93' Yukon Rear Crossmember Replacement

[Katahdin]

I am finally able to get to work replacing my rear fuel tank crossmember (see my intro thread). The big holdup was finding one, either all the ones in the northeast had rusted out or the yard only wanted to sell you a whole frame. My luck finally turned when a salvage yard from North Dakota returned my emails and was nice enough to cut one off and ship it to me via UPS. This is my first repair attempt at anything frame related.

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First you need to remove the rivets. A angle grinder works great for removing the metal, then you need to punch the rivet through with a air hammer. This works great for the rivets you can access outside the frame, but the the two inside-frame rivets on the old crossmember were a PITA! Had to switch to a die grinder chewed up several grinding stones. Once you get the first one (do the inside rivets last) you can hinge the crossmember out and get the last one with the angle grinder.

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Walla! One popped rivet! Repeat 7 more times!

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That's all I have for now. The rest of the afternoon was spent removing loose rust with a angle grinder/wire brush combo. Presently the rear quarter of the frame is soaking in a spray on "Rust Kutter" that I picked up at Tractor Supply. Tomorrow I plan to sandblast the replacement crossmember and install later in the week after the Rust Kutter has cured and been painted over. Hopefully by then the replacement fuel tank and straps will have arrived.

 

[Katahdin]

Got back to work on the 93 Yukon today, here's the salvaged crossmember in a new blasting cabinet I picked up this week from Harbor Freight. I actually put off the project a few days so I could get the cabinet online and try it out.

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Here's the crossmember after about 15 minutes of abrasive blasting in the new cabinet revealing nice shiny metal and not too much pitting. I was very pleased with the results and there were no leaks from the cabinet. The ends were hard to get to as it ust barely fit diagonally, but I touched the ends up outside with a couple quick blasts outdoors with another blaster. Some dryed on tar on the inside of the crossmember had to be chiseled off before it could be blasted.

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Now the crossmember and new fuel tank straps are primed for new paint and hanging on the clothes line to dry.

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Here's the original rusty old fuel tank from the 17 year-old-yukon. The fuel pump and sending unit are relatively new so those are being salvaged and moved to the new fuel tank. I used a rubber mallet and a brass punch to rotate the locking ring so it could be removed.

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Here's the new fuel tank with the old fuel sending unit and fuel pump installed. Front porches are great for doing auto work! I'll go to NAPA tomorrow for some new vent valves and 1/4 inch fuel line.

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I also went back to the frame with a wire brush and rust kutter again. I'll rinse the rk trated areas on the frame off with water tomorrow and hopefully get to priming and topcoating everything this weekend and some reassembly.