domonas

I'm at 65k, never changed brake pad, so I decided to just go for broke... Gonna replace pads, rotors and do a complete brake fluid flush. Any recommendations for brake fluid? I got a synthetic Valvoline DOT 3/4 brake fluid. Any advice otherwise?

fastnoypi

Valvoline DOT3&4 is good stuff. If you want to splurge for full DOT4 , Pentosin is excellent.

iolmaster

iTrader: (1)

I have to ask. What difference can there be in brake fluid? It is just a spacer.

fastnoypi

im not sure what you mean by spacer, its a hydraulic fluid where boiling points can matter when it comes to continued hard braking. Also there are differences in wet saturation points which some brake fluids are more susceptible to pulling water out of the air and causing costly corrosion in your brake system.

slawless

Brakes get HOT. If your brakes get hot enough and the fluid can boil and then you're in trouble. Among other things the higher the number the higher the boiling point. Most cars use a DOT3 or DOT4. There is a DOT5 but it is more for racing applications and is higher maintenance. It tends to readily absorb moisture and needs to be changed more often. Also DOT5 is incompatible with other brake fluids. There is a DOT5.1 but I know very little about it. My BMWs want DOT4. If I were to change the fluid in the RX my OC would make me use DOT4. I don't know what Lexus puts in.

fastnoypi

DOT 5.1 is glycol based and is compatible with DOT 3 and DOT 4. It's not yet widely used in everyday cars but can be used. Its popular with road course and other track events due to the higher dry boiling point of 270*C...a temp that would rarely be seen on a street setup vehicle. Definitely stay away from DOT 5 fluid because it is silicone based. From what i've read OEM fill on Toyota/Lexus is labeled as a DOT3 fluid but is really a DOT 3 and DOT 4 blend like Valvoline DOT3&4...due to borate content found.

tempestv8

I am pretty sure Toyota only specify DOT3 brake fluid for their models, so DOT4 is not recommended. Check your manuals.

Here is an existing discussion: https://www.clublexus.com/forums/sc430-2nd-gen-2001-2010/606221-brake-fluid-dot-4-or-3-a.html

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fastnoypi

lots of bad info in that post. DOT3 and DOT4 are interchangeable and compatible with one another. DOT4 having a higher boiling point and lower wet saturation point than DOT3. ....however DOT3 is the cheap standard issue for alot of commuter car use.





the only fluid that should not be used on this chart is DOT5 ..it is silicone based. Here is more info on DOT4 brake fluid https://en.wikipedia.org/wiki/DOT_4 Noted in the wiki..most cars in the US since 2006 use DOT4, I would think DOT4 is widely compatible due to the global supply chain Toyota/Lexus uses in brake system seal components. I doubt the Australian market uses brake components that are incompatible.

Clutchless

Many bottles of brake fluid are labeled for both 3 and 4 as it is reverse compatible to the lower spec.

domonas

Thanks. Just gonna stick with what I got.

tempestv8

I also drive a Land Cruiser and am a member on the Cruiser forums. If the brake systems are similar, then I'd definitely stick with DOT3, as there are numerous first hand testimonies from owners who have struck problems long term with the use of DOT4 fluid. The symptoms don't manifest immediately.

Toyota states in a TSB, their Brake fluid: "Toyota uses brake fluids containing polymers that act as lubricants for certain brake system components."
It goes onto say: "If replacement brake fluid is used that does not contain such polymers, or contain only small amounts, a part of the rubber seal (Brake Master Cylinder Cup) located at the rear of the brake master cylinder may become dry"

I am not saying that this will be the case with an RX but why take the risk? A new bottle of Toyota DOT3 brake fluid is cheap and works perfectly fine.

fastnoypi

That TSB you refer to is old. It doesnt apply to Toyota past 2006 https://static.nhtsa.gov/odi/rcl/201...0V499-4566.pdf Only a few models were affected due to brake booster suppliers. Feel free to continue to use DOT3 if you like.

fastnoypi

The Lexus manual refers to FMVSS No. 116, DOT 3 or SAE. J1703 brake fluid. FWIW, Valvoline Dot 3 and 4 fluid "surpasses specifications SAE J1703, FMVSS No. 116 and DOT 4 motor vehicle brake fluid"

feel free to compare their SDS sheets Toyota Brake Fluid vs Valvoline Dot3 and 4 Brake fluid