Brake Fluid Flush

[Perales]

I am going to flush by brake fluid for the (my) first time, the procedure seems pretty manageable, I am going to do it old school since I have a teenage son who can press the brake pedal for me. Riceye's writeup seems very doable, http://www.thesamba.com/vw/forum/viewtopic.php?t=187813 but I do have a few newbie questions that I hope you don't mind answering for me.

1) what size brake bleeder wrench will I need? (standard Vanagon brakes)
2) how much DOT4 will I need for a complete flush?
3) the 3/16" clear tubing that riceye talks about (is that ID or OD?), does that just slip over the bleeder valve with a friction fit or is there some kind of coupling that is needed? The Bentley seens to show some kind of valve thingy.

[captainpartytime]

I would also recommend the brake caliper rebuild kit from Van-Cafe. It's essentially the piston o-ring, caliper boot, and hanger pin boots. I would also HIGHLY recommend cleaning out your calipers if you're going to flush the system. I wouldn't waste all that new fluid if it is just going to get contaminated from all the sludge build up in your calipers. Read this first - http://www.thesamba.com/vw/forum/viewtopic.php?t=237822

The powder coating's not necessary but makes them look nice and clean! As for your questions:
1.) either 7mm or 8mm
2.) I just bought a gallon because I also replaced my master cylinder. You could probably get by with a couple quarts.
3.)Probably ID. I can't see why OD would be given. The plastic tubing just slips on to the bleeder screw. If you're going to get the rebuild kit, pick up 4-5 extra bleeder screws as they can break/strip pretty easily.
4.) I think the dual bleeder valves are on the older style brake calipers
_________________
-Kerry

1982 turbo diesel Westfalia

[Captain Pike]

Rebuild the calipers AND replace the rear cylinders as well for a complete job.
_________________
LEARN TO SELF RESCUE
59 Panel bus, 1966 Single cab. 73' 181. 73 Westy. 91' H6 Vanagon 3.3L.
.....................All Current.......................

[82WestyMan]

If you're sure your hydraulic parts are in good shape and not excessively old (ie: its the internal rubber parts that wear with time and use) and all you want to do is a flush
(which is something that should be done every 2 yrs minimum... because brake fluid is hydroscopic - ie: it draws moisture out of the atmosphere)
let me make a suggestion and give you a tip

Remove ALL the old fluid from the Master Cyl reservoir.
Get as much out as you can with a turkey baster and some hose, remove it and clean it if possible
(you remove it without removing the M/C by rocking it side to side and pulling up SLOWLY.... and towels under it to catch the excess)
then refill it with fresh brake fluid.

Now here's a tip... you should be able to 'gravity bleed' the system without pumping the brakes.
Just put your clear hose over the bleeder screw, then into a bottle and then open the screw.
Let it run until the fluid in the clear line runs good and clear.
This may take a lot longer but if your M/C is older, if you bleed the brakes by pumping the pedal thru the full stoke of the M/C bore, this can accelerate the wear on the seals in the M/C
(by running the seals over parts of the bore that have a different wear pattern than the seals are used to)

a suggestion from an old 'front-end & brake' mechanic
_________________
"The floggings will continue until morale improves"
"I never did give anybody hell. I just told the truth and they thought it was hell" - Harry S. Truman
82 Westfalia - w/ a Raby 'Camper Special' engine

[captainpartytime]

[msinabottle]

Have a look at this post:

http://www.thesamba.com/vw/forum/viewtopic.php?t=146671

And build and use that device. The 'how to build it' link is still good, and it will make the whole bleeding and replacement of the brake/clutch system a PLEASANT experience, dear fellow. One of the wisest things I've done automotively.

Best!
_________________
'Winston,' '84 1.9 WBX Westy
Vanagon Poet Laureate: "I have suffered in
many ways, but never, never, never in silence."

[Wildthings]

If your hydraulic parts are in good shape then there is no reason to replace or rebuild your calipers and slave cylinders. That may be a big "if" if you do not know the history of your brakes. Doing a fluid replacement every two years is good policy. The gravity method works well enough, but is slow and requires you to remember to close the bleeder(s) after ten minutes or so. I would use your teenage son to do a little male bonding and to make it go faster.

I wouldn't bother to try to suction out the reservoir to start with, just push the old fluid through the system until the reservoir is nearly empty, try to keep your reservoir from ever being fully empty or you will get air into your system which must be bled out again. Check the level after bleeding each cylinder/caliper.

Most bleeder valves are 7 or 8 mm, but I have seen a few that were 9mm or even 10mm. A quart jug of fluid is pretty cheap and will give you plenty of extra. A soft piece of hose is easier to deal with than a stiff piece of hose, it just fits over the bleeder with no clamp. You only have to deal with the upper bleeders if your calipers have an upper and lower.

[Perales]

[Wildthings]

I have never timed doing a gravity flush, but I would guess 5-10 minutes per wheel. You could probably do one front and one rear at the same time, but I wouldn't try all four at once. Remember the idea is to get clean brake fluid all the way to the wheel cylinders, not just to drain the reservoir. You want to see clean fluid exiting from the bleeders.

[msinabottle]

[Perales]

[rblake3]

I have one of those Motive pressure bleeder things and have used it once and let others borrow it several times. I use the old school method for the most part on all my vehicles, it is actually easier and faster. The only real advantage to using the pressure bleeder is that you do not have to stroke the master cylinder piston which risks getting into the far end of the chamber where the seals can get damaged on the un-honed area. You can put a piece of wood beneath the pedal to ensure your "assistant" doesn't go too far.

-rb
_________________
90 Vanagon Carat Wander Wagon
88 16v GTi
01 1.8T Beetle
94 Miata
Vanagon H4 E-Code Lighting Upgrade page

[captainpartytime]

I don't think flushing the system will help if you have all that sludge inside the cailpers. And if you've never cleaned out your calipers before, it's a good chance yours looks like mine did or worse. You're just going to contaminate your fresh brake fluid. Do yourself a favor and clean those calipers out. This was one of the first projects I did on my van and discovered this sludge by accident. The process is very straight forward and relatively inexpensive (especially w/o the powder coating). The hardest part was re-bleeding the system which you're going to have to do anyway. I would just hate for you to go through all the trouble without doing the job completely. I think you'll be more than satisfied with the complete job.
_________________
-Kerry

1982 turbo diesel Westfalia

[Dufo's Pizza and Auto]

[RicoS]

Some thoughts:

I've seen Vanagon calipers/brake cylinders with 6mm, 7mm and even 8mm bleeders. I just checked a pair of rebuilds I have sitting on the shelf and the bleeders measure 8mm. With the vagaries of rebuilt calipers, you will have to determine what you have and they could even be 1/4" or 5/16". Whatever they are, make sure to use a bleeder wrench or 6-point wrench which fits properly. A bleeder is one thing you don't want to round over.

One of the most painless ways to bleed the brakes is to use a power bleeder. Unfortunately, few have access to a proper power bleeder. The pump-up-jug type of power bleeders have been de riqueur in the garages of most gearheads for some time, but they are not proper power bleeders. A real deal power bleeder is a pressure tank which has a diaphragm separating the brake fluid from the pressurized air and for good reason. What happens whenever moist air is compressed? Eventually, the water vapor is wrung out in the form of condensate. So, pumping up the pressure of the air over some new, clean, hydroscopic brake fluid might not be the thing to do.

Having said that, I use a pressure bleeder all the time. I don't bother with a reservoir of new fluid, I just keep refilling the master cylinder before it is emptied. I apply some air pressure to the master cylinder from a portable air tank with about 10 pounds of pressure in it, which is more than enough pressure.

Also, I have a 500 cc syringe which, if I live long enough, will be hacked into a bungee cord powered, airless power bleeder.

If you go the pedal pumping route, it is a good idea to tape a block if wood under the pedal so that the piston in the master cylinder is not driven to the bottom of the bore where all the rotten shit is residing. An errant excursion of the piston may damage the piston cups.

With the low cost of lifetime warrantied rebuilt calipers, master cylinders and new wheel cylinders, it is hard to justify the time and uncertain performance of doing it yourself.


Rich

[greenbus pilot]

May I add my .002? I too am a big fan of regular brake fluid flushing, and used a Mightyvac suction tool, until all that pumping left my arm tired. So I took an old compressor from a dehumidifier, and connect the Mightyvac reservoir to it. Now, I plug it in, and 3 minutes later the entire line is drained out. If you keep the master reservoir topped off, you can bleed a wheel out in about 3 minutes, with no air entering. Sure beats trying to coordinate a helper, fiddle with the bleeder, tip over your drain catch bottle, etc.
I have read some peoples' claims about air entering a system under vacuum, but i think you would see this as a leak beforehand. I have never had any problems doing it this way.Hook up hose, crack open bleeder, plug in compressor, top off reservoir, and drain fluid. Two minutes per wheel.
I have yet to get any air into the system doing it this way. Works perfectly every time.
BTW- i always use Castrol LMA fluid, which is DOT 4 rated, in all my German vehicles. Hard to find, though- the BIg Box FLAPS rarely even have DOT 4, much less Castrol LMA, but I finally found one that speaks my language.
_________________
Sent from a white van down the street.

[Merian]

Relatedly...

does anybody know what the blue dye was that Ate added to their Ate Blue brake fluid before it was outlawed?
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....

[dhaavers]

x2...

For years, it was super easy to alternate Super Blue & Gold to ensure adequate brake fluid flush...

<shrug>

- Dave
_________________
86 White Wolfsburg Westy Weekender
"The WonderVan"
<EDITED TO PROTECT INNOCENT PIXELS>

[Abscate]

Just add some food coloring dye to the master reservoir just before you flush. A nice Chianti red will wash down favA beans while you flush.

For those stroking out about putting water in your brakes...

1 nature has already done it

2 the math of two drops of food coloring compared to the 0.2% v/v typical of brake fluid is left to the reader as an exercise.
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.ssS!

[slomoracing]

Food coloring is a great idea.

I use power bleeders at work all the time and have noticed that on older systems that actually having someone pump the brakes while you open and close the bleeder will help push sludge out.

My though is that with a vacuum style bleeder is it just pull the fluid around the buildup but with the extra pressure of someone pushing it helps agitate the buildup? This is pure speculation but have seen the same results on different types of vehicles.

Gravity bleed is ok, having an assistant is better. If you’re going down the less costly way.