When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
How to straighten out plastic door top trim strip?
Working on the doors now. The door panel is OK but the plastic trim at the top seems to be bowed a bit and doesn't sit flat onto the carboard panel. I can force it down with hot glue and clamps, but I'm thinking there is a way to relieve the bowing with a little heat once its on there. I suppose it will take to the shape anyway over time, but wouldn't like it to be under so much tension for so long until then. Any tips?
Edit: Found a bunch of buried threads on this. Does anyone make a sheet nut driver? I've heard they can be a PITA to work.
Last edited by Tootie Pang; 10-09-2017 at 11:07 PM.
Re: How to straighten out plastic door top trim strip?
Its possible that someone removed the panel and incorrectly re-installed
it. They prob. didn't get the center "clips" to slide into the mounting holes
in the top of the door frame or they broke them off.
Thats prob. why its bowed in the center!
NOTE that the top rail AND door panel come off as ONE piece as they are
fastened together!
Heres a thread with pics and video of the top rail and door panel install/removal.
ttps://www.thirdgen.org/forums/interior/719426-door-panel-top-rail.html
Re: How to straighten out plastic door top trim strip?
I was studying the disassembled door panel yesterday. This is apparently very common in many cars. It is likely due to manufacturing errors. The bowing occurs due to stresses in the two side sections, not the center top section. You can heat ABS to bend and conform it. It is a very versatile plastic and well understood.
I have a plan. I am going to clamp the ABS center section lengthwise between two long, straight pieces if 1x2 to provide the correct shape and then I am going to heat the side strips with a heat gun. I will report back. I hope to try this this by this weekend.
Re: How to straighten out plastic door top trim strip?
Ok, I did the passenger door and it worked. Very simple. We have an advantage of having straight pieces so clamping between two 1x4s was easy. As I heated it, I could hear and see it it relaxing. Then cooled it in the clamps. I won't be entirely sure until I reassemble the door but I did reattach the door card (after I repaired the torn holes) and the holes all lined up nicely with the pins. I will include that in my follow up. I will take pics when I do the driver's door.
Re: How to straighten out plastic door top trim strip?
Yes heat gun. Did the driver's side door. Took much longer and didn't come out as well but still much improved.
Some observations/notes:
1. The red clamps are to keep the inner (door panel side) edge from bowing out when the main clamp is applied. They are not tight, only snug enough to bring the inner edge straight.
2. The tin foil wrap is to keep the inner wood piece from burning.
3. Heat for a good while, I felt the pieces relax in the clamps.
4. A 2x4 might be better for the top piece. After some heating I saw the 1x4 top piece bowing.
Last edited by Tootie Pang; 10-13-2017 at 10:07 AM.
Re: How to straighten out plastic door top trim strip?
This has been discussed many times that the bowing of the upper door panel is factory and not a time/heat based defect. Brand new ones, back in the day, had the same curve to them. Also, it's not a flat piece of plastic that can easily bow. It's got two sides that go with the top. If you're familiar with wood working, a single piece of wood as a shelf, will bow. Once you add a vertical board to the face, it stops the bowing by adding support.
These plastic panels can only bow, if the front and back "support" pieces got stretched, and that doesn't happen.
In the below pic, from a 1985 brochure, you can see a curve in the upper panel.
And in the pic below, from the 1986 brochure, you can see the curve.
Re: How to straighten out plastic door top trim strip?
Looks like the typical crappy Chevy quality back in the day. If they were supposed to be curved, then why are the holes in the card cut straight and rip out at both ends? I doubt Chevy designed in an every-so-slight curvature. Door top is straight, panel lines are straight. Methinks straight.
Re: How to straighten out plastic door top trim strip?
This has been the discussion points on this subject for many years. If the door panel is straight and the holes are straight, then why is the top panel curved? We don't know!
The holes in the door panel are oblong, not circular, so they were designed to provide some flexibility in their installation. I agree that it doesn't make sense, but I bought some of these brand new at the dealer back in the 90's and they were curved, coming from an air conditioned parts room at a dealership. Heat did not warp these.
Re: How to straighten out plastic door top trim strip?
Yes, from what I read, they were likely manufactured incorrectly. Molded incorrectly at the manufacturer introducing internal stresses that respond to sun.
Re: How to straighten out plastic door top trim strip?
Its not so much a bow as a twisting, at least with mine.Which made it appear bowed/bent.I could tell so because the imprint on the fabric where the trim contacted originally was below the plastic trim.This was at the front where the tri seal is, starting from about the dash pad w/ a taper to it.
Which is not visible in the pics above, but fwiw i dont see any bowing anyway.
10-09-2017, 10:48 PM
