13 January 2023
Sunroof leaks can cause expensive damage, so it’s essential to deal with them promptly. Ed Evans explains
Need to know
Time: 4 hours.
Difficulty: 2 out of 5
Models: Defender, Ninety, One Ten plus other beam axle models.
Tools needed: General workshop tools, trim plug removal tool.
• Wear eye protection when releasing trim clips.
• Protective gloves may be cumbersome when releasing fiddly trim fittings. If not wearing them, take care to ensure fingers are clear if the trim tool slips.
• Follow the manufacturers’ safety precautions when using adhesives
and cleaning materials. Ensure good ventilation.
• Be aware that working overhead in a confined and irregular space to release roof fittings involves a lot of bodily contortion – take it at a comfortable pace.
• Wear eye protection and gloves when using cleaning substances. Eye protection is essential when working overhead to clean a headlining that is still fitted in position.
When Steve Grant and I rebuilt my 1989 pre-Defender Ninety I was determined it would have none of the multiple body leaks that bugged its previous owner. When I bought the truck in 2016, the sunroof had been sealed over with gaffer tape – a desperate and messy cure that illustrated the previous owner’s frustration. Three years later, the sunroof was one of the last items to be fitted to the newly painted roof to complete the rebuild, together with new seals and meticulously applied sealant in all the necessary places.
That worked. The rebuilt vehicle’s first outing was 170 miles of mainly motorway in torrential rain. Not a drop of it came into the cab. A few months later, the sunroof was leaking for no obvious reason, and it was so bad that I dare not drive in rain nor leave the truck outside. I fitted another outer seal – no difference, and eventually resorted to applying sealant all around the seals and glass just so that I could drive it – and still the water poured in. Disgusted with myself for the sacrilegious act of applying sealant to the roof of an otherwise perfect classic, and disgusted with Land Rover sunroofs in general, I locked the old bus in my workshop and went to cool off; besides, that’s when Covid lockdown started, so I couldn’t drive it anyway.
Good roofs and bad roofs
The steel frame here has rusted severely and broken away where it’s bonded to the glass panel. A complete new and expensive glass panel is the only cure
The best ever glass roof fitted to a Land Rover was the tasty two-section targa top fitted to some late Freelander 1 models. These panels were lifted off and refitted by hand – nice and simple without too much stress on the seals. Discovery 2 made up for that, of course. Anyone owning a D2 with a sunroof could expect trouble, and a D2 with twin sunroofs could be a life’s work.
Warning signs of imminent sunroof trouble include a musty smell inside the car, a tendency for windows to mist up, bubbling of the headlining where the lining fabric has fallen away from the backing material, and spots of mildew on the roof and sun visor material. These can all be caused by damp air from a minor leak; the dampness causes the headlining adhesive to fail and the movement of the car completes the separation. Blocked, nipped or detached drain tubes from the sunroof frame have a similar effect, often causing dampness in carpets. Damp front carpets can also be caused by overflow from an air conditioning condensate drain tube, so it’s worth checking this first by poking a stiff wire up the rubber pipe from under the car. Any of these signs of dampness need quick investigation and repair to avoid damage to the headlining, though they are repairable and new linings are available, but it’s quite a job to remove and refit them.
Test and trace
It’s been suggested that a good way to find water leaks is by spraying a hose over the car while a helper inside checks to see where the water is getting in. But this is a waste of time unless the headlining has been removed first (or the interior trim in the case of body leaks). A better method is to dribble a very small amount of water around the glass seal – small enough so that you can see whether it stays on top or seeps in and, importantly, where it seeps in. With the sunroof assembly dry, and the glass open, a close inspection of the seals may reveal small cuts or splits, especially when squeezing or distending the rubber by hand. The rubber might also be permanently distorted or flattened and/or hardened, through age.
Carefully pouring water into the sunroof drain tube will establish if the tube is clear, assuming all the water runs out of the open end under the car
Drain tubes in the corners of the sunroof frame can be inspected with the glass panel fully opened. A wire poked in will confirm any upper blockage, but it’s difficult to know whether the tube has become detached, split or nipped further down. The clear route down the tube can be confirmed by carefully pouring water into the top of each tube and checking that it all runs out from the pipe end under the vehicle. We’re not covering the mechanism on sliding roofs here, but check that it does shut the roof completely. Any wind noise from the sunroof suggests this is the problem. Twin cable sunroofs such as the Freelander 1’s sliding/tipping version often suffer from problems with the mechanism which might fail to pull the glass down completely after closing, and can also leave the glass slightly skewed.
If none of this finds a problem, it’s best to remove the headlining to find exactly where the water is coming in, and then fix the point of ingress.
Fix or replace
This repro seal has an almost right-angle bend which must be made to fit the curvature of the frame perfectly. Patience and perseverance is needed
Those sunroof cable mechanisms are not worth the time and risk to attempt a repair, so a new mechanism is the answer. And it’s the same with rubber seals: they can’t be successfully patched or glued – just fit a new one and preferably a Genuine Land Rover part which will have the precise fit and compression characteristics. I’ve had good seals from Bristol Sunroofs, too.
One area that’s difficult to inspect is the sealing between the sunroof frame and the vehicle’s roof panel, but leaks here are unlikely and are rare.
This Discovery 2’s sunroof is leaking, and the moisture collects at the lowest point of the headlining where it meets the side trim. It’ll dry, but needs fixing now
Then there’s the damaged headlining. The best action here is to remove it, and thoroughly dry it on a windy day before starting the repair. If the lining has pulled away from the base, it will need to be carefully peeled back from the nearest edge to apply fresh adhesive from an aerosol nozzle before pushing and holding the lining back down. Holding the lining down while the adhesive sets can be tricky because of the roof lining’s contours. But sponges or soft cloths placed to fill the contours and then weighted, should hold the shape until set. Serious damage or, for example, central damage that can’t be reasonably reached from the edges, should be left to a specialist. There’s always the alternative of a new headliner.
Removal of the headlining, whether to repair the lining, check for leakage, or to replace it, is a technically easy task. It’s just a long-winded, fiddly job and, when it finally comes loose, it’s handy to have an extra pair of hands to support it to prevent further damage, especially twisting and kinking of the backing material. The headliner is usually held (on our traditional Land Rovers) by a combination of plastic (usually fir-tree) plugs and by the roof fittings such as mirrors, handles and sun visors. The plastic plugs need a trim removal tool to prise them out without damaging the headlining, and a few of them might break so it’s worth buying some spares.
If the headlining and sun visors are spotted with mildew stains (and this happens in normal use even without a sunroof leak), they can be easily rejuvenated. I use a bathroom cleaner with just a tad of bleach added. Just wipe it over with a sponge, rubbing if needed, then rinse off with clean water. Wear rubber gloves and eye protection for this, and wear overalls because the bleach may white-spot your clothes. This is fine for white headlining, but leave the bleach out if restoring material with any colouring in it and, in all circumstances, test a small inconspicuous area first.
Back to the leaky Ninety...
Of course, I couldn’t leave my restored Ninety in the state described earlier with sealant on the sunroof, let alone water still leaking in. The pictures and captions tell what happened next, while showing how to extract and clean up the front headlining, and a delicate approach to leak investigation. Part of the reason for removing the headlining was to be able to see if water was perhaps entering through the joints of the roof panels – that’s another source of water ingress on pre- and early Defender models.
Desperation: The Ninety as I bought it back in 2016, with the sunroof patched up with gaffer tape, yet still it leaked, soaking the interior.
Long-term effects: The sun visors and headlining were discoloured everywhere with mildew. Despite the headlining sagging all over, it was successfully restored.
Perfect job: The effectively brand new sunroof withstood its first 170 miles through a rainstorm, arriving home bone dry. So why did it fail later?
Staining: The front section of headlining is partly held by the sunroof fittings. Here, the cowl over the sunroof handle is removed – note mildew stains at the left.
Delicate plugs: The sunroof’s internal plastic finisher strip is gently prised away from the sunroof frame, taking care not to break the white plastic clips (easily renewed).
Exposure: We can now see the sunroof’s internal frame. At each corner is a quadrant plate held by a single screw. These plates support the headlining around the sunroof.
Saving time: There’s a front and rear headlining, but this job only needs the front section out. Plugs are released to pull the front edge of the rear section down first.
Take care: The forward edge of the rear section now droops down, so a suitable clean wooden prop is fitted to support it to prevent permanent bending.
Pull the plugs: Now the remaining plugs can be removed, across the overlap with the rear section and along the sides over the doors, having first pulled the door seals away.
Specific trim: On this County model, the upper trim needs to be levered out and a wedge fitted to hold it there while that final plug is removed each side.
Fittings: The sun visors are unscrewed and the mirror levered off before unscrewing its mounting plate. This releases the front of the headliner, though it’s still wedged in place.
Final support: The four corner support plates are now unscrewed from the sunroof frame, and the A-post plastic trims removed, leaving the headlining held in by compression only.
Down and out: The front of the headlining is gently eased off the screen frame and lowered to the dashboard as the rear side corners are eased from the upper plastic trims.
Wet clue: After standing in rain with no headlining, one drip developed on the rear corner of the frame, suggesting water was getting inside the frame, not past the glass seal.
Delicate touch: Water from a pipette was placed on the back edge of the sunroof frame. In this area, the water very slowly disappeared between the frame and the roof.
Feeling around: A feeler gauge found the tiny gap between the roof and sunroof frame. It was only 10mm along the length, but I was convinced this caused the deluge.
Local fix: The cure was to force sealant into the gap using a plastic spreader. It took a lot to fill – there was obviously a clear void right through into the frame.
Headliner refresh: A wipe with mould and mildew remover brought the headlining and visors up like new again after drying in the sun. Still looking good at 33-years old.
So, what caused the leak?
We’d originally fitted this sunroof with new seals to a newly sprayed vehicle roof and thoroughly cleaned all the components. Knowing the tendency for all sunroofs to leak, we’d taken extreme care, using a good layer of adhesive sealant between the sunroof frame and the roof, and tightening the frame down gradually and evenly to the roof. So there seemed no reason for this leak to occur, especially given that after the restoration, this Ninety did a 170-mile shakedown trip in torrential rain and came out bone dry.
Perhaps we’d missed cleaning a tiny part of the roof surface, where the sealant didn’t adhere. My bet is that continued use, road vibrations and chassis/body flexing caused a slight change of shape in the roof at that point, producing a gap that the sealant failed to stretch to fill. Whatever, a check around the sunroof with the feeler gauge is now an unusual part of this truck’s regular service routine.
• For parts and repair: bristolsunroofs.co.uk
• Adhesive sealant for sunroof frame to roof: UPOL Tiger Seal.
• For cleaning spotted headlining and other trim: Dettol mould and mildew remover.
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