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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: qayqayt on April 10, 2011, 10:39:37 AM

Title: Tailgate Frame
Post by: qayqayt on April 10, 2011, 10:39:37 AM
When we bought our GM PD-4108 three years ago, the former owner pointed out the rust on the tailgate (engine door) and said "That's one thing you'll have to deal with soon".  I appreciated the honesty and kept it on my "to do list".  I got a friend to weld up a temporary fix last year by strengthing up a couple of key structural spots but this year it was time to quit messing around and get it fixed. 

I know a guy who is a bodyman for the local transit company who is handy with a mig welder.  He patched up many old GM Fishbowls in their time.  So he agreed to take on the project.

We considered removing the entire tailgate which would have made it easier but there's no "quick disconnect" for the wiring on our coach so we decided to do the work with the tailgate on the bus.  We had 3 problems from the start:
- Try not to wreck the paint job on the tailgate and under the rear window
- Keep the curvature of the tailgate intact
- Remove all the rusty structure without letting the frame disintegrate.

We cut away all the wiring supports and worked around the hanging wires.  He started with the top support piece and took it out with an air grinder.  Some if it was okay because of last years "patch job" especially the top corners so he left that intact.  He replaced the rest.  It wasn't so hard to maintain the curve because he didn't replace a very long section.  We then used angle iron from one hinge to the other and welded it in place.  I was a bit worried about this piece because I thought the straight piece might press against the fuel filters and hoses in the area but it fit okay.

The mid frame structural piece was a real challenge because we replaced the full length of the door.  The angle iron had to be curved and we wanted to use 2 pieces to maintain the original strength.  Since we didn't have anything to bend the angle iron with, we levered it into the support for the chain link fence and bent it by hand.  Not exactly a finely tuned bending instrument but these old guys have an eye for stuff like this and both pieces fit almost perfectly.

The very bottom of the tailgate was okay.  Overall it took us 4 hours of grinding, fitting, measuring and welding but we got it done.  No damage to the paint job on the bus.  We put a quick coat of primer on the finished frame and I'll go back and paint it next week.

Every job I complete on the bus creates a new addition for the "to do list".  We zap strapped the wiring all back, but after 40 years it's brittle and I can see some doubtful splices here and there.  I think I'll re-wire most of it and put in an 8 pin disconnect in case I ever have to remove the tailgate.  The only problem is deciding how far to go back there. 

Just thought you'd be interested.....

Bryan
Vancouver BC
GM PD-4108
Title: Re: Tailgate Frame
Post by: fraser8 on April 10, 2011, 06:53:43 PM
Bryan, it's nice to see one of those jobs you've put off finally be completed and have it done with relative ease is always a bonus.. If you're passing through Deroche stop in and say hello