Brake Fluid Reminder

[Mark57]

I recall a post about replacing DOT 3 brake fluid with DOT 5 as being the preferred way to proceed when flushing/servicing the brake system. I am about to undertake such tasks on my pick-up in the near future.

Can someone confirm this advice? Thanks.

<h5>Mark
'57 Transtar
3E-6/7-122 </h5>

[Tom Bredehoft]

I've had dot 5 in my coupe for six years, have not needed to add any, or had any problems with it. The system was completely purged of dot 3 before the dot 5 was added, however.

[img=left]http://www.alink.com/personal/tbredehoft/Bothcars.jpg[/img=left]
Tom Bredehoft
'53 Commander Coupe
'60 Lark VI
'05 Legacy Ltd Wagon
All three Indiana built OD cars

[Mark57]

quote:Originally posted by Tom B

I've had dot 5 in my coupe for six years, have not needed to add any, or had any problems with it. The system was completely purged of dot 3 before the dot 5 was added, however.

Tom Bredehoft

As I had thought. Thanks Tom.[8D]

<h5>Mark
'57 Transtar
3E-6/7-122 </h5>

[rockne10]

System should be completely cleaned with alcohol. I've also heard all rubber parts should be replaced. I prefer to simply keep the DOT 3 and flush it every five years. DOT 3 is hygroscopic, DOT 5 is not.

Ambient humidity will eventually enter any system. Hygroscopic fluid will evenly disperse the humidity, preventing freezing. Eventually, increased levels of hydrogen di-oxide in the metallic system will rust the line from the inside, unless it is periodically flushed.

Non-hygroscopic fluid can cause the hydrogen di-oxide to accumulate in pockets susceptible to interior oxidation or freezing.

I'd sure like to run that by a mechanical chemist to see if it makes any sense. [)]

And, if you replace your lines with stainless steel...

[Mark57]

quote:Originally posted by rockne10

System should be completely cleaned with alcohol. I've also heard all rubber parts should be replaced. I prefer to simply keep the DOT 3 and flush it every five years. DOT 3 is hygroscopic, DOT 5 is not.

Ambient humidity will eventually enter any system. Hygroscopic fluid will evenly disperse the humidity, preventing freezing. Eventually, increased levels of hydrogen di-oxide in the metallic system will rust the line from the inside, unless it is periodically flushed.

Non-hygroscopic fluid can cause the hydrogen di-oxide to accumulate in pockets susceptible to interior oxidation or freezing.

I'd sure like to run that by a mechanical chemist to see if it makes any sense. [)]

And, if you replace your lines with stainless steel...

So, like many things in life, the answer is a definite MAYBE![:0]

<h5>Mark
'57 Transtar
3E-6/7-122 </h5>

[fmarshall]

I use DOT4. Best thing to do with DOT 3, 4 or 5, is to get an extraction pump, like from Griots garage. The one I have comes with a reservoir that you fill with brake fuid and stick it in the reservoir. Then you go from bleeder to bleeder and crack open the bleeder into the hose and open the valve for suction. It takes about 20 minutes to replace all of the fluid in the system.

If you use a different color, it is real easy to see when you are done. Every 1-2 years.

[Skip Lackie]

I've had DOT 5 in two Studes and a Chevy for more than 25 years. One leak (my fault for not tightening a brake line nut enough) and one failure of a brake light switch. If you're gonna be replacing all the rubber parts (hoses and master and wheel cylinder parts) anyway, I would recommend it. You DO need to get all the old fluid out of the steel lines, but a little alcohol or lacquer thinner and some compressed air will take care of that.

If you don't need to replace everything, then just stick to regular brake fluid and bleed the brown stuff out occasionally.

Skip Lackie
Washington DC

[53k]

I have had trouble with DOT 5 leaking where DOT 3 doesn't (at pipe fittings on an Avanti and on rebuilt cylinders on my '53. Billy Thompson at White Post Restorations DOES NOT recommend using DOT5 (at least in the cylinders they re-sleeve in brass).


[img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/R-4.JPG[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/64L.JPG[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/64P.jpg[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/53K.jpg[/img=right]Paul Johnson
'53 Commander Starliner (since 1966)
'64 Daytona Wagonaire (original owner)
'64 Daytona Convertible (2006)
Museum R-4 engine

[Mark57]

quote:Originally posted by Skip Lackie

I've had DOT 5 in two Studes and a Chevy for more than 25 years. One leak (my fault for not tightening a brake line nut enough) and one failure of a brake light switch. If you're gonna be replacing all the rubber parts (hoses and master and wheel cylinder parts) anyway, I would recommend it. You DO need to get all the old fluid out of the steel lines, but a little alcohol or lacquer thinner and some compressed air will take care of that.

If you don't need to replace everything, then just stick to regular brake fluid and bleed the brown stuff out occasionally.

Skip Lackie
Washington DC

Thanks Skip... as I only am replacing the 2 front wheel cylinders (back ones and Master are VG), that makes the most sense for the time being.

<h5>Mark
'57 Transtar
3E-6/7-122 </h5>