2008-2015 Infiniti G37 Parking Brake Problems and Adjustment

By Core Brake Parts Tech Team — Circleville, OH warehouse

The parking brake on a 2008-2015 Infiniti G37 is not part of the rear disc brake at all. It is a small pair of drum brake shoes hidden inside the "hat" of each rear rotor, pulled on by cables from a foot pedal (automatic cars) or a hand lever (manual cars). When a G37 will not hold on a hill, the pedal goes nearly to the floor, or the rear wheels drag after release, the fix is almost always a shoe adjustment, a cable adjustment, or worn shoes and drums, and it is a job most home mechanics can handle if they follow the right order of steps.

How the G37 Parking Brake Works

Infiniti's factory service manual for the G37 calls the system a "parking drum brake." Each rear rotor has a small drum machined into its center section. Behind it, mounted to the backing plate, sit two brake shoes, a star-wheel adjuster, a toggle lever, return and adjuster springs, and anti-rattle pins and springs. When you set the brake, the rear cables pull the toggle lever, which spreads the shoes against the inside of the drum. The hydraulic rear pads and caliper play no part in holding the car when parked.

The control side comes in two versions, depending on the transmission:

• Automatic models: a foot pedal to the left of the brake pedal. The owner's manual says to fully depress it to apply, and to depress it again (with your foot firmly on the service brake) to release.
• Manual transmission models: a hand lever in the console that you pull up to apply.

From the pedal or lever, a single front cable runs to an equalizer, which splits the pull into left and right rear cables. An adjusting nut on the pedal or lever assembly sets cable tension. The G37 does not use an electronic parking brake, so no scan tool is needed to service it.

Common G37 Parking Brake Problems and Their Causes

On many G37s the problem starts right after a rear brake job. The rotor is also the parking brake drum, so whenever the rear rotors are replaced the shoes face a fresh drum surface they have never bedded into. If nobody adjusted the star wheel and ran the break-in procedure, the brake feels weak even though every part is new.

A second cause is simple disuse: many owners of automatic cars rarely set the parking brake, so the adjuster threads and cable ends corrode and stop moving freely. The service manual specifically calls for checking that the adjuster turns smoothly and that the toggle lever, pins and springs are free of rust and damage.

How to Check It: The Factory Notch Count

Infiniti gives a simple test you can do in the driveway. Apply the pedal or lever with moderate force - the manual specifies 196 N (20 kg, 44 lb) - and count the clicks of the ratchet.

If the pedal or lever goes past that range, the system needs adjusting. If it stays within range but the car still will not hold on a grade, the shoes or drums are the problem. The owner's manual gives its own practical test: the car should be held securely on a fairly steep hill with only the parking brake applied.

While you are there, look at the cables and equalizer under the car for fraying, kinks or cracked sheathing, and check that the pedal or lever assembly is tight and not bent. The factory procedure lists each of these as a replace-if-damaged item.

How to Adjust the G37 Parking Brake

The order matters. Adjust the shoes first, then the cable. Tightening only the cable on worn or backed-off shoes makes the pedal feel better for a while, then the travel comes back, and it can leave the shoes dragging.

1. Remove the rear wheels and hold each rotor in place with a couple of wheel nuts.
2. Slacken the cable by loosening the adjusting nut at the pedal or lever assembly with a deep socket. On lever-type cars the console coin pocket comes out to reach it.
3. Remove the rubber adjusting hole plug from the rotor face. Rotate the rotor until you can reach the star-wheel adjuster through the hole.
4. Turn the adjuster with a brake spoon or small screwdriver until the rotor locks and will not turn.
5. Back the adjuster off 5 or 6 notches from the locked position.
6. Spin the rotor to confirm there is no drag, then refit the hole plug. Repeat on the other side.
7. Apply the parking brake firmly ten times or more to seat the cables (the manual specifies 490 N, about 110 lb, on the pedal and 294 N, about 66 lb, on the lever).
8. Tighten the adjusting nut until the notch count falls in the range in the table above.
9. Release the brake and spin both rotors again. Any drag means the cable or shoes are too tight.

Two cautions straight from the service manual: never reuse the cable adjusting nut once it has been removed, and never blow brake dust out of the drum with compressed air - clean it with a vacuum dust collector instead.

Replacing the Shoes and Drums, and the Break-In Drive

If adjustment will not bring the notch count back, measure the parts. The G37 service data lists these limits:

Because the drum is part of the rotor, a drum past its limit means new rear brake rotors. Worn, glazed or oil-soaked linings mean new parking brake shoes, and it is worth replacing the springs, pins and retainers at the same time with a brake hardware kit, since those small parts are what rust and seize. During reassembly the manual calls for PBC or silicone-based brake grease on the backing plate contact points and adjuster threads, and for wiping any grease off the lining and drum surface. The left and right adjusters are handed, so keep each on its own side.

Then do the break-in. Both the owner's manual and the service manual say to break in the shoes whenever the parking brake feels weak or whenever the shoes or rotors are replaced. The factory procedure: with the brake adjusted to spec, drive forward at about 30 km/h (19 MPH) while holding the parking brake on with about 294 N (66 lb) of steady force for roughly 35 seconds, then let the linings cool for about 5 minutes. Afterward, recheck the notch count and readjust if it moved. Do this only on an empty, private stretch of pavement. The reminder chime will sound, because the car warns whenever the parking brake is applied above 4 MPH.

What to Replace at the Same Time, and How Hard the Job Is

The rear rotor has to come off to reach the shoes, which makes a parking brake repair the natural time to service the rear disc brakes too. If your rear pads are low, fit new ones while the caliper is already off, such as these EBC Bluestuff NDX rear brake pads for the 2008-2015 G37. If the fronts are due as well, the matching EBC Bluestuff NDX front pad set or the Hawk HPS front pads for the 2009-2012 G37 Sport complete the job. You can browse more in brake pads and brake parts.

Difficulty: a shoe and cable adjustment is an easy job with basic hand tools. Replacing shoes and hardware is moderate; the springs fight you, and a rotor that has worn a lip against the shoes may need the adjuster retracted through the access hole before it will slide off. Replacing a rear cable is the hardest part of the system, because the factory procedure removes the center console, the heat insulator and the center muffler to route it. If the brake warning light stays on with the parking brake released and the fluid is full, have the warning system checked, as the owner's manual directs. The owner's manual specifies DOT 3 brake fluid for the G37.

Frequently Asked Questions

Does the Infiniti G37 have an electronic parking brake?

No. The G37 uses a cable-operated parking brake with drum shoes inside the rear rotors. Automatic cars use a foot pedal and manual transmission cars use a hand lever.

How many clicks should my G37 parking brake take?

Per the service manual, a pedal-type brake should set in 2 to 3 notches and a lever-type brake in 7 to 8 notches under about 44 lb of force. More clicks than that means it needs adjustment.

Why is my parking brake weak after new rear rotors?

The rotor is also the parking brake drum. New drums need the shoes readjusted at the star wheel and a break-in drive so the linings seat against the fresh surface. Skipping those steps is the most common cause.

Can I just tighten the cable at the pedal?

Only after the shoes are adjusted. The factory sequence is shoes first, then cable. Tightening the cable alone masks worn shoes briefly and can leave the rear brakes dragging.

Do I need to replace the rotors to fix the parking brake?

Only if the drum inside the rotor hat is worn past its 173 mm inner diameter limit, or is cracked or damaged. Otherwise new shoes, hardware and an adjustment are enough.

Sources

1. Infiniti G37 Coupe factory service manual, Parking Brake System (PB) section - drum-in-hat design, notch counts, adjustment steps, lining and drum limits, break-in procedure, grease and dust cautions
2. 2009 Infiniti G37 Convertible Owner's Manual - pedal and lever operation, brake warning light, 4 MPH parking brake warning, break-in requirement, DOT 3 fluid
3. 2011 Infiniti G37 Coupe Owner's Manual - parking brake hill-hold check, break-in guidance, apply and release steps