Monday, 28 May 2018

Beyond Design Life

I just about manage to keep the old ride-on mower limping along from one year to the next. Had to take the deck to be welded - again - a few weeks ago, but then a spring went on one of the tractor drive pulleys. 

Given the bits are like hen's teeth and have to be ordered from either the USA or Germany and can take weeks to be delivered, I concluded a jury rigged fix by removing a spring from the seat, the seat being sprung because it acts as an automatic cut-out for the engine when you dismount. 

The problem was that while the seat spring was of the correct length, it was too fat, resulting in the clearance between the spring and the drive belt disappearing, although I didn't now that at the time, as you're working almost blind without a ramp to put the thing on. Naturally, one pass of the garden resulted in the drive belt shredding and me having to finish the job with the hand mower, but at least the grass, which is now growing like mad, had received a cut before we went on holiday to Cornwall.

I tackled the drive belt yesterday, when the spring issue became apparent but, given the ground clearance is only about 9 inches, I had to put the thing on its side to gain access, which naturally risks damage to the engine because of petrol and oil leakages. Luckily, I'd ordered a suitable spring before going on holiday from a spring emporium on eBay, so the correct (although not original) part was available to me.

Never having replaced the drive belt before, it turned out to be a mammoth task requiring the clutch to be removed, which in itself is difficult enough. Finally managed it and discovered I needed to put the drive belt over the rear axle pulley before putting it over the main drive shaft and had to do it all over again.

A lot of buggering about later and the job was complete, but I wonder what will fail next. You learn a lot about things by keeping them going long after their design life, especially when they're so old that there are no manuals or YouTube videos to help you and all you have is an exploded parts diagram lacking specifications.

I'm going to tackle the next bit of welding myself as I have an electric welding kit. What I don't have is a welding mask, but I see you can now get self-darkening masks which allows more accurate placement of the welding rod. Must get one of those!

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