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Synthetic Brake Fluid

Started by DUC, January 09, 2011, 03:21:18 AM

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DUC

I have went thru all the threads on this topic. But I still have to confirm before I move forward. I had recently rebuit my brake system on my 54 with new rubber on the MC, WC, thoughly cleaned the hydrovac booster, cleaned the hard lines, and replace the soft lines with braided SS. I used Valvoline Synthetic DOT 3 & 4 brake fluid (which is glycol ether) to lube the parts during assembly. At this point I have not filled the system with fluid yet.

My question is it safe, especially with the hydrovac booster?
Chris Henry

1954 Cadillac Series 62 Sedan

Mike Josephic CLC #3877

I'm not sure what your question is.

Using DOT type 4 or type 3 would be perfectly fine.  The "synthetic" term is
kind of meaningless.  They are both "glycol" types in generic terms.

However, I would probably go with type 4 as it has a higher boiling point and
a better additive package vs. type 3.  Both fluids are fully compatable with each
other.  However, it makes no sense to mix them together because you lose the
benefit of DOT 4's better properties.  DOT 4 has been the new industry standard
since 2006.   

You can check this site for more info:
http://www.v8register.net/articles/Brake%20fluids%20article%20R5%20Bob%20Owen%20230109.pdf

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

DUC

There's no mixing involve. I think it just means its compatible with both types.

Heres what I bought.
http://www.autozone.com/autozone/accessories/Valvoline-12-oz-DOT-3-and-4-synthetic-brake-fluid/_/N-25ah?counter=0&filterByKeyWord=brake+fluid&fromString=search&itemIdentifier=33408_0_0_

I wanted to know if it was ok to use with the old booster seals that I cleaned and reinstalled.
Chris Henry

1954 Cadillac Series 62 Sedan

dplotkin

I have DOT 5 in a high performance show car with expensive paint & stainless steel lines. I used DOT 5 because stainless steel lines are harder to seal and present a small but very consequential risk of leakage & wrecked paint. I use DOT 3 in everything else and will use 4 when I flush them.

For what it is worth, I would not reccomend DOT 5 in old cars unless you are using stainless steel lines. Pedal feel is not quite as good. It cannot be used in cars with pressure type stop lamp switches as it will wreck the switch & leak out. I know few Cadillac owners drag race their cars but that is how I discovered DOT 5's cheif limitation, when the line lock (anti-roll staging device) on my 61 Plymouth leaked out the DOT 5 I use. Stick with conventional brake fluid in antiques, but watch that paint!!!

Dan
56 Fleetwood Sixty Special (Starlight silver over Dawn Grey)
60 Buick Electra six window
60 Chrysler 300 F Coupe
61 Plymouth Savoy Ram Inducted 413 Superstock
62 Pontiac Bonneville Vista
63 Chevy Impala convertable
63 Ford Galaxie XL fastback
65 Corvette convertable 396
68 Chrysler New Yorker

Mike Josephic CLC #3877

What did you clean the lines with?  Alcohol is the normally recommended
product.  If you did that, then installed new rubber, lubing it with the fluid,
the product you bought is perfectly fine to use.  Despite the name, in the
specs it states "Meets or exceeds DOT 4" so that's fine.

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

Don Boshara #594

I have had DOT-5 in my '40 with a pressure switch and standard steel brake lines for 28 years with no problems. Did flush the system and replaced the fluid about 10 years ago. I wouldn't use DOT-5 in a car with power brakes where there's a chance that the booster diaphragm could fail and allow the brake fluid to be sucked into the engine.
1940 Sixty Special
1966 Mustang Cpe

dplotkin

I forgot about that. Silicone turns to sand when burned, doesn't it?
56 Fleetwood Sixty Special (Starlight silver over Dawn Grey)
60 Buick Electra six window
60 Chrysler 300 F Coupe
61 Plymouth Savoy Ram Inducted 413 Superstock
62 Pontiac Bonneville Vista
63 Chevy Impala convertable
63 Ford Galaxie XL fastback
65 Corvette convertable 396
68 Chrysler New Yorker

DUC

Mike Josephic, first I blew the old fluid out with my air compressor. Then I first flushed the lines with aerosol carb cleaner followed by aerosol brake cleaner several times blowing it out the each time. The reason I used the carb cleaner is it cut through the gunk in the wheel cylinders better then brake cleaner.

So why do you use alcohol?
Chris Henry

1954 Cadillac Series 62 Sedan

Mike Josephic CLC #3877

Mike Josephic, first I blew the old fluid out with my air compressor. Then I first flushed the lines with aerosol carb cleaner followed by aerosol brake cleaner several times blowing it out the each time. The reason I used the carb cleaner is it cut through the gunk in the wheel cylinders better then brake cleaner.

So why do you use alcohol?
   

Chris:

The reason alcohol is best for this use (denatured alcohol is one kind, available at any
hardware store) is because those other cleaners you mentioned are not good for the
rubber parts in the brake system.  Carb cleaner, brake cleaner can contain chemicals such
as acetone, trichloroethylene, etc., that will be absorbed by the rubber and cause it to
swell.

This, of course, leads to possible leaks at the wheel cylinders and elsewhere.

So unless you are ABLSOUTELY sure that none of this came into contact with your
rubber parts, you may want to consider replacing those parts before recharging the
system.

Mike



1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

DUC

I didn't reuse the old rubber. All new wheel cyclinder rubbers, new braided lines were used, and the booster rubber seals where cleaned with warm/hot soapy water and thoroughly rinsed/dryed.

So no, none of the rubber came into contact with the mentioned cleaners.

Denatured alcohol is safe for rubber parts... I didn't know that.


Has anyone put the self adjusting brake mechanism from a newer model on these cars?


Chris Henry

1954 Cadillac Series 62 Sedan