DIY windscreen replacement

[Mr MXT]

The windscreen on my mk2 track only MX5 has smashed and needs replacing. Obviously it isn’t insured and Autoglass want £520 for the privilege.

Is it a DIYable job if I can get hold of a second hand screen?

[Pastor Of Muppets]

If you are a hands on type it's not overly difficult, removing an undamaged screen say if you needed it for another car can be a challenge,
if you can remove the old screen then you can replace it, plenty details online, you will need a helper though.

[The Road Crew]

Make sure your get the proper adhesive! Black silicone isn't going to cut it... Properly bonded screen forms part of the cars crash structure.

I'd happily have a bash at fitting one into a track car.

[t400ble]

Find a local fitter to do it

[V8covin]

The Road Crew said:

Make sure your get the proper adhesive! Black silicone isn't going to cut it... Properly bonded screen forms part of the cars crash structure.

I'd happily have a bash at fitting one into a track car.

Not just the adhesive,need the primer too

[E-bmw]

Youtube will likely have a few videos showing the details.

Autoglass can normally be beaten by some significant margin.

Consider buying a second hand one & getting a local place to fit it.

https://www.ebay.co.uk/itm/182061148609?fits=Model...

[Glassman]

Fag packet maths:

Windscreen: 85.00
Trim: 15.00
Adhesive Kit: 25.00
Tools: 30.00

Advantages: you could have fun with it and it's in the spirit of DIY-ing something on your car.

Downsides: If you've not done it before, there's a lot that can go wrong. Very wrong. You will also have to collect the windscreen (if from the suggested ebay seller above, that'll be Leeds). Plus, after spending a couple of hundred quid, it might need redoing if it goes badly.

A Mazda screen supplied and fitted by a local independent will be about the same sort of money. He might even be an enthusiast.

[Glassman]

The Road Crew said:

Properly bonded screen forms part of the cars crash structure.

Whilst torsional stiffness does come under that heading, it's not really as critical as it sounds. For example, a properly bonded windscreen is vital for the containment of airbags.

During my career of fitting windscreens I've seen more than a few badly fitted windscreens. To date, haven't heard one story of a badly fitted windscreen being cited as a cause for anything to justify these statements.

[Mr MXT]

Thanks everyone.

Glassman said:

Fag packet maths:

Windscreen: 85.00
Trim: 15.00
Adhesive Kit: 25.00
Tools: 30.00

Advantages: you could have fun with it and it's in the spirit of DIY-ing something on your car.

Downsides: If you've not done it before, there's a lot that can go wrong. Very wrong. You will also have to collect the windscreen (if from the suggested ebay seller above, that'll be Leeds). Plus, after spending a couple of hundred quid, it might need redoing if it goes badly.

A Mazda screen supplied and fitted by a local independent will be about the same sort of money. He might even be an enthusiast.

Glassman - can you give me examples of what might go wrong that I might not have considered? Aside from cracking the screen, I’m thinking things like the screen leaking, the trim getting damaged or the adhesive looking unsightly, all of which I can live with.

It might be fun to give it a go…

[Glassman]

Mr MXT said:

Glassman - can you give me examples of what might go wrong that I might not have considered? Aside from cracking the screen, I’m thinking things like the screen leaking, the trim getting damaged or the adhesive looking unsightly, all of which I can live with.

It might be fun to give it a go…

It's a track-only car so I can see why you'd want to give it a go and not care too much about finesse.

As a going wrong guide, the cutting out will depend on two main factors: the fit of the damaged screen you are about to remove, and what tool(s) you use.

If it's the factory fit, the adhesive will be soft and easy to cut through, but you have to remove the trim first. Warming it up to soften it will help. Some trims do harden with age and so the heat gun approach will really help. Tackling it with a knife (many in the trade will) will cost you a few blades and you'll score the paintwork. I know you're probably not that bothered but it's just not good to scratch a car; any car.

Cutting the goalpost shape will be easier than the bottom. If you use a cold knife, you won't cut much along the bottom with one of them, especially when you get to the corners. The cold knife is effective if you have the correct technique (and it's not having a sharper blade if you're struggling to move the tool along). Wiring might be best for DIY. You might need an assistant but again, technique: it's all about angles not power.

Cutting back is best done with a chisel taking care to leave ~0.5mm of the old urethane on the pinchweld.

Most if not all aftermarket windscreens are heavily contaminated with a silicon-based product (from the final manufacturing process) and this will need to be neutralised with an appropriate cleaner. In the trade we have specific products for this. I'm not aware of what is available retail (BMW sell a cleaner which is a degreaser formulated to use as a pre prep wipe).

I would also think about using a 12-15mm 'universal' trim as the specific MX5 trim needs to be pushed in after the screen is fitted. You'll also need damming tape for the original-style trim.

Overall, it's the safety aspect when cutting out. Kevlar gloves, protective sleeves and goggles will be a good start. The most cuts I got were in the early days and just when I got complacent.

The rest is about prep and using the right products.

PUR is no good without primer (unless you use a primer-less product like Sika). Primer (or PUR) is no good on a contaminated substrate.

Might be a good thread to start? If you do let me know and I'll happily point you in the right direction for products and tools. You could end up paying way over the odds buying from some sellers.

[Leptons]

I’d speak to some smaller independents first. I had a Screen put in my Vivaro last year for £130. Obviously a much bigger screen than an MX5!

[ShampooEfficient]

Track car? Cut the whole front screen off and fit a little fly screen.

[Glassman]

Leptons said:

I’d speak to some smaller independents first. I had a Screen put in my Vivaro last year for £130. Obviously a much bigger screen than an MX5!

He/they couldn't have had much of a margin at 130.

Not the hardest screen to do by any means, but there's still a bit of graft involved.

[abzmike]

Having stood watching a fitter at work, although it doesn’t look difficult, there is a strong element of ‘the knack’.... how hard to pull at fittings, how to release seals, how much adhesive to use etc.

[PhillipM]

Glassman said:

PUR is no good without primer (unless you use a primer-less product like Sika). Primer (or PUR) is no good on a contaminated substrate.

Might be a good thread to start? If you do let me know and I'll happily point you in the right direction for products and tools. You could end up paying way over the odds buying from some sellers.

Just to hijack the thread slightly but do you know anywhere I can get small quanties of silane primer for glass? Need to fit a windscreen to the buggy shortly and none of the fitters around here want to touch anything that isn't just a normal job, look like doing it ourselves again, struggling to find the primer in anything other than trade size bottles though.

[Mr MXT]

To round off the thread, I found a new screen on ebay for £80 and a local fitter who would fit it for £50. At that price it doesnt seem worth having a go myself!

Autoglass are taking the p*ss with their pricing structure!

[Panamax]

Mr MXT said:

To round off the thread, I found a new screen on ebay for £80 and a local fitter who would fit it for £50. At that price it doesn't seem worth having a go myself!

Exactly. Good result. £50 including materials, disposal of the old screen and 20% VAT is a bargain and a half. He's not making much of a living out of that.

As regards Autoglass my understanding is they supply new windscreens and fit them neatly into road cars. £520 doesn't sound out of order to me.

[Glassman]

PhillipM said:

Just to hijack the thread slightly but do you know anywhere I can get small quanties of silane primer for glass? Need to fit a windscreen to the buggy shortly and none of the fitters around here want to touch anything that isn't just a normal job, look like doing it ourselves again, struggling to find the primer in anything other than trade size bottles though.

It would have to be compatible with the adhesive you're using. I wouldn't advise cross-use.

Take this to email if you like?

[PhillipM]

Just a moisture cure polyurethane, but yes, might save cluttering here!

[drmotorsport]

I've replaced windscreens and glass with polycarb on my racecars over the years. Hardest part is cutting the glass out without cracking it (on a donor car), and slicing yourself up or the paintwork. Cut the old adhesive back to a very thin coating and degrease. Apply new warmed up PU adhesive to the car and prime new glass if necessary (I use the Wayside kits from Ebay). Plonk your new window in the car and carefully press to ensure good contact. Apply tape to hold in place while setting.