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Letter to the editor
| 题名： | Letter to the editor |
| 正文语种： | eng |
| 作者： | Dani Rathke |
| 摘要： | In last month's article 'Brake Expectations', pp10-12 , Graeme Murphy at Thomas Armstrong Aggregates says: "Even with an [parking brake] imbalance a vehicle will still pass..." That's only true up to a point. Section 73 (Parking Brake Performance) of the HGV inspection manual states: "There may be occasions where the specified brake effort is met but, if the brake effort from any wheel on an axle is one third or less than the brake effort from another wheel on the same axle, it may be necessary to consider deficiency 1 b or 5a of section 59 depending on the operating system (e.g., cable, rods, air or hydraulic)." So in essence, if the parking brake has a major imbalance across the axle (67% or more, as described above) then testers can refer to section 59 of the manual (Brake Systems and Components), which indicates a major deficiency for 'a brake rod, clevis joint, linkage, relay, lever, pin, pivot, slack adjuster or cable - with abnormal movement indicating incorrect adjustment, or excessive radial free play' [1 b] and a dangerous deficiency for 'air actuators, hydraulic master and wheel cylinders, valves and servos defective in operation and brake performance affected' [5b]. Therefore, it is possible for parking brake to fail for imbalance across an axle, even if the performance figure is met. |
| 出版年： | 2021 |
| 期刊名称： | Transport engineer |
| 期： | Jul. |
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