DOT 5 vs DOT 3
Thread Starter
Instructor
Joined: Mar 2001
Posts: 197
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From: Shoreham NY
DOT 5 vs DOT 3
About four years ago, I replaced the brakes on my '72 with stainless steel sleeved brake calipers, new master etc all from Muskegon Brake.(Excellent company by the way) Last month, I noticed a leak on the left front caliper and ordered a seal kit from Muskegon. When I took the caliper apart, two of the pistons were pitted and there was a lot of rubber residue in the caliper. Ordered new pistons flushed the entire system and replaced the DOT 5. Everything is back to normal. I am now being told by a Corvette repair shop owner that DOT 3 is a better way to go because DOT 5 causes damage to the rubber seals, lines and pistons. Any thoughts or reactions? :confused:
Burning Brakes
Joined: Jun 2002
Posts: 932
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From: Lyons IL
Re: DOT 5 vs DOT 3 (7vette2)
I am no expert but just changed all calipers and master and put Dot 5 silicone in. They say silicone won't cause corrision like dot 3 fluid.
Again no expert wait for others to respond.
Again no expert wait for others to respond.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Re: DOT 5 vs DOT 3 (7vette2)
When I did the exact same thing about 6 some years ago, put 5 in my rebuilt stainless system with new seals, it lasted about 4 years.....in front, still ok in back now...been about 6 years like I say....now the front's were rebuilt with the newer style O ring pistons....I allways use dot5 fluid, that dot3-4 trash is for the birds....might as well fill the system with water...
GENE
GENE
Burning Brakes
Joined: Dec 2001
Posts: 1,003
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From: GA
Re: DOT 5 vs DOT 3 (7vette2)
I was told that if you have a show car that doesn't see much road use or very little anyway that silicone (DOT5) is a good way to go otherwise dot 3 or 4 is better for those of us who like to get alot of use out of our rides. Proper care and servicing of the brake system to insure that moisture does not get into or should I say stay in the system will prevent corrosion from forming. Brake fluid will boil if it gets hot and air pockets will form and be replaced with moisture. I try to use a good high temp brake fluid and make sure it stays flushed every year or so. I haven't had my vette quite a year yet but my other vehicles get the treatment and this one will too. Motorcycles are a real pain for this problem and from what I've heard vette's are a real PITA for brakes. I've been lucky enough not to be afflicted with this yet but I'm sure it'll come sooner or later. Sorry so long but thought I'd ramble :cheers:
Safety Car
Joined: Feb 1999
Posts: 3,631
Likes: 14
From: Fountain Hills AZ
Re: DOT 5 vs DOT 3 (7vette2)
I think your "expert" may be just parroting another urban legend. Most of the deterioration that you saw in your system was caused by water and by the corrosion that was caused by water. Dot 5 greatly reduces the amount of water that forms in the system and that's why it's recommended for classics that don't see a lot of miles. Besides it's much higher cost and the need to completely flush the non-silicon fluid before using it, Dot 5 has more "give". That "give" makes it unpopular with road racers and unsuited for use in ABS systems but it's not anything that would be noticed in our cars under normal use.
Race Director
Joined: Jul 2002
Posts: 13,858
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From: A 12/8 man in a 4/4 world
Re: DOT 5 vs DOT 3 (7vette2)
i put rebuilt rear calipers on recently. the guy at the corvette parts store recomended dot 5. he sez thats all they use when doing break systems.
who am i to argue. no problems with braking system altho its only been a coupla weeks
who am i to argue. no problems with braking system altho its only been a coupla weeks
Le Mans Master
Joined: Apr 1999
Posts: 6,134
Likes: 46
From: Raleigh North Carolina
Re: DOT 5 vs DOT 3 (Got79Fever)
Put DOT 5 in my C2 in 1983... opened it up last year and the fluid is as clean as the day I put it in. No water, no corrosion, no crud. I drained it all into a container and re-used it. No problems whatsoever. Firm brake pedal.
Just converted my 70 to DOT 5, am converting my two Mustangs, Silverado, and Crown Victoria to DOT 5, and am converting a 1980 Vette to DOT 5 today.
Any problems with this stuff are due to in-ept installation... failure to properly service the system before changeover. A system with DOT 3/4 will normally have "rust rings" in the master cylinder. Bleeding the system allows the seals to go past the rust rings and get chewed up by the rust. Then you have a mushy pedal because the seals are tore up, and it all gets blamed on the DOT 5.
However... even though it is great stuff.. the seals will still eventually fail, and you will get leaks. The seals take a "set" and lose their elasticity, then start to seep. You still have to "rebuild" the system now & then.
I have personally tested all or most of the myths that I have heard on this forum about DOT 5... they are just that .... myths.
The only one that I haven't bothered to test is the "high altitude" one.
Just converted my 70 to DOT 5, am converting my two Mustangs, Silverado, and Crown Victoria to DOT 5, and am converting a 1980 Vette to DOT 5 today.
Any problems with this stuff are due to in-ept installation... failure to properly service the system before changeover. A system with DOT 3/4 will normally have "rust rings" in the master cylinder. Bleeding the system allows the seals to go past the rust rings and get chewed up by the rust. Then you have a mushy pedal because the seals are tore up, and it all gets blamed on the DOT 5.
However... even though it is great stuff.. the seals will still eventually fail, and you will get leaks. The seals take a "set" and lose their elasticity, then start to seep. You still have to "rebuild" the system now & then.
I have personally tested all or most of the myths that I have heard on this forum about DOT 5... they are just that .... myths.
The only one that I haven't bothered to test is the "high altitude" one.
