Another brake bleed-flush job

[cannon man]

did those brakes over last 2 days. geting old fluid out was hardest part. master cylinder holds alot. fuid was light amber in color. got the speed bleeders from OEMY. they work great. had DW cycle the pedal with elec motor boost. took no time at all. hardest part was crawlin under the monster. made a mess when i over filled the master cylinder. you realy can't tell where the level is. used pop cycle sticks to check n that worked well. fluid out of lines n calipers was darker than out of cylinder. glad it's done. took a little over 3 quarts of dot 3. that's my story n i'm stickin to it. next week we're off to quartzsite.
dave

[Campingman]

Quote:

Originally Posted by cannon man did those brakes over last 2 days. geting old fluid out was hardest part. master cylinder holds alot. fuid was light amber in color. got the speed bleeders from OEMY. they work great. had DW cycle the pedal with elec motor boost. took no time at all. hardest part was crawlin under the monster. made a mess when i over filled the master cylinder. you realy can't tell where the level is. used pop cycle sticks to check n that worked well. fluid out of lines n calipers was darker than out of cylinder. glad it's done. took a little over 3 quarts of dot 3. that's my story n i'm stickin to it. next week we're off to quartzsite. dave

If you went to all the trouble to drain your system why did you re-add DOT3? Why not at this time go to DOT5? Much higher boiling point.

[DriVer]

Quote:

Originally Posted by Campingman If you went to all the trouble to drain your system why did you re-add DOT3? Why not at this time go to DOT5? Much higher boiling point.

Campingman, Because long story short .... DOT5 is totally incompatible with our hydraulic systems, will damage the ABS equipment and will void anything that an owner may have as a warranty.

[cannon man]

don'think you can do that. Driver, OEMY, what about it. also, if you got these brakes that hot they would be history.
dave

[cannon man]

driver beat me to it.

[oemtech]

As I have said before in other threads... DOT 4 has a higher boiling point but DEGRADES faster than DOT 3 once it start absorbing moisture. DOT5.1 is costly.

Once you have Speed Bleeders installed you can change yearly for about $15.

As for emptying the master cylinder I have a vacuum operated container.



To put the brake fluid back into the master cylinder I modified a small garden sprayer.



Yes - That is a bottle of DOT 4... But, it was on sale and was only in the system for one RV season. I replaced it with DOT 3 from Wal Mart.

[max49]

Just for clarification, and I know OEMy already mentioned 5.1 but; I have been told that DOT 5 is incompatible with DOT 3 & 4 but DOT 5.1 is compatible with 3 and 4 and it would'nt hurt any thing if they were mixed a little. I know it sounds confusing.
Do you guys agree with this? Is DOT 5.1 that much better? and if so, how?

[depchief]

The Workhorse chassis guide in the section "Filling the Master Cylinder" states that Delco Dot 3 is preferred.

The following is from the Chassis Guide, page 72.

Thoroughly clean the reservoir cover before removal to avoid getting dirt into the reservoir.
Remove the cover and inner rubber diaphragm, add fluid as required. Use Delco Supreme No.
11 Hydraulic Brake Fluid (Dot No. 3) or equivalent.
CAUTION:
Do not add DOT 5 brake fluid to the master cylinder reservoir. DOT 5 fluid is silicon
base whereas the correct DOT 3 fluid is Glycol based. The two will not mix and the DOT
5 fluid can cause major damage to the anti-lock brake module and other brake
components.
CAUTION:
Do not use shock absorber fluid or any other fluid that contains mineral oil. Do not use
a container that has been used for mineral oil or a container that is wet from water.
Mineral oil will cause swelling and distortion of rubber parts in the hydraulic brake
system and water will mix with brake fluid, lowering the fluid boiling point. Keep all
fluid containers capped to prevent water contamination.

[max49]

I knew it would be confusing.



DOT 5.1

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Not to be confused with DOT 5, a silicone based fluid.
DOT 5.1 is one of several designations of automotive brake fluid, denoting a particular mixture of chemicals imparting specified ranges of boiling point.
A brake fluid's dry boiling point is the temperature at which the pure fluid will boil. Wet boiling point concerns the boiling temperature when the fluid contains water.
In the United States, all brake fluids must meet Standard No. 116; Motor vehicle brake fluids[1]. Under this standard there are three Department of Transportation (DOT) minimal specifications for brake fluid. They are DOT 3, DOT 4 and DOT 5.1.
DOT 5.1, like DOT 3 and DOT 4, is a polyethylene glycol-based fluid (contrasted with DOT 5 which is silicone-based). Polyethylene glycol fluids are hygroscopic and will absorb water from the atmosphere, which is necessary to prevent sheer and undiluted water in the braking system, which is very corrosive.
As of 2006[update], most cars produced in the U.S. use DOT 3 brake fluid.
[edit] Boiling points

Minimal boiling points for these specifications are as follows:
Boiling point ranges
Dry boiling point Wet boiling point
DOT 3 205°C (401°F) 140°C (284°F)
DOT 4 230°C (446°F) 155°C (311°F)
DOT 5 260°C (500°F) 180°C (356°F)
DOT 5.1 270°C (518°F) 191°C (375°F)

I found this interesting also. Nothing new but it's the first time I read about calipers sticking because of water when it had nothing to do with WH brakes.

MOISTURE IN THE BRAKE SYSTEM
Water/moisture can be found in nearly all brake systems. Moisture enters the brake system in several ways. One of the more common ways is from using old or pre-opened fluid. Keep in mind, that brake fluid draws in moisture from the surrounding air. Tightly sealing brake fluid bottles and not storing them for long periods of time will help keep moisture out. When changing or bleeding brake fluid always replace master cylinder caps as soon as possible to prevent moisture from entering into the master cylinder. Condensation, (small moisture droplets) can form in lines and calipers. As caliper and line temperatures heat up and then cool repeatedly, condensation occurs, leaving behind an increase in moisture/water. Over time the moisture becomes trapped in the internal sections of calipers, lines, master cylinders, etc. When this water reaches 212º F the water turns to steam. Many times air in the brake system is a result of water that has turned to steam. The build up of steam will create air pressure in the system, sometimes to the point that enough pressure is created to push caliper pistons into the brake pad. This will create brake drag as the rotor and pads make contact and can also create more heat in the system. Diffusion is another way in that water/moisture may enter the system.
Diffusion occurs when over time moisture enters through rubber brake hoses. The use of hoses made from EPDM materials (Ethlene-Propylene-Diene-Materials) will reduce the amount of diffusion OR use steel braided brake hose with a non-rubber sleeve (usually Teflon) to greatly reduce the diffusion process.

[oemtech]

If you Google DOT 5.1 you will see everything from 250 ml to 8 oz bottles.

Example - 8 oz for $17.99 = $72 a quart!!! But, they wll sell it for only $6.74 for 8 oz or about $27 a quart x 3 (flush & bleed) for a grand total $81.

[max49]

Here's some for $10 for 500 ML.

Motul*Brake fluid, DOT 5.1 (N-S) - 500ml at Tree Fort Bikes - Online Bicycle Shop

Is'nt that a 1/2 ltr? If so, it seems like it would be worth a little extra to get an extra 90 or 117 degrees before it boils especially for the problematic WH/ Bosch calipers.

What would be the drawback or bad side of it?

On edit, I see they recommend replacement at 1 to 2 year interval. This may or may not be a problem since many are changing once a year or so any way. It is promoted as racing product so this may not necessarily indicate a shorter lifespan than DOT 3 or 4

[oemtech]

Max,

500 ml for $9.95 and it takes 946 ml = 1 quart if my math is correct or about $20 x 3 = $60. So DOT 3 at $15 you can change every year for 4 years spend the same amount of money. Will the DOT 5.1 last 4 years and what would the boiling point be in 4 years compared to fresh DOT 3 replaced yearly?

[DAN L]

Quote:

Originally Posted by max49 Here's some for $10 for 500 ML. Motul*Brake fluid, DOT 5.1 (N-S) - 500ml at Tree Fort Bikes - Online Bicycle Shop Is'nt that a 1/2 ltr? If so, it seems like it would be worth a little extra to get an extra 90 or 117 degrees before it boils especially for the problematic WH/ Bosch calipers. What would be the drawback or bad side of it? On edit, I see they recommend replacement at 1 to 2 year interval. This may or may not be a problem since many are changing once a year or so any way. It is promoted as racing product so this may not necessarily indicate a shorter lifespan than DOT 3 or 4

my experience with the motul 5.1 is that it is much more hydroscopic than dot 3 or 4 brake fluid. i used to use 5.1 in my motorcycles clutch and brake systems and had to change it every 6 months in hawaii. i now use castrol lma (low moisture affinity) dot 4 brake fluid in everything i operate.