Removing and replacing rear axle gears.

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John Illinois
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Removing and replacing rear axle gears.

Post by John Illinois » Fri Jan 10, 2020 4:31 pm

I have new axle shafts and need to install old gears. My press is about 2” too short for the axle between the ram and the press bed. There is room to press the shaft down in the gear. What is a good way to move the gear down. How tight is the interference fit?

John
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Mark Nunn
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Re: Removing and replacing rear axle gears.

Post by Mark Nunn » Fri Jan 10, 2020 5:04 pm

Is the problem you're having with getting the gears off the old axles? If yes, you can shorten them with a chop saw to fit your press. I am in the same boat at the moment and will go through the same process when my axles arrive.

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CudaMan
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Re: Removing and replacing rear axle gears.

Post by CudaMan » Fri Jan 10, 2020 5:19 pm

I cut the uprights of my press and bolted in very beefy extensions with way oversize grade 8 bolts.

In retrospect, I could have also bolted extensions to the bottoms of the base irons. :)
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John Warren
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Re: Removing and replacing rear axle gears.

Post by John Warren » Fri Jan 10, 2020 8:15 pm

It looks like it fits in the press, just put a piece of tubing under the gear to space it up. The problem comes when you re-install it. Then the bed has to go far enough down to get the axle and the gear in between it.
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Scott_Conger
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Re: Removing and replacing rear axle gears.

Post by Scott_Conger » Fri Jan 10, 2020 10:42 pm

John in Illinois

you will solve the problem you're asking about. The following is for you after that:

1. you MUST measure the axle with proper and accurate tools to be CERTAIN that the diameter will give the proper press fit. Axles are often large by a thou or two and have very small burrs that will cause a devil of a problem and that is the difference between success and disaster

2. you MUST protect the axle threads when you press the gear on and I highly suggest you GOOGLE "MTFCA rear axle gear removal" and then satisfy yourself that you have chosen a method that a) will protect things, and b) is easy to do for you. I will not recommend a method of protecting the axle taper and threads but believe you can make an informed decision yourself after doing the research
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John E. Guitar
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Re: Removing and replacing rear axle gears.

Post by John E. Guitar » Sat Jan 11, 2020 12:33 am

Are you asking how to move the gear down the shaft to remove the two half moon retainers?

I drop the bed of the press right down and have the gear sitting on a cupped tool that supports the gear in the area between the teeth and the axle shaft and press down on the threaded end of the axle shaft (with a nut fitted to protect the thread). It can be quite tight, I’ve had some gears that needed 15 tonne before they budge. The shaft may flex a bit. You need to make sure the shaft is as close to vertical as you can get. I always wear a face shield for this, it’s a bit outside my comfort zone.

I will be doing this tomorrow and can take a few photos and post them.


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Re: Removing and replacing rear axle gears.

Post by jab35 » Sat Jan 11, 2020 1:07 am

When I did mine I made an axle support using square tubing and some angle iron. I welded a plug in one end of the tube and welded an angle iron 'collar' around the outside of the open end, making the finished tube a couple inches shorter than the distance from the threaded end of the axle to the point the gear needed to be pressed on to remove/insert the half moon keys. I placed an aluminum 'pad' inside the closed end of the tube and rested the threaded end of axle with an axle nut to help carry the load on the aluminum pad. The collar of the tube rested on the press supports, and the whole thing was very stable. Others have described how to load the gear to press it on, and how to support the gear to push the axle out after removing half moon keys. My used Ford gears went on new Snyder's axles with about 1800-2700 pounds force, it may have taken more to break the gears free of the old axles, I didn't check that. I think Ford spec's call for a minimum 0.001" interference and I believe that is a theoretical force of 1000 lbs for clean and greased parts, some are tighter due to tolerances allowed, and as others have cautioned make sure burrs and dings are removed. Took longer to make the fixture than it did to change the gears, but the fixture made it easy and safe (in my view), be safe with this and good luck, jb


Scott C.
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Re: Removing and replacing rear axle gears.

Post by Scott C. » Sat Jan 11, 2020 1:22 am

John, where in Illinois are you? I am only about 30 miles east of Danville off of I74. My press is tall enough to do it.

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RajoRacer
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Re: Removing and replacing rear axle gears.

Post by RajoRacer » Sat Jan 11, 2020 10:36 am

Here's the cage I made up for pressing gears back on.
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axle cage.JPG

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RajoRacer
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Re: Removing and replacing rear axle gears.

Post by RajoRacer » Sat Jan 11, 2020 10:49 am

Forgot to add - I use an old rear wheel hub to press against using a steel axle shim to protect the new taper.


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Re: Removing and replacing rear axle gears.

Post by Scott_Conger » Sat Jan 11, 2020 11:23 am

Steve

I really like that cage. It's hard to impress folks how much energy is stored up and the potential human and shop damage that can occur with unfixtured parts if they get away under load...particularly with parts of this length. Kudos to you for a well thought out design. Thanks for sharing.
Scott Conger

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John Illinois
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Re: Removing and replacing rear axle gears.

Post by John Illinois » Sat Jan 11, 2020 11:52 am

Thanks to all for your helpful responses. I did not understand how you could press such a long thin shaft with force , protect the threads,and not bend it.
Also in my shop I try to always do things safely. This is an excellent thread.

John

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John E. Guitar
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Re: Removing and replacing rear axle gears.

Post by John E. Guitar » Sat Jan 11, 2020 9:12 pm

Here's my setup to remove the half moons. You can't see the top of the shaft very clearly but it has a nut on it to protect the thread.

The highest I've had to go is around 15 tonnes.



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John E. Guitar
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Re: Removing and replacing rear axle gears.

Post by John E. Guitar » Sat Jan 11, 2020 9:17 pm

Here's the setup to install the gear on the shaft. I use a bearing heater to heat the gear up to 115°C and a freeze spray to shrink the shaft. The photo of the frosted shaft only shows the top area being cooled. I apply the freeze spray for the full length of the gear location.

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