CASEBOOK: Flex plate fun

Knoffel Pretorius, a local butcher, appeared in this column about eight years ago when he had a problem with shock absorbers on his 1989 Toyota Hilux. Older readers may recall that his birth certificate said “Christoffel”, which soon morphed into “Stoffel”, but behind his back people called him Knoffel (garlic) because of his fondness for Italian food.
Well, the Toyota is long gone; Knoffel exchanged it in 2010 for a new Isuzu KB300 automatic double cab 4×2.
A few weeks ago, the Isuzu developed an engine knock that sent Knoffel scurrying to my office. I calmed him down with some biltong, rusks and coffee, because the process of eating numbs the brain. I explained that it might not be an engine fault; many other items may cause a knocking sound.
Hennie took the bakkie on the road but returned with the news that the dull thud he heard sounded like a worn main bearing. Knoffel begged me to try and spend as little money as possible. I assured him he’d be in good hands … we know how important it is to be on friendly terms with a butcher.
Hennie and Japie first removed the engine/gearbox unit and then separated the gearbox from the engine. Japie marvelled at how thin the flex plate was. It is a plate fitted between the engine and torque converter and has to be thin to absorb crankshaft vibrations.
Hennie took one look at the plate and realised that his quest was over. There was a crack in it and he knew from past experience that this could cause a knocking sound. It was relatively simple
matter to leave the job right there, order a new  flex plate and then  fit it.  The engine and gearbox were left undisturbed.

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