現象：汽車行駛中制動時，制動減速度小，制動距離長。
Phenomenon: When the car is braking, the braking deceleration is small and the braking distance is long.
原因：
Reason:
1.總泵有故障。
1. The main pump is out of order.
2.分泵有故障。
2. The pump is out of order.
3.制動器有故障。
3. Brake failure.
4.制動管路中滲入空氣。
4. Air seeps into the brake pipeline.
診斷：
Diagnosis:
液壓制動系統產生制動效能不良的原因，一般可根據制動踏板行程(俗稱高、低)、踏制動踏板時的軟硬感覺、踏下制動踏板后的穩定性以及邊疆多腳制動時踏板增高度來判斷。
The reasons for poor braking efficiency of hydraulic braking system can be generally judged by the stroke of brake pedal (commonly known as high and low), the soft and hard feeling when pedaling brake pedal, the stability after pedaling brake pedal and the increase of pedal height when multi-pedal braking in frontier areas.
1.一般制動時踏板高度太低、制動效能不良。如連續兩腳或幾腳制動，踏板高度隨這增高且制動效能好轉，說明制動鼓與磨擦片或總泵活塞與推桿的間隙過大。
1. When braking, pedal height is too low and braking efficiency is poor. If two or more feet are braked continuously, the pedal height increases with this and the braking efficiency improves, which indicates that the gap between the brake drum and the friction disc or the piston of the main pump and the push rod is too large.
2維持制動時，踏板的高度若緩慢或迅速下降，說明制動管路某處破裂、接頭密閉不良或分泵皮碗密封不良，其回位彈簧過軟或折斷，或總泵皮碗、皮圈密封不良，回油閥及出油閥不良?？墒紫忍は轮苿犹ぐ澹^察有無制動液滲漏部位。若外部正常，則應檢查分泵或總泵故障。
When braking is maintained, if the pedal height drops slowly or rapidly, it indicates that the brake pipeline is broken somewhere, the joint is not sealed properly or the pump cup is not sealed properly, the return spring is too soft or broken, or the main pump cup and ring are not sealed properly, and the return valve and the oil outlet valve are not good. You can first step down the brake pedal and observe if there is any leakage of brake fluid. If the exterior is normal, the fault of the sub-pump or the main pump should be checked.
3.連續幾腳制動時,踏板高度仍過低,且在第二腳制動后,感到總泵活塞未回位,踏下制動踏板即有總泵推桿與活塞碰擊響聲,是總泵皮碗破裂或其連續幾腳，回位彈簧太軟。
3. The pedal height is still too low when several feet are braked continuously. After the second foot is braked, the piston of the main pump does not return to its position. When the pedal is stepped down, there will be a clash sound between the main pump push rod and the piston, which is the rupture of the main pump cup or its continuous feet, and the return spring is too soft.
4.連續幾腳制動時踏板高度稍有增高，并有彈性感，說明制動管路中滲入了空氣。
4. The pedal height increases slightly and has a sense of elasticity when several feet are braked continuously, which indicates that air is infiltrated into the brake pipeline.
5.連續幾腳，踏板均被踏到底，并感到踏板毫無反力，說明總泵儲液室內制動液嚴重虧損。
5. Continuous several feet, the pedals have been pedaled to the bottom, and feel that the pedals have no reaction, indicating that the main pump storage chamber brake fluid serious loss.
6.連續幾腳制動時，踏板高度低而軟，是總進油孔中儲液室螺塞通氣孔堵塞。
6. When several feet are braked continuously, the pedal height is low and soft, which is blocked by the ventilation hole of the screw plug of the storage chamber in the total oil intake hole.
7.一腳或兩腳制動時，踏板高度適當，但太硬制動效能不良。應檢查各輪磨擦片與鼓的間隙是否太小中高速不當。若間隙正常，則檢查鼓壁與磨擦片表面狀況。如正常，再檢查制動蹄彈簧是否過硬，總泵或分泵皮碗是否發脹，活塞與缸壁配合是否松曠。如均正常，則應進而檢查制動軟管是否老化不暢通。
7. When one foot or two feet are braked, the pedal height is appropriate, but the braking efficiency is too hard. Whether the clearance between the friction disc and the drum is too small, medium and high speed should be checked. If the clearance is normal, check the drum wall and the surface condition of the friction sheet. If normal, check whether the brake shoe spring is too hard, whether the main pump or sub-pump cup is inflated, and whether the piston and cylinder wall fit is loose. If they are all normal, the brake hose should be further checked for ageing and obstruction.
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