How to Fix a Sliding Door That Won’t Glide

By Mick — lead handyman, Newcastle NSW.

I get a sliding door call-out roughly every fortnight. Customer says “it’s stuffed, I need a new door”. I rock up, look at the bottom edge of the door, find the little plastic plug covering the adjustment screw, give it three turns with a Phillips driver, and the door glides like it’s on rails again. Then I have to have the awkward conversation about the call-out fee for a 90-second job.

The honest truth is that 90% of “broken” sliding doors aren’t broken — they’re just out of adjustment, or the rollers have seized up because nobody ever lubricated them. Aussie doors are particularly susceptible because we live in a salty coastal country. The bearings inside those rollers rust, the door starts to drag, the homeowner forces it harder, and eventually something genuinely does break. But by that point you’re past the easy fix.

Worth saying up front: most Aussie sliding doors I work on are 25–30 years old and still have their original rollers. The systems that come out of Capral, Stegbar, A&L and Trend factories are honestly built to last. So when one starts dragging, the first instinct should be “what’s wrong with the existing setup” rather than “time for a new door”. I’ve adjusted doors that were installed before I started in the trade and they’re still going.

One thing I’ll say up front: the lubricant matters. WD-40 is the wrong stuff for sliding door rollers — it’s a water dispersant, not a lubricant, and it actually attracts dust. Every Aussie sliding door manufacturer I’ve seen specs silicone spray. Get a can of Selleys RP7 Silicone or CRC Silicone Spray and bin the WD-40 for this job.

What you’ll need

• Phillips #2 screwdriver (PH2) — or PH2 bit on your cordless on the lowest clutch
• Flathead screwdriver to pry the trim plug
• Vacuum cleaner with crevice tool
• Stiff brush (toothbrush or detail brush)
• CRC Silicone Spray or Selleys RP7 Silicone — NOT WD-40
• Clean rag
• Torch
• Replacement rollers (only if Steps 1–7 don’t fix it) — Cowdroy, Brio or Doric depending on your door brand

Step 1: Diagnose the problem first

Open and close the door slowly and watch what’s happening. Three common patterns:

• Drags along the bottom track — door has dropped, needs roller height adjustment
• Catches at one specific spot every time — debris in the track, or a flat spot on a roller
• Whole door feels heavy and grindy — rollers are seized or bearings are corroded

Don’t skip this step. The fix depends on the cause.

Step 2: Vacuum the bottom track properly

Most “sticky” doors are 50% solved by cleaning the track. The crevice tool gets into the channel; the toothbrush dislodges the compacted muck on the corners. Aussie houses get a particular kind of crud in tracks — pollen, sand, dog hair, dead bugs — and it forms a hard ridge that the rollers ride up over. Vacuum, brush, vacuum again. Don’t use water — it makes the corrosion worse.

Step 3: Find the adjustment screws

Look at the bottom edge of the door — at each end, you’ll see either a small plastic plug (Stegbar, Trend, Capral) or an exposed Phillips screw head (older A&L doors). The plug pops out with a flathead screwdriver. The screw underneath is your roller adjuster.

Step 4: Adjust the roller height

Turn the screw clockwise to raise the door (it pushes the roller down, which raises the door body off the track). Anti-clockwise lowers it. Quarter-turns at a time. Adjust both ends until the door sits parallel to the top frame and clears the bottom track by 1–2 mm. If you have to crank one side way more than the other, the door is racked and you’ve got a bigger problem (Step 9).

Step 5: Test the glide before lubricating

Slide the door slowly. If it now glides smoothly, brilliant — go to Step 7. If it still grinds or catches even with the height correct, the rollers themselves are the problem and you’ll need to drop the door out (Step 6).

Step 6: Lift the door out to inspect the rollers (only if Step 5 fails)

Wind the adjustment screws all the way anti-clockwise to retract the rollers fully into the door. Get a helper. Lift the door straight up so the rollers clear the bottom track, then tilt the bottom of the door OUT toward you and lower it. Heavy doors are genuinely heavy — get help, don’t be a hero. With the door on its side on a soft floor, look at the rollers. Spin them with your finger. A good roller spins freely for several seconds. A seized roller doesn’t spin at all or grinds when you turn it.

Step 7: Silicone spray, generously

With the rollers exposed (door out, or just retracted into the door body), give them a proper soaking with silicone spray. Spin them by hand to work the silicone in. Wipe excess off the door body so it doesn’t drip onto your floor. Do the top track and rollers too if your door has them — they’re usually the forgotten ones.

Step 8: Coastal homes — silicone the track itself

This is where the Aussie coastal gotcha matters. Salt air corrodes the steel components inside the rollers and the track edges, even on aluminium-framed doors. A quick wipe of silicone along the bottom track every six months adds years to the life of the rollers. Don’t use grease — grease catches dust and turns into grinding paste. Silicone leaves a dry-feeling lubricant film.

Step 9: If the door is still bad — replace the rollers

Seized roller bearings can’t be revived. Once the steel inside has corroded, the only fix is new rollers. Take the old roller assembly to a glass and aluminium supplier (not Bunnings — Bunnings only stocks generic ones that often don’t fit). Cowdroy, Brio and Doric are the three big Aussie brands. Match the assembly exactly — there are dozens of variants and “looks similar” doesn’t equal “fits”.

Step 10: Reinstall and final adjustment

One more bit before reinstall: while the door’s out, take 30 seconds to clean the head track too. Most installs have an upper guide running along the top jamb that the door’s top edge slides through. That guide collects dust and dead bugs that increase friction. Wipe it out with a rag and silicone-spray the inside. Doors that glide smoothly at the bottom but feel “sticky” near the top are usually fighting the head track.

Tilt the door bottom back into the track, lift it up to clear the bottom guide, then lower the rollers onto the track. Re-do Step 4 (height adjustment). Slide the door fully open and closed five or six times — there should be no scraping, no dragging, and the door should coast a good 100 mm under its own momentum if you give it a gentle push from the middle.

Common things that go wrong

Patterns I’ve run into on coastal and inland call-outs:

• Adjustment screw spins forever with no effect. The internal cam mechanism on the roller has stripped out. You can buy the roller carriages new from a glass and aluminium supplier — Cowdroy, Brio, Doric — but you have to drop the door out (Step 6) and replace the whole carriage. About $40 a pair.
• Top of door rubs the head track. You raised the door too high. Wind both ends down a quarter-turn at a time until you get 1 mm clearance at the bottom and the top doesn’t rub.
• Door drops back down within a week. The adjustment screw isn’t holding because the locking notch inside the roller is worn. Replace the rollers — adjustment alone won’t hold.
• Track itself is bent or worn. Run a finger along the top of the bottom track. If you can feel a wave or a flat-spot, the aluminium track is worn and replacement requires removing the door frame — that’s a glazier’s job, not DIY.
• Multiple sliders, only one acts up. Often it’s the door that gets used most — kids’ room, back patio. The neighbouring doors are still on the original rollers. Service them all while you’ve got the silicone out and you’ll save yourself doing it again next year.

The Mick rule

Before you spend $1,200 on a new sliding door, spend ten minutes with a Phillips screwdriver and a can of silicone spray. Nine out of ten “broken” sliders are just out of adjustment or full of crud. And if you live anywhere coastal, get a six-monthly silicone treatment into your maintenance routine — it’s the difference between rollers that last 20 years and rollers that last 5.

Got a sliding door that’s properly stuffed — racked frame, broken track, glass damage? Send us a write-up.