robertely Posted August 20, 2020 Share Posted August 20, 2020 Greetings again. Having double checked my propshaft and found nothing wrong, I've opened up my gearbox and found the cause of my jamming up problem. On the lower gear (arrowed) there is a pin that appears to be damaged (arrowed in second photo). When the pin slides in the gearbox is free to move, but when it slides out the gearbox jams up. Can anyone advise what this pin does and how it should look? I've had a good look on the search function here but couldn't find anything specific. Does anyone have any diagrams or info? Thanks again Link to comment Share on other sites More sharing options...
KenHupp20 Posted August 21, 2020 Share Posted August 21, 2020 That pin holds the two gears together,bronze hub in between. Parts number 247,248,249,250.Eight pins (248). Ken Link to comment Share on other sites More sharing options...
trimacar Posted August 21, 2020 Share Posted August 21, 2020 I'd say you're going to be taking that apart to fix. Not that difficult, just make notes/pictures as the Model 20 gearbox comes apart, and goes back together, in a very specific sequence. Is that top gear really worn, or is it just a camera angle trick? Good luck with fix, while apart I'd check all the bushings, I had two in my gearbox that were slap worn out. 1 Link to comment Share on other sites More sharing options...
robertely Posted August 21, 2020 Author Share Posted August 21, 2020 Thank you Ken. Might someone have a parts diagram or a link to one? I'm just about to start stripping it down so may be back with more photos or questions. Regards Robert Link to comment Share on other sites More sharing options...
KenHupp20 Posted August 21, 2020 Share Posted August 21, 2020 Let’s see if I can do this.... Link to comment Share on other sites More sharing options...
robertely Posted August 21, 2020 Author Share Posted August 21, 2020 Gearbox is stripped and things are a little clearer now..... I assume I just need to make up 8 new pins and clamp the parts together again with the bronze sleeve reattached to the hub. Looks like the other 7 pins must have snapped off at various times. I only found the remains of the one final pin in the housing and don't recall any bits falling out in previous oil changes so must have been like that for many years. Link to comment Share on other sites More sharing options...
robertely Posted August 21, 2020 Author Share Posted August 21, 2020 1 hour ago, KenHupp20 said: Let’s see if I can do this.... Perfect! Thanks Ken Link to comment Share on other sites More sharing options...
robertely Posted August 21, 2020 Author Share Posted August 21, 2020 3 hours ago, trimacar said: I'd say you're going to be taking that apart to fix. Not that difficult, just make notes/pictures as the Model 20 gearbox comes apart, and goes back together, in a very specific sequence. Is that top gear really worn, or is it just a camera angle trick? Good luck with fix, while apart I'd check all the bushings, I had two in my gearbox that were slap worn out. Thanks for that. Wasn't too bad in the end. Bit of a mind challenge to get the gears out though! Think it was the camera as the top gear looks pretty good.... Link to comment Share on other sites More sharing options...
trimacar Posted August 21, 2020 Share Posted August 21, 2020 Yes the gear looks good! I remember doing my gearbox, it wasn't that difficult to take apart or put together, I just remember that if you tried to do things out of order, the next piece wouldn't go in. I think it was the bushing in your picture, plus the very rear bushing in the housing itself, that were bad on mine....so needed new bushings....I don't have machine tool capability, took it to a friend with a machine shop, we never discussed price. When done, he told me it was a big job, and he couldn't charge me the amount the hours cost. He was very fair with me, but it was still hundreds of dollars... Link to comment Share on other sites More sharing options...
KenHupp20 Posted August 21, 2020 Share Posted August 21, 2020 (edited) Look closely at the drawing of p/n 247. I think you need to make a new bushing,I think it should be the total length of the gears.Yours looks sheared off.Looked at one again,there seems to be two pieces(?) to the bushing,or one piece with an oil groove.You will find out when you press it out. Ken Edited August 21, 2020 by KenHupp20 Add information (see edit history) Link to comment Share on other sites More sharing options...
robertely Posted August 21, 2020 Author Share Posted August 21, 2020 Yes, the bushing has snapped off at that point. I was thinking of getting the grooves lined up and brazed? I know a very good welder, but if not I guess I'll need to get someone to machine a new bushing made up. I'll check that it's all one piece all the way through as well. The lower gear may be more problematic. What initially looked like a beautifully machined finish to the back of the gear for some reasons of clearance became suspicious when I realised that there was nothing to clear. There surely can't be a reason for this gear to be narrowed so I'm guessing it has been beautifully turned down by the reverse pinion. There is no excess wear or damage on the other gears or the arm though. So I'm looking at getting a new gear made up, new bushing for that gear, new bushings x 2 for shafts on the case, 8 x pins and then reassembly. Link to comment Share on other sites More sharing options...
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