geolab

To remove the Windshield and the rear windscreen, few approaches are considered by repair facilities in general.
1- Windshield replacement,
2- Windshield staying, and the contour treated for rust.
3- Replacement and rust treatment

In this DIY, the option is number 3 for front Windshield, thus removing and replacing the front + rust treatment,
and number 2 for rear, thus removing- treating rust, and remounting same windscreen.

Each approach is slightly different....

The tools needed for both is :

1- Cold Knife with 4.5 centimeters clearance height. The clearance is needed for the rear top windscreen area, for the knife not to touch the metal sheet.
2- Tough strong threaded tape for covering all areas not to scratch metal.
Choose a contrast color for the tape, from the color of your car, would be clearer.
3- 2.5 centimeters Putty knife (file the edge to cut like blade)
4- cheap rotary grinder
5- Set of stitch cutter blades would be handful, they come in all forms, and mount on a pen-like handle.

To start, the majority of the time spent is in the preparation of the cold knife and its blades.
The most important thing in all the DIY is the cold knife.

The blades of the cold knife are L shaped, and they come unsharpened.
To sharpen the blades, you need the bench rotary grinder
I toured the web, and watched all cold knife videos to learn how to sharpen the blades on a grinder.
I realised that ALL the cold knife demo videos, teach you to grind the cold knife blade from the bottom of the L shape, which is logic....
You place the bottom of the blade on a running grinder stone, with an angle, and the grinder sharpens the blade to a cutter. No need to force, gently , because the grinding stone eats the blade like butter. Do wear Protection gloves, glasses etc.

VERY IMPORTANT:
When You Sharpen the L blade from the bottom, the cutting angle of the blade forces the blade to move upwards when pulling the cold knife.
This is the way to go when you want to change the windshield, or my option number 3.
Because of the grinding angle, the blade flows upward, and at instances, would reach and cut a bit of the windshield plastic contour.

If the windhield stays, or my option number 2, the L shaped blade has to be grinded from the INSIDE, as in the picture.
Thus, the angle would make the blade flow downwards, to the metal contour, and impossible to touch the windshield.
The blade should be grinded and sharpened to a razor finish.
I test the blade on a piece of paper, and when it slices through, you are ready.

As of my experience, i would always use a blade grinded from the inside, with a downward flow, even if it scratches the metal, unless the metal is not to be treated. By treated I mean ZERO treated.
My Rear OEM windscreen showed zero rust, even after windscreen removal. As I was going to go for a full respray, I ground down to metal and FOUND two 5 mm rust spots. Sarcastically I was happy I found rust, and going to bare metal was a good choice.

For front windshield, remove top dash, and unclip antenna.
Remove all rubber seals inside out.
With all area masked with tape, introduce blade sideways from area with largest gap between metal and windshield, blade tip towards you of course.
Twisting gently the cold knife clockwise and towards you a few millimeters, introduce the blade tip in the urethane. Go very gently...if it blocks, go back out, and re-do.
The Blade in, start by pulling a bit to get the feel.
You will notice it is really easy and the urethane feels buttery.
Now pull the knife around the whole contour, and you're done.
Warning: at any moment the blade is stuck, you are out of the urethane.
Go backwards a bit and retrace the cut in the middle of the urethane.
It should always feel soft and easy.
I sharpened my blade TWICE through each windshield. When you want to sharpen the blade again, slide back the blade all the way till its entrance spot, unless you fall on a gap, through the way.
You will laugh when you know how easy it went when you finish.

For the rear windshield, I started as per workshop manual from passenger top side - until driver top side.
Stopped and lifted the bottom of the windscreen a few millimeters with a rag,
and cut the top.
the rear windscreen took 5 minutes after I learnt on the front one.
enjoy

geolab

here is the video, shot in cold weather...

fuch

Well done!!

If you ever need work in the uk you can come and help me out...

bravo20

Thank-you for taking the time to well document these procedures,great detail.

IXLR8

Good info, George.

Were you able to cut the windscreen out without scraping the paint and zinc undercoat under the screen and edges? That is what worries me and why I don't really want to leave this job to a shop when the time comes.

Looked at the video, but was unsure of what you were doing along the way in each step.

geolab

For the front Windshield, I did not care about the windshield, so this is why I grinded the blade knife edge, from outside so the blade pulled up towards windscreen whilst I was pulling.

For the rear, I grinded the blade angle from inside, and the urethane was cut in the middle, never touching windscreen, or metal.
My rear windscreen was original mount, and I am going to reinstall it.
The zinc undercoat is a thin layer on the glass. If you arrive at this layer, your windscreen is useless.

1- removed front windshield
removed headliner clips,
retrieved the headliner from windshield contour,
taped the contour
2- Covered contour area for cleaning
cleaned countour area until bare metal
treated metal and etched surface
3- removing rear windscreen
started on upper right
stopped at upper left
placed rag under bottom windscreen to raise it a few millimeters
(you could see in the video the stuck cold knife bends whilst raising the windscreen )
cut the top of windscreen.
4- cleaned rear contour to bare metal and etched surface
5- PPG D831 etch primer
6- PPG D834 (dp40 or dp4000)

the cleaning and etching I omited from the movie because it is useless watching someone scratch I presume
the suction cups were here for nothing, I placed them thinking the windshield was heavy, maximum 3 kilos
fooled me twice, placed them on the rear two

voila

IXLR8

I was referring to the zinc primer (at least I hope it is a zinc-rich primer) under the paint, but if you don't scratch the paint in the process, it isn't an issue.

I only asked because a shop that installed a windshield on a less than two-year-old friend's car must have really taken their time in the installation. The windshield frame was rusting less than a year later.

How easy does the remaining urethane compound clean up around the windshield frame? Did you use any specific product?

geolab

Yes the etch primer is in the video.
there is a very thin zinc or tin solder on the glass itself, about 2 - 3 mm, running around the edge of the windscreen from inside. I thought you meant that.

The remaining urethane cuts like butter with a blade cutter.
You should keep about 2 mm if you do not want to treat the contour metal.
do not try to rip the remaining urethane if you do not want tor treat the metal. It will bring the paint and primer with it.
As I went to bare metal, I pulled on the urethane sticking on the paint, it took out the whole paint/primer with it on several spots.
I am talking about the original factory mounted urethane here.
take a brand new cutter, and shave it regularly with long steady cuts, no problem...


They must have used the electric or pneumatic blade.
I am testing for rust progression
I took a piece I cut from the rear fenders, factory painted
you know the pieces I took off, for the turbo S fender ducts.
I took the metal down to bare metal in Mid-May, in the bottom picture, degreased it twice, and placed a hefty drop of water each week since on the same spot, and let it sit.
Practically four months, you could see the rust progression, it is not huge me thinks.
ps: you could distinguish original paint-primer-galvanisation (light blue color)

geolab

for contour surface cleaning and treatment, I tested a handful of treatments to remove the urethane. The best products renders the urethane softer, thus useless.
Useless because you need the urethane hard to be easier to remove with the putty knife.
As for the metal, best is dremel.
I tried even sandblasting, and it is not effective....
So down to bare metal
Phosphoric etching 2-3 days, with several coats.
degreasing - degreasing - degreasing
Zinc phosphate primer
Seal primer with epoxy phosphated primer
then paint

geolab

painted

IXLR8

George, what is that cut-out in the windshield support for and the hole next to it? Is that for the antenna wire?

You know, this method of window installation has been used on cars for a while now. My daily driver Honda has been through thirteen harsh winters and no rust, but then it doesn't have that rubber trim covering it up and retaining moisture.

Elonash

Awesome !!! I was really waiting for this post

Georges do you mean there is NO way to remove the front windshield without damages in order to reinstall it afterwards ?

Thanks for this precious diy

Elo

Neil Perry

Hi Alex,
The cut-out is for the radio antenna wire from the front windscreen,
it plugs into a connector behind the clock.

Neil

geolab

Hello Elo, all I have explained, is how to remove the windshield without damage to anything.
In my case, I did not care for the front windshield.
But if you want to reinstall the same windshield, like I am doing for the rear windscreen, there is no problem. Follow the DIY above.

You could see in the pictures and video, I have removed the front and rear windshields without masking anything, because I was going to repaint the car.
But even without masking tape, I did not scratch anything.
prepare the cold knife blade well, and you will scratch nothing.
But mask the area for peace of mind

Neil Perry

Hi George,
Great write-up, you have proven that it is possible to remove and install the front and rear glass, without damage.
From my experience with others doing the work (so called professionals), I thought it was impossible.
I guess that it just takes time

If I ever need new front or rear glass,
and seeing what you have achieved, I will be doing it myself, with a far better job and way less grief.

Thanks for your great write-up.
This is a great place

Neil