Heated rear window repair.

[Colin Stamp]

Hi all,

I recently bought a second-hand car and, too late to take it back, I've noticed that the bottom half of the HRW doesn't work. Having happily fixed a few in the past using silver-loaded paint I wasn't too concerned, but I looked closely at it today and, rather than the small breaks in the metal layer I was expecting, there seems to be no metal at-all over large lengths of the failed elements. There are translucent sections up to about 20cm long. It doesn't look like damage and I wonder if they were malformed and have never worked. The car is a 59 reg so I'm surprised no-one got it fixed under warranty though.

Any bright ideas on how I might fix this? I very-much doubt whether silver-loaded paint will work. Donkey's years ago, I fitted a "Linwood" HRW kit and was very happy with it. I reckon I could do something with one of those but I can't find anything like it for sale now.

Cheers,

Colin.

[dennis]

Whatever you do be careful not to break it and have to get a new one on the insurance. ;-)

[ARW]

+1

[Adrian]

My guess is that the rear window'd been pimp-tint filmed, which has been removed, taking chunks with it.

Which is the exact reason I have a total of three working elements in the Shogun window...

[Colin Stamp]

I'll try to be careful with the lump hammer whilst I'm tapping the new element into place.

Cheers,

Colin.

[ARW]

Unless you have a garage or do not need the car for a while then don't tap the new element into place until Autoglass or whoever have confirmed that they have a window in stock - it's not unknown for them to take a couple of days to locate one. And remember that a bonded window means you may not be able to use the car for another 12 hours after it is fitted.

[Colin Stamp]

I don't think that's it in this case. The car came with welding-glass in the back as standard.

It could have been some other big sticker though...

Cheers,

Colin.

[fred]

Might be worthwhile touting around various fitters for a non insurance, will leave car at your place all day so you can do it when you like price. That is the way to get the best deal and it may not be much more than your glass excess. Also, it doesn't involve making a claim, yes, it is a claim that has to be declared on changing insurer, even if they say it does not affect your no claims discount.

[Lobster]

Colin Stamp grunted in news:LJudneSKU8iDN- [e-mail]:

Many years ago (pre-ebay) I solved this by buying a new rear hatchback door for my Sierrs from a scrappy for about a fiver; I just swapped the glass with demister wires over to my own car; was very straightforward.

(IIRC I was then particularly chuffed at managing to flog on the wiper motor from the new door for more than I'd paid for the whole door...)

[Bill]

On a slightly related situation a colleague of mine managed the perfect heist of a small statue some years ago.

He had an estate car and managed to reverse into a 3' high pedestal that had a statue of a cherub sitting on top of it. The cherub wobbled and fell through the tailgate glass and laid down in the back of the car, there was next to no noise and no one noticed. He could quite easily have just driven away complete with cherub. It was darned heavy and took two of us to put it back in its' rightful spot. I don't know how he worded the insurance claim, but it must have raised a chuckle somewhere along the line.

Just a pity that there was no CCTV handy, it would have raised a few quid on "You've been framed"

[SteveW]

A group of us were once returning to two cars on two different floors of a car park in Nottingham. We were in front and on the higher floor, when a car drove past us at speed and dived down the down ramp. One of us commented that we hoped the others weren't still on the next down ramp (there were no stairs). Next there were a few squeals and a crash. We ran down and discovered that the car had missed the next down ramp completely and obviously feeling a prat in front of his passengers, the driver had reversed at speed - straight towards our friends. One dived one way, one the other, but the third was stuck in the middle, decided he couldn't get out of the way fast enough either way and went up instead. He landed straight through the rear windscreen of the car that would have otherwise flattened him and we found him half sat, half lying in the boot surrounded by glass and totally unscathed.

SteveW

[fred]

In article , Lobster writes

Man after my own heart, well done.

[Michael Chare]

To remove the battery from my car you have to remove a piece of plastic at the bottom of the front windscreen that covers the wiper motor etc. The plastic is held in place by pushing into a slot just below the glass.

One time I just punched the plastic to get it to go into the slot. A few days some cracks appeared coming from the bottom of the screen. This would have caused an MOT failure. The man from autoglass knew why the glass was broken!

[Colin Stamp]

I'd certainly look into that to keep everything above board if it turns out I can't fix it without a new window. Then, depending on the cost...

Cheers,

Colin.

[Colin Stamp]

Actually, I think I'll try the silver paint after all, perhaps with a single strand of 0.2mm copper wire embedded in it or something.

I'll have to do some rough calcs on resistance. Does anyone know how many W/m^2 the average HRW dissipates?

Cheers,

Colin.

[Andrew Gabriel]

Dad managed to clean one off the rear window of an old Citroen just by using Windowlene to clean it (back when windowlene was a thick pink syrup which came in glass bottles). It didn't initially look different, still having the lines across, but there was no metal left on them.

[Colin Stamp]

Good point. Actually I'd really like to fix the heater myself if possible. Then I'll get that nice warm (and mist-free) feeling of having done it myself.

Cheers,

Colin.

[newshound]

ISTR they are at least ten amps these days. Checking the fuse would give a clue. It's a shame you can no longer buy the "stick-on" ones which were common before HRWs became standard. You probably want nichrome wire rather than copper.

[Colin Stamp]

The HRW and mirror heaters share a 40A fuse. At a total guess, I'd say

15A for the HRW and 5A for the mirrors plus a 50% margin, but it may be sized for the saloon. My estate with its narrower window may be lower.

Still, I'm guessing at around 200W for the whole window. It has 12 elements, so 1.2A per element at 14V, which makes them 12 Ohms. They're

1.2m long, so I need around 10 Ohms per metre to match the (totally guessed) originals.

Yep. I reckon you're right about nichrome. 28SWG looks about right...

Cheers,

Colin.

[Reentrant]

Check your policy. On mine the "glass excess" of £65 only applies to the front windscreen. For any other window, or the sunroof, the full excess applies and it may also count as a declarable claim with loss of NCB at renewal. Normally a front windscreen claim doesn't count.