I want to remove the old grease from my rear hub speedo drive.Anybody got any ideas? I have got it soaking in petrol but it could take a long time
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Morning Stuart. I had 3 of these to rebuild, 2 of which had components which needed replacing. The fork in the worm gear which drives the cable, into which the cable spade locates, was badly worn on one. On another, the end cap which incorporates the grease nipple was damaged, with a large hole in the end and no ball bearing. I was fortunate enough to buy a complete unit for spares, the grey one in the photos, at not too much money, on which the thread for the mounting nut was completely stripped, rendering it unusable.
To strip, firstly remove the split pin which retains the driven pinion, and slide the pinion off the shaft. Remove the split pin which retains the end cover for the bevel gear which drives the cable. You will see the other cover; the one with the grease nipple; has 4 indents in it's perimeter, into which the pot metal of the body; no doubt Mazac; has been punched as the method of retaining the cap. Carefully remove the peened metal. Then tap the ends of the bevel gear shafts,. One will move and one will turn. When they move sufficiently they will drive their end caps out with them.The easiest one to come out first should be the one with the cap retained by the split pin. Once they are out, de-grease, thoroughly clean & inspect all components for wear or damage; including the threads on the body; hopefully none. At that point I resprayed and lacquered mine with rattle cans, and packed with fresh grease. To re-assemble, insert the cable-driving bevel gear shaft first, then the other one, replace caps, new split pins, ensuring you adequately peen the metal back into the indents of the appropriate cap.
There you have a completely refurbished speedo drive, like new, which should go on for another 40 years or so!
Cheers. IanLast edited by IanCordes; 01/11/2019, 10:58 AM.
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There are also different directions of rotation! I had two of them (one off my Scottish and another my brother found in his garage!) which I took in to Colin East of East Resorations. He rebuilt the Greeves specn one and the other was opposite handed so that is still in bits in a box for rebuild by Colin sometime in the future. I believe he still has some parts to rebuild these gearboxes to the specn you require.Ian Wilkinson '61 Scottish 24TD118
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Originally posted by IanCordes View PostMorning Stuart. I had 3 of these to rebuild, 2 of which had components which needed replacing. The fork in the worm gear which drives the cable, into which the cable spade locates, was badly worn on one. On another, the end cap which incorporates the grease nipple was damaged, with a large hole in the end and no ball bearing. I was fortunate enough to buy a complete unit for spares, the grey one in the photos, at not too much money, on which the thread for the mounting nut was completely stripped, rendering it unusable.
To strip, firstly remove the split pin which retains the driven pinion, and slide the pinion off the shaft. Remove the split pin which retains the end cover for the bevel gear which drives the cable. You will see the other cover; the one with the grease nipple; has 4 indents in it's perimeter, into which the pot metal of the body; no doubt Mazac; has been punched as the method of retaining the cap. Carefully remove the peened metal. Then tap the ends of the bevel gear shafts,. One will move and one will turn. When they move sufficiently they will drive their end caps out with them.The easiest one to come out first should be the one with the cap retained by the split pin. Once they are out, de-grease, thoroughly clean & inspect all components for wear or damage; including the threads on the body; hopefully none. At that point I resprayed and lacquered mine with rattle cans, and packed with fresh grease. To re-assemble, insert the cable-driving bevel gear shaft first, then the other one, replace caps, new split pins, ensuring you adequately peen the metal back into the indents of the appropriate cap.
There you have a completely refurbished speedo drive, like new, which should go on for another 40 years or so!
Cheers. Ian
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Originally posted by 350biker View PostThere are also different directions of rotation! I had two of them (one off my Scottish and another my brother found in his garage!) which I took in to Colin East of East Resorations. He rebuilt the Greeves specn one and the other was opposite handed so that is still in bits in a box for rebuild by Colin sometime in the future. I believe he still has some parts to rebuild these gearboxes to the specn you require.
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This is off the original subject which Stuart posted about, but if it helps, the number which is stamped on the end cap will indicate the specification; ratio, clockwise or anti-clockwise etc. All mine which appear suitable for Greeves, are stamped BG 2504/01. Whether Greeves did fit different specification drive units, depending on 18" or 19" wheels, trials or roadsters, I don't know. I doubt they changed the drive unit. The ratios could be more easily varied by changing the number of teeth on the drive ring in the hub (44 in a TES for example), and the driven pinion, 14 teeth on a TES. Checking the parts book for your model will tell you the spec.
Ian
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How many teeth on internal bevel gears on yours Ian? I think the hub gear and its pinion (44 & 14) are common to all so presumably the internal ratios of the angle drive were dependent on wheel size or more likely the use, a 400 trials tyre on the same 18" wheel would make less turns per mile than a 3.25 road tyre.
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No, road bikes have 18" rear wheel and 3.25 tyre. The front was 19" x 2.75, as far as I know only the Anglian had a 19" rear wheel. (some of the very early bikes may also have had a 19" rear wheel)
So your gearbox is the lower ratio 1.5 to 1 the other set up (5:12) is 2.4 to 1 so would be for a 19" wheel & result in a higher speedo reading if fitted to the 18" wheel.
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