I want to replace the tail spring/saddle assembly with a new one from Airframes Alaska, however, the saddle tube is being a bugger. No obvious bends, but a little corrosion visible inside the tube. Clevis pins out, Kroil oil, propane torch, brass drift punch, same diameter socket/extension with 1.5# hammer, pound pound pound, no joy. About all I have left is a cutoff wheel on both sides of the spring, but not a lot of room to work there and it's steel to boot. Any other ideas? Thanks!

I read an article of all that stuff and they said the best was a 50/50 mix of ATF and acetone. I tried it and it worked way better than any of the commercial stuff.
KenW

Try Mouse Milk.
Its not very oily but it penetrates really well.

No luck with 50:50 Acetone:ATF; Mouse Milk next.

If you are willing to destroy the inter tube you may be able to slit the inter tube in 3 places with a hacksaw blade and then peel the sections out.
Just a suggestion. Personally, I chose to machined a tool which acts as a punch and a socket with a through bolt to press the pin out. The punch has a smaller diameter on the end that acts as a guide and keeps it centered and a shoulder which presses against the end of the tube without deforming it. You can apply a lot more force in a more controlled manner this way. It also allows you to maintain the pressure while heating the saddle. Sorry I don't have any photos of the tool and it is up in my hanger. I also used the same tool to press the new pin in without deforming it.

Tim

I used a hacksaw blade. The rubber deal is pretty thick so plenty of room to stay away from the casting riveted to the tail section. Took some time but I got it with out hurting anything important.

Mouse Milk no go; I'm fearful of splitting the tube longitudinally because of potential damage to the castings. There's only a 1/4 inch or so between the front of the tube and the bulkhead, so that must of took a while with hacksaw blades! I have a 4inch cut off tool - I'll see if t can cut across the rubber tomorrow. Thanks.

Give the mouse milk some time like a day.

I have had to hack saw several ones out over the years on ones that were bent. No other way to get them out in that case. I have had a few that were just rusted in and took a lot of effort to get them out.

I would try to brace the opposite side of the tail up against something solid like a truck bumper with the proper protection of the skin and paint. You will probably have to get creative.Then I would use a bearing driver of just the right size to pound it out and resort to a air hammer for extra measure.

Without bracing the other side a lot of energy is lost when you are pounding on the tube.

Mouse milk didn't work after waiting overnight. I couldn't figure out a safe way to use power to cut the saddle tube, so I ended up using a hacksaw. Three hours of moving about 1/4" in and out. Tap Magic, a tool lube, helped. After the tail spring was removed, I still couldn't pound out the tube. The rubber bushing at the tip of the spring was also difficult; I ended up hacksawing it up to, but not through the metal, and forced a screwdriver in between it the tube it rests in, and after an hour or so, got it out. I cleaned up the bulkhead and inspected it; no cracks, applied primer. Getting the new rubber bushings in was difficult; apparently some installations require metal washers (supplied), but I could barely get the rubber in by itself. The saddle tube was also hard; I ended up having to place another jack at the next bulkhead so there was less pressure on the casting alignment. Finally got it done.

Here's some pictures:

1. New tail spring.

https://www.flickr.com/photos/129286532 ... ed-public/

2. Starting to cut.

https://www.flickr.com/photos/129286532 ... ed-public/

3. Removed tail spring.

https://www.flickr.com/photos/129286532 ... ed-public/

4. Cleaned up bulkhead.

https://www.flickr.com/photos/129286532 ... ed-public/

5. Installed.

https://www.flickr.com/photos/129286532 ... ed-public/

Next, I want to change out the innards of my Scott 3400 tailwheel, and put it on a baby Bushwheel fork. The baby Bushwheel 3200 I had before is different than this; the bearing is on top - is that bearing pressed on, and will I need a puller to disassemble the unit?

Anybody know of a manual for this? The Cessna service manual is not helpful. Thanks for all of your help!

jrc111 wrote:Next, I want to change out the innards of my Scott 3400 tailwheel, and put it on a baby Bushwheel fork. The baby Bushwheel 3200 I had before is different than this; the bearing is on top - is that bearing pressed on, and will I need a puller to disassemble the unit?

Anybody know of a manual for this? The Cessna service manual is not helpful. Thanks for all of your help!

Just went through this, but with a stock fork.

The top bearing is indeed pressed on, but it's easy to get off. There are two holes on the bottom of the fork. Use a drift (1/8" maybe?), and alternate tapping through both holes. The drift will be pressing directly on the inner race of the bearing, and it will eventually come off the shaft.

You might need a press to put the bearing back on. My old bearing was in good shape, so I reused it, and I could 'just' press it on with a big socket by hand. The new bearing was tight enough that it would have required a press.

If you can, find a copy of the MAF Scott 3400 overhaul manual. It was very easy to follow and is better than the Cessna manual, from what I've been told. You will need a digital pull scale of some sort if you use the MAF manual.

You will probably have the top bearing on and off a few times as you adjust the shims, but it is well worth the effort to get right.

I need to take mine apart again, as the steering arm is in bad shape internally. Unfortunately, it's the one part I didn't order because it's the most expensive part in the stack by far.

Good info, thanks ! Ron

Here's a drawing for the XP Mods 3400 series t/w. A Bushwheel catalog I have also has a good exploded drawing of the 3400 series, it might be available on the Airframes Alaska website?