DOT 4 Class 6 Instead of DOT 3?

[skyactiv]

Didn’t DOT 4 come out in the 60’s or 70’s because Lincoln or Continental had a big car that would boil DOT 3 brake fluid?

 

[nthach]

The title actually poses a very good question
Let's take a Ford Recall/TSB for example
Anyone who knows CD3 cars knows the ABS modulator/pumps are failure prone, causing a loss of braking ability

"In some of the affected vehicles, a chemical reaction between aged DOT 3 brake fluid and the zinc plating
inside the Hydraulic Control Unit (HCU) may result in a gel formation. A normally closed valve may be stuck
open, which may result in extended brake pedal travel"

Remember, all these cars were factory recommended to use DOT 3

The solution is
"If the HCU passes the inspection, the brake system will be pressure flushed with DOT 4 brake fluid,
the DOT 3 reservoir cap will be replaced with a new DOT 4 cap, and you will receive an updated
owner’s guide insert"

The fluid they recommended is Motorcraft PM-20 DOT 4 LV

• New Low Viscosity formulation, faster response at lower temperatures
• Recommended for new ABS brake systems with stability control
• Check brake fluid reservoir cap or master cylinder reservoir, owner guide and / or workshop manual for proper brake fluid usage
• Required for certain vehicles beginning in 2012-2013 model years
• Meets FMVSS DOT 4 and ISO 4925 Class 6 standards

Now while it's not 100% gospel, I think this is a perfectly acceptable justification for using DOT4 LV in a DOT3 setting

As long as the shorter service life of 4/4LV is understood

Neither my Fusion/Milan fall into the date ranges for the recall/CSP, but I think it would be reasonable of me to use DOT4 LV the next time I do a thorough brake fluid flush and pressure bleed?

I would think it's gotta be better than the factory DOT3 that's in there now?

Similar reasoning is behind why Toyota and Honda push their brake fluids over aftermarket even though it’s all DOT 3 - chemistry. The Japanese-spec fluids made by CCI are similar glycol borate ester chemistry as a Euro DOT4/5.1 but includes more lubricating qualities to keep master cylinder cups supple. The borate esters have a much higher affinity for water while inhibiting corrosion. Some Japanese indie shops used Castrol GT LMA instead of OE.

Despite ATE and Bosch supplying the Japanese with ABS/ESP modulators(more so on Hondas, Subarus and Nissans - Toyota uses Advics/Denso modulators mostly), they still want DOT 3 vs. DOT 4LV. I have Motorcraft DOT 3 in a Toyota, I believe it’s made by CCI in Illinois.

 

[michaelluscher]

Similar reasoning is behind why Toyota and Honda push their brake fluids over aftermarket even though it’s all DOT 3 - chemistry. The Japanese-spec fluids made by CCI are similar glycol borate ester chemistry as a Euro DOT4/5.1 but includes more lubricating qualities to keep master cylinder cups supple. The borate esters have a much higher affinity for water while inhibiting corrosion. Some Japanese indie shops used Castrol GT LMA instead of OE.

Despite ATE and Bosch supplying the Japanese with ABS/ESP modulators(more so on Hondas, Subarus and Nissans - Toyota uses Advics/Denso modulators mostly), they still want DOT 3 vs. DOT 4LV. I have Motorcraft DOT 3 in a Toyota, I believe it’s made by CCI in Illinois.

TIL
I always remember hearing the Motorcraft DOT3 was desirable due to it being one of the "better" DOT3s available at the time
I've had this old bottle sealed up indoors forever

This is a CCI fluid?

What about this Valvoline DOT3&4?
Where does it stand?

 

[tbm5690]

As an update, I ended up sticking with DOT 3 in the MDX. My liter of ATE SL.6 wasn't going to cover both vehicles, so it was just as easy to purchase separate DOT 3 as called for and I like the longer service interval. Additionally, I wasn't doing a flush of any sort, just bleeding at all 4 corners so I figure any remaining DOT 3 in the ABS module, etc. would best be remedied mixed with newer DOT 3 vs a LV DOT 4.

 

[Ray S]

Richard Ehrenberg, a well-known Mopar guru, and a member of the SAE, wrote this concerning the mixing of brake fluids:

Upgrading brake fluid to DOT5, do you rinse?

Hey guys, I'm going to flush out the old DOT 3 from our '67 Satellite and 'upgrade' to DOT 5... when I've ejected all the DOT 3, should I flush with anything else to "rinse" it before pouring the DOT 5 in the MC and completing the bleeding process? Maybe it's not a bi...

board.moparts.org

Rick Ehrenberg https://moparaction.net

MOPAR ACTION TECH GUIDE

Mopar Action Techmeister Rick EhrenbergMopar Action Tech Guide:ENGINES:470ci stroker: Big Shot-Mopar Action 1988360 Heads: Breath Easy-Mopar Action Feb 1989Stage 5 Hemi Heads: Hemi Comeback-Mopar Action Oct 1989Small BlockParts ID: Small Block Restor

www.moparaction.com

 

[Ray S]

Richard Ehrenberg, a well-known Mopar guru, and a member of the SAE, wrote this concerning the mixing of brake fluids:

Just to follow that up, I'll be power flushing the M375 (8 cylinders total) soon and will push 2 quarts of 5.1 or ESI6 through - whichever is on sale. Last time was DOT3 (2 quart flush).