2008 Lexus LX570 Brake Fluid Type and Flush Interval

By Core Brake Parts Tech Team — Circleville, OH warehouse

The 2008 Lexus LX570 uses glycol-based brake fluid that meets SAE J1703 or FMVSS No. 116 DOT 3. Lexus's 2008 Warranty and Services Guide lists "Replace brake fluid" at the 36 months or 30,000 miles service, and again at 60,000, 90,000, 120,000 and 150,000 miles. If your truck tows, climbs mountain passes or has missed a change, do not stretch that interval.

Below is what the spec means, why the fluid wears out even when the reservoir looks full, how the LX570's powered brake system changes the bleeding job, and what to check while the wheels are off.

The Correct Brake Fluid for a 2008 LX570

Lexus service information for the 3UR-FE powered LX570 of this generation specifies brake fluid meeting "SAE J1703 or FMVSS NO. 116 DOT3." Those two labels describe the same class of fluid: a polyglycol-ether based fluid with minimum boiling points set by the federal standard. Look for DOT 3 printed on the bottle.

FMVSS 116 sets the minimum performance for each grade. The numbers below are straight from the standard:

Two practical takeaways. First, a quality DOT 4 fluid exceeds DOT 3 minimums, and fluid makers such as Castrol state their DOT 4 is compatible with fluids meeting DOT 3 or DOT 4, so topping off with DOT 4 will not harm the system. Lexus's printed spec is still DOT 3, and staying with it is the simplest answer. Second, never put silicone DOT 5 (the purple fluid) into an LX570. It is a different chemistry, and the standard requires the purple dye precisely so it is not mixed into a glycol system by mistake.

Why the Fluid Needs Replacing on a Schedule

Glycol brake fluid is hygroscopic: it pulls moisture out of the air through hoses, seals and the reservoir cap every time the truck is driven or parked in humid weather. The level in the reservoir does not change, but the boiling point drops. That is why FMVSS 116 lists a separate, lower wet boiling point for each grade.

Castrol notes that as little as 3.5 percent water can reduce brake fluid effectiveness by up to 40 percent, and recommends draining and changing fluid once water content goes above roughly 2.5 to 3 percent. On a heavy three-row SUV like the LX570, a long downhill grade with a trailer attached is exactly where a low boiling point shows up as a soft, sinking pedal. Moisture also feeds internal corrosion in calipers, lines and the ABS and stability-control hydraulics, which are far more expensive to replace than a few bottles of fluid.

The Lexus Maintenance Schedule for Brake Fluid

The 2008 Lexus Warranty and Services Guide covers the GX, LX and RX. For all three, it places brake fluid replacement on these services:

• 36 months or 30,000 miles: replace brake fluid, inspect brake lines and hoses, visually inspect pads and rotors.
• 72 months or 60,000 miles: replace brake fluid again.
• Repeats at 90,000, 120,000 and 150,000 miles on the same schedule.

The same guide asks owners to visually check the brake fluid level on the see-through reservoir at every fill-up. After off-road driving through deep sand, mud or water, Lexus lists a daily check of brake lines and hoses, brake pads and rotors, and the parking brake linings and drums. A 2008 LX570 is now well past its original schedule, so if you have no record of a brake fluid change, treat it as due now.

How the LX570's Brake System Affects a Flush

The LX570 does not use a simple vacuum booster. Its brake actuator uses an electric pump and an accumulator to store hydraulic pressure, which is why the Lexus bleeding procedure starts with the accumulator before the wheel lines. In outline, the service information calls for:

1. Filling the reservoir with the specified fluid and keeping the level between the MIN and MAX lines the whole time.
2. Bleeding the accumulator: with the engine switch at IG, letting the pump run, then switching off and pumping the brake pedal repeatedly, several cycles in a row, while confirming the pump run time stays within the factory limit.
3. Bleeding the brake lines at the calipers with a clear tube on each bleeder, and tightening the bleeder plugs to the factory torque.

If air gets into the actuator, a pressure bleeder and a gravity bleed may not be enough, and a scan tool that can run the actuator may be needed. For that reason many owners leave the flush to a shop with Lexus-capable diagnostics. If you do it yourself, follow the factory service manual step by step, never let the reservoir run low, and wipe up spills quickly because glycol fluid damages paint.

Signs Your LX570 Brake Fluid Is Overdue

• Dark fluid: new DOT 3 is colorless to amber. Brown or black fluid is old and contaminated.
• Soft or long pedal after hard use: heat from towing or long descents boiling moisture-laden fluid.
• Brake warning light or low level: the level drops slowly as pads wear. A sudden drop means a leak, so check hoses, lines and calipers before simply topping off.
• No service record: on a truck this age, missing records mean the fluid is almost certainly past its interval.

What to Check or Replace at the Same Time

A fluid flush is a good moment to inspect the whole hydraulic and friction system, since the wheels are already off:

• Pads and rotors: measure pad thickness and check rotors for scoring, heat spots and runout. We carry Hawk Talon drilled and slotted rear rotors for the 2008 LX570, plus a wider range of brake pads and brake rotors.
• Hoses: cracked, swollen or rubbed rubber hoses let moisture in. See our brake hoses.
• Calipers: a seized slide or piston shows up as uneven pad wear. Browse brake calipers if one is sticking.
• Parking brake: Lexus lists the parking brake linings and drums for inspection after off-road use, so look at them while the rear wheels are off.

Frequently Asked Questions

What brake fluid does a 2008 Lexus LX570 take?

Lexus specifies brake fluid meeting SAE J1703 or FMVSS No. 116 DOT 3. Any sealed bottle labeled DOT 3 meets that spec.

Can I use DOT 4 in my LX570?

DOT 4 is also glycol-based, exceeds DOT 3 boiling point minimums and is sold as compatible with DOT 3. It will not harm the system, but the factory spec is DOT 3. Never use silicone DOT 5.

How often should the LX570 brake fluid be changed?

The 2008 Lexus maintenance schedule lists brake fluid replacement at 36 months or 30,000 miles, then at 60,000, 90,000, 120,000 and 150,000 miles.

Is an LX570 brake flush a DIY job?

It can be, but the LX570's pump-and-accumulator brake actuator means the procedure starts with bleeding the accumulator, and air in the actuator may need a scan tool. Follow the factory manual exactly or use a shop.

Why does my brake pedal get soft when towing downhill?

Old fluid holds water, which lowers its boiling point. Sustained braking can boil it and create vapor pockets. Fresh fluid and healthy pads and rotors are the fix.

Sources

1. Lexus 2008 GX, LX, RX Warranty and Services Guide - brake fluid replacement intervals, fill-up and off-road inspection items
2. Lexus LX 570 3UR-FE service information: brake bleeding - SAE J1703 / DOT 3 spec and accumulator bleeding procedure
3. 49 CFR 571.116, FMVSS No. 116 Motor vehicle brake fluids - dry and wet boiling point minimums and color requirements
4. Castrol brake fluids - moisture effects, water content change thresholds, DOT 3/DOT 4 compatibility