How to replace a windscreen on a 1996 750iBy Paul Dean
Tools requiredThese are the main tools I use everyday to fit windscreens at work Dash knifeScraper Safety glovesSingle edged blade scraperPanel toolLatex gloves13mm socket and ratchetSmall dibberLarge dibber Kent tool
We first start inside the car we remove the tax, insurance and mot discs from inside the windscreen. Then we remove the mirror grab the mirror by its support bar and twist anti clock wise.
Now use the small dibber (8) to gentlyPry the tabs on each side of the rainsensor
Now you should end up with something like thisNow with the drivers door open pull On the edging trim to make it easier to Remove the A post cover (non air bag)
In the corner at the bottom of the A post you will see the connectionFor the heating element squeeze the tabs together and pull upwards to Disconnect.
Use the small dibber (8) to removeThe dust caps on the drivers side wiperArm. There are 2 of them then, undo both13mm nuts underneath with the socketAnd ratchet (7)Now lift the dust cover on thePassenger wiper arm and undo the 13mm nut underneath with the socketAnd ratchet (7)
These are pullers, I had to use 2 different types as the driver and passenger wiper Arms are different widths. The one on the left fits the drivers side and the larger oneon the right does the passengers side. The legs grip the under side of the wiper armAnd the threaded part of the tool screws down on to the wiper spindle to apply Pressure to pull the wiper arm off the spindle . These are often sized on.
Now you should be at this stageReady to remove the scuttle or coverUnder the wipers. In the picture you can see the smallRectangular clips that hold the scuttleTo the bulk head. There are 10 to remove.Use the small dibber(8) to lever up theCentre of the clip enough to get the panelTool( 5) in to remove the centre completely.
Once you have the centre part of theClip out, use the small dibber(8) againTo remove the bottom part of the clip,Do this to all the clips and then remove Scuttle.Now you should be at thisStage.
We now go to the 2 side trims1 on each A post. Using your handsLift up the trim, its on locking tabs.Moving down the trim gently liftinguntil its free from all its clips. Use the small dibber(8) pry out the topRubber trim, Be careful it has metal in itAnd can be easily be damaged. I wouldReplace this with a new one but didnt Realise at the time I would need one.But fortunately I was able to reuse it.
Now use the Kent tool (10) to cut outThe top half of the windscreen. I startedCutting out the corner that had too muchGlue, it was very difficult to cut through,A bad sign that there is worse to come.The windscreen on this car had beenReplaced before. As you can see, thisIs a sign that it has been badly done.This excess glue was blocking the pathOf the water flow from the sunroof drain tube on the drivers side.
With the top half of the windscreenCut out we need to cut out the bottomAlong the dash. Using the Dash Knife(1) and some glass cleaner dashOut the bottom of the windscreen. Start in the corners first then alongThe middle. The glass cleaner helpsThe blade of the Dash Knife(1) slideThrough the glue while cutting.
This picture shows that there was wayToo much glue used to bond the oldWindscreen into the car.
As you can see again too much glue was used and no spacers were used toStop the windscreen being pushed down too far making it very difficult to dash Knife out, I ended up breaking the drivers side bottom corner of the windscreenTo remove it from the car.
Use the scraper tool (2) to cut the oldGlue away. Clean any dirt and moisture that mayBe near the glue line. Then using aEtch primer wipe all the way alongThe glue line on the car. This helpsThe new glue to bond to the car.
Take the tin of black top primer and shake it for 30 seconds. Use a swab apply the black top to the car anywhere the old glue is missing and where paint is showing.Also apply black Top primer to any where metal is showing through from whenCutting back the old glue, or where the bond line is missing. Along the bottom of The windscreen bond line use 3 lengths of damming tape. This looks like draft Excluder tape, this stops the new windscreen from being pushed flat and makesIs easier to cut out next time.
This is the new windscreen, part number 2433gngn3 for my car. There are 6 typesIn total, all the same shape but with different features, 2433 is the windscreenNumber. Gn (green) is the glass colour, the second gn (green) is the colour of theTop tint (sun shading). There are different types of sensor, sensor on the glass andA sensor clips to a bracket like mine, hence 3 in the order code. But there is also aDifference in the gap from the mirror boss and rain sensor bracket. which you need To watch Out for, as the cover that clips over the sensor when the sensor is Reattached to the bracket will not fit around the mirror. There are 2 measurements 32mm and 50mm, mine is the 32mm.
Clean the inside of the windscreen With glass cleaner and tissue, thisIs to remove any grime and dirt.Then etch prime the windscreenAround the edge where the glue willBond to the windscreen.Turn the windscreen over and clean, useSome masking tape to hold the electricalConnection out of the way on the inside.Straighten the top trim and fit to the topOf the windscreen. Place 2 pieces ofMasking tape on the top of the windscreenFolded over to be used to hold the Windscreen in place, so it doesnt slideDown while the glue is drying. Not doingThis can let the windscreen slide downAnd cause wind noise or worse leak.
Using the cordless 12v glue gun apply a bead of glue to the old glue lineThe nozzle on the glue gun has a inverted v cut into it, so when you place theWindscreen on to the new glue line it flattens the inverted v to form a evenwidth across the glue. In the factory the robot is able to do this glue line inOne movement with one joint. I cant do this so you have a few joints one at the topAnd in the case of the 7 series the bonnet(hood) is in the way so you end up with3. Using a dibber mix the start and stop points of the glue at each joint to form a Continuous glue line.
Using 2 single suction cup lifters, 1 on each side of the windscreen and a double in theMiddle. Lift the windscreen up and guide the windscreen under the bonnet before Placing in one movement down on the glue lining up the windscreen with the top edgeOf the aperture and side. Use the masking tape closest to you at the top of the screenTape it to the roof to hold the windscreen in place while you then run around the other side and align the windscreen and use the masking tape on that side to holdThe windscreen in place. Then gently push down on the windscreen to make sureIt has contacted the glue evenly all the way around.
Once the windscreen is in place start rebuilding the car starting with the scuttle,The wipers, as a precaution we advise to fit new wiper blades as the old ones May scratch the new windscreen. Then fit the side trims, rain sensor, mirror,Connect the heating element connection, refit A post cover and edging trim.Test wipers and the rain sensor is functioning. Place a new disc holder for the tax, insurance and mot discs. The car can not be driven for 1 hour from when the Windscreen was placed on the glue.
Once the hour has passed remove the masking tape from the roof/windscreen.Inform the customer they can not wash around the windscreen with a power Washer for 3 days. Most cars can be done in 1 hour or less from start to finish,So now you know how its done, I took my 7 for a test later on and no wind Noise great!!!! All set till the next time.
Author and photography
Paul Dean Myse7enThe 7 Series Register