By Core Brake Parts Tech Team — Circleville, OH warehouse
The 2012-2015 Scion iQ uses a hand-lever parking brake that mechanically applies the shoes inside its rear drum brakes. Most iQ parking brake complaints come down to three things: a lever that pulls up too far because the rear shoes or cables need adjusting, a brake that will not release because a cable has corroded or frozen, or a warning light that stays on. Toyota specifies 6 to 9 clicks of lever travel, and that number is the quickest health check you can do in the driveway.
How the Scion iQ Parking Brake Works
US-market iQs pair front disc brakes with rear drum brakes, and the parking brake is built into those rear drums. When you pull the lever between the seats, a cable pulls on a lever attached to one of the shoes inside each rear drum. That lever spreads the shoes against the drum and holds the car. There is no electronic parking brake motor and no separate small drum-in-hat shoe set like you find on cars with rear discs. Before buying parts, look through the rear wheel spokes: a round drum with no caliper confirms the drum setup described here.
Because the parking brake uses the same shoes as the service brakes, its condition is tied directly to how well the rear drums are adjusted. Drum brakes use a self-adjuster, a threaded screw with a notched star wheel, that takes up clearance as the shoes wear. Depending on the design, the adjuster works during reverse stops, forward stops or parking brake applications. If that adjuster stops working, shoe-to-drum clearance grows, the rear brakes do less work and the parking brake lever has to travel farther before the shoes grab.
The owner's manual procedure is simple. To set it, hold the brake pedal down and pull the lever all the way up; the brake system indicator comes on. To release it, raise the lever slightly, press the button on the end and lower it completely.
Factory Specs Worth Knowing
| Item | Toyota specification (2014 iQ owner's manual) |
|---|---|
| Parking brake lever travel | 6 to 9 clicks, pulled up with 44 lbf (200 N) |
| Rear brake lining wear limit | 0.04 in. (1.0 mm) |
| Front brake pad wear limit | 0.04 in. (1.0 mm) |
| Brake pedal free play | 0.04 to 0.24 in. (1 to 6 mm) |
| Brake fluid | FMVSS No. 116 DOT 3 or SAE J1703 |
If your lever goes past 9 clicks with a firm pull, something in the rear brake system has too much slack. If it stops in fewer than 6 clicks, the cable or shoes may be adjusted too tight, which can make the rear brakes drag.
Common Symptoms and What They Mean
Lever pulls up too high or the car rolls on a hill
This is the most common complaint on any drum-rear car. Toyota's own inspection list asks two questions about the parking brake: does it move smoothly, and can it hold the vehicle securely on an incline. If the answer to either is no, the usual causes are worn rear shoes, a seized or worn self-adjuster, or stretched cables. The self-adjuster star wheel and lever wear grooves over time, and once they stop engaging, the adjuster quits advancing even though the shoes keep wearing.
Brake warning light stays on
On the iQ, the red brake system warning light does double duty. It comes on when the parking brake is not fully released, and it also warns of low brake fluid or a brake system malfunction. If the light goes out once the lever is lowered all the way, the system is normal. If it stays on with the lever fully down, check the fluid level first. A low reservoir often means the front pads and rear shoes are worn, because the fluid level drops as the pistons move out, or it can point to a leak such as a weeping rear wheel cylinder. A buzzer also sounds if you drive off with the parking brake engaged once the car reaches about 3 mph.
Rear brakes drag, get hot or smell after driving
Toyota warns that driving with the parking brake set overheats the brake components, hurts braking performance and increases wear. The same thing happens, more slowly, when a cable is sticking and holds the shoes lightly against the drum. Carefully feel near both rear wheels after a short drive: one side noticeably hotter than the other points to a sticking cable or shoe on that side.
Parking brake will not release in cold weather
Water that gets into cable housings or drums can freeze and lock the shoes. Toyota's winter driving advice for the iQ is to park, move the shift lever to P and not set the parking brake when it may freeze, blocking the wheels if needed. A cable that sticks in cold weather every winter usually has a damaged boot or corroded housing and should be replaced.
How to Check and Adjust It
- Count the clicks. With the car on level ground, pull the lever up firmly and count. Between 6 and 9 is in spec.
- Inspect the rear shoes first. Remove the drums and compare lining thickness against the 0.04 in. (1.0 mm) limit. Look for fluid on the shoes, which means a leaking wheel cylinder, and check that the self-adjuster star wheel turns freely.
- Adjust the shoes before the cable. Brake and Front End's guidance is that the rear brakes must be serviced and adjusted first; cable adjustment only takes up cable slack. Tightening the cable to cover for worn or poorly adjusted shoes leads to drag and uneven wear.
- Adjust the cable per the factory procedure. Make changes in small steps, recheck the click count, and confirm both rear wheels spin freely with the lever down.
- Check the cables and boots. Stretched cables cause excessive lever travel, and torn boots let water in. If you run out of adjustment range, replace the cable rather than forcing it.
Use the factory service manual for the exact adjustment location, procedure and any torque values. Do not guess on parking brake adjustment; a brake that is too loose will not hold, and one that is too tight will cook the rear shoes.
What to Replace at the Same Time
If the rear shoes are near the wear limit or contaminated, replace them as an axle set along with the hardware. Brake and Front End recommends replacing the self-adjuster mechanism whenever shoes are replaced, because worn adjuster threads and star wheels are the main reason drum brakes lose adjustment. Inspect the drums for scoring and heat marks, and check the wheel cylinders for seepage behind the dust boots. Browse brake shoes and drum brake hardware kits for the parts involved.
While the car is apart, check the front brakes too. The iQ is a light car, but the fronts still do most of the stopping. If the front pads are due, the EBC Redstuff ceramic low-dust front brake pads for the Scion iQ are a quiet, clean daily-driver option, and the EBC Yellowstuff street and track front pads for the iQ suit owners who drive harder. Flush the DOT 3 fluid if it is dark or has not been changed in years.
How Hard Is the Job?
Counting clicks and inspecting cables is an easy driveway job. Cable adjustment is moderate and mostly takes patience. Replacing rear shoes and self-adjusters on a drum brake is the hardest part for a first-timer, because the springs and adjuster must go back in the right orientation. A self-adjuster installed on the wrong side turns the wrong way and will not adjust at all. Work one side at a time so you always have the other side as a reference. NHTSA recall data lists no brake-related recalls for the 2012-2015 iQ, so parking brake issues on these cars are normal wear and maintenance rather than a known defect.
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Shop Brake Pads & Kits →Frequently Asked Questions
How many clicks should the Scion iQ parking brake have?
Toyota specifies 6 to 9 clicks when the lever is pulled up with 44 lbf (200 N) of force. More than 9 means the rear shoes or cable need attention.
Does the Scion iQ have rear disc or drum brakes?
US-market iQs use front disc brakes and rear drum brakes, with the parking brake acting on the rear drum shoes. Look through the rear wheel to confirm on your car.
Why does my iQ brake warning light stay on after I release the parking brake?
Make sure the lever is fully down first. If the light stays on, check the brake fluid level; the same light warns of low fluid and brake system faults.
Can I just tighten the parking brake cable?
Only after the rear shoes are inspected and adjusted. Tightening the cable to make up for worn shoes or a seized self-adjuster causes dragging and uneven wear.
Should I use the parking brake in freezing weather?
Toyota advises not setting it when it may freeze. Park in P and block the wheels if needed so the shoes cannot freeze to the drums.
Sources
- 2014 Scion iQ Owner's Manual (Toyota) - lever travel 6-9 clicks, lining and pad wear limits, DOT 3 fluid, set and release procedure, warning light and buzzer, winter parking advice
- 2012 Scion iQ specifications (CarSpecs) - front disc and rear drum brakes
- Drum Brake Self Adjusters (Brake and Front End) - how self-adjusters work, failure causes, replace with shoes
- Adjusting Parking Brakes (Brake and Front End) - adjust service brakes before cables, stretched cables, drag from over-tightening
- NHTSA recall data for the Scion iQ - no brake-related recalls listed
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