Timeline for How to diagnose a parking brake that does not hold the vehicle on inclines?
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 17, 2021 at 12:57 | comment | added | adatum | I used a flat screwdriver to adjust the star wheel like the service manual describes but without first loosening the cable at the pedal. | |
| Aug 17, 2021 at 2:21 | comment | added | F Dryer | The top hat style disc rotor using the inside portion of the hat as the parking brake can be confusing to many. Did you follow procedures as follows; tovenza.com/parking_brake_system-659.html. I use park pawl as the lever to adjust the star wheel. | |
| Aug 16, 2021 at 1:43 | comment | added | adatum | Sorry, I don't understand your comment. What do you mean by the brake pawl? The star wheel (parking brake adjustment) just looks like a double sided-fork with a (regular, not reverse) threaded section to set the distance between the forks, which is effectively "pre-tensioning" the parking brake by adjusting the resting distance between the shoes and drum. The threading direction shouldn't make a difference. Am I missing something? Also, I updated the OP/question with pictures of the brake shoes. Does the contact patch pattern tell you anything? Would it benefit from bedding in? | |
| Aug 15, 2021 at 20:06 | comment | added | F Dryer | Star wheels, threaded for left and right hand threads work with the brake pawl. Anyone not knowing this should not be working on brake systems. This is basic knowledge of drum brakes. The incorrect star wheel on the wrong side simply screws by pawl operation, retracting brake shoes. This has the effect of more brake pedal travel to move retracted brake shoes and disable the parking brake. Experts in brake shops determine whether or not a new drum is warped, requiring machining or not. Experts, not diyers without dial calipers or more than average knowledge of brake systems. | |
| Aug 15, 2021 at 16:03 | comment | added | adatum | Wouldn't the drums already be machines, and the shoes be expected to have minor imperfections? The service manual's installation instructions include a bedding procedure (step 24) which I doubt has been done: tovenza.com/reassembly-643.html Btw, I think the star wheel is installed backwards, not that it should matter. Also, most of the work was done by a Toyota dealer. Another independent garage that tried adjusting also had no luck. | |
| Aug 14, 2021 at 20:53 | comment | added | F Dryer | New drums and brake shoes should be matching their contours with only initial star wheel adjustment. Without being there in person, it's difficult to determine why these drum bakes aren't able to serve as parking brakes. This is the responsibility of the repair shop since they did the work. Loud noises from these brakes seems to be something this repair shop overlooked. When new, drums may require machining to remove minor imperfections to mate to new brake shoes for minimal break-in period like a new car needs breaking in on new brakes and engine. | |
| Aug 14, 2021 at 3:25 | comment | added | adatum | Yes I am aware of the star wheel, which is what the mechanics used for adjustment. Unfortunately, even expanding the shoes to the point where the parking brakes started clacking loudly on the highway was not sufficient have the parking brakes hold the vehicle. My latest thought is that the shoes need to be bedded in, since it appears only small patches are making contact with the drum. | |
| Aug 14, 2021 at 2:44 | history | answered | F Dryer | CC BY-SA 4.0 |