BN4 Windscreen Shims?

[Bugeyze]

After around 12 months since installation I have a cracked screen, I have ordered a replacement and before I fit it does anyone have any tips, suggestions to prevent this happening again.
Screen is triplex and was installed with new brackets and seals, I made shims for both sides and they are installed 2 left and 2 right, when I purchased the car it didn't have a screen so I have no idea of the original configuration.
Soft top was up and car outside on a wet night.

All suggestions appreciated.

Thank, Graham.

 

[Bugeyze]

Re: BN4 Screen shims??????????



This may help.

 

[DerekJ]

Re: BN4 Screen shims??????????

Are you referring to the shims that fit between the windscreen posts and the bulkhead where the fastening bolts are located? If so there may be some trial and error involved as these bodies were never exact and may have undergone some structural changes over 50 years or so.

 

[Deleted member 19315]

Re: BN4 Screen shims??????????

Are you referring to the shims that fit between the windscreen posts and the bulkhead where the fastening bolts are located? If so there may be some trial and error involved as these bodies were never exact and may have undergone some structural changes over 50 years or so.

I agree. When refitting my BN4 screen the screen pillar shims ended up with 2 on the off side and 1 on the nearside. I thinks its important not to inadvertently have one pillar leaning back further than the other when they are tightened . It seems to me that this could try to twist the flat screen and lead to such a crack. Mine is apart again at present while the body is refreshed so I may come to regret touching it again if mine too breaks on re-assembly.

 

[Bob_Spidell]

Re: BN4 Screen shims??????????

I'm replacing my BJ8's windshield which, of course, is a different animal, but I've noticed all mounting screws that could possibly touch the edge of the glass were short--almost too short, IMO, for strength--to guarantee they would not contact the glass. I think if anything besides the glazing rubber could contact the edge of the glass it would create a stress point from which a crack could ensue.

 

[Brinkerhoff]

Re: BN4 Screen shims??????????

The top shouldn't be so "tight" that you have to push the windshield back with the palm of your hand so it can be latched.

 

[Jack T]

Re: BN4 Screen shims??????????

Wow, that picture has me worried. I just installed mine and had to put some extra pressure on that corner to get the windshield frame lined up with the pillar. I had shimmed and positioned the pillars after test-fitting the windshield in the frame without the bottom weatherstrip. After installing the weatherstrip, I had to 'persuade' the lower right corner in so that I could attach the frame to the pillar.

What is the dimension of the new glass you buy these days? My original glass measures a full 1/4" thick. I couldn't get the new glazing rubber to fit, went to a local auto glass shop and they had glazing rubber that was about half as thick. It worked like a charm.

 

[Bugeyze]

Re: BN4 Screen shims??????????

Thanks for your replies,
derekj, yes the shims between the posts and bulkhead, I fitted the whole windscreen assembly with the bolts into the bulkhead loose, then made shims with slots to fit around the bolts, filled gaps between post and bulkhead both sides of car and then tightened.

Haasad, do you mean by leaning back, leaning toward or away from the body? I'm not sure how wrong shimming would make it lean forward or back.

Bob, the crack does appear to start very close to one of the corner bracket screws, this will be my first check on disassembly.

Jack T, I'm not sure of the dimensions, old screen still fitted and new one should be here tomorrow.

 

[Jack T]

Re: BN4 Screen shims??????????

Thanks for your replies,
derekj, yes the shims between the posts and bulkhead, I fitted the whole windscreen assembly with the bolts into the bulkhead loose, then made shims with slots to fit around the bolts, filled gaps between post and bulkhead both sides of car and then tightened.

Just my opinion, but I think my method of firmly fitting the posts first, making sure the screen will fit at both sides with no stress, may be better than fitting the entire assembly in one operation. Final tightening of the posts could put some stress in the assembly that is not immediately apparent.

 

[Deleted member 19315]

Re: BN4 Screen shims??????????

Jack yes that makes sense . I was trying to say that if the pillars were out of line with each other it may induce a twist across the screen which could cracking it. Hope that makes better sense.

 

[Bugeyze]

Re: BN4 Screen shims??????????

Jack, I like your method, for final assemly did you have to loosen the pillars to insert the bottom weather strip under the "foot" of pillar?

 

[Jack T]

Re: BN4 Screen shims??????????

Jack, I like your method, for final assemly did you have to loosen the pillars to insert the bottom weather strip under the "foot" of pillar?

No, I installed the seals under the pillars prior to final tightening. I used trim adhesive to attach the seals to the base of the pillars to keep them in place while I adjusted them. Throughout the process I test-fitted the screen/frame assembly several times to arrive at the proper position of the pillars.

 

[Bugeyze]

Re: BN4 Screen Shims?

Well another year another screen, car was put away last November in a Carcoon, soft top up, taken out of hibernation today and screen is broken RH side again. After replacing screen last I year did many miles, some on rough roads with top up at times, with no problems. new screen ordered.

 

[Bugeyze]

Windscreen replaced, it lasted 2 days then cracked in the same place, hours spent fitting / removing / fitting frame with the cracked glass looking to find where and why it was being stressed. The problem was the rubber on the leading edge of the sidescreen was bumping the pillar forward when the door was closed. Rubber trimmed and screen replaced (2 weeks so far) all looking good.