Ok, What do I need to do to replace DOT 5(silicon) brake fluid with DOT3? Do I need to replace seals? or do I have to replace hard parts as well. School me on this one... reason for replacement question is spongy pedal and poor hard braking. Any info will be a help. Thanks Dennis
You'll need to flush out your lines and replace all the rubber parts (seals, etc.). If you don't, the rubber can swell and render your brakes inoperable. Once done, you can relax and forget you even have brake fluid.
how can you tell dot 5 from dot 3 brake fluid ? the reason i ask, is because this got me wondering as to which fluid i have in my 55 pontiac. as far as i know, it has whatever fluid the car came with when new...nothing has been upgraded. so, if i have original type fluid...is it dot 5, or dot 3 ? is there a way to tell which kind is in my car just by feeling it, or smelling it ? nothing is wrong with my brakes...i am just curious as to which brake fluid is in it, incase i ever need to add any.
beetle juice, Your '55 definatly came with DOT 3. DOT 5 didnt come along till the early 80's I believe. I never switched one out but was told to go from #3 to #5 you just need to flush the system with alcohol. But thats not the same to go from #5 to #3.like was stated,gotta change the rubber stuff. I can tell the difference by smell and by the feel of it but you need to be familar with it to do that. Good Luck, Normal Norman
i'm not wanting to switch it...just wondering what is in it...more than likely, it's the old style dot 3. i was just wondering, in case i ever need to add brake fluid...so i don't put the wrong stuff in it. thanks.
I switched my f-150 to dot-5 , i just blead the system 3 times to get all the dot-3 out ,no issues at all.The seal swelling issues i've run into came from dot-3 in a dot-4 import
Anyone running DOT 4? I just redid everything in my 55 buick's brakes (new dual master, new lines, new wheel cylinders, hoses, everything). Master Power Brakes sent me a bottle of DOT 4, and I used that, I think it has a higher boiling point than DOT 3, but its still the same base chemical (glycol?) as DOT 3.
DOT4 is compatable with DOT3 and won't adversly affect the seals, etc. It just has a higher boiling point. It's the Dot5 Silicon fluid that doesn't mix with DOT3. I'm running DOT4 in my system. Flatman
Is there any problem with mixing "sythetic" DOT3 with regular DOT3. I didn't notice the "synthetic" label on the bottle until after I topped off the resevoir in the Galaxie. I hope I didn't screw up! Tom
dot 3 is usually brown or clear and dot 4 is blueish in color if anyone else was wondering about color identification... my .02
I swapped from 5 to 3. I flushed everything out good, still screwed everything up. Ruined every rubber part. Wheel cyl cups (twice), master cyl cups, every rubber line swelled closed. I will never use DOT 5 again!
Now that's a new one, "cause I have brand new silicone fluid that's not purple. I had a gallon jug of military silicone and it was purple and another single quart non-military that was purple. I put silicone in my '55 Chevy 29 years ago and it wasn't purple. Still have some of that in the bottle on the shelf. The most recent purchase of 2 quarts of silicone wasn't purple. Maybe I have new old stock fluid. Don't think there's a shelf life on this stuff.
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