Don't Buy Univair Tailwheel Springs - January 2022

[tonycondon]

Last fall I decided to pre-emptively replace the tailwheel springs on my 120. They were old, I didn't want them to break. etc etc. I ordered the stack of springs from Univair (early version, single bend). Also I bought a bunch of the other parts from Univair to get my plane back to the "correct" parts back there.

Go to install today and the Shackle fits over the stack of springs fine but the AN4-21 bolt wont go through! springs are too thick, or the holes in the shackle are in the wrong place. I worked on clamping the springs tight, trying to force it, etc etc. Won't go. Called Univair. Took a minute to explain my issue, sent them a photo. The salesman took a look at their in stock springs and shackles and sure enough they don't fit. Now they're trying to figure out which springs are too thick or what is wrong. But long story short, if you order Springs from Univair for your 120 or 140 today, they aren't going to be the right size. I'll keep the forum updated once the situation is resolved.

In the meantime I guess I'll just make airplane noises...

[6277]

I had the same issue years ago. Can't recall where I bought the spring set. I had to elongate the holes in the shackle slightly.

[6277]

More. The tiny "button" in the shackle fell out after a couple of flights. Replaced it with a tiny button head screw that I had to grind down a little to make it fit the hole in the spring set, then a washer and bolt on the top.

[6643]

The tiny "button" in the shackle fell out after a couple of flights.

How did that happen? The head of the button should be bigger than the hole in the shackle...

[6277]

In the original bracket, the button was "forced fit" or swaged into the bracket. After a few flights it came loose from the bracket. I bought a small socket cap screw and shaped it to fit into the spring set hole. Then I fastened it to the bracket with a washer and self-locking nut.

[6643]

Interesting...

Maybe I've never seen one that was original.

Read this Neal Wright article on the subject.

[tonycondon]

Mine weren't quite right either. Per serial # I should have the single bend, but had double bend. And my springs didn't really parallel each other anyway. Tailwheel spring had been drilled out and "oversize" bolt was used.for attachment. Threads were in bearing. Can't load picture. File too large.

Anyway I lored.over the Wright articles and hopefully soon will have it all "right"

[elliotblock]

I’d like to report I had this same issue with recently purchased springs from Univair. I had purchased a NOS Cessna shackle from a different source.

I reamed the hole in the shackle to get the bolt to fit.

Elliot

[tonycondon]

Univair is working on an approved mod to get their parts to fit their other parts. It'll take some time because paperwork and the FAA is involved. I'm working on getting an owner produced part made so I can fly in the meantime. I'll advise here when Univair has parts that fit their other parts.

[simonlowther]

My 120 is s/n 11102 built October 46. It has the zero bend (straight) spring set which I think no one actually sells any more.

Characteristics are it tracks dead straight, no shimmy but somewhat difficult to 'break' to a tight turn. it does not worry me presently at all but in the interests of preventing problems and doing things right should I change these to the single bend set when Univair get there proverbial sorted?

Cheers
Si