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| Thread ID: 145903 | 2018-02-27 04:22:00 | Truck-Trailer Quality Rant | Terry Porritt (14) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 1446792 | 2018-03-01 04:24:00 | There was a prime example of a truck-trailer bogey malfunction on the downhill stretch of Ngauranga Gorge this morning. No-one was hurt but it sure caused chaos. Read here (www.stuff.co.nz). Beats me why they’d bother to report traffic problems in the Ngauranga Gorge. :D Just for fun, my guess is Brake Compressor Failure. :D What you recon Prefect? :) |
B.M. (505) | ||
| 1446793 | 2018-03-01 06:34:00 | I see where you are coming from, used to be Telarc accredited too before IANZ. That was my job in DSIR Engineering Metrology and worked closely with the DSIR metallurgists, in fact worked closely with metallurgists all my working life including my boss for years. You have to start somewhere, and conformance to appropriate standards is the starting point. If materials and methods dont conform then you don't have any basis for confidence. Since all this steel will be imported, most likely from China, it is more than possible that the cheapest fake certified steel has been used, as it has elsewhere. Lab tests on the steel should be on the agenda. Probably no one remembers now the CNG Bogap gas cylinder scandals, cheap cost cutting Italian crap in that instance, and very dodgy acceptance by the MOT at the time despite failure to conform to gas cylinder standards. i don't think the truck issue is a steel problem as it would have been more wide spread. it seams to be a design issue centered around one company. one of the pictures it looked like they probably had the draw bar stiffeners ending right where the weld was joining the center tube together (the crack was way to straight for a normal crack). a stress point where fatigue cracks start right where a weld is, is guaranteed to fail. there is a minimum spacing required. saw a truck come into family workshop with a chassis crack and you could see why, they have a plate ended sharply instead of smooth and the crack started at that sharp join. real basic stuff. when you have modern light weight trucks you have to be perfect with your design. |
tweak'e (69) | ||
| 1446794 | 2018-03-01 07:02:00 | Beats me why they’d bother to report traffic problems in the Ngauranga Gorge. :D Just for fun, my guess is Brake Compressor Failure. :D What you recon Prefect? :) When you lose air on large the brakes on the rear axles go on because the air pushes them off against a spring. The only way to lose brakes in a large truck is having no friction linings or massive slack in the adjuster. This happened to a truck I had worked on (not the brakes) an Onyx Stirling worst truck in the Western world over the North Shore killing the runner. Smaller trucks have air over hydraulic brakes so loss of air can mean on a incline you could not force the brakes on unboosted enough and the truck will run away on you. Smaller yet again vacuum over hydraulic same problems but you would have to ignore a warning light and buzzer before failure. There have been heavy trailer drawbar cracking for yonks in NZ. One trailer made in NZ I have forgotten the brand had to have the welds ground out and rewelded. |
prefect (6291) | ||
| 1446795 | 2018-03-01 19:22:00 | The truck trailer breakdown in Ngauranga Gorge was reported on RNZ at the time as a broken axle. Assuming tweek'e is right, (he always is :) :thumbs: ) then in this day and age for there still to be poor design and welding practice is rather pathetic. Although there is such a history of poor quality "fake" steel being imported, going right back to fake high tensile bolts some 20 odd years ago that it's about time stricter controls were instigated before finding out after the event. A importer/buyer cannot rely only on possibly dodgy manufacture's certificates. |
Terry Porritt (14) | ||
| 1446796 | 2018-03-01 23:18:00 | The bogey (if that is what it is called) from yesterday's accident in Ngauranga Gorge, was some 20 to 30 feet BEHIND the front of the truck and its container which was sitting on the roadway :( | Zippity (58) | ||
| 1446797 | 2018-03-02 06:12:00 | The truck trailer breakdown in Ngauranga Gorge was reported on RNZ at the time as a broken axle. Assuming tweek'e is right, (he always is :) :thumbs: ) then in this day and age for there still to be poor design and welding practice is rather pathetic. Although there is such a history of poor quality "fake" steel being imported, going right back to fake high tensile bolts some 20 odd years ago that it's about time stricter controls were instigated before finding out after the event. A importer/buyer cannot rely only on possibly dodgy manufacture's certificates. thanks terry ;) tho i would never say always. fake steel is still a problem and will always be. its so easy for them to pull some out of a pack and slip in lower grade. thats why any decent construction site will test every bit of steel. you always going to have the human element. thats why they put checks in place to pick up if a crowd isn't doing things right. edit: family actually had some mixed up steel. someone mixed up a pack and they got some very very hard steel. welded fine but when they went to drill it......o boy big problem. |
tweak'e (69) | ||
| 1446798 | 2018-03-02 06:16:00 | i.imgur.com | zqwerty (97) | ||
| 1446799 | 2018-03-02 06:20:00 | i.imgur.com ouch. not a fun ride and one expensive mistake. |
tweak'e (69) | ||
| 1446800 | 2018-03-02 07:17:00 | Is fake steel something like polished aluminium? | gary67 (56) | ||
| 1446801 | 2018-03-02 07:42:00 | Is fake steel something like polished aluminium? Taking that as serious:), "fake" steel is sourced from dodgy Chinese manufacturers, it may have inclusions, be of poor quality, or just not up to the specificaions claimed on the test certificates. After the main supplier of nuts and bolts in NZ, Ajax/GKN closed down, cheap Chinese HT bolts were imported, indeed US imported lots as there manufacturers found it difficult to compete on price, and they had problems too. These bolts were nowhere near high tensile. An air traffic control tower in Wellington broke and fell over when the crap bolts failed, I think it was Hawkins Hill. Then recently there was the Chinese imported reinforcing mesh being out of specification, "fake" certificates ......... |
Terry Porritt (14) | ||
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