Re: How do YOU do a brake fluid flush ?
[Re: dOoC]
#2742119
02/11/20 11:13 PM
02/11/20 11:13 PM
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Joined: Dec 2005
Posts: 11,611 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,611
Fulton County, PA
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Well cMac ... how would YOU shuck and jive if you jsta quoted on a complete brake fluid flush for 180$ when the way they do it does NOT flush out ALL the contaminated fluid ? I just clean the MC, add clean fluid and push it out all 4 corners until it runs clean. Call it a day.
If the results don't match the theory, change the theory.
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Re: How do YOU do a brake fluid flush ?
[Re: CMcAllister]
#2742153
02/12/20 01:24 AM
02/12/20 01:24 AM
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Joined: Jan 2003
Posts: 3,122 Auburn WA
Dave_J
master
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master
Joined: Jan 2003
Posts: 3,122
Auburn WA
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The only way to totaly get the calipar 100% clean is to pull it apart. No amount of bleeding will get all the crud out. But, is it needed most times? NO.
If I buy a used car and know the brake fluid is Expresso colored its time to pull the piston (s) out and clean. This is when I spend the $100 bucks or so and get all new flex hoses too.
Case in point. My 78 LRT has been sitting dead for 15 years. I am building its 410 stroker now and when I get the truck in the shop I will be replacing the master cylinder to a 2 bolt, the vac booster, the rubber flex hoses and any of the steel lines as needed. I will be pulling the Calipers and wheel cylinders apart to clean and inspect them. Its easy work.
One of the first things I drilled into my sons head, "If you add to the GO you have to add to the WHOA" .
Retired, US ARMY 1973-1994 ASE mechanic, Electrical 1994-1997 Retired GTE/VERIZON/FRONTIER 1997-2015
Posting cheap tech help (CRAP) here since Nov 97, 1000's of posts, some may be good.
03 Suzuki Burgman 650(Burger King) Scooter 65 Formula S Cuda 78 Little Red Express Truck 98 Buick Regal (wifes car)
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Re: How do YOU do a brake fluid flush ?
[Re: dOoC]
#2742193
02/12/20 10:12 AM
02/12/20 10:12 AM
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Joined: Dec 2007
Posts: 18,157 Mass
DAYCLONA
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 18,157
Mass
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My understanding with DOT5 is that the system has to be entirely flushed COMPLETELY ..,, the plus with 5 is that you never have to worry about any moisture contamination But there can/could be issues with seal compatibility, DOT5 can deteriorate or swell some seals depending on their rubber composition...
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Re: How do YOU do a brake fluid flush ?
[Re: DAYCLONA]
#2742239
02/12/20 12:31 PM
02/12/20 12:31 PM
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Joined: Dec 2005
Posts: 11,611 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,611
Fulton County, PA
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The only way to totaly get the calipar 100% clean is to pull it apart. No amount of bleeding will get all the crud out. True. But fluid can become dirty, contaminated and/or absorb moisture. Clean fluid and bleeding usually helps a pedal if you're paying attention.
If the results don't match the theory, change the theory.
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Re: How do YOU do a brake fluid flush ?
[Re: Cuda340]
#2742642
02/13/20 07:04 PM
02/13/20 07:04 PM
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Joined: Jan 2003
Posts: 1,482 Lake Orion, MI
goldduster318
pro stock
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pro stock
Joined: Jan 2003
Posts: 1,482
Lake Orion, MI
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[ DOT 5 is silicone based, but from my understanding they can be mixed with DOT3 &4. The DOT won't leave it up to the end user to make that call whether they can be mixed or not, they are compatible correct? Please elaborate on pedal feel. Does the DOT 5 compress more than the glycol based 3 and 4? On a fresh system why would it be a disadvantage to run 5?
Jeff DOT5 could cause some gelation or possibly be incompatible with the seals in the master cylinder as well. Chemicals that aren't intended to be mixed. DOT5 can't absorb water or air from the fluid, it will not be absorbed and is more difficult to bleed, will not keep the water in suspension so any pools of water (there is moisture in the air) won't benefit from any protection the gylcol fluid could provide. You absolutely want the fluid to absorb it vs it pooling separately (like oil and water separate) This along with the slightly higher compressibility would make your pedal longer. It also will not flow through your ABS valves like the glycol fluid, so it will mess with the calibration at the very least. Maybe I’m missing something but how can fluid become dirty, contaminated and have moisture if the system is closed? Now if you have a line brake then I say maybe. The system is absolutely not closed. The master cylinder has venting in it in all cases so fluid can flow when there is a leak or a need for more volume (such as pumping). They are usually venting slits or small holes in the membrane that are hard to see. The dirt is usually either from pushing the pistons back in during a pad change OR some level of leeching from the rubber parts, or wear of the seals or bores.
Last edited by goldduster318; 02/13/20 07:08 PM.
'70 Duster 470hp 340/T56 Magnum/8 3/4 3.23 Sure-Grip
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Re: How do YOU do a brake fluid flush ?
[Re: cudaman1969]
#2742643
02/13/20 07:04 PM
02/13/20 07:04 PM
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Joined: Jan 2003
Posts: 1,894 Harriman NY
71GTX471
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,894
Harriman NY
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Cudaman its foolish not flush & bleed your brakes,It takes so little & the gaines are huge. Maybe I’m missing something but how can fluid become dirty, contaminated and have moisture if the system is closed? Now if you have a line brake then I say maybe. Brake fluid is highly hygroscopic moisture gets in regardless through the M/C lid seal & caliper/wheel cyl.seals the fluid becomes discolored & rust forms,the pedel feel can be night & day after flushing,try it I dare U.
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Re: How do YOU do a brake fluid flush ?
[Re: John_Kunkel]
#2742645
02/13/20 07:12 PM
02/13/20 07:12 PM
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Joined: Jan 2003
Posts: 1,894 Harriman NY
71GTX471
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,894
Harriman NY
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Air leakage at the bleeder threads when using a clear tubing will fool you in to thinking you have air in the system . That's what motivated me to get a pressure bleeder. I find it tends to happen more frequently with power bleeders they create more velocity & pull air through the threads easier.
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Re: How do YOU do a brake fluid flush ?
[Re: 71GTX471]
#2742835
02/14/20 12:40 PM
02/14/20 12:40 PM
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Joined: Jan 2003
Posts: 25,877 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
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Posts: 25,877
Rio Linda, CA
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power bleeders they create more velocity & pull air through the threads easier. Huh?????
The INTERNET, the MISinformation superhighway
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Re: How do YOU do a brake fluid flush ?
[Re: John_Kunkel]
#2742839
02/14/20 12:47 PM
02/14/20 12:47 PM
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Joined: Jan 2003
Posts: 3,122 Auburn WA
Dave_J
master
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master
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Posts: 3,122
Auburn WA
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power bleeders they create more velocity & pull air through the threads easier. When you loosen the bleeder screw and put a Myovac suction type device on and pull a vacuum it can suck air around the screw threads. The power bleed system that pushes fluid from the master cylinder will not do this.
Retired, US ARMY 1973-1994 ASE mechanic, Electrical 1994-1997 Retired GTE/VERIZON/FRONTIER 1997-2015
Posting cheap tech help (CRAP) here since Nov 97, 1000's of posts, some may be good.
03 Suzuki Burgman 650(Burger King) Scooter 65 Formula S Cuda 78 Little Red Express Truck 98 Buick Regal (wifes car)
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Re: How do YOU do a brake fluid flush ?
[Re: Dave_J]
#2742857
02/14/20 01:37 PM
02/14/20 01:37 PM
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Joined: Dec 2005
Posts: 11,611 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,611
Fulton County, PA
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When you loosen the bleeder screw and put a Myovac suction type device on and pull a vacuum it can suck air around the screw threads.
Very true. Use a clear hose on the bleeder, watch and listen. You will see it. Pulls air around the threads and out the bleeder. It can trick you into thinking it still has air in it. That's why I like to push, rather than pull, fluid through the last few times I crack the bleeder to see what's coming out.
Last edited by CMcAllister; 02/14/20 01:45 PM.
If the results don't match the theory, change the theory.
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Re: How do YOU do a brake fluid flush ?
[Re: 71GTX471]
#2742946
02/14/20 07:31 PM
02/14/20 07:31 PM
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Joined: Jan 2004
Posts: 8,290 fredericksburg,va
cudaman1969
master
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master
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Posts: 8,290
fredericksburg,va
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Cudaman its foolish not flush & bleed your brakes,It takes so little & the gaines are huge. Maybe I’m missing something but how can fluid become dirty, contaminated and have moisture if the system is closed? Now if you have a line brake then I say maybe. Brake fluid is highly hygroscopic moisture gets in regardless through the M/C lid seal & caliper/wheel cyl.seals the fluid becomes discolored & rust forms,the pedel feel can be night & day after flushing,try it I dare U. So when you say “pedal feel” you’re saying water can be compressed but brake fluid can’t? Or that the water and fluid will combine to make it feel bad? Or water is heavier and will go to the lowest line and rust it through (if it sets for a long period of time)? Or maybe if the fluid still moves around it won’t rust but the discoloring gives you the impression its no good? Kinda like rotating my cans of soup in the pantry to keep them fresh. Like I said, never in the 55 years of messing with cars have I ever changed fluid and my brakes have always worked very fine. Like washing lug nuts, useless 40+ cars through the years
Last edited by cudaman1969; 02/14/20 07:34 PM.
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Re: How do YOU do a brake fluid flush ?
[Re: cudaman1969]
#2743030
02/14/20 11:09 PM
02/14/20 11:09 PM
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Joined: Dec 2005
Posts: 11,611 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,611
Fulton County, PA
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Water can not be compressed. But it will cause rust and corrosion. Moisture (humidity) will be absorbed by brake fluid and it will also substantially lower the boiling point of the fluid causing the pedal to go away if you manage to reach that boiling point.
If the results don't match the theory, change the theory.
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Re: How do YOU do a brake fluid flush ?
[Re: cudaman1969]
#2743070
02/15/20 03:22 AM
02/15/20 03:22 AM
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Joined: Jan 2003
Posts: 3,122 Auburn WA
Dave_J
master
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master
Joined: Jan 2003
Posts: 3,122
Auburn WA
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Cudaman its foolish not flush & bleed your brakes,It takes so little & the gaines are huge. Maybe I’m missing something but how can fluid become dirty, contaminated and have moisture if the system is closed? Now if you have a line brake then I say maybe. Brake fluid is highly hygroscopic moisture gets in regardless through the M/C lid seal & caliper/wheel cyl.seals the fluid becomes discolored & rust forms,the pedel feel can be night & day after flushing,try it I dare U. So when you say “pedal feel” you’re saying water can be compressed but brake fluid can’t? Or that the water and fluid will combine to make it feel bad? Or water is heavier and will go to the lowest line and rust it through (if it sets for a long period of time)? Or maybe if the fluid still moves around it won’t rust but the discoloring gives you the impression its no good? Kinda like rotating my cans of soup in the pantry to keep them fresh. Like I said, never in the 55 years of messing with cars have I ever changed fluid and my brakes have always worked very fine. Like washing lug nuts, useless 40+ cars through the years If not flushing works for you, carry on carrying on. But I will not follow your example nor do I recommend it to others. YMMV.
Retired, US ARMY 1973-1994 ASE mechanic, Electrical 1994-1997 Retired GTE/VERIZON/FRONTIER 1997-2015
Posting cheap tech help (CRAP) here since Nov 97, 1000's of posts, some may be good.
03 Suzuki Burgman 650(Burger King) Scooter 65 Formula S Cuda 78 Little Red Express Truck 98 Buick Regal (wifes car)
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