Brake Fluid Flush- How much do I require?

I'm using this guide from myturbodiesel and he says to bleed .150L from the clutch cylinder and .250L from the wheels. In total that's 1.15L and the instructions list 1L as the amount of replacement fluid. Does this mean that u will have to buy a second bottle to cover the .150L from the clutch? Obviously I'm driving a manual.

For reference here's the guide: http://www.myturbodiesel.com/wiki/brake-fluid-and-clutch-bleeding-and-flush-mk5-vw/

I used a liter and about 1/2 of those small cans.

You want to flush enough to get the old stuff out. At least most of it. Brake fluids are alcohols and/or ethers. They absorb water over time. If the water content become too high it will begin to corrode the innards of the brake system. This is more of a problem in humid climates as compared to deserts.

Ol'Rattler said:

I used a liter and about 1/2 of those small cans.

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Do you think it'd be alright if I used 1L of the "low viscosity" dot 4 and then maybe .150-.200L of the standard dot 4?

I have never heard of "low viscosity" brake fluid. DOT 4 is the spec it is made to, so that any brand that has that rating should be fine. The "low viscosity" thing might just be marketing.

Ol'Rattler said:

I have never heard of "low viscosity" brake fluid. DOT 4 is the spec it is made to, so that any brand that has that rating should be fine. The "low viscosity" thing might just be marketing.

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I agree with this. A "low viscosity" DOT 4 brake fluid would be the motor oil equivalent of the VW 507.00 5W-30 oil our Passat burns, but a "Lite" version. That's a big no.

Rico567 said:

I agree with this. A "low viscosity" DOT 4 brake fluid would be the motor oil equivalent of the VW 507.00 5W-30 oil our Passat burns, but a "Lite" version. That's a big no.

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Sorry I'm not sure I understand. You agree with the poster, who is saying it is okay to mix them, or do you disagree with the poster? The Low viscosity is a specification is given from vw and the author of the write up is very thorough, I'm sure he wouldn't have made an oversight that large.

Here's some fluid info from Pentosin.
http://www.pentosin.net/pressreleases/pentosin_technicalfluid_guide.pdf

Super DOT 4 for VW's up to 2005 and DOT 4 LV (low viscosity) for 2006 and newer. It says not to mix LV with regular DOT 4. If you're going to do the job, do it right. Spend the extra money and buy another bottle. Having leftovers is better than not having enough.

It is very smart to flush the brake fluid. So many people never do and they have no idea the problems it can cause.

mikec944 said:

Having leftovers is better than not having enough.

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Besides, another liter does not cost all that much.

mikec944 said:

It is very smart to flush the brake fluid. So many people never do and they have no idea the problems it can cause.

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Doing so every 4 years in my cars (and 2 in my motorcycles) prevents internal corrosion. The original calipers in my last car are now in their 16th year with the new owner.

As an added bonus, your bleeders have less of a chance to seize. I also apply some grease to the exposed threads

993er said:

As an added bonus, your bleeders have less of a chance to seize. I also apply some grease to the exposed threads

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Great idea! I do the same. I carefully applied a thin layer of anti seize to the threads at the 2 year mark (with brake fluid flush).

My friend never took care of his 2003 Jetta VR6. This past summer it had 2 seized calipers and needed pads and rotors all the way around. This along with a few other things forced him to get rid of it. Now he has a 2011 Passat TDI and a car payment. His VR6 was a great car that he would still have if he had just taken better care of it.

mikec944 said:

Great idea! I do the same. I carefully applied a thin layer of anti seize to the threads at the 2 year mark (with brake fluid flush).

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Well as you may know, they only seal at the tip, so there is nothing preventing salt and moisture working their way down the threads. Dumb design!

mikec944 said:

This past summer it had 2 seized calipers...

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Whenever I replace my pads (every 5 years), I pump the piston out about 3/4 of the way, lift the edge of the silicone rubber boot and clean the area under the boot and around the piston with lots of alcohol moistened cotton swabs until they come out clean (takes bout 30 to 40). I then apply silicone grease under the silicone boot and press the pistons back in.

mikec944 said:

Here's some fluid info from Pentosin.
http://www.pentosin.net/pressreleases/pentosin_technicalfluid_guide.pdf
Super DOT 4 for VW's up to 2005 and DOT 4 LV (low viscosity) for 2006 and newer. It says not to mix LV with regular DOT 4. If you're going to do the job, do it right. Spend the extra money and buy another bottle. Having leftovers is better than not having enough.
It is very smart to flush the brake fluid. So many people never do and they have no idea the problems it can cause.

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Do you think I'll be able to store the leftover brake fluid? If the lid is kept on and it's stored in a ziplock bag, I'd like to think it'll last at least a year.

I'd not try to store the fluid. Its not that expensive and too easy to contaminate once the container is opened.

The idea is to flush the system. This takes more than just the system capacity and involves a couple of volume exchanges. Buy 2 liters and run it through the whole system. Start by noting your level when you begin. Suction out as much as you can in the reservoir and replacing that with new fluid. Then do 2-3 reservoirs-full for each wheel and maybe one reservoir for the clutch actuator. On the last wheel keep flushing until you bring the fluid down to the original level.

If you combine the flush with a brake pad change then you can also open the caliper bleed nipples when pressing in the piston. This will allow the most worn fluid to flush directly out of the caliper instead of being pushed back up into the line. Once all pads are replaced do the flush procedure as described above. In that case you bring the final fluid level to the MAX line on the reservoir.

Good luck!

Beckley411 said:

Do you think I'll be able to store the leftover brake fluid? If the lid is kept on and it's stored in a ziplock bag, I'd like to think it'll last at least a year.

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Sorry...by my leftovers comment, I wasn't implying that you can keep it around for next fluid flush. Brake fluid bottles/cans always say to use fluid from unopened cans. The only way to be sure if the fluid is good is to test it with an electronic brake fluid tester or brake fluid test strips. Either way, they are more expensive than buying a new can. The 250ml cans are only $6-7. Personally, I would buy a new can if topping off a year or so down the road.

If you know what you are doing, you can easily do it with a tad less than 1 L. While my TurboDiesel gives good information, the technical service manual indicates .2 L per wheel, so 4 wheels is app .8 L.+ .15L for the cylinder= .95 L

Best is to get 2 L. That way if there is an accident, mis-measurement, you just want to run more or inadvertently over amp, you don't have to drop what you are doing and have to go out and get another liter.

Ol'Rattler said:

I have never heard of "low viscosity" brake fluid. DOT 4 is the spec it is made to, so that any brand that has that rating should be fine. The "low viscosity" thing might just be marketing.

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Rico567 said:

I agree with this. A "low viscosity" DOT 4 brake fluid would be the motor oil equivalent of the VW 507.00 5W-30 oil our Passat burns, but a "Lite" version. That's a big no.

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Low viscosity DOT 4 (aka DOT 4+) is made for modern braking systems that have ABS, ESP, and the like. It is the preferred fluid for these systems.

On my 97 I go through about 2 liters when doing a flush of just the brakes. 3 if I do the clutch also. Im a bit on the overkill side though. Fluid is not expensive compared to the car, tree, or person you could hit by not being able to stop.