The International Cessna^® 170 Association

Well, I finally got aound to pulling the the first gear leg in order to install
the 180 legs. After removing the shim blocks on the top of the gear leg and pulling the leg off we found substantial intergranular(sp?) corrosion.
The plot thickens.

Obtained replacement brackets from P.Ponk with an STC but no instructions. They tell me its the same as the cessna part.

I've ordered both the parts manual and the 100 series service manual, but I believe we need something else. Has anyone changed these brackets and is there a service bulletin or some other related instruction for this repair. It is obvious this is a big job with regards to sheet metal work etc., as Cessna never had intended for these to be changed. Any and all ideas most welcome. Thanks.

PS: I obtained my STC for the gear from AERO LLC of Maine for $200.
PPS: It has become obvious to me that this is an area that needs to be looked at on everyones a/c. You can't or may not see it without at least unbolting the shim blocks on the outer gear bracket.

If your A&P puts a extra inspection hole in the floor over the area of the casting, it will make the job much simpler.

Hello Marty,
I have been down this road before so I will tell you what my mechanic did to install the new brackets. We started by drilling out the floor panels from the door posts back towards the flap handle but not all the way. After drilling about half way on both sides you will be able to roll them towards each other and tie them together to hold them out of your way. Once you get this done, the gear boxes will be visible and easier to work on. There are two bulkheads or spars that the gear boxes are bolted to that have about a half inch rolled lip at the top that forms an I-beam structure(the rivets holes you drilled to remove the floor panel will be along this rail). You will not be able to twist them to remove, they fit with too close of tolerances for that. The directions from P-Ponk say to cut this lip, half inch front to back, then roll(bend) the lip edge up on each spar so the bracket can slide out the top. My mechanic thought that this would weaken the structure holding the gear boxes, so we drilled out about 14 inches or so of the skin on the outside of the gear boxes where the wing strut enters the fuselage. This enabled us to knock the brackets out through the bottom side of the spars with no damage or weakening of structure. This was on an A model, but the P-Ponk brackets were made for both models. The A model has the same size bolts front and back. Yours will have a larger bolt in the back from the factory so you will not have to enlarge the rear bolt holes in the spar like on the A model. It's not an easy job and I hope I never have to do it again. Make sure you have jacked the plane up safe and secure because you will have to crawl in and out of the plane a lot. I built a support that went up under the motor mount that was about 6' long and put aircraft jacks on each side. We also built two tall saw horses that we put under each wing where the lift struts bolt on for extra security. Hope this helps, if you have any questions send me a pm. Good luck! Randal