Automobile & Light Truck Certification Test A5 BrakesHydraulic System Diagnosis and RepairEasy
A technician is bleeding a hydraulic brake system that uses a diagonal split. After bleeding the right rear and left front wheels, the technician notices the brake pedal still feels spongy. Which of the following is the MOST likely next step to properly bleed the system?
- ABleed the right front wheel, then the left rear wheel.
- BBleed the left rear wheel again, then the right front wheel.
- CBleed the left front wheel again, then the right rear wheel.
- DBleed the left rear wheel, then the right front wheel.
Show answer & explanationAnswer & explanation
Correct answer: D. Bleed the left rear wheel, then the right front wheel.
In a diagonal split system, the bleeding sequence typically involves bleeding the furthest wheel from the master cylinder on one diagonal circuit, then the closest wheel on that same circuit. Then, proceed to the other diagonal circuit. After bleeding the right rear and left front, the next logical step is to bleed the remaining wheels on the opposite diagonal: the left rear and then the right front.
Why the other options are wrong
- A. This sequence is incorrect for a diagonal split system after the initial two wheels have been bled.
- B. Re-bleeding the left rear wheel is not the primary next step; the other circuit needs to be addressed first.
- C. Re-bleeding the left front wheel is not the primary next step; the other circuit needs to be addressed first.
Brake Bleeding Sequence (Diagonal Split)
The procedure for removing air from a vehicle's hydraulic brake system, ensuring proper pedal feel and braking performance, following a specific order for diagonal split systems.
- Diagonal split systems connect one front wheel to the opposite rear wheel.
- Bleeding typically starts with the furthest wheel from the master cylinder.
- It's crucial to follow the manufacturer's specific sequence, but general rules apply.
Memory trick: Diagonal splits need a criss-cross cleanse.