removing gear dogs

[Alan L]

OK, from what I've read here, there are two ways;
1) use special tool. Don't have one.
2) Use dremel and cut old one off. I do have one. But not keen to use it this way.
3)?? Any other options?
Thanks
Alan

[dtw]

Used a MAPP torch to heat up the dog, banged away with BIG chisel/drift and ball peen hammer, and repeated. Took a long time but got it off.

Used a hydraulic press to put the new dog on.

[SP2]

Are you talking about removing gears from the pinion shaft of a (915) tranny?

[Alan L]

I'm trying to remove the synchro dogs off 2nd gear from a 930 box.
I have an oxy/acetylene torch, and a hydraulic press - not sure if I have a MAPP torch - what is that- sorry I'm an antipodean.
Was a bit worried about applying heat to the gear - which has probably already had special heat treatment.
Alan

[KFJ_SC]

This idea worked perfectly for me: 915 syncro hubs question

[SP2]

Sorry Alan, I can't help you. Once I got this far into disassembly I let JW do it for me.

[cgarr]

You should really use the tool or make one to do the job cold. Heat for both removing and installing makes the square splines expand and lock even more, its not like removing something off a round shaft. Take a good look at it and you will see what I mean.

[Porsche_monkey]

I think I just zip cut under the edge and forced a screwdriver intot he gap, do it in two or three places equally spaced, it does not take too long.

[ChrisBennet]

Originally Posted by Alan L

I'm trying to remove the synchro dogs off 2nd gear from a 930 box.
I have an oxy/acetylene torch, and a hydraulic press - not sure if I have a MAPP torch - what is that- sorry I'm an antipodean.
Was a bit worried about applying heat to the gear - which has probably already had special heat treatment.
Alan

For the 930 dog teeth, there is no tool for 2nd gear.* Heat the dog teeth with a torch and use a wood chisel to work the teeth off. This will wreck the wood chisel but you need something thinner than a normal chisel to open up a gap.

When you install the new dogs, use red Loctite on the splines.

A MAPP torch is like a propane torch but uses MAPP gas instead of propane. MAPP gas burns hotter.

-Chris

* The tool is touted as working on 1st and 2nd gear but it doesn't actually work on 2nd gear - at least not on a stock 2nd gear.

[Alan L]

OK, thanks guys.
I get the picture - heat and hammer. I like the option posted by Kirk - but unfortunately the 930 dogs don't have the circlip lip. I do have an idea for making a tool that may work. I'll try that first. If it works, I'll post it. Otherwise - hammer and heat.
Thanks
Alan

[Matt Monson]

For 930 dogs, it's really a challenge. I feel that cutting them is generally the best bet. Also be aware that when you press on the new dog, you will likely distort the ID of the gear. Usually you need to hone the gear afterwards to make sure that it's not going to bind on the needle bearings upon reinstallation on the shaft.

[Alan L]

OK guys, as always this Pelican board is worth its weight in gold. So, here is what I did.
It was not as sucessful as I had hoped, but I'm pretty sure the Mk 2 version would work a treat and solve a pig of a job.
I ground up/hacksawed some 'teeth' (4) approximately the same profile as the gear teeth - but about 5 mm longer. (I smoothed them down with a file and then fine wet/dry so as not to scar the gear teeth)(pic). I inserted them where they would best marry with the dog teeth, but as near to 90 deg to each other as possible. I bound them to the gear and used the press to push the dog off. I used a bit of heat while the press was pushing.
It moved the dog about 0.5 mm, but then the system started to fail. The binding was letting loose on a couple and the 'teeth' were riding out. Also the dog was lifting at the point of the teeth, but lagging behind in between.
So, Mk2 - use as many teeth as you can usefully insert (about 6), and a better binding might be 2 x exhaust clamps - maybe a bit stronger.
I resorted to a bit of dremel and chisel to finally ping it off - but it must have been very close to pinging free, as it did not take too much after that to prise it off with a couple of screwdrivers wedged down the back.
I'm reasonably confident this could work well.
(The pic is withthe new dog - just for demo)
Regards
Alan