Maintenance FAQ for 7xx/9xx/90 Cars
Motor/Crank Preventive Maintenance. [Query:] My sunroof
motor has failed. Can I buy a rebuild? [Response: Bruce]
Look into converting it to the manual crank system. The manual gear, crank
and cover are cheaper than the electric motor unit . How many on
this board have had trouble with your sunroof motor sticking in the open
position? They never seem to stick closed, only open. How many have had
the replacement motor fail to operate within 6 to 18 months? For everyone
with a sunroof in a 200, 700 and 900: Remove the crank handle and
tighten the gear assembly screws. For electric sunroofs remove the cover
and tighten the motor mounting screws. They all work loose over time and
will cause the drive teeth and/or the drive cables to bind, wear out or
get the lid out of time and the roof will not close. This little
procedure will save you $100's of dollars.
Won't Retract Properly.
Sunroof Stuck Open: Check Electricals.
[Query] The moonroof on my 95' 940 opened tonight and immediately stuck
in the ventilation position. The switch makes a clicking sound but the
sunroof does not move. The fuse looked fine but I changed it anyway. Any
suggestions? [Response: Rob Bareiss] You wouldn't be the first
person to have a bad sunroof switch in a 740/940 with a power sunroof.
It's likely to be the switch- replacement is pretty straightforward.
Get a new one from Volvo, and it comes with a short piece of cable and
the connector. How do you tell if it's a common failure item? It'll
be IN STOCK at your local dealer (unless they just sold the last one...)
Sunroof Sticks When Closing.
[Symptom: I have a 90 740 GLE and noticed that the sunroof is getting stuck
when trying to close. I took out the motor, lubed everything and the motor
appears to work fine. Also when the sunroof is closed if you look on the
outside it doesn't appear to be sitting flush like it should.] [Diagnosis:]
If your guides are not broken then you may just be out of adjustment. Adjustment
is accomplished by loosening a number of screws, moving the roof and re-tightening.
A Haynes or Bentley manual will help you through. If you do need to remove
the sunroof there is an easy method. Open the roof to the vent position.
Use a screw driver or needle nose pliers to release the springs that hold
the sunroof liner to the roof. Push the liner back into the space where
the roof would normally retract. This will expose all parts, and adjustment
screws. [Response: Rob Abel] Our sunroof in our '93 940 acts goofy
at times. Clicks and doesn't move - gets stuck - usually open - have had
to close it manually by taking off cover and using screwdriver. On ours
it's the switch. I take it out about once every two months, take it apart,
clean up the contacts, and it works fine for the next two months.
The only manual that will adequately address this is the Volvo factory
body manual (Body Fittings: Exterior/ TP 8202201). None of the others do.
Electric Sunroof Stuck Open: Alignment.
[Query] The power sunroof on my '91 940T has stopped functioning, and is
stuck all the way "open" (tilted up, rather) and won't go back down. This
follows a few weeks of CLICCLICKLCLIK when opened/closed, and some erratic
operation. [Response: Kerry] (Applies to 1986 765) With your sunroof in
the vent position you can remove the sunroof liner and check all the bolts
on the mechanism and rail. To remove the liner:
With the liner out of the way you can check
all the bolts and screws and stuff. When I checked mine, I found two screws
VERY loose and one about to fall out. Use some locktite blue on any you
have to tighten up.
Get a coat hanger and cut out the straight
part. Bend the end to form a small hook
Pull the edge of the sunroof liner down at
the end sticking up (remember your sunroof should be in the vent position)
You will see two spring loaded hooks which
are attached to the sunroof liner and hooked to the sunroof. These hold
the liner in place. They are at the back of the sunroof, one left and one
You can unhook them with your coat hanger
The sunroof liner can then be slid back out
of the way (don't push it to far back)under the roof and above the headliner.
The other thing is to remove the cover
from the sunroof motor. There is a large screw with a button in the middle
on the motor assembly. Turning the screw with a screwdriver will depress
the button and allow you to move the sunroof BUT, it also adjusts the stop
location for open and closed.
Sunroof Won't Open to Vent Position.
from Ken Dibnah] If you have a 740 with an electric sunroof, when the roof
is in the fully closed position you should be able to push the closed switch
again and have the rear of the roof pop up to the 'vent' position. If you
have a manual roof, after it reaches the closed position you feel a bit
of resistance; you then continue moving the crank in the closed direction
and the rear of the roof should pop up to the 'vent' position.
If your roof does not move at all, you
must NOT pry up the rear edge manually as there are cast tracks at the
rear of the panel that hold it in place and you will break, bend, or damage
the tracks, roof or the panel.
Most likely it is out of alignment and
too tight for the minimal leverage applied by the motor to move it, as
well as being thoroughly gunked up. The secret to lack of motion is most
likely binding in the up and down motion of the panel. If manual, try moving
the crank back and forth, bearing in mind that the first motion the roof
makes is that up and down motion at the rear of the panel. If there
is resistance to the crank motion immediately, there is 'likely' to not
be any damage in the screw mechanism, just binding of the panel in the
If nothing moves as you move the crank
towards 'vent', push up gently through that small rectangular opening inside
the headliner on the rear of the panel to help it along, by just pushing
it free of the roof. The tracks at the rear of the panel move the panel
up and down, either to pull it down before retracting or to pop the rear
of the panel up for the 'vent' position, and if they are damaged or too
gunked up, they will resist opening. The device that is connected
to the motor/crank via screw cables slides back and forth in these tracks,
raising and lowering the panel, which will not be possible unless you can
move the crank/motor. Try to get it high enough to be able to peer inside
the roof from the outside to unhook the headliner clips - once you get
those, all is revealed and you will be able to see why your roof is not
Sunroof Adjustment. [Tip from Tom Irwin] Most of the posts
I've seen here describe access as through the rear with the roof up in
tilt/vent position. Something about unhooking some springs or clips
to remove the "push back guard(?)" then push back the headliner panel into
the roof....then something about some chingas with a torx screw.
WRONG! Not on this run of 960's anyway.
It took me a while to figure this out, so I hope someone will benefit.
Basically the rear of the roof , when parked, was always about 5mm's below
the roof line, while the leading edge was flush. I can hear this
at highway Speeds.
Don't do anything to the "push back guard",
(not necessary) or look for springs or clips, (there aren't any.)
Just leave the roof in parked position. Push back the panel was far
as it will go without undoing anything. Up on both side of the roof,
parallel to the tracks, you will find one per side of black/grey injection
molded, plastic strips. Lift the lower edges and they snap right out.
Now there are 4 bolts with an 8mm head.
one each at the front and rear of each track, left and right. Loosen
each of these 1/2 of a turn. Push up one corner at a time, til it's
flush with the roof line, then cinch the corresponding bolt tight.
Snap the strips back in place and you are done.
Wind Flap. [Query:] The wind flap (I assume that's what it is)
that pulls down just as the lid docks doesn't pull down far enough and
the lid jams into it preventing complete closure. [Response: Dennis
Jeong ] Tilt the roof up and pull both of the cover flap spring rod
loose (it pulls toward the rear of the car). There is one towards each
upper corner of the cloth cover . Close the roof and pull the inner cover
towards the rear of the car. Check the top of the roof, if it's flush then
look at the adjustable catch on the front edge of the roof panel. It should
not tightly hold down, there should be a little play. There are four
copper colored screw, two per side side. These determine the overall height
of the panel and it's fit. Loosen the front catches then adjust the
copper screws. Play around with it, you'll figure out how it works.
DO NOT FORCE ANYTHING. If you break anything, you'll need to get a used
part. The sunroof mechanicals are sold as a unit only. Very expensive.
Sunroof Repair. [Tip from Warren Bain. See also Ken Didnah's
overhaul tips below.] These are the procedures I used to fix my sunroof.
Mine would not flip up in the back, in fact one side would not flip up,
the other would. The sunroof would retract but would not close without
my help. I determined one control mechanism was broken so I bought both,
since one was bad, the other might not be far behind, and I didn't want
to do this repair twice.
The first and most important step is to
determine the extent of your sunroof problem. Will it move at all, will
it retract ok and not close, will it flip up in the back? I will not discuss
the more involved procedures, cable replacement, sealing strip replacement,
cable sleeve replacement or complete removal of the frame. I will also
not discuss 140's and 240's since I have only experience with 700's. Some
900's have a moonroof, a glass panel instead of stamped steel, like my
965, and I will not address them. I will discuss adjustment and control
When you have determined the extent of
the problem and want to continue, open the sunroof to the ventilation position.
From the outside, release the spring clips from the sunroof lining, a pair
of needle nose pliers works for this.
See it wasn't that bad! Take your time, have
a friend assist, maybe even videotape the entire procedure, just in case.
Close the sunroof.
Pull down on the headliner just forward of
the interior lights.
Pull the sunroof lining back so it is inside
Look at the control mechanisms to determine
the extent of the repair. Are they ok, are screws missing or
are they loose? If the screws are loose, tighten them, if missing, find
If the sunroof needs more extensive repair,
remove all screws and lift out the sunroof.
Remove the electric motor or manual crank.
Doing this will allow for proper control mechanism centering, a procedure
I needed to repeat.
Replace the mechanisms by removing the two
SMALL circlips with a small screwdriver. Do one side at a time so the other
can be used for reference.
Transfer the spring to the new control mechanism
and place the new one where the old one was, make sure the small plastic
covered tab is in it's slot and on top of the flat metal 'spring'.
Replace the circlips, again needle nose pliers
Do the same to the other side.
Align the control mechanisms with the slots
for the small plastic covered tabs, slight back and forth motion works
The control mechanisms should now lay flat
and be loose, not tight under tension. The sunroof is supposed to be closed
You will notice the cranking mechanism is
nothing more than a modified worm gear arrangement.
Make sure the sunroof retracting mounts, up
front and to the side, are properly positioned and as far forward as possible.
Replace the sunroof.
Replace the screws leaving them loose so the
sunroof can be adjusted for height, which will be done now. Do not
try to operate the sunroof at this time since it is loose and the liner
would be pushed back into the bowels of the car never to see the light
Adjust the sunroof height by operating the
sunroof SLIGHTLY in the rearward position and also in the ventilation position,
flipped up in the back.
Close the sunroof and make adjustments. It
should sit down slightly from the roof but there should be no gaps.
Make sure the spring clips are installed in the rear edge of the sunroof
and the large springs are attached to the large pin on the control mechanism.
Apply oil or grease to the control mechanism
slots which should be an annual event. I found one of mine had dried out
grease and was nearly ready to break.
When you are happy with the positioning of
the sunroof, move the liner forward and flip up the sunroof to reattach
the clips to the lining.
Operate the sunroof and enjoy.
Overhaul. [Tips from Ken Dibnah on stuck sunroofs] Is the
roof manual or electric? If it is electric, there may be electrical problems
with switches, wires and fuses, which I will not deal with. Will it open?
My experience with them is the 'tracks' at the rear of the roof that raise
and lower the panel, pot metal I think, break and jam everything up. Also
the roof is rarely cleaned or lubricated: if this is done carefully, the
only thing to do is to replace worn/broken bits and then adjust the 4 adjusting
screws, one at each corner.
You may also have to
replace the sealer that lives around the perimeter of the sliding panel,
as it may not provide the exact clearance required to allow movement yet
I will assume it is
electric and the motor works (that may need an overhaul
- usual motor clean-up with commutator-cleaning and possibly lubrication,
although it may have sealed bearings (most likely)). If it
does not work, remove the panel that covers
it and use the tool that is supplied in the tool kit, inserted in the shaft,
to manually move it. Also, when you look at the motor, there is a guarded-by-paint
screw that I
believe is used to adjust the microswitches,
but I have not observed any change when I fiddled with my own. There may
be an issue with these switches as to positioning when the motor stops,
but bear in mind it is possible to toss the motor and use a crank/manual
version from another model.
Do you know how to
get at the roof? Open up the rear roof part in the vent position and peer
inside. There are 2 clips that are best removed/gripped with needle-nose
pliers, unclip them and these will release the head-liner cover from the
moving panel. Go back inside the car and push the headliner back in its
slot, but not too far in lest it get jammed, as it likes to do; everything
is now revealed.
The panel just sits
on the tracks in the front, and is actually a loose fit. Most likely you
will see that the screw/worm that drives the roof back on either side will
be gummed up with old grease/lube, in typical Volvo fashion; I found that
liberal doses of WD40 loosened the goo so it was possible to remove a lot
of it. Re-lube was done with spray lithium grease, but beware the close
proximity to headliner et al, the grease fairly flies about and careful
masking is required.
If you need to remove
the roof, close it as far as required to reach the rear screws; the screws
at each corner remove easily and the panel then lifts out (I have contemplated
putting in a glass roof like a
780....hmmmm). Put a blanket on the roof
so you have somewhere to set the panel. Taking it off may not be necessary,
but it would make it easier to clean all the tracks. I used a dry stick
lube on the tracks,
but I think something less viscous might
help the operation (perhaps the aforementioned lithium grease?), but I
would worry about getting it on clothing etc. I have a vague memory of
some cables and small springs? I do not have them on my roof, but maybe
on an older one? Other car I worked on was a crank-driven roof on an 85
740 GLE, but I think there was no involvement with these cables, except
to unclip 'em when the panel came out? If yours doesn't have 'em, forgive
my 'old' moment.
If you replace broken
tracks/racks, I would replace them in pairs, as whatever shock that has
caused the roof to fail may have affected both sides. As I recall, they
are involved with split-rings, diabolically
small and determined to shoot far under
The front of the roof
pops up into position only by riding up on the collapsed wind deflector.
There are (2?) rubber snubbers that sit under the deflector, only glued
in, and frequently these have vanished,
therefore not encouraging the roof to
finish in the flush position. The rear pops into place by the action
of the racks, those that are most likely damaged, and its position is adjusted
by the screws that you
remove to take off the panel, as well
as by the position of the worms when the motor shuts off - you can observe
this as the worm should sit in the bottom of the rack, holding it flush,
when the motor
You can remove all
the tracking/guides/bearing surfaces from the car, just by undoing everything
and replacing it in order, but why would you want to? If a worm has broken,
perhaps, but cleaning in situ should suffice.
With the roof out,
your experience should allow you to fix whatever I have neglected to mention.
Look for warping, physical damage etc.
Sunroof Motor Overhaul.
[Tips on Motor and Cam Follower Overhaul]
There have been some comments recently about 740 electric sunroof problems.
My experience with my '90 740 GLE follows. Perhaps it may be of use to
Problem: occasionally, if the sunroof
were opened to either the full back or full tilt position, it would not
be possible to move it out of these positions. When pushing the switch,
the click if the motor solenoid could be heard, but the motor did not operate.
Sometimes, persistence paid off and the roof would close after a few tries,
but on other occasions, the only way to get it to close was to remove the
plastic panel covering the motor and with a large common screwdriver turn
the drive shaft 1/4 turn in the closed direction (as evidenced by movement
of the roof) after which the motor would respond to the switch input.
Diagnosis: I concluded there was a problem
in the switch(es) internal to the motor unit.
Remove the motor as follows:
Remove the two screws holding the plastic
cover (2 #10 torx screws)
With the motor out of the car, remove the
white plastic cover over the switch cam (I'm making up names as I go here).
It is held in place by three snap clips and is easy to remove. This will
reveal a large (2+ in dia) white plastic cam disk that is driven by the
motor/gearbox output gear. On this disk are three cams. There are black
plastic cam followers that activate one microswitch each on the top and
bottom cams. On the middle of the three cams there is a white plastic follower
that moves a plastic leaf that in turn activates both microswitches. The
black cam followers had fairly sharp points that rested on the surface
of the cam, while the white one had a rather blunt point. My conclusion
was that the white one had worn to the point that it no longer activated
the microswitches reliably. To overcome this I glued a piece of cardboard
(as in cereal box, although others may come up with a preferred method)
to the ivory coloured plastic leaf the follower contacts. The cardboard
was positioned so that the follower would contact it, thus compensating
for the presumed wear to the tip of the follower. I then applied some grease
to the surface of the cam with the hope of minimizing further wear and
put everything back together.
Cut the headliner as required to get access
to the motor - only cut areas that will be covered by the plastic cover.
Obviously when the car was built, the motor was installed first and then
covered by the headliner.
Remove two small Phillips screws near
the rear of the motor housing, 1 10mm nut at the front, and one large Phillips
screw that connects the motor ground to the body just in front of the motor
(front and rear refer to the ends of the car that have headlights and brakelights
Withdraw the motor and undo the connector
(may be a little easier said than done depending on the amount of slack
in the cable)
Result: So far the sunroof has operated
100% reliably. I hope my conclusion about wear to the
cam follower was correct and that the
roof will continue to work properly.
[Tips on Motor Electrical Overhaul from
1) If your motor "clicks" but doesn't
move, remove motor cover (2 phillips) and get access to the motor connector
(comes in from left side). The blue and red wires at the two prong
connector should be +12V or –12V depending on sunroof momentary switch
position. If you’re getting proper voltage to the motor verify brown ground
wire is well grounded (very important!). If I recall correctly an
improperly grounded motor will “click” but not move.
2) You will be removing the motor so it
would be best to put sunroof in vent or closed position with a screwdriver
on the manual override. Either of these two positions will
allow the motor and sunroof to be timed correctly when reinstalling the
3) If voltage and ground check out – reconnect
connector and unscrew (2 phillips) and unbolt nut (10mm) and let motor
hang (not a good idea but what the heck). Now test the motor while
electrically connected including the ground. Again, make sure the
ground is well grounded. BTW, if the motor moves you will have to
retime the motor :-) more on this later. If the motor works normally it
is likely your sunroof is binding and you should drop the headliner and
dive headfirst into that problem.
4) If motor still just clicks test the
motor itself by putting 12V across the actual motor terminals (not the
connector) and see if the motor runs smoothly. Reverse polarity to
verify both directions.
A properly working motor will rotate
(as seen from the bottom and in vent position) CCW about 1 turn to closed,
pause, push SR button again and CCW about 8 turns to full open. Not exactly
sure about # of turns.
If the motor still just clicks then it
will likely one of the two microswitches located in the timing gear cover.
1) Pop off the three tabs and carefully
rotate the white nylon cover out of the metal motor case leaving the motor
wiring connected. This plastic cover contains two microswitches,
a selenoid (remember "click") and three small pointed plungers. FYI:
These plungers are actuated by the sunroof motor driven timing gear which
remains in the case. The timing gear has three alignment points on three
levels which correspond to vent, closed and full open. The center
point on the middle level is "closed." This will help when you retime
2) Remove the micoswitch holder pin at
the corner (some have a slot to adjust switch position and small retainer
clip) and remove the microswitches as a pair (they are soldered together).
They can be removed without removing anything else by using a small jewelers
screwdriver to move the microswitch plungers out of the way of the selenoid
actuator. Now, use photographic memory or paper to record colors
of wires on each switch (you'll be sorry if you don't). Unsolder just one
side of the common copper ribbon holding the microswitches together (just
one side is good, leave the other side attached to the other switch). Then
unsolder the remaining wiring (two black leads) which hold the switches
to the selenoid.
3) With switches free test each one for
high resistance through the normally closed circuit – the front (blue or
red) connections to side terminals. My switch had 63 Ohms across these
terminals when they should've been around 1-2 Ohms.
At this point you should find a bad microswitch.
You can repair (as below) or replace from a good electronics store (i.e.
not Radio Shack) be sure to get a switch with lug terminals not spade
type. Spade type will not fit when placing switches back into the
4) Now open switch case by carefully drilling
out one side of two small metal retaining rivets. Punch rivets through
with small screwdriver. Open case carefully to avoid spring, switch
assembly from flying behind/over/under workbench. Sand contacts lightly
with sandpaper. Reassemble case and epoxy switch case cover (you'll never
do this again). Resolder switches and reassemble them into the cover.
5) Turn the motor manually with a screwdriver
to ensure the three level plunger in the cover will fall somewhere between
the three timing points on the timing gear. But don’t align the gear
points directly with the three level plunger – they will interfere when
putting the cover back on. Replace the cover which contains the microswitches
and selenoid onto the motor case.
6) I suppose now would be a good time to
bench test the motor. If no 12V supply is available (I use an old
Sun computer power supply) test in the car (see below).
Retiming motor (electrically installed
1) Make sure motor is electrically connected
to sunroof connector and ground. Now, run motor CW (as seen from
below) until it stops, push on momentary switch again. If no movement
then motor is in vent position.
2) If sunroof is in vent position motor
can be reinstalled. If sunroof is in closed position push sunroof
button to rotate the motor CCW to the closed position. Now the motor can
be reinstalled. This may take some trial and error but if the motor
is working correctly you’ll figure it out eventually – HeHe.
Won't Stop at Close: Motor Defective. [Query:] My sunroof
will not stop in the closed position and therfore the user must get out
and look at the roof to make sure it is closed properly. The local dealer
says the "stop" mechanism in the motor has failed and the only solution
is to replace the motor or live with the nuisance. [Response: Rob
Bareiss] Replace the motor or live with it. You might get lucky and
find a good one in a junkyard. If that fails locally, try calling
the used parts suppliers who advertise at the Brickboard. They have more
nationwide connections. I will bet that they won't guarantee one of those
motors once it's out of their sight. Alternately you can bite the bullet
and buy the $300 motor new from your friendly local dealer. Seems to be
happening to a lot of '88's lately. Can't guess why except they're about
the right age to fail, and they're among the earliest cars to have this
Replace Motor with Crank. [Query:] My sunroof motor has died
and I do not want to spend $400-500 to replace with a new Volvo motor.
Can a manual sunroof crank device replace an existing sunroof motor? How
extensive is it to perform, or is it a square peg into a round hole...
Do you know of a good aftermarket manual crank or motor unit available?
[Response: W. Bain] I have a manual crank in my '86 744Ti and it
is blissful. My 965 has an electric motor. Go to the junkyard and find
one with a manual crank, remove the handle, the plastic trim section where
your motor would be, the crank fits in there, the gear mechanism and keep
ALL screws. Make sure the sunroof control mechanisms are good and the sunroof
itself sits in the roof properly, i.e. flat and level. The crank mechanism
needs to be centered properly otherwise i will need to be re-centered.
Screw the crank mechanism into the frame, add the plastic cover and then
the crank itself.
[Query:] We just got an 89 740GL, the owner said that the sunroof only
leaked when washed with a high pressure spray. This is not the case,
it just rained and the headliner is wet. I looked at the seal? if
that's the black strip that goes around the whole sunroof, it seemed ok.
I'd imagine that the water goes past that seal and into that black gutter
type thing on the aft side and drains overboard. I don't have a manual
yet so I'm not sure how this is supposed to work. [Response:
Tony Stanley] If its a factory fitted sunroof the 'seal' is not to meant
to be a perfect seal and the gutter should carry away the water.
The chances are the drain is blocked, or the hose is kinked. They
drain to the front and rear. The front goes down the A pillars flowing
out behind the front wheel, the rear goes out the C pillars and down the
rear quarter panel, flowing out behind the wheel. [Response: Dick]
Front drain holes are in the front corners---a little compressed air will
help to clear them. The rear drain holes are not easily gotten to from
the sunroof as they go down way in the back corners. Best suggestion is
to get at drain pipes in the trunk. Can use a shop vac to suck the hoses
clear---those comming from the top, and blast those going down. You will
have to separate the hoses in the trunk.
FAQ for 7xx/9xx/90 Cars
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