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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32367 Location: Reading Pennsylvania
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Posted: Thu Jun 11, 2015 4:23 am Post subject: Flush Out Metal Brake Lines? With What? |
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As I remove, clean and rebuild my entire brake system, I am struck by the amount of jet black brake fluid and amazing amount of crud and Goo in the system.
Cleaning, honing and rebuilding the various hydraulic components is easy and quick.
New brake hoses is a no brainer,
But I Wonder about what is in those many feet of metal pipe.
I read about the frequent failure of new cylinders and everyone shouts that they are garbage.
Are they?
Or is years of built up brake line goo the real culprit?
Does new brake fluid (like new oil in an old old engine or an old automatic transmission) dissolve the Goo and carry problem causing bits to the cylinders?
So, is brake line flushing called for?
Is it a good idea or will it create worse problems as bits break loose over time?
What product should be used?
Obviously if this is done, I imagine do it without rubber parts connected.
Are there any hidden valves / equalizers that will be damaged if nit removed?
A method? Rubber hose and funnel?
Dave _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert
Last edited by djkeev on Thu Jun 11, 2015 3:41 pm; edited 1 time in total |
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morymob Samba Member
Joined: November 09, 2007 Posts: 4683 Location: east-tn
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Posted: Thu Jun 11, 2015 4:36 am Post subject: |
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Only thing i ever used is fresh fluid, i guess u could fill lines with the same thing u flush ac lines etc, let 'em sit overnight then reflush, should cleaned now. I takke apart even new cyls , check bores, relube cups, pistons, bores with a hi temp non petroleum base silicon lube , never had any stuck pistons or weeps after use till next brake lining job, my2cts. As usual no warranty offered at this time., I started this lube yrs back on a '74 mazda rx4 front sticky front calipers. |
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tjet Samba Member
Joined: June 10, 2014 Posts: 3522 Location: CA & NM
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Posted: Thu Jun 11, 2015 5:37 am Post subject: |
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I used alcohol on my '59, followed by a brake fluid flush |
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danfromsyr Samba Member
Joined: March 01, 2004 Posts: 15119 Location: Syracuse, NY
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Posted: Thu Jun 11, 2015 6:29 am Post subject: |
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I would be concerned alcohol would negatively effect the rubber components. _________________
Abscate wrote: |
These are the reasons we have words like “wanker” |
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Steve M. Samba Member
Joined: July 30, 2013 Posts: 6777 Location: Fort Lauderdale, Fl.
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Posted: Thu Jun 11, 2015 7:50 am Post subject: |
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For the amount of time alcohol is going to be in the system for just flushing it I don't think it would be a problem. A concern yes, but realistically your not letting it sit overnight where seals could be softened if they were effected at all.
If your doing a brake job where you are changing the master cylinder and the rubber hoses at each wheel then you could disconnect all the wheels and just run it through the system before you change out the cylinder and hoses.
The question for me is what fluid is able to clean "brake fluid" so it is actually doing something in the metal lines to remove residue.
If your changing your fluid every two years then I wouldn't worry about residue. Of course, what is the unknown history of the car for the past 30 years?
Of course is there any alcohol left over in the lines to dilute your brake fluid or if you blew it out with compressed air did you leave moisture in the lines for the agoraphobic brake fluid to absorb...where do the possibilties end??? Are we getting into the realm of Hollywood movie crime plots?
If your worried about your rubber hoses if they are not new have somebody else step on the brake pedal while you have a hand on a rubber hose to see if they are swelling under brake pressure
I just flush mine with clean brake fluid when I change it being anal about getting the cap back on the bottle and reservoir within 30 seconds to prevent air being absorbed during the final fill.
If you think alcohol does clean the brake lines then use it and flush out any alcohol with clean brake fluid before you finish the brake job.
I also replace the bare rubber hoses with steel braided over the rubber to keep the hose restricted. I had one Land Rover 109 where I could not get effective brakes until I put a hand on the hoses to feel them to find out they swelled with brake pressure. You cannot build up pressure if the hoses do not hold it. |
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Vanagon Nut Samba Member
Joined: February 08, 2008 Posts: 10333 Location: Sunshine Coast B.C.
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Posted: Thu Jun 11, 2015 9:01 am Post subject: |
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This may be extreme, and there may be too much back pressure, but if you're disconnecting the lines.... spray brake parts cleaner through each metal line follow up with compressed air?
The older style calipers have a "separate" set of lower bleeder screws for brake flushing only. (noted in Bentley)
FWIW, on my most recently failed wheel cylinders, the pistons that still sealed had a very thin layer of dry type stuff, like a stain, (normal?) at outward end. Some of same seen at relevant portion of cylinder. The fluid was clean though as were the rest of the bores. I have pics somewhere but can't find right now.
Not to get OT, but under normal conditions with proper spring loaded wheel cylinders, is piston travel really short? e.g. 1 mm?
If so, and if like me a given driver tended to be gentle with brake use, if a given wheel cylinder piston didn't move much, could this help cause the seal to dry out? Just a WAG. I imagine the 'magic' rubber formulas are a larger factor. _________________ 1981 Westy, 15º ABA
1988 West, 50º ABA
Vanagon VAG GAS engine swap Google Group:
https://tinyurl.com/2f24rmh
VE7TBN |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32367 Location: Reading Pennsylvania
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Steve M. Samba Member
Joined: July 30, 2013 Posts: 6777 Location: Fort Lauderdale, Fl.
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Posted: Thu Jun 11, 2015 10:10 am Post subject: |
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Something I came across as you got me curious!
"This is an easy one. Brake fluid is made from a combination of chemicals called esters. They absorb moisture from the air and eventually break down. As they do, they turn dark. Also, as the fluid ages and becomes more acidic, it begins to eat at the rubber brake system seals. The corrupted rubber turns the fluid dark, too. If you read your owner's manual, it should tell you that the fluid must be changed every 2-3 years. Brake fluid SPOILS with age. Be careful, though. You should use ONLY the fluid sold at your car-makers dealership. Often times, different brake fluid "esters" are not compatible with each other, and rubber seal damage occurs. European car brake fluid, e.g., is a synthetic vegetable oil. If it is mixed with other types, it causes severe corrosion. Asian cars have a different composition, as well." |
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bluebus86 Banned
Joined: September 02, 2010 Posts: 11075
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Posted: Thu Jun 11, 2015 10:37 am Post subject: |
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djkeev wrote: |
Thanks for the thoughts.
I did some googling and two suggestions jump out (remember no rubber in the system right now) .....
AC system cleaner
Brake cleaner
Fill the tubing up with either, let it sit and then blast it all out with compressed air.
Bleed well to remove moisture upon reassembly.
Thoughts?
Dave |
do not flush the pipes thru any new brake components. flush them into a waste catch bucket.
you can start with compressed air, and follow with denatured alcohol (Ethanol) as ethanol is not going to leave a residue. non residue brake cleaners can also be safe to use. follow up with \more compressed air.
NEVER use mineral spirits, paint thinners and such!!!!!
note that unless you have an air dryer on your compressor, the air you blow thru will be moist and leave moisture in the pipe(s). you should ideally filter the air to keep dirt out as compressors do tend to get dirty. that is why car painted use filters, and dryers so they get CDA (Clean Dry Air) when they spray. One important point is that some air compressors use an oil lubricated compressor, other are a dry type. the oil type compressor will introduce oil into the air supply and you do not want this to happen, hence an oil filter /separator would be required. you could also by compressed air cans that are clean and dry. an old worn oil type compressor will likely introduce more oil, so use caution. oils will destroy brake rubbers. my compressor is the dry type, no oil. automotive paint stores should be able to supply the proper filters, and separators if you are concerned with less than clean compressed air
however unlike when painting a car, a little moisture in the air you use wont be harmful because you will be flushing the hygroscopic brake fluid thru the system later and that will remove the moisture.
so use the non residue brake cleaner or alcohol these will assist in dissolving the crud, crud that brake fluid did not dissolve.
Blow it out in to a catch waste bucket not thru the rubber parts.
then you can assemble the system and flush a couple quarts of fluid thru it to remove all traces of water.
However if the pipes are really dirty that indicates to me that the fluid was not serviced properly at one time and there may be extensive corrosion in the pipe which if really bad could corrode thru the pipe walls. In which case replace the pipe(s)
You may also find that you can ream out the pipe s with a thin metal wire, a long length of MIG welder wire works great if you know someone with a MIG, ask for a long enough length of wire to get the job done I suppose you could even put one end of the wire on a drill motor and spin it around like a plumbing snake for an initial clean (this may help you economize on the amount of brake cleaner or alcohol you use)
also be sure to use brake cylinder grease on the calipers and cylinders to help prevent corrosion and improve rubber piston seal life,
have fun. _________________ Help Prevent VW Engine Fires, see this link.....Engine safety wire information
Stop introducing dirt into your oil when adjusting valves ... https://www.thesamba.com/vw/forum/viewtopic.php?t=683022 |
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Merian Samba Member
Joined: January 04, 2014 Posts: 5212 Location: Orygun
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Posted: Thu Jun 11, 2015 12:02 pm Post subject: |
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I like the last answer best, but I'd not even try - just replace the metal pipes and send the old ones to the metals recycle bin.
This is a critically important safety system, which you know. Think about your kids & grandkids(??) and the answer will be obvious.
brake line goo means a PO really effed up, so watch out for other issues
BTW, DOT 3 brake fluids have a mix of ethers and glycol in them. DOT 4 contains borate compounds also. And, NO anti-freeze is not a good substitute even tho the chemistry is similar. Dunno re esters - maybe only in DOT 4? |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32367 Location: Reading Pennsylvania
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Posted: Thu Jun 11, 2015 2:17 pm Post subject: |
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Merian wrote: |
I like the last answer best, but I'd not even try - just replace the metal pipes and send the old ones to the metals recycle bin.
This is a critically important safety system, which you know. Think about your kids & grandkids(??) and the answer will be obvious.
brake line goo means a PO really effed up, so watch out for other issues
BTW, DOT 3 brake fluids have a mix of ethers and glycol in them. DOT 4 contains borate compounds also. And, NO anti-freeze is not a good substitute even tho the chemistry is similar. Dunno re esters - maybe only in DOT 4? |
Yeah, I agree but I'm not going to replace something that only needs a good cleaning.
I'll clean them out and see if I just get Goo or does rust come along for the ride.
I hate rplacing brake lines though on a Beetle or Ghia it's almost a must do item.
Brake cleaner it is then.....
Thanks! _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32367 Location: Reading Pennsylvania
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Terry Kay Banned
Joined: June 22, 2003 Posts: 13331
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Posted: Thu Jun 11, 2015 4:10 pm Post subject: |
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Think about some experimentation here first.
I like the thought of alcohol first because it absorbs moisture quick & then evaporates fast.
Faster than brake parts cleaner, & I don't think it will absorb any moisture.
It's an external cleaner not so much for inside of the lines.
Might want to check his out prior to the operation. _________________ T.K.
Last edited by Terry Kay on Fri Jun 12, 2015 5:14 am; edited 1 time in total |
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Howesight Samba Member
Joined: July 02, 2008 Posts: 3255 Location: Vancouver, B.C.
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Posted: Thu Jun 11, 2015 4:17 pm Post subject: |
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Hey Dave:
I'll chime in. Remember that most brake fluids contain a number of chemicals designed to clean out corrosion and trap water in the brake fluid solution (to avoid the water turning to steam, among other things)?
For this reason, the best brake system cleaner is brake fluid, DOT 4 to be specific. You might consider bleeding your system until only clear, new fluid appears at the bleeders, then repeating a few weeks later. The brake fluid needs time to work its cleaning magic. _________________ '86 Syncro Westy SVX |
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Merian Samba Member
Joined: January 04, 2014 Posts: 5212 Location: Orygun
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Posted: Thu Jun 11, 2015 4:23 pm Post subject: |
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if or when nothing comes out, how will you know there is not a wad of gunk stuck in there that just won't budge, but CAN interfere with a panic braking situation??
or... move later and create a critical blockage at the wrong moment?? |
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tjet Samba Member
Joined: June 10, 2014 Posts: 3522 Location: CA & NM
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Posted: Thu Jun 11, 2015 9:44 pm Post subject: |
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not to change the subject too much, but these pressure bleeders work great. I have one. Make sure you get the correct MC adapter
http://www.motiveproducts.com/
IMO, they will add life to your master cylinder, as the pedal pump up procedure damages the piston seals |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32367 Location: Reading Pennsylvania
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Posted: Fri Jun 12, 2015 2:08 pm Post subject: |
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So.......
Many say to use ............ "Alcohol" .......... for flushing the lines.....
Obviously not Distilled drinking Alcohol ...... though who knows? I've had some bottom shelf Spirits that might be better used for Automobile service!
But what alcohol?
Methanol
Methyl alcohol, or methanol, has a boiling point of 65 degrees Celsius and is flammable. The formula for methanol is CH3OH. Uses for methanol include obtaining formaldehyde, synthetic gasoline, plastic masses and coloring matter. Methanol is poisonous.
Ethanol
Ethyl alcohol, or ethanol, is the alcohol that people can drink. The boiling point is 78 degrees Celsius and is also flammable. Ethanol can be used as a fuel on its own or as a mixture. It will burn to give off carbon dioxide and water. Ethanol is also added to perfumes and cosmetics.
Propanol
Propanol, also known as propyl alcohol, is commonly used as a solvent in everything from printing ink to cosmetics. It is also used in the production of raw materials such as amphetamines. Physical properties include colorless, smelling similar to ethanol with a boiling point of 97.15 degrees Celsius.
Glycerol
Glycerol, which may be known as glycerin, is found today as a byproduct in the manufacturing of soaps and is not poisonous to humans. It can be found in medicines and numerous food products such as ice cream. It is thick in consistency with a sweet taste. Glycerol will turn into a solid once it is cooled.
Butanol
Butanol, or butyl alcohol, is a clear, flammable liquid with a boiling point of 170 degrees Celsius. It is volatile with a strong alcoholic odor. It is used as a solvent for paints and in the production of all sorts of products ranging from safety glass to brake fluid.
Not an Alcohol but a distilled mineral product?
Well, obviously not this one!
Dave _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert |
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tjet Samba Member
Joined: June 10, 2014 Posts: 3522 Location: CA & NM
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Posted: Fri Jun 12, 2015 10:03 pm Post subject: |
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Use this one
djkeev wrote: |
.....
..... |
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[email protected] Samba Member
Joined: June 02, 2011 Posts: 1593 Location: Louisville, ky
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Posted: Fri Jun 12, 2015 10:37 pm Post subject: |
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Since you have all these chemicals sitting around, isn't the obvious answer to scrape some goo out, an put just a little of the goo in 5 bottle caps or some small container like that. Dribble a little chemical in each bottle cap and see which one does the job.
When you're putting everything back together you might want to consider DOT 5 since you got everything apart and clean. It is not hydroscopic so it doesn't suck in the moisture and cause rust. It doesn't attack rubber and it doesn't hurt paint. |
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IdahoDoug Samba Member
Joined: June 12, 2010 Posts: 10234 Location: N. Idaho
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Posted: Fri Jun 12, 2015 10:56 pm Post subject: |
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I think you'll do fine by the system to put fresh fluid through it of the correct type and then flush again a couple weeks later. Brake fluid is very effective at cleaning and you won't have solids in there like dirt, etc - just discolored brake fluid and possibly some thicker version that can be dissolved with fresh fluid. Fresh fluid will have a detergent/solvent effect.
So I say a minimally invasive technique involving a flush now and a flush in a few weeks. Disconnecting all the rubber bits to do a flush with harsher chemicals may result in a stripped fitting, broken retainer bracket, etc and also the harsh chemical may have some unforeseen effect vs using 100% fully compatible brake fluid.
A similar debate happens with auto trans flushes vs a simple drain and refill. The former is harsh enough to move goo into delicate valves, the latter slowly dissolves the goo so it comes out with a subsequent fluid change out.
DougM _________________ 1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader |
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