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Carry thru H block question

https://www.forum.cessna170.org/forums/viewtopic.php?t=16983

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Carry thru H block question

Posted: Wed Dec 18, 2024 1:26 am
by Bruce Fenstermacher
I got the following question from long time member Bruce Kown from Alabama
`I'm knee deep in the restoration of N1387C C170A. I am installing the lift
ring option because its so handy when changing the gear out & lots of other
things, N3843V has them as a part of the float kit & I have used them
rather than jack the 180 gear legs that don't like to be jacked.

The lh block has a little intergranular corrosion starting & I want to
change it. I rounded up a dozen replacment candidates and none are like
the one I took from N9059A the donor 170A. The earlier 170A blocks have
more metal(shorter slot) and are like the ones in the A & B parts manual
showing the lift ring option. I even checked Browns stock & his blocks have
the long slot & won't support the lift ring kit. Any answers

Thanks

Bruce Kown
Anybody have anything they can share.

Re: Carry thru H block question

Posted: Wed Dec 18, 2024 3:24 am
by n2582d
Take a look at Accessory Kit AK175-12P. On page two is this note:
Screen Shot 2024-12-17 at 7.14.06 PM.png
This Accessory Kit isn't specifically for the C-170A but I think any reasonable A&P would see that it applies as the design is the same as the early 172's which are covered by the Accessory Kit. The front blocks, p/n 0411129, and the rear blocks, p/n 0512122, share the same part numbers in both models.

For what it's worth, I'd also follow AK175-12P rather than fig. 77 in the C-170A IPC when choosing the nuts on the eyebolts. An MS21043L5 is stronger than a AN365-524.

Re: Carry thru H block question

Posted: Wed Dec 18, 2024 3:44 am
by bkown
Thanks
I had figured that must be the case after seeing the L19 data.

I will continue to look for the old style block with a 5/16 drilled hole because its got to be a structurally much better installation
and admit that Im picky to a fault.

Bruce Kown

Re: Carry thru H block question

Posted: Wed Dec 18, 2024 3:47 am
by bkown
Agreed on the nut choice.

Re: Carry thru H block question

Posted: Wed Dec 18, 2024 4:38 am
by n2582d
Bruce,
The same block was used in Cessnas as fast and heavy as the early C-210's. Personally, I wouldn't worry about the later style blocks being weaker. I'd be more concerned about hidden intergranular corrosion in a 70 year old used part. Good thinking looking at the L-19 data. NOS L-19 parts are readily available. For the forward blocks their p/n is 0613165, rear = p/n 0611250. If money is no object the superseding new p/n's from Cessna are S4628-339 for the front and S4628-1377 for the rear.
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