How to Install New Sill Plates

Contributed by:

Kim Ouye (Silver Bullet)

Installing a new sill plate is not a difficult task but removing the old adhesive is time consuming.


1 Plastic putty knife 

1 1” Sponge type paint brush 
1 3M General Purpose Adhesive Cleaner 
1 Permatex Weatherstrip Cement 
1 Thin piece of plastic about 1” wide, 4” long 
1 10lb Fishing line or dental floss (not pictured)
1. Carefully pull out the door seal just above the sill, it is held in by some weather strip cement. Hold it out of the way so you can work. It is not necessary to remove the plastic trim that sits above the door seal. (Note: This step is optional, but makes it easier to remove and install the sill plates) I didn’t do this first but I wish that I did, that’s why the sill plate is missing in the following picture.
2. Remove the old sill plate. Work some fishing line or dental floss under the front or the back of the sill plate and saw away about 4-5 inches of adhesive. Then gently lift up on the sill plate until it comes off. Most of the adhesive strips will stick to the car (2 white strips in the picture below). 

3. Use a plastic putty knife to remove as much of the adhesive strips from the sill without using the adhesive remove. Push along the length of the adhesive strip until it rolls up into a narrow strip. Then scrape off the rolled up strip from one end to the other. You will remove about 50% of the adhesive. Use “3M Adhesive Remover” to soften the remaining adhesive. Apply with a 1” sponge paintbrush, let soak for a few minutes, scrape with the plastic putty knife. It will come off in layers, be patient and repeat this process until it is completely removed. 


4. Remove the door seal adhesive with the adhesive remover. Use the 1” sponge brush to apply. Let it sit for a few minutes. Scrape it off with the plastic putty knife and wipe away the remaining with a rag.
5. Some of the door seal adhesive may smear on the sill. Remove it using the adhesive remover and a clean soft rag.
6. Wipe down the sill with a damp cloth then dry it. You are now done with the time consuming portion of the install.
7. Peel back the edges of the protective plastic coating on the new sill plate to make sure it does not get pinched under it when you install it.
8. Place the new sill plate on the sill and check the positioning. The outer edge should touch the side of the sill. I bent the back inside corner of the sill plate upward a bit to clear the inner edge of the sill channel so the plate would sit a little flatter. The back edge of the plate should be in the sill channel that was made for it. Note: If you skipped #1, you will have to work the sill plate under the door seal until the sill plate butts up against the sill.

9. Remove the remaining plastic coating.

10. Skip the next two steps if you skipped step #1.

11. Insert the weather strip adhesive tube into the weather strip channel on the inner portion of the sill and put a bead of adhesive for the full length. Note: To direct the adhesive better, I cut off the end of a spare trunk drain plug and stuck it on the end of the tube (see the black rubber piece on the adhesive tube in the Tools picture.

12. Push the door seal back into the channel from one end to the other. Press every couple of inches to make sure it seats into the adhesive.  hen run your finger along the entire length and push it in.

13. Wipe down the sill plate with a damp cloth and dry.

14. Repeat for the other side.

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