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The
failing of this City-City
coach on the brake roller test at the FleetWatch Brake and Tyre
Watch day has led to a positive response from MAN and Autopax
where standards will be improved via the installation of brake
testers at all MAN dealers and Autopax depots enabling more
rigorous testing during servicing, with Autopax committing to
a weekly test of every bus! What a great response! |
Why did
FleetWatch and its partners originally embark on our Brake & Tyre Watch project? Simply because we knew that the state of roadworthiness of hundreds of vehicles on our roads left much to be desired and unless this was exposed and highlighted, nothing would change. What we wanted to see was improvement and we guessed that by openly exposing the unroadworthiness of trucks in daily operations, operators would take note and implement actions to improve the situation. We also wanted to empower the cops by training them into identifying brake and tyre faults on trucks.
It thus came as heartening news to all of us when FleetWatch received a letter from Geoff Du Plessis, CEO of MAN Truck & Bus, on the positive actions being taken following the Discontinuation of Service notice issued during our Centurion test day to a City-to-City coach operated by Autopax and maintained by MAN.
On being brought in for testing, three main faults were discovered. The first was that the brakes on the left hand wheel of one of the rear axles were not functioning. The rolling road brake machine display showed that the left hand wheel was achieving almost no braking force at all (approx 1 kN) while the right hand wheel showed that the wheel was achieving a brake force of approximately 20 kN.
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Although reflections dim
the view, the dials show a
clear imbalance of over 30% between the brake force on the left and
right hand wheels on the same axle. For this reason the whole
vehicle failed the brake test.
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Says Enoch Silcock, technical director for WABCO Automotive South Africa: "This is clearly an imbalance of over 30% between left and right hand wheels on the same axle. The SANS 10047:2006 specification for vehicle test stations dictates that a vehicle must not have more that 30% brake force imbalance between brakes on opposite sides of the same axle. (SANS 10047:2006 5.56.1.1.1 .c). For this reason the whole vehicle failed the brake test."
Another fault was that one of the engine mounting bolts was loose and the third was that the inner tyre on one of the rear sets of twins was completely deflated. For all this, the coach was taken off the road.
Rob Handfield - Jones, editor of AutoDealer, was there on the day and in his report, highlighted this coach for its faults. This article was picked up on by an extremely concerned Geoff Du Plessis who immediately took action. Let's pass it on to Du Plessis to tell it in his own words:
Dear Patrick and Rob
Further to the article printed in "AutoDealer" of the 26th March detailing the results of the initiative of FleetWatch to improve safety for all road users, I would like to firstly congratulate you on this initiative and then share some of the findings and actions from our MAN perspective. We must add that the response hereunder is shared without prejudicing our rights and is meant in the spirit intended.
First off, we were very concerned to find that the bus shown was not only an MAN but one under maintenance contract with our organisation. There were three issues resulting in the vehicle being pulled off the road namely: 1. An imbalance in the braking system; 2. Loose engine mounting bolt and 3. a deflated tyre on the one axle.
Handling the last first, it is noteworthy that the same experts who are part of the team giving advice on tyres are also contracted to do the tyre maintenance on the vehicle - and they would have not released the unit on the next trip. A 100 % tyre pressure and condition inspection is done prior to departure from the Autopax depot. The tyre was also obviously recently deflated as there was no damage to it and it was returned to duty after inspection (the valve extension had actually failed).
With respect to the loose engine mounting bolt, we are guilty as charged. In terms of impact of this, the design of the system is such that the weight of the engine would still be carried by the engine mounting and the issue would manifest itself as a vibration. These types of issues would be normally picked up by the driver, who always advises of issues at the service interval, or as they develop.
In terms of the first and biggest issue, we have had some fascinating results come to the fore. Despite the usual pressure testing, combined with test driving, the imbalance was not evident. It must also be noted that the vehicle has ABS as a standard and any imbalance would be managed through the system in the event of a major braking event. Nevertheless, we have seen by this experience that our system of brake testing is fallible and only an active brake dynamometer test is capable of showing this type of imbalance. These tests are part of the annual COF and not part of standard servicing procedures!
Interesting to note too is that there still remain inconsistencies between the test stations as even after the bus was passed at two subsequent tests, it failed again at the Wabco test facility!
Having reviewed the situation, we have immediately undertaken to procure and install brake testers at all of our dealers. Noteworthy too is that Autopax have undertaken to do the same at their depots enabling more rigorous testing during servicing, with Autopax committing to a weekly test of every bus!
In addition, when we saw that this situation could arise, we initiated an immediate action to take every bus on maintenance contract over a brake tester before the Easter weekend. This was not only done to great effect but satisfied us that this issue you picked up on was an isolated incident .
On reflection, I can say that we have had great value from the exercise. It is, of course, a great pity that the exposure was not what we look for as suppliers or operators. However, despite that, we have both learnt from the experience and have taken significant action to avoid any recurrence of this type of situation.
Best regards
Geoff du Plessis
Chief Executive Officer
MAN Truck & Bus (S.A.) (Pty) Ltd
With a response such as this, it all becomes so worthwhile and we lift our hats to Geoff Du Plessis as well as to Autopax on the positive actions they have taken to improve the standards of road safety in the fleet under their responsibility. After all, road safety is what it's all about. As Du Plessis told me: "It's going to cost us around R3-million to invest in these facilities but that's nothing compared to the cost of a life." Way to go Geoff!
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