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Brake fluid and lines #2957126
08/24/21 11:48 PM
08/24/21 11:48 PM
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robertop Offline OP
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OK, guys, here we go again. I just got my 69 Hemi bird's power brake master cylinder from White Post and they do not recommend DOT 5 brake fluid, a bummer.
The question now is this: to prevent leakage of some DOT 3 or 4 on my underhood paint, does anybody recommend any type of sealant on the brake line fittings before installation on the master cylinder? Also, will I have to flush all the lines of any DOT 5? I did not observe any leaks from the front or back lines at the wheels, but I don't remember the compatibility of different fluids.

Re: Brake fluid and lines [Re: robertop] #2957133
08/25/21 12:03 AM
08/25/21 12:03 AM
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Originally Posted by robertop
OK, guys, here we go again. I just got my 69 Hemi bird's power brake master cylinder from White Post and they do not recommend DOT 5 brake fluid, a bummer.
The question now is this: to prevent leakage of some DOT 3 or 4 on my underhood paint, does anybody recommend any type of sealant on the brake line fittings before installation on the master cylinder? Also, will I have to flush all the lines of any DOT 5? I did not observe any leaks from the front or back lines at the wheels, but I don't remember the compatibility of different fluids.


Ask them WHY they don't recommend it.
If they're concerned about a "spongy" feel of the pedal only,
that's something you can accept.

Re: Brake fluid and lines [Re: PhillyRag] #2957160
08/25/21 04:06 AM
08/25/21 04:06 AM
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Copper Dart Offline
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i too would like to hear why no dot 5 fluid?
i have had several harleys that use dot 5 and the custom chopper i built i used dot 5 too.
i understand about water naturally dissipating in dot 3-4 and the troubles with it accumulating in low areas when using dot 5 but the function/feel of dot 5 shouldnt be an issue.
i am going to use dot 5 and make it a point to do a fluid flush annually on my toys. Paint damage from leaks is more of an issue than having to service cars that mostly sit in the garage looking pretty.
Not to highjack this post but I would love to hear other viewpoints on dot 5 and dot 4 pros and cons.
copper


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Ricky Valdes
Re: Brake fluid and lines [Re: robertop] #2957167
08/25/21 07:42 AM
08/25/21 07:42 AM
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SportF Offline
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Do you think DOT5 will cause brake failure? DO you think NAPA or anyone else would sell you the stuff if that was even a small possibility?

There is so much BS on this fluid out there its astounding! Use it and forget about it.

Re: Brake fluid and lines [Re: SportF] #2957188
08/25/21 09:22 AM
08/25/21 09:22 AM
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AMEN!!!

Joe

Re: Brake fluid and lines [Re: jlatessa] #2957193
08/25/21 09:35 AM
08/25/21 09:35 AM
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therocks Offline
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Just dont mix them The early wheel cyls etc some would swell with 5.I used it in my 58 Harley when I installed all new stuff That was like 30 years ago.Never a problem but it was all new.Rocky


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Re: Brake fluid and lines [Re: therocks] #2957202
08/25/21 10:19 AM
08/25/21 10:19 AM
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Copper Dart Offline
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Just my opinion and what ive come to understand (or misunderstand so check for yourself) about DOT 3-4 and DOT 5 brake fluids.
Dot 3-4 is water based, Dot 5 is silicone based. Don't mix them, flush thoroughly before converting from one to the other.
On the other hand, maybe post the short term and long term findings of not flushing and mixing of the 2 types of fluids in your project, I know I for one would be very interested in the outcomes. smile
H2O always, always finds its way into the brake system PERIOD.
Dot 4 easily dissipates the sneaky H2o throughout the brake system and dilutes it making it a non-issue.
Dot 5 on the other hand, does NOT mix with water and has a habit of accumulating in low points/bottoms of the brake lines and system.
As Dot 4 collects moisture, it becomes increasingly corrosive throughout the system attacking mostly the master, proportioning valve, wheel cylinders and calipers.
This is why most highly recommend servicing the brake fluids.
Dot 5 allows tiny water drops to sit in a relatively small areas and do the wonders that water does to metals so efficiently and effectively.
We affectionately refer to as rust and rust is no friend to anything about this hobby! So the water just sits and works like a microscopic drill bit until it breaches the barriers we call brake lines. Scary part is it could cause a complete hydraulic system failure (leak) possibly without warning and most likely at a emergency stopping situation.
Maintenance is a must with all aspects of this hobby folks.
These are my expressed opinions and are not the opinion of the station or this broadcasting service.
Copper

Last edited by Copper Dart; 08/25/21 10:27 AM.

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Re: Brake fluid and lines [Re: SportF] #2957204
08/25/21 10:23 AM
08/25/21 10:23 AM
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Originally Posted by SportF
Do you think DOT5 will cause brake failure? DO you think NAPA or anyone else would sell you the stuff if that was even a small possibility?

There is so much BS on this fluid out there its astounding! Use it and forget about it.

iagree And we have used it on sevedral buiilds with no issue other than one needs to bleed it a bit slower as it seems to have more off a tendency to aerate if you push the fluid through to fast. Also not a bad idea IMO to re-bleed once or twice after sitting overnight.

NO SEALANTS of any kind as the seal is made on the flare not the threads.
IF you need to flush the lines, do so with brake clean and low pressure air. Do be aware that things like calipers, master, wheel cylinders will need to be removed preferably taken apart and cleaned or replaced twocents beer

Re: Brake fluid and lines [Re: TJP] #2957342
08/25/21 04:51 PM
08/25/21 04:51 PM
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Not sure of their reasoning but I just put Wilwoods on my Fury and their instructions specifically said to not use Dot 5. 3, 4 and 5.1 were all ok, but they don't want you to use Dot 5.


'18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III
Re: Brake fluid and lines [Re: Copper Dart] #2957365
08/25/21 06:03 PM
08/25/21 06:03 PM
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Originally Posted by Copper Dart
i too would like to hear why no dot 5 fluid?
i have had several harleys that use dot 5 and the custom chopper i built i used dot 5 too.
i understand about water naturally dissipating in dot 3-4 and the troubles with it accumulating in low areas when using dot 5 but the function/feel of dot 5 shouldnt be an issue.
i am going to use dot 5 and make it a point to do a fluid flush annually on my toys. Paint damage from leaks is more of an issue than having to service cars that mostly sit in the garage looking pretty.
Not to highjack this post but I would love to hear other viewpoints on dot 5 and dot 4 pros and cons.
copper


Moisture is an issue with either fluid.
Flushing very periodically is a must for either.
Just a question of rust/corrosion in a few areas or across entire system.
I thought that rubber sealing was an issue with 5.
3/4 has a tendency to swell seals for better a seal.
But no such reaction with 5.
Therefore there could be minor leakage in areas.
Does 3/4 mixed with H20 have a more "corrosive" effect then just plain H20 ??

Re: Brake fluid and lines [Re: PhillyRag] #2957437
08/25/21 08:54 PM
08/25/21 08:54 PM
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A kwik rundown on the fluids says that 3, 4, & 5.1 are all glycol based hydroscopic fluids (absorb moisture).
Dot 5 is silicone based and does not.
I'm sure there's more to be learned about the subject wink

BRAKE FLUID INFO

Re: Brake fluid and lines [Re: Copper Dart] #2957516
08/26/21 04:04 AM
08/26/21 04:04 AM
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robertop Offline OP
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A white Post told me the supplier of seals they use does not like DOT5 because it swells the seals in time and causes failures. Now I have a system full of DOT 5 and it should be well flushed before putting in some 3 or 4 fluid; a PIA. Is anybody out there that has used DOT 5 for a few years without problems?

Re: Brake fluid and lines [Re: robertop] #2957534
08/26/21 07:54 AM
08/26/21 07:54 AM
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SportF Offline
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Let me say this again, if it swelled seals or caused failure because its mixed, nobody would sell it. Just think of the legal liability.

With hundreds of millions of vehicles around the world this stuff gets mixed every day everywhere.

Internet BS, and it just won't go away.

Re: Brake fluid and lines [Re: SportF] #2957546
08/26/21 09:40 AM
08/26/21 09:40 AM
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Originally Posted by SportF
Let me say this again, if it swelled seals or caused failure because its mixed, nobody would sell it. Just think of the legal liability.

With hundreds of millions of vehicles around the world this stuff gets mixed every day everywhere.

Internet BS, and it just won't go away.
iagree


Common sense, the least common of all the senses.
Mom.

For fear of ridicule, society stifles creativity.
Ricky Valdes
Re: Brake fluid and lines [Re: SportF] #2957549
08/26/21 09:51 AM
08/26/21 09:51 AM
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Silicone fluid in my 65 Satellite with a FACTORY front disc conversion has been flawless for over 20 years with no replacement of anything. (master or wheel cyls etc) This car is a slightly driven hobby car. On the other hand, my race car with Wilwood front discs did not like silicone fluid . The pistons would not retract properly in the calipers causing extreme drag on the front wheels. Same story with Aerospace front discs, but when I flushed and went to Dot 3, the Aerospace brakes have also been flawless for a number of years now. Just my experience with these fluids.


62 Dodge Dart Wagon 65 Plymouth Satellite
Re: Brake fluid and lines [Re: robertop] #2957554
08/26/21 10:10 AM
08/26/21 10:10 AM
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Not sure anyone actually responded to OPs original question. His question is should he put sealant on brake line fittings. Answer is absolutely not. Sealant is only used on tapered fittings such as pipe thread.

Re: Brake fluid and lines [Re: 70Duster] #2957560
08/26/21 10:30 AM
08/26/21 10:30 AM
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Originally Posted by 70Duster
Not sure anyone actually responded to OPs original question. His question is should he put sealant on brake line fittings. Answer is absolutely not. Sealant is only used on tapered fittings such as pipe thread.


hey Hey Hey now, you did not read my previous post in it's entirety spank spank LOL beer

Re: Brake fluid and lines [Re: TJP] #2957759
08/26/21 08:10 PM
08/26/21 08:10 PM
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robertop Offline OP
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[Well, guys , here is my final reply: if I decide to go back to DOT 3 or 4 and flush the system, do you have an idea of how much fluid we are talking about? The car is a 69 Hemi roadrunner with front discs. Thank you all!

Re: Brake fluid and lines [Re: robertop] #2957966
08/27/21 11:24 AM
08/27/21 11:24 AM
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two pints should be sufficient. three if you really want to be absolutely, positively, sure.
beer

Re: Brake fluid and lines [Re: moparx] #2958002
08/27/21 01:36 PM
08/27/21 01:36 PM
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Originally Posted by moparx
two pints should be sufficient. three if you really want to be absolutely, positively, sure.
beer
iagree up scope wrench


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