Restoration of the sunroof on a Volvo 780 Bertone

By Jonas Hagberg

Gothenburg Sweden

This document is created to give you some guidance in how to restore you sunroof in the best way possible with the original parts and in a reasonable budget. Since the sunroof is no longer available from Volvo, it’s up to us enthusiast to unite and do what is possible with the limited parts we have left.

Read though this whole document before you start so you don’t miss out on anything!

Remember to be as careful as you can though out this operation, since even the glass is a rare piece and you don’t want it to get damaged.

 

Tools needed.

-Philips head nr2 screwdriver

– Sharp knife (snap-off knife is to recommend) or a wire (the kind they use to remove windshields)

– Angle grinder or similar with a wire brush

– A good table with a towel on (to lay the removed sunroof on once it’s out)

– A friend as a helping hand

-Camera or cell phone to take pictures along the way as a reminder of how to put it all back.

Removing the sunroof.

  1. Start by opening the sunroof to a 1/3rd way open.
  2. Undo the 3 screws in each corner of the front of the frame the once that holds the plastic console on the side of the frame (part number 26 in the exploded view picture in the end of this document). Be careful with the consoles since you can’t by then new.
  3. Remove the plastic console and close the sunroof again.
  4. Remove the 2 screws along each short side of the frame to release it from the slides.
  5. Ask a friend to help you to carefully lift the sunroof out. Lift the front up slightly and slide it out in an angle.
  6. Place it on a table to analyse the damage.

Disassemble the seal and glass from the frame.

  1. First thing you have to do is to check with you local Volvo pars dealer if there is a new seal in stock or if he can get one ordered.

If not visit www.skandix.com or www.GCP.se. The original parts number is 1376082. (“Sealing strip” as it is called in the catalog)

  1. Once you’ve established that you can find a new seal you can start by removing the old one. If you don’t have a new one remove it carefully so that it can be reinstalled.
  2. Next you separate the glass from the frame. It’s glued on to the frame so you will need to cut through the glue with either a snap-off knife or a wire.
  3. For last remove the rubber strip on glued in the drain channel. See below

Frame damage analysis.

  1. Start by removing as much old glue and paint as possible with the wire brush angle grinder.
  2. Look at the frame to see how corroded it is. The thing to keep in mind is that the most important piece is the drain channel at the back of the frame. This transports the drain water to the larger drain and later to the drain pipes. This drain need to be whole for the water not to leak in your headlining. If you find a hole in this bit as I did on mine mend it by welding in a new piece of metal.
  3. Now look at the rest of the frame. Most frames will be badly corroded in the place where the glass and glue meets the frame. But don’t worry too much about that. Remember that the most visual bits are the edges that’s folded toward the centre of the frame (seen in picture below). If rust is found but it’s not rusted thought then don’t mind more about that and move to the next step. If it’s a hole however then fix it with a new piece of metal and a weld.
  4. The last bit you need to look at is the outer lip of the frame (the bit that the seal was clamped on to) this one needs to be whole all the way around to hold the seal in place once it’s assembled. It it’s rusted through, weld in a piece.

The reason why you should not weld more than necessary is that the metal is very thin and the structure is weak. This will only lead to a frame that’s bent out of shape by the heat.

drainchannelimage

Prepare the frame for paint.

  1. The next step is where the magic happens. You will now have the frame electro galvanized to improve its rust withstanding features in the future.

(Electro galvanization is a method used to put a strong layer of zinc on metal to be used as an anode. This means in practices that the “rust” oxidation will eat of the zinc rather than the metal. Which is a good thing. It’s common to see zinc treated metal in colours of gold and silver. But black is also usually available.)

In this process the frame will be dipped in a bath of lye acid. This acid will attach to the rust particles and anything on the frame that isn’t metal and remove it. But a great tip is to have the most corroded areas cleaned or sandblasted before this process.

The paint used on the old frames can sometimes take long even for the lye acids to clear off. So if you want a perfectly zinced frame back from treatment its best to remove all the paint yourself before with either sandblasting or paint stripper.

This is all down to how pedantic you are. I just focused on the corroded and visible areas and left some of the paint on in areas which later would be covered by other things.

  1. When the frame is back from the zinc treatment you will note that all the rust is replaced by a nice layer of zinc which will stand rust for many years. However, to really give this frame its original look it’s going to be painted matte finished black. But fist attend to any rust pores ore weld repair you have done on the frame (only areas which are visible when it’s assembled) with some Zinc compatible body filler.
  2. Next you paint the frame with a Zinc compatible primer.
  3. Finish of with matte finish back paint.
  4. Glue back the rubber strip in the drain channel

Rustholes

What you can see in this picture is that my finished frame still have a lot of leftover rust holes in the flat surfaces that will be against the glass. The rust pores and further spreading is dealt with by the zinc treatment. If it’s hard to see what I’m on about look at the picture on the page before. All the holes you can see on the flat surface was left as they were. They were only filed them out with the glue later on when the specialist installed the glass.

Glass damage analysis

  1. Now take a look at the glass itself. How damaged is the black surrounding moulded that covers the edge of the glass? Mine was pretty terrible and had worn off in many places.

If yours are as well, follow the next step, otherwise move along to next headline.

  1. Since the black sounding is a type of ceramic moulded made during the process of forming the glass this is hard or close to impossible to redo. My glass specialist tried to apply a special primer to replicate this bit, but the result looked sloppy. The answer was foil wrapping.
  2. Go to a place where they wrap cars in foil or a place which is specialised in making company logos on cars or anything similar and ask them to put a matte black UV resistant foil on the outside of your glass to replicate the black surrounding edge. Don’t place the foil on the inside! Since this is where the glass glue is supposed to go. Once done it will look as my finished product on the picture below.

FoilPicture of one completed sunroof

 Assembly

  1. Once you have your glass, frame and rubber seal sorted it’s time to have it all assembled. There are two ways for this:
  2. Have a glass specialist to do it. The same specialist that will replace a broken windshield would most times gladly assemble you sunroof for a reasonable cost.
  3. DIY! Just remember that this is a bit tricky. You need to find the right glue and primer for the glass. (Primer is for the glue to attach properly to the glass). Also fitting of the seal is a work itself. To get it right in the corners you need a special technique with the heat gun. If you go to hard (heat to much) the seal will melt and look horrible. Then it’s a lot of money wasted.

Assembly by glass specialist

  1. Find a specialist that knows what he is doing. I managed to find one in town which was well understood in my cars rarity and that the parts I gave to him was even more rare and expensive. So he took it on with that in mind.
  2. Remember to point out to them to put some extra glue in the areas on the frame that you left with holes in them (in the areas where the glass meets the frame). When the glass is clamed together with the frame this extra glue will fill the holes and by a light spreading of it with a finger it will look almost invisible ones everything is in place.

Assembly DIY

  1. Find a clean table to work on
  2. Place a towel or anything that will prevent scratching of both frame and glass.
  3. Apply glass primer according to product specification.
  4. Test fit the glass and seal to get the feel of how it’s supposed to fit together. Remember that the seal is supposed to join together at the rear of the frame (at the long side of the frame closest to the drain). Also see that you fit the glass in the right way. Along the long sides of the glass the black surrounding edge is different in thickness. The thin part of the surrounding is supposed to face the drain (rear of the frame/car) as well.
  5. Once you’re happy with the test fit. Take it apart and apply glue.
  6. Lay the glass in place and clamp it down carefully with as little force as possible. Have some piece of cloth or anything else that’s soft in between the clamps and the glass.
  7. Make sure that you leave en equal sized lip of frame around the glass so the seal will fit properly.
  8. Once the glue have dried test fit the seal again. Cut it to size and try to shape the corners with a heat gun. A hairdryer would be the best because it doesn’t get to hot.
  9. Once you are happy take it off again and apply glue on the frame lip and on the rising edge of the glass. Not too much since you don’t want glue on any visible piece of glass.
  10. Remember to put some glue in the edges of the seal (where it joins together)
  11. Work with it so that the best fit is reached.
  12. When the glue is dry you have one complete sunroof in excellent condition.

 

sunroof assmb

Exploded view of the sunroof assembly.

Questions?  Please email info@780coupe.com

 

 

 

By | 2017-11-17T12:49:46+00:00 January 8th, 2016|Home, Uncategorized|3 Comments

3 Comments

  1. Jarle March 24, 2016 at 8:15 pm

    I have an issue With the glass sunroof on my 780 (I dont like the glass !).
    Can it be exchanged with a metal type one that also has the venting option ?

  2. Mika Lagerström April 5, 2016 at 11:32 am

    Hi!

    Great article!

    What glue did you use to attach the seal? I am a bit confused because I have two glasses and in both of them the lip where the seal goes is much wider on the rear side of the car than on the front side. So the sealing is much harder to put in place on the rear side of the car.

    I purchased one seal but I cut it too short and I wasn´t able to put it in place properly. It´s coming off in some places.
    Now I have purchased another and would really like to succeed.

    The professional already sandblasted the frame and glued the glass but putting the seal in place seems to be very difficult…

    Thanks!

    -Mika Lagerström

  3. Jacqueline Manderscheid July 8, 2016 at 8:48 am

    Thank you for this post.
    For some reason the sunroof of my 1991 Volvo 780 (the Coupe) has trouble closing. It operates fine on the track, but the wind shield stays up without my help (manually hold it down) while I am holding the button to slide the window shut. Seal is good. Pretty awesome sunroof for a 25 year old gem of a vehicle.
    Jacqueline Manderscheid
    Boise, Idaho US

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