Am I going to have to Replace my Firewall???

[bluesky65rs]

I am out of town but my mechanic found this when he removed the bushings that needed to be replaced on the firewall.
These are the Upper and Lower

[c170b53]

The important stuff is in the inside, if the stringer engine mount fitting is ok, you’re going to be ok, the firewall needs to be blended smooth. The two rubber bushing are crushed together in the fitting by the exterior and interior washers. Hard to say but you might find the fitting damaged. Its replacement would be much easier.

[bluesky65rs]

Thanks Jim

[n2582d]

Do a search here on stringer assembly p/n 0511282 and bracket p/n 0411281-6. Also study this conversation regarding aluminum bushings in place of the original rubber ones. A new bracket (0411281-6) is hard to find. It could be that Univair's 0411281-4 is the same extrusion with a smaller hole diameter than the 5/8" hole in the C-170 bracket. If so, it could be modified to conform to p/n 0411281-6. Cessna Support may be able to answer that. P/n 0411281-5 also looks like the same extrusion. It also looks like you may need to replace/fabricate the spacer p/n 0453110.

Stringer.jpg

[bluesky65rs]

Do a search here on stringer assembly p/n 0511282 and bracket p/n 0411281-6. Also study this conversation regarding aluminum bushings in place of the original rubber ones. A new bracket (0411281-6) is hard to find. It could be that Univair's 0411281-4 is the same extrusion with a smaller hole diameter than the 5/8" hole in the C-170 bracket. If so, it could be modified to conform to p/n 0411281-6. Cessna Support may be able to answer that. P/n 0411281-5 also looks like the same extrusion. It also looks like you may need to replace/fabricate the spacer p/n 0453110.Stringer.jpg

Thank you Gary. I actually found a salvage yard that had a good set of brackets. I think we are going to fabricate the spacer. Any advice?

[n2582d]

Spacer should match the thickness of the firewall attach angle. My spacer measured .065”. .063” 2024T3 should work.