Type 3 brake fluid

[batoni]

Hi folks
Just had mr Jim Adney rebuilt my calipers,new master cyliders,and l pretty much collected all the parts to change my entire breaking system,mr Adney adviced to put DOT 5 silicone fluid.
Just need information what is a total capacity of entire breaking system?
I found locally in Advance auto parts some dot5 fluid,it comes in 12 ounce(354 ml) bottle.
How many bottles do I need?
It is late notchback

[woodenscouts]

I usually change to dot 5 when everything gets rebuilt. I get a quart and after bleeding everything i still have a bit left in the jug. You will probably need more than 12oz. Also when switching to synthetic, make sure everything to do with the hydraulic part of the brakes is new. Its not compatible at all with even a trace of the old fluid. Some people flush out the lines but new is all I do.
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[raygreenwood]

[batoni]

As always,mr Ray is one of the best person on this website to scientifaclly explain to us ordinary folks here how things work,and give us apropriate wxplanation. That is PRICELESS!!!
Like I said,I am changing entire braking system,new rotors,calipers rebuilt by mr Jim Adney,stainless braided hoses,rear drum cylinders and main brake hardline made od CuNi by mr Adney. The only thing that will remain on the car would be metal curved lines on the front and rear wheels. So,mr Ray,do I have to flush them with alchol and pressure air them before starts mounting other parts I purcased and mentioned above???
And last question,how much total of DOT 5 do I need for the entire system?
I purchased 3 bottles of 12 oz each. Would that be enough,or I need more?
Just a reminder,I am bringing all the parts from Florida to Europe ( where my Notch is located)very soon,so I want to avoid any missing parts.
Thanks

[raygreenwood]

[woodenscouts]

to actually answer your question, yes 3 12oz bottles will be enough
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69 square
69 bug convert
62 bug
61 baja

[Bobnotch]

When I'm doing a complete brake system rebuild, meaning all new hoses, rebuilt calipers, rebuilt master cylinder, new wheel cylinders, and new steel lines, I'll use 2 bottles of DoT 5 fluid. The first bottle is used to refill ALL of the lines, and about 3/4 of the 2nd bottle is used for bleeding of the system. I'll buy 3 bottles though, and carry the 3rd bottle in the car so I have some IF needed.
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http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
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[batoni]

THIS IS THE ARTICLE FROM MR JimAdney that I received regarding silicone.FAQ,hope it will be helpful to type 3 comunity

Background:

Modern standard brake fluids fall into two classifications: DoT-3 and DoT-4. The difference is in the boiling point. DoT-4 has a higher boiling point than DoT-3. The boiling point must be no lower than the specified temperature even when the fluid has a certain (small) amount of moisture in it. The boiling point comes down as the water content goes up.

The motivation for the development of Silicone Brake Fluid came from the U.S. military in the late 1960s. At that time the military used 3 kinds of brake fluid: one for tropical climates, one for temperate and arctic climates, and one for storage--to prevent corrosion. The military was interested in eliminating the expense and hassle of having to change fluids any time vehicles were taken in and out of storage or moved around the world.

A Silicone Brake Fluid became available in the early 70s under a number of labels, but the only manufacturers were Dow-Corning and General Electric. A formulation was finally achieved in the late 70s that satisfied DoT criteria and this became DoT-5 Silicone Brake Fluid.

I've been using Silicone DoT-5 since 1979 in a multitude of cars--mostly air-cooled VW's. Since changing over to exclusive use of DoT-5 I have almost completely eliminated the need to rebuild disk brake calipers and master cylinders. I have this in cars that are daily drivers and in cars that get driven less than once a year. I figure it pays for itself in every car every year, since I had found myself doing some kind of brake maintenance almost every year on my older cars.

Altogether, I have installed DoT-5 Silicone Brake Fluid in more than 60 cars over 3 decades. Of all those, I have had two problems. One was a Volvo where the master cylinder failed a few months later, and inspection revealed that a piece of dirt had come loose and lodged under one of the seals wearing a groove in it. This was the result of corrosion during the years that this car had normal DoT-3 or 4 in it, even though it was the vigorous installation of the DoT-5 which broke the chunk of oxide loose from the master cylinder piston. The second was a TR-3, rebuilt by the owner, that I could never get to bleed properly; that system finally worked when it was taken to a shop that understood British cars--they replaced all the brake parts and put DoT-5 back in with no problems. Since I did none of the mechanical work on that car, I never got to see the actual cause of the difficulty.

The benefits:

1) Silicone brake fluid is non-hydroscopic. That is, it does not absorb water out of the air. Normal (DoT-3 & 4) fluids are all hydroscopic and their properties--boiling point, viscosity, viscosity as a function of temperature, and propensity to cause rusting of the metal parts of the brake system--change as the water content changes, all in the undesirable direction. It is a little known fact that ALL DoT-3/4 fluids need to be replaced periodically; every 2 years is probably adequate, every 4 years is definitely too long. Once properly installed, DoT-5 Silicone Brake Fluid never needs to be replaced.

The hydroscopic nature of DoT-3/4 fluids also means that whatever fluid inevitably wicks past the brake component seals, now eagerly absorbs moisture. It is this wet brake fluid which causes the corrosion just outside all the brake system seals. A small amount of silicone fluid there causes no particular problem.

2) Silicone Brake Fluid is an excellent lubricant for metal-to-rubber and metal-to-plastic contact points. This is in stark contrast to the Girling LMA DoT-4 which I tried as an affordable alternative to the hard to get and expensive OEM ATe Blue DoT-4. I found that master cylinder primary and secondary cups were wearing out typically in 2 years with Girling LMA. This was consistent with the "squeaky clean" pedal feel that I found with this fluid. While Silicone Brake Fluid is a poor lubricant for metal-to metal contact, there is very little of that inside a typical hydraulic brake system.

3) Silicone DoT-5 does not thicken in the cold temperatures that we get occasionally in this part of the country. At -25 F even dry DoT-3/4 gets quite thick and brakes get sluggish; wet DoT-3/4 is even worse. I realize this may not be a problem for most of you.

4) Silicone Brake Fluid does not attack paint like DoT-3/4 fluids do. So fluid that leaks out on your car will not destroy your paint and promote rusting.

The drawbacks:

1) Silicone Brake Fluid is expensive. It costs maybe 4 times as much as regular fluids, plus you need to use a lot of it to do the job right. I figure about 1.5 quarts for one of my VWs. If you have taken everything apart and don't need to do a lot of flushing, the job can be done with a bit more than half a quart.

2) Time consuming to install. You can't just pour it in and bleed the brakes. I figure two people for two hours, one hour if you know exactly what you are doing and have everything ready.

3) Not particularly environmentally friendly. It should not be flushed down the drain or allowed to get into the water table. While I don't think it has any particular noxious properties, it is persistent in the environment. It does not break down like DoT-3/4.(Have you ever smelled an old brake part from the junk yard?) So take care how you dispose of it. Dow-Corning recommends disposal by incineration. I have avoided the problem by just recycling it myself. More on this later.

4) Silicone fluid might not be suitable for new cars with ABS. This is not at all clear at this time. The manufacturers are adamant about just using their fluid. This may be due to the fact that ABS systems use a pump which requires the metal-to-metal lubricity of DoT-3/4, or it might just be a marketing ploy. At this time I recommend caution. For this reason, I have NOT installed it in our '96 Ford Taurus.

Note that it IS safe to ignore the very specific warning in the Robert Bentley VW manuals not to use Silicone Brake Fluid in the VW water cooled cars. These cars have brakes that have the same materials made by the same manufacturers as the air cooled cars. I have done a dozen of these cars; Dow-Corning has done hundreds. Most of these brake components were made by ATe (Alfred Teves, GMBH) Germany. Teves makes brakes, brake components, and brake fluid. Last I heard they did not market a Silicone Brake Fluid, but they DO buy DoT-5 Silicone Brake Fluid from Dow-Corning to use as an assembly fluid so their parts won't rust on the shelf. Why this warning exists in the manuals remains something of a mystery.

5) Silicone Brake Fluid that you spill on your car will make it hard to repaint that area unless it is cleaned off very carefully. It does not clean up with water.

Installing Silicone Brake Fluid in your car:

There are several possible ways to do this. They are all aimed at filling your system with 100% Silicone fluid. The extent of your success at this job will be proportional to the degree that you rid your car of the old fluid. If you intend to do this job, please read through the whole FAQ and make sure you understand EVERYTHING before you start. Note that these instructions assume that you are already familiar with standard and appropriate brake system practice. If you are not, you will need to find someone who is, to help you, or study up on these things first.

1) If you are a manufacturer, all you need to do is clean out your existing pressure bleeder equipment and fill it with Silicone Brake fluid. Then just install it in your cars the same as you did before. This is obviously the easiest and cheapest way to do it. Unfortunately, it might add $5 per car to the manufacturer's cost, so we are not likely to ever see it happen. It is in general use in some fleet applications, the military, the post office (I think?), and Harley-Davidson Motorcycles.

2) If you have an old car that previously had DoT-3/4 in it, you should get the hydraulic system into good shape first, then flush DoT-5 through it to replace as much of the old DoT-3/4 fluid as possible. Since the Silicone does not mix with the old fluid, flushing can only be done by creating as much turbulence as possible in the volumes where the old fluid is present, in order to create a "slurry" and carry out the old fluid, as well as any accumulated dirt, water, and rust. This means that you must pump the brake pedal HARD on the down stroke, and let it up relatively easily; do not slam the pedal into the end of its travel--that could damage the master cylinder. It is not necessary to close the bleed valve on the upstroke, but you should be bleeding through a clear plastic tube that leads to the bottom of a clean container that will catch your flushing fluid and prevent air from being sucked back up into the hydraulic brake system.

When you flush the system one wheel at a time, you will observe that the fluid first comes out muddy (rust) or amber (typical DoT-3/4 color.) Then the color will turn cloudy. This cloudyness is the slurry, or mixture, of the Silicone Brake Fluid and the old fluid--sort of like oil and vinegar. Eventually the cloudyness will go away and be replaced by the purple color of the DoT-5. Once this happens you have successfully flushed that wheel and can move on to the next.

Turbulent flushing is easy to achieve in the master cylinder and in drum brake cylinders. However, it can be quite difficult in most designs of disk brake calipers. Since one of the principle benefits of Silicone Brake Fluid is the prevention of frozen calipers, they deserve some special care. Here's the problem: Silicone Brake Fluid is lighter than regular fluid; it floats on top. Thus the large cavities in a brake caliper may still be half full of old fluid while the exiting fluid appears to be coming out clean. This problem is especially bad with dual (or more) chamber calipers.

The best way to attack this problem is to remove the calipers and rebuild them, and the best way to get rid of the old fluid is to flush the disassembled caliper parts with water because standard fluid is completely soluble in water. This can only be done with the calipers disassembled. If the caliper is particularly dirty or greasy I will scrub it with soap and water, then rinse it with clean water, blow out all passages and finally rinse in alcohol and blow everything out. Dry it quickly to avoid rusting, and make sure to remove ALL traces of water. Let dry overnight in a warm, dry place. As a rebuilding lubricant use only Silicone Brake Fluid, or another silicone lubricant, not DoT-3/4 or any petroleum product.

Since it would be counterproductive to take your nice freshly rebuildt calipers and flush dirty fluid thru them, I just leave the off until the master cylinder and lines have been flushed. Do do this, make some brake line caps from old brake hose female ends; just cut off the rubber hose and weld the metal closed. Make enough to cap off all your caliper lines. Use these caps to allow the rest of the brake system to be flushed and bled, removing one cap at a time to flush its line until everything is clean.

Now you can install your clean, rebuilt calipers onto the car and let them slowly fill with DoT-5 until air stops coming out the bleeder valve.

If your calipers are in good shape, you can, as an alternative, unbolt the calipers from the steering knuckles and hang them upside down so the bleeder valves are on the bottom. Place a slab of wood or something between the brake pads to prevent the pistons from popping out of their bores when your helper pumps the pedal. Now the standard fluid will flush out selectively through the bleed valve which is now on the bottom (remember, the standard fluid is heavier.) Aircooled VWs, made 7/71 or later, came with a second bleeder valve on the bottom of the caliper. This makes these calipers easy to flush on the car, without inverting them. Just do all the flushing via the bottom bleeder valve, then finish off by bleeding any air off the top. These late calipers also have the advantage that it is easy to come back a week, a month, or a year later, and bleed just a bit of fluid out to eliminate the last drops of old fluid which is bound to persist.

Recycling old fluid:

Silicone Brake Fluid is expensive, but, unlike DoT-3/4 it does not absorb or mix with water. You can let your DoT-5 flushing residue stand until the silicone and standard fluids separate (the silicone is lighter and rises to the top.) Decant the silicone portion into a clean container and shake it vigorously with an equal amount of clean water. Any DoT-3/4 fluid will be absorbed into the water and, after letting it separate again, the recycled Silicone Brake Fluid can again be poured off the top.

I decant the Silicone Brake Fluid from the DoT-3/4 once, and twice from clean water, filtering each time. As a final step, I heat the decanted silicone fluid to about 110 C to verify that there is no water in the end product.

If you do this and keep it clean (NO PETROLEUM OIL!) the recycled silicone fluid can be reused to flush the next car. I typically use recycled Silicone Brake Fluid to flush a car, then do a final bleed with virgin DoT-5 Silicone Brake Fluid. This is preferable to throwing it away since it is difficult to dispose of properly. Dow-Corning recommends incineration.

Notes:

1) Color: The DoT-5 certification requires that Silicone Brake Fluid be purple. The dye that is used is only required to be stable enough to stay purple until you pour it out of the original container. It turns out that the purple dye is more soluble in DoT-3/4 fluids, so Dot-5 that has been flushed throught a system full of DoT-3/4 will have lost its color to the DoT-3/4 and the Silicone Brake Fluid will now be clear or slightly amber. Something also happens to this purple dye after it has been installed in a car for a year or more; that fluid will also be clear. The loss of color is not a problem; it's just a dye.

2) Fluid inter-compatability: Occasionally one comes across statements claiming that there is a problem with silicone and regular fluids reacting with each other. Nothing could be further from the truth. I have a small vial containing DoT-5 and Girling LMA that has been mixed since 1979. In that time there has been no change that I can discern other than color; the silicone is now clear and the once amber LMA is now green. This change happened the very first time I shook up the vial. I assume that the green is the result of the mixing of the amber and purple dyes, both of which appear to be much more soluble in the LMA than in the DoT-5.

2) DoT-3/4 fluids: These are classified as poly-glycols and are a mixture of compounds all chemically very similar to Ethylene Glycol, better known as antifreeze. These compounds have a sweet taste, but are poisonous. They should not be left out where your pets can get to them. Every year a few dogs die after drinking brake fluid or antifreeze. I believe the lethal dose for a person is about 100 cc.

3) Material compatibility: Brake fluids must be carefully chosen to be compatable with all the materials exposed to them in the system. British cars were once notorious for using natural rubber seals that required special brake fluids. It is my understanding that by 1970 no one was still making brake components or even rebuild kits containing natural rubber parts. If you have a British car that still has 30+ year old rubber brake parts in it, then you probably need to be concerned, but only because of the age of those parts. DoT-5 Silicone Brake Fluid, however, will be fine. Silicone Brake Fluid is compatable with all 4 of the elastomer material families ever used in hydraulic brakes.

Š Jim Adney, 1997
[email protected],
minor revisions 2002, 2004, 2005

[batoni]

So,mr Ray,as per your advice few months ago,I bought Centric 134.333000 rear cylinders from Rockauto,and per you advice also steinless braided hoses from cip1,evwrything else is from mr Adney. Can you please point me where to buy appropriate denaturated alcochol,any web site? Or local retailer?
Also,want to thank other folks answering my questions.

[daos]

just an aside - it's hygroscopic, not hydroscopic. different thing altogether.
and non-hygroscopic is called hydrophobic. yes, it's a little confusing.

[Max Welton]

I was not comfortable with just flushing out the system. My MC, calipers and rear cylinders were all new so I disassembled each of them and cleaned the parts directly. Used some DOT 5 as I reassembled each. The rest of the system was dry.

There was nothing notable about the bleeding process except that the body was off the pan. That made the process laughably easy.

Max
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