2006-2011 Chevrolet HHR Brake Fluid Type and Flush Interval

By Core Brake Parts Tech Team — Circleville, OH warehouse

Every 2006-2011 Chevrolet HHR uses DOT 3 brake fluid. GM's owner manuals call for Delco Supreme 11 or an equivalent DOT 3 fluid in the early years and GM DOT 3 Hydraulic Brake Fluid in the later years, always new and from a sealed container. GM does not print a fixed mileage for replacing it; the schedule calls for a brake system inspection at every oil change or every 12 months, so the fluid gets changed based on its condition, and a test strip is the easiest way to decide.

What brake fluid the HHR takes

The spec did not change over the HHR's run, only the way GM wrote it. The 2007 owner manual lists the hydraulic brake system fluid as Delco Supreme 11 Brake Fluid or equivalent DOT-3 brake fluid. The 2011 manual lists DOT 3 Hydraulic Brake Fluid under a GM part number. Both are DOT 3 glycol-based fluid, and any fresh DOT 3 fluid that meets the federal standard is the correct fluid for this car.

One detail catches owners of manual-transmission HHRs off guard: the brake master cylinder and the hydraulic clutch share one reservoir. The 2011 manual says so directly. That means old, wet fluid affects the clutch master and slave cylinders too, and a clutch-side leak will drop the brake fluid level and can trigger the brake warning.

DOT 3 vs DOT 4 vs DOT 5 in an HHR

Federal Motor Vehicle Safety Standard 116 sets the minimum boiling points for each grade. DOT 3 must boil no lower than 205 C (401 F) when new and 140 C (284 F) wet, meaning after it has absorbed a set amount of water. DOT 4 raises those minimums to 230 C (446 F) and 155 C (311 F). DOT 5 is a silicone fluid with a different chemistry.

• DOT 3: what GM specifies. Always correct.
• DOT 4: also glycol-based with higher minimum boiling points. Many techs use it in DOT 3 systems, but GM's manual for this car names DOT 3, so that is what we recommend.
• DOT 5 (silicone): do not put it in an HHR. It does not mix with glycol fluid, and GM's manual warns that the wrong fluid can badly damage hydraulic parts.
• Anything petroleum-based: never. The manual warns that even a few drops of mineral oil such as engine oil can damage brake and clutch parts so badly they have to be replaced.

How often to flush HHR brake fluid

GM's maintenance schedule for the HHR lists a brake system inspection at every engine oil change or every 12 months, whichever comes first, along with a visual fluid leak check. There is no line item that says replace the brake fluid at a set mileage. That does not mean the fluid lasts forever.

Glycol brake fluid pulls moisture out of the air through hoses, seals and every time the cap comes off. That is why the federal standard requires every container to tell you to keep brake fluid clean and dry and to keep the container tightly closed to prevent moisture absorption. As water content climbs, the boiling point falls toward the wet minimum, and the corrosion inhibitors in the fluid get used up. Once those inhibitors are gone, corrosion starts inside the system, including the ABS unit on cars that have it, the master cylinder bore and the rear wheel cylinders.

The practical way to decide is to test it:

1. At each oil change or brake inspection, pull a sample from the reservoir.
2. Dip a copper test strip. Phoenix Systems, which makes the widely used BrakeStrip, says to replace the fluid when copper reaches 200 ppm or higher, following Motorist Assurance Program guidelines.
3. If the strip fails, or the fluid is dark and cloudy, flush the whole system rather than topping off.

Every HHR on the road is now well over a decade old. If you have no record of a fluid change, assume it is due and test it now.

Symptoms that point to old or low fluid

• Brake warning light or BRAKE FLUID message: the 2011 manual says the message and the brake system warning light come on when the reservoir level is low.
• Soft or sinking pedal: moisture-laden fluid can boil during long downhill stops and leave vapor in the lines, which compresses and makes the pedal feel spongy.
• Pedal travel increasing quickly: GM tells owners to see a dealer if the pedal does not return to normal height or travel increases rapidly.
• Dark fluid in the reservoir: new DOT 3 is nearly clear; dark brown fluid is old and contaminated.
• Clutch pedal problems on manual cars: a soft or sticking clutch pedal can come from the same tired fluid, since the clutch shares the reservoir.

A falling level is not a reason to keep adding fluid. GM explains there are only two reasons the level drops: normal lining wear, which lets the level fall as the caliper pistons move out, or a leak. If the pads are thin, replace the brake pads and the level comes back up. If the pads are good and the level keeps dropping, find the leak before driving further.

Doing the flush on an HHR

A flush replaces all of the fluid in the lines, calipers and wheel cylinders, not just what sits in the reservoir. On the HHR this is a straightforward driveway job for someone who has bled brakes before.

1. Clean the reservoir cap and the area around it before opening it. GM calls this out to keep dirt out of the system.
2. Remove most of the old fluid from the reservoir and refill with new DOT 3 from a sealed bottle.
3. Bleed each wheel in the order the factory service manual lists, keeping the reservoir from running low so air is not drawn in.
4. On rear-drum cars, the rear bleeders are on the wheel cylinders, which are often seized on an older HHR. Soak them with penetrant and use a six-point wrench.
5. On manual-transmission cars, bleed the clutch hydraulic line too, since it draws from the same reservoir.
6. Top the reservoir to the full mark, wipe up any spills immediately, and road test at low speed first.

Brake fluid damages paint. The owner manual warns that spilled fluid can harm the finish and should be washed off right away. On cars with ABS, if the reservoir was run dry or air got into the modulator, the service manual procedure may call for a scan tool to cycle the ABS valves during bleeding.

What to replace at the same time

A fluid flush is the right moment to look at the parts the fluid touches and the parts that affect how much fluid sits in the calipers.

• Front pads and rotors: the HHR has front disc brakes with wear indicators that squeal when pads are worn. Our 2006-2011 Chevrolet HHR front brake kit covers pads and rotors in one order, or shop brake rotors separately.
• Rear shoes and drums: the manual notes that rear drums have no wear indicators and should be pulled and inspected at every tire rotation. Replacement linings are in our brake shoes collection.
• Rubber brake hoses: cracked or swollen hoses let moisture in. See brake hoses.
• Master cylinder: if the pedal sinks slowly with no external leak, the master cylinder seals may be bypassing internally. Replacements are in master cylinders.

GM recommends replacing brake linings as complete axle sets and inspecting the rear brakes whenever the front pads are replaced.

Frequently Asked Questions

Can I use DOT 4 in my Chevy HHR?

DOT 4 is glycol-based and compatible with DOT 3, but GM's owner manual for the HHR specifies DOT 3. Using the specified fluid is the safe choice unless a shop recommends otherwise for a specific reason.

Does GM have a brake fluid change interval for the HHR?

No fixed mileage is printed. The maintenance schedule calls for a brake system inspection at every oil change or every 12 months. Test the fluid at that inspection and replace it when it fails.

Where is the brake fluid reservoir on an HHR?

It sits on the master cylinder at the rear of the engine compartment on the driver's side. On manual-transmission cars the same reservoir also feeds the clutch.

Why does my HHR brake fluid keep getting low?

Either the pads are wearing, which is normal and slow, or something is leaking. Check the pads first; if they are thick, look for wet spots at the calipers, rear wheel cylinders, hoses and, on manual cars, the clutch slave cylinder.

Is Delco Supreme 11 still required?

No. The early manuals list Delco Supreme 11 or an equivalent DOT 3 fluid, and later manuals simply list DOT 3. Any new DOT 3 fluid from a sealed container meets the requirement.

Sources

1. 2007 Chevrolet HHR Owner Manual (GM) - Delco Supreme 11 or equivalent DOT-3 for the brake and clutch hydraulic systems
2. 2011 Chevrolet HHR Owner Manual (GM) - DOT 3 spec, shared brake and clutch reservoir, fluid warnings, rear drum or disc brakes, brake inspection every oil change or 12 months
3. 49 CFR 571.116, FMVSS 116 Motor Vehicle Brake Fluids - DOT 3 and DOT 4 minimum dry and wet boiling points, container moisture warnings
4. Phoenix Systems, Brake Fluid Copper Testing - 200 ppm copper replacement threshold per MAP guidelines
5. 1A Auto, 2006-2011 Chevrolet HHR rear brakes - HHR rear drum brake and shoe service