Switching to DOT 5 Brake Fluid

[Dale S.]

Re: I have to agree, Norris

I read that Dot 5 does not absorb water. Therefore water collects in drops and rust forms where the drops are(cast pieces). I hope not as I have had Dot 5 in my C-2 for about 10 years. dale

[Dale S.]

Re: I have to agree, Norris

I read that Dot 5 does not absorb water. Therefore water collects in drops and rust forms where the drops are(cast pieces). I hope not as I have had Dot 5 in my C-2 for about 10 years. dale

[Terry M.]

Re: I have to agree, Norris

I think you will be OK so long as you don't top off your master cylinder with water, or open it outdoors while it is raining.
Water gets into a system with DOT3/4 because glycol hydraulic fluid has an affinity for water. DOT5 has no affinity for water, therefore short of the above actions, there is no water to get into the system. I am probably due for the second flush of the DOT5 system on the 1970. There was no sign of anything other than DOT5 in it when I last flushed it a decade ago. I still flush it every ten years, just because it seems like the thing to do. The only sign of deterioration was the fluid is no longer purple.

[Terry M.]

Re: I have to agree, Norris

I think you will be OK so long as you don't top off your master cylinder with water, or open it outdoors while it is raining.
Water gets into a system with DOT3/4 because glycol hydraulic fluid has an affinity for water. DOT5 has no affinity for water, therefore short of the above actions, there is no water to get into the system. I am probably due for the second flush of the DOT5 system on the 1970. There was no sign of anything other than DOT5 in it when I last flushed it a decade ago. I still flush it every ten years, just because it seems like the thing to do. The only sign of deterioration was the fluid is no longer purple.

[john daly]

Re: Switching to DOT 5 Brake Fluid

hi terry,

I beleive the SAE paper you are referring to is SAE-740128 titled "The Performance Characteristics of Silicone based fluid" The abstract reads:

Silicone based brake fluids have demonstrated performance characteristics that are improvements over current brake fluids. They do not absorb water through elastomeric brake hoses, and their boiling point and low temperature viscosity do not change in service. The tendency toward brake system corrosion and the vapor pressure of silicone brake fluids are minimal. Silicone brake fluids are compatible with brake system components and will function as an effective brake fluid even when mixed with glycol brake fluids.

hope this helps

john

[john daly]

Re: Switching to DOT 5 Brake Fluid

hi terry,

I beleive the SAE paper you are referring to is SAE-740128 titled "The Performance Characteristics of Silicone based fluid" The abstract reads:

Silicone based brake fluids have demonstrated performance characteristics that are improvements over current brake fluids. They do not absorb water through elastomeric brake hoses, and their boiling point and low temperature viscosity do not change in service. The tendency toward brake system corrosion and the vapor pressure of silicone brake fluids are minimal. Silicone brake fluids are compatible with brake system components and will function as an effective brake fluid even when mixed with glycol brake fluids.

hope this helps

john

[Dale S.]

I guess I am due *NM*

[Dale S.]

I guess I am due *NM*

[Harmon C.]

Re: I have to agree, Norris

Mike

I think on this subject some tend to overkill on how much cleaning needs to be done. I have never torn fresh rebuilt calipers apart and have had good results. Each person who restores a Corvette must decide how far to go with each parts restoration and we all go overboard sometimes.
Lyle

[Harmon C.]

Re: I have to agree, Norris

Mike

I think on this subject some tend to overkill on how much cleaning needs to be done. I have never torn fresh rebuilt calipers apart and have had good results. Each person who restores a Corvette must decide how far to go with each parts restoration and we all go overboard sometimes.
Lyle

[Gary Bishop]

A photo of Sludge.

Here is a photo of the sludge.

[Gary Bishop]

A photo of Sludge.

Here is a photo of the sludge.

[Mike McKown]

Re: A photo of Sludge.

My systems do not have signs of that in them. Aside from the obvious separation of large quantities of each type fluid, that looks like what you'd find in a Dot 3 system.

Looks like somebody just added one type fluid to the other to top off. You can't do that or you'll get the results you displayed. That looks like a large amount of water in your sample.

[Mike McKown]

Re: A photo of Sludge.

My systems do not have signs of that in them. Aside from the obvious separation of large quantities of each type fluid, that looks like what you'd find in a Dot 3 system.

Looks like somebody just added one type fluid to the other to top off. You can't do that or you'll get the results you displayed. That looks like a large amount of water in your sample.

[Terry M.]

Re: A photo of Sludge.

I have cans of DOT5 labeled as a STP product. The directions on the can direct one to use the DOT5 fluid to flush out the glycol fluid. The SAE paper I referenced earlier showed the results of using this method of installing DOT5, the black sludge, and specifically recommended against using this method.