake "assembly lube" on them. It is compatible with silicone brake fluid. Besides you must bleed the system after installing a new component anyway. Now if the component was previously used in a DOT 3 system (calipers or master cylinder) I would tear it down and totally clean it before using it.

 

[Assel]

in my M1009 there was some DOT 4 , a shop replaced a brake hose and filled up the wrong fluid, so it had a mix (on a pre pre owner...) and I had a strange goo in the master cylinder, + about 2 yrs after that it started leaking everywhere so I replaced ANYTHING rubber on the brake system and filled it with DOT3. no problems since. If you want to switch the brake fluid from silikone to DOT3 I recommend changing everything thats rubber, changing the fluid somehow may eat up those components.. maybe someone can explain this better

 

[rustystud]

in my M1009 there was some DOT 4 , a shop replaced a brake hose and filled up the wrong fluid, so it had a mix (on a pre pre owner...) and I had a strange goo in the master cylinder, + about 2 yrs after that it started leaking everywhere so I replaced ANYTHING rubber on the brake system and filled it with DOT3. no problems since. If you want to switch the brake fluid from silikone to DOT3 I recommend changing everything thats rubber, changing the fluid somehow may eat up those components.. maybe someone can explain this better

I do know what you mean about the rubber components rotting faster after converting to DOT 3. I've seen this happen many times. I have no answer as to why this happens though. With DOT 5 (silicone fluid) the fluid actually helps lubricate the rubber seals and helps extend the rubber components lives. Maybe after years of having the silicone lubricate them then going to DOT 3 (which actually shortens rubbers life) it causes some massive rubber failure ? Maybe some chemical engineers can chime-in here and help explain this.