anotherfive Posted March 4, 2016 Report Share Posted March 4, 2016 Just interested in why the metal shaft of this assembly seems to wear and fail before the rubber seal. Seems to go against what you would expect. Over to you Stephen Hawkins !! Quote Link to comment Share on other sites More sharing options...
ourian Posted March 4, 2016 Report Share Posted March 4, 2016 I'm going with - The shaft isn't hardened. The rubber seal hardens with age Initially the carbon particles in the rubber seal abrade the shaft producing minute particles of steel which embed themselves in the rubber seal. The surface of the seal in contact with the shaft then becomes like sand paper and abrades the shaft even further. Quote Link to comment Share on other sites More sharing options...
peterb Posted March 4, 2016 Report Share Posted March 4, 2016 Hmmmm, well the water pump shaft on the GG is rotating at crankshaft speed up to 7,000 rpm, water/coolant is a non lubricating medium so that with the spring force of the lip of the seal pressing onto the shaft, wear will eventually occur, through a combination of high rotational speed, friction of the seal against the shaft and the non lubricating qualities of the water/ethylene glycol mix. The Viton seal usually wears as can be seen by the loss of it's sharp edge. Bye, Peter B. Quote Link to comment Share on other sites More sharing options...
lineaway Posted March 5, 2016 Report Share Posted March 5, 2016 Happens this way on most bikes. I can`t complain as mine lasted ten years. Quote Link to comment Share on other sites More sharing options...
anotherfive Posted March 5, 2016 Author Report Share Posted March 5, 2016 Thanks everyone for those answers, I might get some sleep now !! Quote Link to comment Share on other sites More sharing options...
richt Posted March 5, 2016 Report Share Posted March 5, 2016 (edited) Gas Gas introduced a new shaft which is a better steel and improved Heat Treatment during manufacture. Since about 2004. Detail were on Jim Snell's web site . It seems as now they no longer import GasGas and all the 'How to fix it' videos are only available as cached copies. Water Pump information, Pro 2002~13: Beginning in 2004, there are three changes to the waterpump. 1 The center shaft has a new heat treatment. The part number remains the same. 2 The impeller is made of a new material. The part number remains the same. 3 The outer bushing (drain cap) is made of a new alloy. It has a much longer life than the original model. The new cap uses a “Torx” bit for removal, and installation. The original one used an Allen wrench. (See photo) The part number remains the same. Edited March 5, 2016 by richt Quote Link to comment Share on other sites More sharing options...
doc_d Posted March 7, 2016 Report Share Posted March 7, 2016 Speaking of GasGas water pumps, I just picked up a used 2014 GasGas TXT PRO 250. I've heard the water pumps are considered wear items. I suspect the one in my bike is original. Should I replace it preemptively or should I wait for it fail? How many hours are people getting out of them? Thanks! Doc Quote Link to comment Share on other sites More sharing options...
crazybond700 Posted March 7, 2016 Report Share Posted March 7, 2016 The seal and shaft wear. You can check by taking appart and look if you can feel a groove in the shaft. When it goes bad you will get milky oil, which might screw up your fibre clutch plates. Not that expansive, I replace when I do some big maintaince. Quote Link to comment Share on other sites More sharing options...
biffsgasgas Posted March 14, 2016 Report Share Posted March 14, 2016 Speaking of GasGas water pumps, I just picked up a used 2014 GasGas TXT PRO 250. I've heard the water pumps are considered wear items. I suspect the one in my bike is original. Should I replace it preemptively or should I wait for it fail? How many hours are people getting out of them? Thanks! Doc If the oil starts to look milky then its time. I would get a spare but wouldn't replace it just because. --Biff 1 Quote Link to comment Share on other sites More sharing options...
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