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Lakehouse 2 · 04-13-2018, 04:22 PM

According to the "Maintenance" section of the Owners Manual DOT3 is specified. But in in the "Capacities and Specs" section, DOT4LV is specified? The master cylinder reservoir cap has DOT3 on it. I called Ford corporate and after giving them the vin number I was told to use heavy duty DOT3. My local Ford dealer says I can use 3, 4, 4LV, or 5.1 as they will all mix. He suggests 4LV because it is cheaper than 5.1, has about the same boiling points and has a thinner viscosity which he says help the anti-lock brakes to work better in cold weather.
A mechanic friend of mine who lives in another state suggested I get a tester that checks the moisture content of the brake fluid. That's how he determines when to change brake fluid. He will be visiting soon and will be bringing his tester for me to try. Has anyone done this??

BFlinn181 · 04-13-2018, 05:01 PM

DOT 3, 4, 4LV, or 5.1 can be mixed if necessary. Brake fluid isn't that expensive that I'd 'cheat' on doing a full flush periodically. After all, it's the fluid that stops you when you need it. I'd use DOT 3 as that's what is on the cap and Ford said to use it. DOT 5 is the only one to stay away from, it's silicone based and doesn't play nice with components of your brake system.

I wonder how accurate a moisture tester can be, you're only testing what's in the reservoir, not 20' away at the back axle. The reservoir would absorb water first, the rest of the system is pretty much not exposed to moisture. Walmart has synthetic DOT 3 for under $12 a gallon, why leave the old stuff in the system at that price? It's not that hard to flush the system, but it's easier with two people. You only need one person if you buy a vacuum brake bleeder kit, or a pneumatic brake bleeder kit.

TeJay · 04-14-2018, 11:43 AM

BFLinn181,

Excellent response as usual. I'm also glad to have read it because I want to flush my brake fluid after the temps get above 60 for more than a day.

Remember this very important point concerning brake fluid. It is the ONLY fluid in a vehicle that does not circulate. It would be nice if it did then it could be filtered.

Moisture can very easily be absorbed through the smallest opening even past seals. According to reliable sources within 1 year of manufacture most brake systems contain 1% to 2% moisture. The military went to silicone brake fluid years ago because they have many vehicles that set in fields for extended periods then are called into service at a moments notice. Silicon does not absorb moisture like regular BF.

I've serviced many, many brake systems over the years and always encountered rusted and badly pitted wheel cylinders on all 4 wheels. The fluid does not circulate and if most of the moisture is absorbed through the master cylinder how is it that rear wheel cylinders can show rusting pitted interior parts after 6, 8 or 10 years of use???

The moisture must get in some how and I was told it gets in past the wheel cylinder seals and even through the rubber lines. Sounds crazy I know but it must get in some how.

Lakehouse 2 · 04-14-2018, 05:05 PM

TeJay,

What method will you use to flush your brake system? I'm very familiar with the old manual method but it has been many years since I was able to convince the DW to help me with that job! The biggest issue I see, other than finding a helper, will be to keep the master cylinder reservoir full. The Master cylinder on our MH is almost touches the bottom of the dashboard. I had a heck of a time just to get the cover off the reservoir to see what fluid it called for. Any advice will be appreciated.

TeJay · 04-15-2018, 09:56 AM

John,

I'll use a hand held vacuum pump to remove the fluid from each wheel. I think I still have a good one in the garage. They are easier to get these days and not to costly. We always start at the furthest wheel from the MC so that would be right rear then left rear etc.

If you transfer the old fluid to a jar as you evacuate it you can measure how much you take out so the MC does not run dry. Most of the specific bake fluid pumps have a container for that purpose. When you see the color change from old to new take out a little more then move on.

As with most of the DIY stuff we really never see all the prior set up which makes those DIY TV shows look so professional, smooth and very easy. LOL!!! Never in real life.

I'll also probably set up some sort of hand pump with a 1/4" hose or tube into the MC. At the same time I'll cover the MC with a 1/4" piece of wood with maybe a lead weight or Velcro strap so I can keep it tight and still check the fluid level a little easier.

It's never good to keep the top open to long because of moisture absorption. I also realize that you can't stop all the moisture absorption but at least don't make it easier.

I have been remiss in not doing our 2013 chassis yet so I'll probably get some decent equipment because I do want to do it every 3 years max. There really is no substitute for good tools and equipment.

You know the brake fluid will eat automotive paint. The newer hardened paints with a clear coat are better but they may or will discolor the black paint under the hood. Correct preparation and good pumps will minimize spills and even drips.

Have fun!!! It's 30 degree here in AR today so no outside work. Very cold for AR this time in April.

I just checked on Amazon and they have some nice bleeding kits for $20 and up. I'll get one that has a storage box for $30. The mityvac I'm familiar with.

BFlinn181 · 04-15-2018, 10:34 AM

What TeJay said, with one addition. The day before crawl underneath each wheel position and spray the bleeder valves with PB Blaster or similar penetrating oil. The biggest obstacle I've run into over many DIY brake jobs is rusty bleeder valves that can break off instead of coming loose.

purrin along · 04-15-2018, 03:13 PM

Thanks for all the good advice guys.It's time to do mine, and warm enough also.

Lakehouse 2 · 04-16-2018, 07:33 AM

TeJay

Thanks for the tips. I may just give this a try when the temps warm. It's still cold here in northern OH, snowing at the moment,but it did hit 70 the other day for a little while. The weathers been like a one of the roller coasters at Cedar Point.

bruce91 · 04-18-2018, 05:27 AM

A few months ago i flushed my brake system. I bought 8 16oz of motorcraft dot 5.1 from rockauto.com and had 1 1/2 containers left over. I could have used less but getting used to the fill opening waay up high i spilled a bit. I have a mityvac brake bleeder which i used AFTER trying the gravity method on one wheel which i read about being easy to do. Easy yea slow you bet, i'd rather watch grass grow.
If i didn't already have my mityvac brake bleeder a set of speed bleeders would be a cost effective way to DIY. I bought a set of 4 (SB3824 after an email to them to get the correct fitment) for my next flush for $28 +S&H.

https://www.amazon.com/Mityvac-MV683...+brake+bleeder

http://www.speedbleeder.com

Bob Hyatt · 04-18-2018, 10:37 PM

And DO NOT use pliers, vice-grips, channel locks, etc on those bleeder valves. Use ONLY a box-end wrench, and a 6 point box end is better. That avoids the completely round bleeders I have seen many times...

Sometimes "corners" are good.

Lakehouse 2 · 04-19-2018, 07:15 AM

Bruce91,

Thanks for the info on the "speed bleeders". I think I will give them a try. Seems like the simplest method. I just have to figure out what size bleeders I need for our '14,18000# chassis and how much fluid to have on hand.

bruce91 · 04-20-2018, 03:53 PM

Quote:

Originally Posted by Lakehouse 2

Bruce91,

Thanks for the info on the "speed bleeders". I think I will give them a try. Seems like the simplest method. I just have to figure out what size bleeders I need for our '14,18000# chassis and how much fluid to have on hand.

Email them with your information and they will let you know the correct one's to get.