|Gearbox rear coupling flange
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|Author:||landy [ Tue Jun 12, 2018 10:15 am ]|
|Post subject:||Gearbox rear coupling flange|
I'm in the process of rebuilding a D124 gearbox and need to remove the cardan shaft flange in order to replace the rear mainshaft seal.
So far the flange has resisted all attempts, using first a large 3-legged puller and then a 30 Tons hydraulic press, both with the addition of heat, to come off its taper. In the latter case the outer circumference of the flange was beginning to distort.
The recommended AEC tool (Part No 352-429) seems to be a dummy flange with a central thread for an extractor screw (Part No 352-374). I guess this tool would avoid the distortion and apply the force directly to the centre tapered boss.
Does anyone have one of these extractor tools that I could borrow, or any other suggestions as to how the flange may be removed.
Thanks for any assistance you can provide. Regards, landy
|Author:||0853 9769 [ Sun Jun 17, 2018 12:11 pm ]|
|Post subject:||Re: Gearbox rear coupling flange|
Well Mate, there is often a "Dung Hill Rooster" out there who likes to shoot down the suggestions, but you pays your money & takes your choice. Judge for yourself if I know what I am on about.
The best pullers have a very fine thread. UNF is ideal and I made my puller using a very fine but very hefty size (without going up the workshop I cant remember the exact size - 'bout 1 1/4" or so. Fine threads are lower geared so make a better lever).
An old flange with the centre gassed out is ideal. Weld the nut to the centre of this. then hey presto you have a puller that you can bolt onto the existing flange all the way round.
Slacken, but dont remove the 3rd motion shaft nut. Undo it about four or five turns.
Fit your puller, do the main centre bolt up nice and tight, but dont overdo it.
Now, dont listen to the oxy acetylene boys. Talk to a propane Man. Yeah yeah I know, hottest flame known to Man and all that. But you want to soak the heat in without it being too focused on a small area. You want a big old Seivert Lamp, like old time plumbers used. Still available and not a lot of cash. Sort of thing you might find in a Smithy. You will need a full flow pressure regulator as well, as a normal one wont allow enough gas flow. (Couldn't singe the fur on a mouse with a normal one).
Light yer lamp, and you will already be enjoying yourself. Roars like F*ck. Play the flange up with some heat, but not too hot - just when if you spit on it its gone in a second, but certainly NOT dull red. Now, take your sledge hammmer and hit the effin centre bolt of the puller. The reason I suggest leaving the 3rd motion nut on is that if you forget, you might need fresh underwear when it flys off unexpected.
What I forgot to suggest though, is you need a brass disc to act as a soft drift, to act between the puller bolt and 3rd motion shaft. Take care using this method, sometimes the flange will leap off before you get to swing the sledge.
I do have a couple of cogs for a Mat box, but not sure if I want to let 'em go. What were the bearings like in yours?
If your fitting a new flange, lap it in with FINE grinding paste. Coarse looks like a quick route, but you can spend more time removing the tram lines it causes than the original aim of bedding in. This goes for valves as well, but thats a another matter.
Oh, and if you have another old flange kicking about that's surplus, you can gas the centre out of that two, weld a rear hub nut to it, and then you can use a rear hub nut spanner to hold the flange whilst you do up the 3rd motion shaft nut up FT. From memory they are 1/4" split pins that are freely available still.
As always, I sign off by name.
0777 962 8923
|Author:||landy [ Tue Jun 19, 2018 7:48 am ]|
|Post subject:||Re: Gearbox rear coupling flange|
Paul, many thanks for your enlightening and entertaining reply. You sound like someone who has done the job, rather than had a mate who might have seen it done 'back in the day' - how I hate that saying!
I'd come to the conclusion that sacrificing a spare or scrap coupling was the next move, but note your useful comments about thread forms and heating, although we were using Propane. I nearly always leave the nut on loose when extracting tapers, protects the thread a bit too. I've lapped-in a few tapers in my time, have to be careful not to go too mad to avoid taking too much off and consequent fouling of the parts - been there etc.
The 'box I'm stripping is pretty noisy in the bearings, but the gears look ok. I'm actually putting a spare one back in which just needed the seals changing, strangely the flange came off that one easily. I do have another spare 'box from a Matador as well.
While we're on gearboxes, do you have a smart way of getting the clutch brake disc off the input shaft? Managed to get one off easily with the peg spanner and heat, but the others won't shift. Part of the problem is holding the shaft from turning.
Now to find a spare coupling; if only that one would come off my spare gearbox!
Again, thanks for taking the trouble to reply. Regards, Ian Dyckhoff
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