Sliding door track profiles and sill caps: what fits your door

The short answer

A sliding patio door rolls on a track in the sill. On some doors it is a raised rail, and the wheels on the rollers are shaped to sit on it. When that rail is dented or worn, it can sometimes take a cap. There are two kinds:

• The door maker's own part. Andersen calls it the sill track cap and sells a replacement through Andersen.
• An aftermarket repair cap. Prime-Line, a parts maker, sells stainless steel and plastic caps that fit over the existing rail. Its stainless cap measures 1/4 inch wide.

For Andersen's cap, Andersen says to contact Andersen. For Prime-Line's, Prime-Line asks buyers to compare its drawing with the original. This site leaves work that needs the sliding panel out to a professional.

First, make sure the track is the problem. The track repair page separates dirt from damage, and track wear from roller wear. This page picks up once the question is which part fits.

Every statement here comes from a maker's own guide, installation sheet, or product page, linked at the bottom. Each applies to that maker's products only. This site is not affiliated with any of them.

What the track is

JELD-WEN's vinyl patio door guide defines it plainly:

"The track on the sill of a patio door that guides the panel as it opens and closes."

Andersen calls it "the bottom channel where the door glides."

The track's shape and the roller's wheel go together. Prime-Line says the grooved-edge wheels on one of its roller assemblies "are designed to glide on a single raised aluminum or steel track." For one of its tandem rollers, its fit guidance reads:

"Verify housing dimensions, roller size, mounting configuration, and track profile before purchasing for compatibility"

So the track profile is part of matching a roller, not only a cap. The roller repair page covers the roller side.

Height matters too. JELD-WEN's wood door guide says rollers set too low can make the panel drag on the lower track. It says to adjust them just high enough to clear the sill track and keep the weatherstrip hidden when the door is closed.

Two ways a track is built

A separate part set into the sill. Pella's assembly instructions for its 250 Series sliding patio door list the sill track as its own part: "Installed in the sill, must be removed for frame installation." Pella says it is "Required for vent panel operation." The vent panel is the one that slides: Pella's instructions set it in place "making sure the rollers are aligned with the sill roller track." The same instructions say the track goes in with its longer outside leg toward the interior and its shorter leg toward the exterior, and that it must slope toward the exterior. So the track has a set shape and a right way round.

That sheet is an assembly and installation document for the door frame. It is not an owner's repair guide, and this page does not pass its steps on.

A cap that is part of the frame. Andersen describes its sill track cap as "the part of the frame in which the rollers sit."

To find out which kind of door you have, start with the maker. The label guide shows where makers put a label, an etching, or an order number.

The maker's own cap: Andersen

Andersen's article on rollers checks the cap at the same time as the rollers, with the panel out:

"With the patio door panel still removed, check the frame sill track cap, which is the part of the frame in which the rollers sit, for denting or bad scratches. If there is damage, the sill track cap should be ordered in addition to the bottom rollers."

It says to contact Andersen to order a replacement sill track cap. It also says that if there is no visible damage, replacing rollers might not be necessary to improve the door's operation.

The article gives no dimensions or part number for the cap. It does not say whether an aftermarket cap suits an Andersen door, so this page does not either.

Aftermarket caps: what Prime-Line sells

Prime-Line sells caps that fit over the rail already in the sill. One of its listings says it plainly: "Cap slips on existing damaged track." The old rail has to be there for the cap to sit on.

Stainless steel. Prime-Line describes its D 1579-1 cap this way:

"The patio door track cover measures 1/4 inch wide and 8 ft. long, but can be cut to any length to fit your door or window."

It says the cap is for worn or damaged sliding glass door aluminum tracks, that it snaps over the old track, and that it is attached with silicone adhesive, which is not included. Its instruction sheet covers the stainless repair track in 6, 8, and 10 foot lengths.

Plastic. Prime-Line's D 1572 is a 96 inch roll of black plastic track cap for worn or damaged patio door aluminum tracks. It says the cap also helps quiet doors as they slide, and that it can be cut to size.

How a cap is measured

Prime-Line's pages point to three things to check:

1. Width. The D 1579-1 stainless cap is 1/4 inch wide. The drawing on its instruction sheet marks two dimensions, 1/4 inch and 3/16 inch. The sheet's text does not say which dimension each one marks.
2. High spots. Prime-Line's description of its 48 inch cap says the old track is first prepared by grinding any spots that are wider than the original track width, and cleaned.
3. The drawing. For its plastic cap, Prime-Line asks buyers to "refer to the line art drawing and compare with your original item before purchasing." Its instruction sheet adds that its drawings are typical for this style of part and may not show a part identical to the one you are installing.

None of Prime-Line's cap pages names the door brands its caps fit. A cap that fits the rail also has to suit the rollers that ride on it, which brings back the roller's own fit guidance above.

Before asking about a repair, the photo guide shows which pictures of the track to take, with the door in place.

When this is a professional's job

This site does not give steps for fitting a cap, for three reasons:

• The panel. Andersen checks its sill track cap with the panel removed, and its article has the owner take the panel out; this site does not pass those steps on. JELD-WEN marks operating panel removal "For Professionals Only," and warns that panel removal "can be awkward and could cause physical injury or product damage."
• The instructions are silent on it. Prime-Line calls installation quick and easy, but its instruction sheet does not say whether the sliding panel has to come out first.
• The warranty. Prime-Line warrants its caps against manufacturing defects for one year, and says that in no case is it responsible for user related damage or damage incurred during installation.

Whether a worn door is worth repairing at all is a separate question. The repair or replace guide covers it.

Caring for the track

Andersen says to clean its sill track with a soft-bristle brush and warm, mild soapy water. It also says:

"Important: Do not use lubricant on the track; this will cause the rollers to slide, instead of roll."

JELD-WEN's guides say otherwise for JELD-WEN doors: clean the sill track, then lubricate it with silicone spray on a cloth. Follow the guide for your own door.

What this page does not cover

None of the documents we opened catalogs track profiles or gives the rail width for any maker's door. So this page does not say which profile a given brand uses. We found no Milgard, MI, Marvin, or MITER Brands document on track caps. The glossary explains other terms a quote may use.

Asking about a repair

To ask about a track in Plano, Allen, McKinney, or Frisco, use the contact page. Say who made the door if you found a label, and attach the track photographs. The operator reviews every inquiry and replies with the next step. Sending the form is not a booking.