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TR2/3/3A DOT 5 Brake Fluid

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R

Redoakboo

Jedi Warrior
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Is there a difference between DOT 5 and DOT 5.1? Most of these are synthetic, will these work O.K. in a 54 TR-2 brake system?

Dick
 
Yes, pretty big difference between 5 and 5.1. Former is silicone, later is glycol based. It's an odd numbering system.

Ed
 
It is my understanding that Dot 5 will NOT take paint off, whereas DOT 5.1 will take paint off. I like DOT 5 and use it in both my TR250 and my TR3.
Bob
 
Can't mix DOT 5 & 5.1. Advantage of DOT 5 is it is silicone and will not absorb moisture and like Bob said it won't take the paint of if you spill it. 5.1 has a higher boiling point and will absorb moisture. Not a good thing for our cars.
I have it in my TR3As system. Love it! Also in my TR250 however I kept have an issue with the clutch slave cylinder. The DOT5 would leak out if I didn't drive it for a while. From what I understand is that the molecules in silicone are smaller and can get past the rubber seals. So recently I rebuilt my slave cylinder and will be running DOT4 in it. I'm in Ohio so it will be some time yet before we get LBC weather around here.
 
I have used DOT5 in my GT6 for years, and have never had a leak of any kind so not sure if I am just lucky or what. I don't see a reason that it would leak though. Definitively it does not damage the paint as I spilled a bunch by accident.
Hope that helps
 
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