DOT 5.1 Brake Fluid

Hi Guys --

For a Tacoma that will be regularly towing a heavy trailer, I'm considering changing to a 5.1 Motul brake fluid for the higher boiling point rating. Has anyone had experience with this spec fluid in a 2006 or other 2nd gen?

Thanks!

 

IMO, you do not want to use DOT 5 fluid - it is really for "race" cars.

Last I looked, DOT 5 was not compatible with DOT 3 and 4 fluids - meaning, you have to flush/clean your entire system before adding fluid. Also, IIRC there is a property about DOT 5 that is not daily driver friendly.

A good DOT 4 fluid should be all you need. I've been running Valvoline fluid for almost 20 years, and have never had any brake issues.

More important than the specific fluid is to flush the brake system regularly to clean out dirt, corrosion and rust.

 

For a vehicle that will be towing a heavy load, and therefore experiencing heavier-than-average breaking forces, wouldn't this be a good idea? The Motul bottle says DOT 3 & 4 compatible.

I'm not trying to argue, just talking this through. Are there actually any reasons why this fluid won't work, other than that it is commonly used in high-performance applications?

 

If it is compatible, then the specs have changed since I last looked into DOT 5 (many years ago) so my thoughts are that relevant...

On the surface, I'll say the answer to your question is 'yes'. But, is it really needed? More important are steel braided lines and good pads and rotors (and drums and shoes.)

 

Check out the picture - claims DOT 3 & DOT 4 Compatible.

I'm currently installing Brembo Rotors, Hawk Pads, and SS Goodrich Lines.

 

you arnt heating the fluid up enough to cause issues.... brake fade will come with glazing of parts.

running fresh fluid that the book recommends (probably dot 3) will be your best bet.

 

If you were talking about swapping out DOT4 to DOT5.1 on a motorcycle I would say yes. Automotive wise when it comes to a Tacoma pickup I would stick with DOT4.

 

It is indeed compatible just like it says on the bottle and does provide a higher boiling point like DOT 5 while maintaining the ability to absorb water like DOT 4 and DOT 3. I would use it if you believe that you are likely to experience higher fluid temps due to towing especially if you are towing heavy loads or in hilly regions. Why would that be overkill?

 

I use that exact fluid in my sequoia. I changed brake fluid at 50k (yes I am OCD!) I used the hawk ceramic pads and I hate them. The oem pads had 30% of their life left. The dust is horrendous and I have a fortune spent in wheel cleaner. That fluid was chosen because it is nearly impossible to get 100% of the fluid out. I used a mighty vac and pumped out the master cylinders and then pulled as much as I could through the bleeders on the calipers. The compatibility allows you to get "most" of the fluid out and still mix with any residual fluid. I change fluid based on time not miles. The fluid absorbs water and makes the pedal spongy. I highly recommend the fluid. Change your power steering fluid while you have your hands dirty! I run amsoil power steering fluid in there. Good luck!!!

 

Silicone brake lube

Bendix BL20 Ceramic Brake Lubricant

http://www.amazon.com/Bendix-BL20-Ceramic-Brake-Lubricant/dp/B004TGVP14
Brake pads
http://www.hawkperformance.com/performance-street/pads/performance-ceramic
PWR steering fluid
http://www.amsoil.com/lit/databulletins/g2577.pdf

 

This is what we're working on Customer's truck. We sell the orchard sprayer that does this....

 

the difference you have felt is simply new fluid. Not the dot 5.1 fluid..... OP stick with a quality dot 3 or 4 fluid and change on the regular.

 

Thanks for your input guys

 

If you already had the 5.1 fluid, would you use it in this application?

 

I believe that the 5.1 is less hygroscopic or water seeking. That was one of my reasons for the upgrade. I do my own wrenching, so materials cost is quickly erased by doing the work myself. I tow an enclosed 7x14 trailer with the sequoia so I did an upgrade on brakes and fluid. Irregardless of whether it was the 5.1 or just new fluid, it was a good move. It was the highest performance fluid with compatibility that I found. Cool sprayer... We have a ton of orchards and vineyards here on the lake.

 

^Not quite correct. It's true DOT 5/5.1 have a slightly higher boiling point (356F) when contaminated with 3.7% water compared to DOT 4 (311F) and to DOT 3 (284F). The primary benefit of DOT 5/5.1 is they don't thicken at extremely cold temperatures. DOT 4 is twice as viscous as DOT 5/5.1 at -40F.

DOT 5 and 5.1 have the same performance requirements. If the fluid is silicone, it is classified as DOT 5. If the fluid is polyglycol ether, it is classified as DOT 5.1:

http://www.gpo.gov/fdsys/pkg/CFR-2011-title49-vol6/xml/CFR-2011-title49-vol6-sec571-116.xml

 

DOT 5 is completely unnecessary. Snocross sled use DOT 4, motocross bikes use DOT 4, we run DOT 4 in our race car for 30 minute races. If these applications don't need DOT 5, a truck towing a trailer certainly won't require DOT 5.

 

Engines don't "require" Mobil 1 synthetic... Rims don't require Michelin tires... But it has become rather proven that they out perform other mfg's. My sequoia cost over $45k new. My taco was $31k. These fluids are pennies in comparison. Do I need it? Nope. Do I run generic walmart oil in my engine? Nope. How long did the cheap ass bridge stones last on my sequoia? 35k. I once again kick myself for ATTEMPTING to contribute anything to the group. OP, good luck and I can personally endorse your questioned product. I am a mechanical engineer, a licensed pilot, a licensed captain, and I have built 4 classic cars. Good luck with your sprayers they look awesome!

 

So I run this at local track events.


20+ min sessions of hard braking and accelerating on sticky tires heats the brakes up to the point there calipers change colors and rotors glow. I even have had one brake fire.

The heat your going to generate towing will not exceed what track cars see during a session. I run Motol 600 in the car. It lasts around 1 year of track days before it needs to be flused. I would focus on better pads. Pick a more aggressive pad that handles heat better. Most the time you don't boil fluid you actually heat up pads past the point of friction and hence you loose bite. Aggressive pads will dust more and make more noise when cold. Its a trade off.

 

thanks for the input - I value all different opinions and experiences. Glad you shared yours.

These sprayers are excellent - they have been a time-tested, solid implement for our family business to sell & support. Built local in Central, CA!