Flushing an old brake system...What's a Safe chemical to use?

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Hemioutlaw

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Hey y'all,
In the process of freshening up the brake system on my 69' Cuda that has sat for a while and prior to reassembly I'd like to run some type of cleaner or solvent thru the lines. Was planning on disconnecting the lines at the calipers and rear brakes and introducing the cleaner followed shortly thereafter with an air blast at the MC connections.

There's also an OEM proportioning valve and Line-Loc in the system which leads me to two questions:

1) As I obviously don't want to introduce any contaminants into the system is there a preferable product to use that won't leave any harmful residue. I've got sea-foam, Gumout and plenty of brake cleaner here but just a little curious as to which would be best.

2) Also I think I can flush the lines without disconnecting at the proportioning valve and Line -Loc but can't admit to being certain about this.
 
I WOULD NOT use any solvent//any kind of solvent will probably destroy the piston seals in the master cylinder /calipers/wheel cylinders or the o rings in your proportioning valve /line lock.... brake fluid itself is a good cleaner//fill the system let it sit a few hours and flush with brake fluid...It will absorb any water in the system..
 
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Hey y'all,
In the process of freshening up the brake system on my 69' Cuda that has sat for a while and prior to reassembly I'd like to run some type of cleaner or solvent thru the lines. Was planning on disconnecting the lines at the calipers and rear brakes and introducing the cleaner followed shortly thereafter with an air blast at the MC connections.

There's also an OEM proportioning valve and Line-Loc in the system which leads me to two questions:

1) As I obviously don't want to introduce any contaminants into the system is there a preferable product to use that won't leave any harmful residue. I've got sea-foam, Gumout and plenty of brake cleaner here but just a little curious as to which would be best.

2) Also I think I can flush the lines without disconnecting at the proportioning valve and Line -Loc but can't admit to being certain about this.
Denatured alcohol.
 
Use brake clean in a can aerosol format. That’s what it’s made for. Then blow dry after. Wait a day before filling with fluid to allow any possible residual pools of brake clean to evaporate in case some was left after blowing with compressed air.
 
Well not surprising but as usual nobodies in agreement on what to use .....Ha

For the folks that recommended using brake fluid itself it's without a doubt not going to cause any problems other than how the hell do I introduce it back into the system (brake lines) when its not under hydraulic pressure... I've already got one of those little pump oil cans and a super small funnel but i've yet to attempt it preferring to elicit at least a days worth of responses and opinions prior to flushing.

Ideally the aerosol based brake cleaner with the plastic spray tip would be the easiest and the cans I have clearly state that they are residue free but nowhere on the can does it mention actual flushing of lines...

To the internet I go and actually found an Alarming article (Welders Pay attention) on the active ingredient in Brake Fluid combining with Argon to form Phosgene which is Deadly.

Be Extremely Careful When Using Brake Cleaner!


Internet consensus: Use Alcohol, Brake Fluid or Brake cleaner.

Back to square one so guess i'll just hook the lines to my new MC and try gravity bleeding it with Brake fluid.
 
Gravity works. On most brake systems.
Brake cleaner is to clean/degrease external brake components, like rinsing off brake dust from backing plates.
Will remove oil from the shoes to some extent.
Denatured alcohol is one, brake fluid is the other.
considering the consequences of using anything other than brake fluid,i would stick with what actually belongs in there.
 
To add,suck out everything from master cylinder and start with fresh.
With front disc brakes,squeeze calipers in,and then remove fluid from master.gets rid of a lot of fluid. Less fresh fluid needed to flush afterwards.

a friend has a coleman stove fuel tank he uses, and flushes from bottom up. Fill tank, pump it up and away you go.
 
Well not surprising but as usual nobodies in agreement on what to use .....Ha

For the folks that recommended using brake fluid itself it's without a doubt not going to cause any problems other than how the hell do I introduce it back into the system (brake lines) when its not under hydraulic pressure... I've already got one of those little pump oil cans and a super small funnel but i've yet to attempt it preferring to elicit at least a days worth of responses and opinions prior to flushing.

Ideally the aerosol based brake cleaner with the plastic spray tip would be the easiest and the cans I have clearly state that they are residue free but nowhere on the can does it mention actual flushing of lines...

To the internet I go and actually found an Alarming article (Welders Pay attention) on the active ingredient in Brake Fluid combining with Argon to form Phosgene which is Deadly.

Be Extremely Careful When Using Brake Cleaner!


Internet consensus: Use Alcohol, Brake Fluid or Brake cleaner.

Back to square one so guess i'll just hook the lines to my new MC and try gravity bleeding it with Brake fluid.

the day is not over :poke:


a piece of silicone hose in fresh container of brake fluid on one end and a vacuum bleeder at the wheel cylinder/caliper
 
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