Plating my spring plates...
 

For one of my winter projects I decided to refresh the spring plates and replace the worn bushings on my ’87 Carrera. I want to re-plate the spring plates in yellow zinc, and have checked several platers in my area (northern Detroit suburbs). They all will plate them, but will not clean them up before hand; that’s my job. For those that have re-plated their spring plates, was there any issue plating the inside of the tube, down where the spline for the torsion bar is? Will aluminum oxide blast work in cleaning them up? The fit between the torsion bar and spring plate tube is so close I am paranoid about messing with this inside area. Did you do any special prep there? Any other words of wisdom in the whole process? TIA for the input…

Spline Fit
 

Can say that with my high mile 87 but very nice rust free southern car that I just did my spring plate bushings this past weekend. No re-plating for me, mine were just dirty, no rust at all. When we pulled them off, the torsion bars looked perfect and stayed in place, didn't move at all, even the grease on the T-bars looked new. I could feel that the inner spline wasn't stuck either. I'd say with mine, even thought the fit is good, its certainly no press fit. I'd block or cap the inner tube of the torsion plate and leave it alone if it was me. I used a 4" grinder and wire wheel to clean the outer surface of the old rubber. Worked fast and great. Last used the sandpaper provided by elephant with the bushings and a little brake cleaner prior to glue. Those surfaces looked perfect.

Thanks for the input. I was thinking about trying to block off the tubes also, as you suggest. Has anyone done this? I am no plating expert, but can you just plug the end with a rubber plug prior to plating?

When I did a total suspension refresh/upgrade years ago, I took a bunch of stuff into the local plater. I had everything plated in cadmium (he was grandfathered in, and could still do this) except for my new 930 rotors (too big for his tumbler) so they were plated via hanging and were done in yellow zinc. I didn't clean anything as the plating process (as I recall) required a dip in some sort of acid bath prior to plating. That would eliminate any sort of plug, but I don't think you have anything to worry about "fitment wise"....it's not like a layer of powder coating, paint, etc. Personally, I wouldn't worry about that aspect, but that's just me....YMMV. Good luck!

.Thanks for the encouragement. I do tend to be a bit over cautious. Ok; I'm going to clean and plate everything. I took off the rubber bushings and wire brushed and sanded the tubes. It's clear I had to go well into the plating for that, so I need to plate. Gonna do the whole shebang...

just for anyone else who comes across this, when you plate these parts the zinc only goes inside the tube an inch or so. Some kind of science reason for that. But the splines don't get touched. No where near.