Differences in 70 Seat Release Buttons?

[Pat M.]

Hi everyone. I recently scratched up one of the seat release buttons on my 70 and I ordered a repo part to replace it. But I noticed that the repo buttons (shown on the right, below) are thicker and have more rounded edges than the buttons already on my car. Has anyone else noticed this, and is either design closer to the original piece? Thanks, Patrick

[Chuck S.]

Re: Differences in 70 Seat Release Buttons?

...I recently scratched up one of the seat release buttons on my 70 and I ordered a repo part to replace it. But I noticed that the repo buttons (shown on the right, below) are thicker and have more rounded edges than the buttons already on my car. Has anyone else noticed this, and is either design closer to the original piece?...

Pat, I'm a little confused by your question...are you asking us to evaluate which of these two buttons is best for your car, and one of them is apparently an original? Do you have some reason to doubt the originality of the button off your car?

I'm interested in your post because I recently reviewed my chrome parts to determine which would really require replating. The plating on my original seat release buttons was damaged, but the material appeared to be electroplated plastic because of the light weight and thin cross section. If they are plastic, then replating is probably not worthwhile.

My first inclination was to replace them, but your question has prompted a closer examination...they appear to be mildly magnetic, so perhaps these buttons are a fabricated steel stamping with welded pins. However, there appears to be a zinc diecast appearance where the plating is completely gone in one spot, and the buttons have a metallic clink when they strike each other. Perhaps they can be replated...known issues with repro accuracy may make that worthwhile, and I will proceed in that direction.

As for the examples in your photo, my originals appear rounded like the repro on the right, but my buttons have more pronounced rounding on the corners, and less so on the edges. The release button on the left appears to have less rounding than mine, and have sharper edges. If button on the right is an "original" release button off your car, this could be due to your buttons being an earlier version than mine (my car's build is G30); Or, one of us has already had our release buttons replaced with later service parts or repros.

I can't imagine any of my car's previous owners being concerned enough with the seat release buttons' finish to procure new ones, but the seat cover inserts were changed (crushed blue velour...shudder), so one never knows for sure.

Edit: If you're saying BOTH of the seat release buttons in the photo are repros, then I would say NEITHER is a good reproduction of the original part...this assumes that mine are original. The left button has too little rounding, particularly on the corners, and the right button has too much general rounding across the button surface. Anyone that has seen a lot of original buttons, like an experienced interior judge, should be able to spot either as a reproduction in my opinion. In your place, I would have the originals replated, or use them as is...judges would rather see original parts in worn condition than nice shiny repros.

[Warren F.]

Re: Differences in 70 Seat Release Buttons?

Pat,

I just went out and looked at the seatback release buttons on both my '71's. They are a March & April '71 build. Both have the style you show on the left. I also have an original NOS box with one and it is also that same style. The ones on the car, after tapping them appear to be chrome plated plastic. The NOS one is also chrome plated plastic.

[Pat M.]

Re: Differences in 70 Seat Release Buttons?

Hi Guys. Chuck - My car was completely restored in 2003, before I purchased it. So I don't know if the buttons that came on my car are originals or not.

All of the new buttons for sale I've seen are thicker and have more rounded corners than my car's buttons, similar to the button on the right in my picture. EDIT - The buttons that came on my car look identical to the button on the left of my photo.

This led me to wonder which button configuration is closer to originals, since it is quite possible that the buttons on my car are incorrectly configured repos.

I'd like to have both of my buttons appear correct, regardless of what configuration that may be.

Thanks for the responses, Patrick

[Alan S.]

Re: Differences in 70 Seat Release Buttons?

Pat,
To add to the mystery, the original buttons on my 71 (#6589, mid-Jan build) are like the one you show on the right. The reproductions I bought from Smart Parts are like the one you show on the left. So, the answer to your question is ?????.
Regards,
Alan


Chuck,
I think you're right about zinc. They are so light I've always thought plastic. The chrome bubbles up on the buttons just like the chrome on my side exhaust covers. Are they zinc, too?
Regards,
Alan

[Chuck S.]

Re: Differences in 70 Seat Release Buttons?

Chuck,
I think you're right about zinc. They are so light I've always thought plastic. The chrome bubbles up on the buttons just like the chrome on my side exhaust covers. Are they zinc, too?...

Alan, I have never examined the side exhaust covers closely, but it's quite possible...the intricate longitudinal fins would be hard to duplicate in any other material. GM styling used a lot of diecast on C3s, and especially 70-72...all of the front and side grilles, headlight supports/doors/bezels, wiper door, front and rear plenum grilles are all precision diecast of pot metal or aluminum.

I also have a little bubbling on one of the buttons, and the substrate definitely appears to be metallic where the plating is missing. However, zinc diecast wouldn't explain why the buttons are mildly magnetic. The wall thickness in the middle of each side is very thin, maybe 0.040-0.045", but thickens in the corners by maybe 20-30%.

From your description of your 71 release buttons, I'm thinking there must have been a configuration change during the 70 model year...when it happened, I doubt anyone knows for sure. Maybe Reba will chime in here and help us figure out what happened.

[Alan S.]

Re: Differences in 70 Seat Release Buttons?

Chuck,
Always wanted to ask... what is 'Pot Metal' and why the name. The name always makes me think it's all the left-overs mixed together like bad soup.
Regards,
Alan

[John H.]

Re: Differences in 70 Seat Release Buttons?

Chuck,
Always wanted to ask... what is 'Pot Metal' and why the name. The name always makes me think it's all the left-overs mixed together like bad soup.
Regards,
Alan

That's fairly accurate - zinc die-castings are actually an alloy of zinc, tin, lead, and traces of other common elements, which are literally melted in a refractory "pot" before being pressure-fed to the injection mold. Thus, "pot-metal".

[Jack H.]

Re: Differences in 70 Seat Release Buttons?

Like John says, the term 'pot metal' is VERY generic referring to a class of metal alloys that will remain molten in a 'pot'. Alloys of zinc-cad, zinc-tin, lead-antimony and LOTS of others (without specific mix composition) fall into this category. That's one of the reasons it can be hard to find the right 'brew' to dichromate/color these castings. You need to know what composition of 'pot metal' you're working with!