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  1. #1
    FEP Power Member 85stanggt's Avatar
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    Default Cracks in Dash Hull - Cause? and Repair

    Haven't been on in quite a while. But I noticed this in the Stang a few weeks ago and meant to post. It started with just one and now there are two!

    I did see this has happened to others and their various techniques used to repair. My repair plan is to use orthodontic acrylic, which is great for gluing plastics and is extremely strong. Since the cracks are at the early stage, I can push in from the front of the dash and they meet perfectly together and virtually disappear. I was hoping to glue from behind and not require any finishing on the front.

    My real question for posting this is WHY is this happening? I was concerned that a support for my dash maybe loosened and the weight of the dash over bumps caused flex and then these cracks. Is it just the crappy plastic or is there something else going on?

    Here are some pictures (first with no flash, second with flash):



    1985 Mustang GT Convertible
    Stock and original @ 213k, except for dynomax ultraflos.

  2. #2

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    My '86 has a smaller crack in the same, exact location.

  3. #3
    FEP Super Member Gemini1999's Avatar
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    Have you pulled the dash out multiple times?
    Bryan

    1983 Mustang GLX Convertible
    1984 Mustang Turbo GT Convertible

  4. #4

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    Quote Originally Posted by rose62 View Post
    My '86 has a smaller crack in the same, exact location.
    DITTO - on an '85. Single crack. I wasn't concerned. Now I am. Dash as never been out.

  5. #5

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    I have had three '85 Mustangs over the years. Every one of them had the same cracks. One even had a hole left in it when the two cracks eventually merged. I have tried repairing the cracks from the back and the front with epoxy, but a new crack would form next to the original after a few years. Surely, somebody on here has figured out a solution.

  6. #6
    FEP Super Member JTurbo's Avatar
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    I have 4 cars right now. The only one that has cracks in the dash hull is the 86 GT vert.

    I wonder if being a vert with additional chassis flex is part of the problem....
    1979 Indy Pace Car Mustang 302 / 5spd
    1982 Mustang GT T-Top 302 / 4spd
    1986 SVO Mustang - 1C

  7. #7

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    Quote Originally Posted by dwbarnes View Post
    I have had three '85 Mustangs over the years. Every one of them had the same cracks. One even had a hole left in it when the two cracks eventually merged. I have tried repairing the cracks from the back and the front with epoxy, but a new crack would form next to the original after a few years. Surely, somebody on here has figured out a solution.
    You have never owned a motorcycle with plastic fairings on it. You have to stop-drill cracks in plastic or they will run forever. I haven't actually done a search but I imagine if you google how to stop-drill a crack something will come up. It works.
    Also, I imagine a lot of cracks are caused by people who don't totally remove the dash to swap the heater core and leave it hanging there. One of mine that I have owned since 1986 (and put several cores in over the years) has no cracks and the other was cracked when I got it. I think my repair looks okay. Not perfect but you haven't seen the car, LOL. It's FAR from perfect everywhere else.












  8. #8

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    I have a spare dash that was given to me for free because its all busted up. I think I am going to experiment with it before I pull the dash out of my T-top and make the repairs to it. Homer302's fix looks better than most I have seen over the years.

  9. #9

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    Afaik, the dashes break for the same reason that the windshields crack. Over time, torque delivery takes its toll on a car body- especially if it wasn't braced up with subframe connectors and strut tower brace, etc.

    straight connectors that get welded at the rear then jacked into place will provide more support than connectors pre-bent to the ideal shape that would have been needed when the body was new.

    At one time my 86GT had a broken windshield, a popped dash, and a 1 7/8" twist in the body when it was just sitting there without any torque being applied. And cracks in the floorpan to match too.

    I took it to a frame shop. They pulled the body back straight, repaired the floor, ground out and welded weakened areas where the rockers and floor meet, replaced the windshield using the proper adhesive, installed weld in subframe connectors that were welded in back then bolted to the rear seat mounts and heated and jacked into place.

    It made all the difference in the world. Some foxes just weren't built all that well from the factory.

    One little dent in the beer can and it looses all strength until it's properly straightened, relieved, and reattached.

    ive always considered the flexible flyer nature of a fox to be like a beer can on wheels.

  10. #10
    FEP Power Member 85stanggt's Avatar
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    Quote Originally Posted by Gemini1999 View Post
    Have you pulled the dash out multiple times?
    I haven't, but my dad's own the thing since new and Ford did 2 or 3 heater cores in it. There were no cracks at all for its whole life. Then when I came up to CT for school, the crack developed earlier this year. Maybe due to the horrible roads up here? In FL, where it's mostly smooth, no issues? Maybe the bitter cold?

    So, where are the dash braces? I want to get under there and make sure the bolts are all snug and not loose. I remember getting under there years ago and the nuts holding the column on were loose.

    Really don't want to deal with this because I just don't have the time at the moment, especially if I have to pull the whole dash to repair. But I don't want it to get worse.
    1985 Mustang GT Convertible
    Stock and original @ 213k, except for dynomax ultraflos.

  11. #11

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    Drill the cracks and they will stop

  12. #12
    FEP Senior Member
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    My 85 is cracked exactly like that too

  13. #13
    FEP Power Member 85stanggt's Avatar
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    Quote Originally Posted by erratic50 View Post
    Drill the cracks and they will stop
    Well that doesn't sound like it'll look too good...

    Quote Originally Posted by tiptopss View Post
    My 85 is cracked exactly like that too
    Seems to be a common thing then. Never had this until very recently.
    1985 Mustang GT Convertible
    Stock and original @ 213k, except for dynomax ultraflos.

  14. #14
    FEP Super Member gr79's Avatar
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    I remember adding a dash brace to my 79.
    Bought from dealer.
    Did this as soon as i found out the later years had them from factory.
    Location is center dash, bottom, hull to trans hump
    short, metal tubing with bends, ends pinched and drilled for bolts.
    The middle shakes, so any support there is a plus.
    Thing is: does this transfer more shock and lead to more cracks?
    How much is enough or too much?
    I feel the dash material and other areas used back then was too brittle.
    Needs more steel bracing inside?

  15. #15
    FEP Supporter webestang's Avatar
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    Mine cracked as well......


    Scotty
    1985 Fox Notch 4-banger Ranger tube header Eastwood Royal Blue
    1988 Fox LX 5.0 AOD Vert BBK 170mph speedo Candy Apple Red
    1999 Mustang Coupe V6 Auto Chrome Yellow (My Pop decided to borrow this instead of the Vic "It's too big!"...LOL)
    1996 Crown Vic LX 4.6 Silver "Gort" Daily Driver

    Past Pony's.....
    68 Coupe Inline-6 3-Speed-Man. Primer
    78 II Hatch 302 3-Speed-Auto Sunroof Black
    81 4-Eye Coupe 4-Banger 4-Speed-Man. White

  16. #16

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    Webestang, like the stock looking radio, where did you locate that,


    Sent from my iPhone using Tapatalk

  17. #17
    FEP Supporter webestang's Avatar
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    Quote Originally Posted by jjltthomas View Post
    Webestang, like the stock looking radio, where did you locate that,


    Sent from my iPhone using Tapatalk
    $17.49 closeout sale at Autozone, made by Dual, has cassette player and aux port.

    Scotty
    1985 Fox Notch 4-banger Ranger tube header Eastwood Royal Blue
    1988 Fox LX 5.0 AOD Vert BBK 170mph speedo Candy Apple Red
    1999 Mustang Coupe V6 Auto Chrome Yellow (My Pop decided to borrow this instead of the Vic "It's too big!"...LOL)
    1996 Crown Vic LX 4.6 Silver "Gort" Daily Driver

    Past Pony's.....
    68 Coupe Inline-6 3-Speed-Man. Primer
    78 II Hatch 302 3-Speed-Auto Sunroof Black
    81 4-Eye Coupe 4-Banger 4-Speed-Man. White

  18. #18
    FEP Power Member 85stanggt's Avatar
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    Default

    In the middle of fixing this right now. I am able to approximate the two crack surfaces together pretty well so that the crack isn't as obvious. Will post some pictures up when complete...I don't even know what it'll look like yet, because it is all suspended and braced in place.

    But I am not drilling or doing anything from the front. I pulled the dash and glued the whole back side of the dash using orthodontic acrylic, which sticks to this type of plastic extremely well. It also is very very strong when set, so I'm hoping the added material and strong bond keeps the cracks from growing.

    Interestingly, there was a tab of plastic bracing that is part of the dash hull design that the crack ran right through. My personal opinion is that the crack started as a combination of things: cold weather up north, which the car has never endured, bad roads, and back bracing of the dash.

    The last one became obvious when I got the dash out. The brace that attaches below the glove box was quite loose because someone used the air box screw for the top mounting, which would not tighten down against the body nut. Additionally, I had used the bolt near the radio to attach some grounds, which meant when I loosened it and tightened it back down, it was tightened in a place where the dash was hanging rather than suspending it.

    This is one of the crappiest jobs to have to do for sure.
    1985 Mustang GT Convertible
    Stock and original @ 213k, except for dynomax ultraflos.

  19. #19
    FEP Power Member 85stanggt's Avatar
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    My main fear is doing this and having another crack show up somewhere else. If that happens, I don't know what I'll do. I can't disconnect all of those million connectors again to get this thing out. No way
    1985 Mustang GT Convertible
    Stock and original @ 213k, except for dynomax ultraflos.

  20. #20

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    Honestly, I think we're all destined to have the cracks. The plastic gets old and "dries" out.

    Others have posted about installing SFCs. Have you welded a set on your car?

    The poor dash doesn't stand a chance with the way our cars flex. Make your car more rigid, that will help.

    in the end though, Ford made them to last just long enough.

  21. #21

  22. #22
    FEP Power Member grtskydog's Avatar
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    Default Cracks in Dash Hull - Cause? and Repair

    Quote Originally Posted by erratic50 View Post
    Afaik, the dashes break for the same reason that the windshields crack. Over time, torque delivery takes its toll on a car body- especially if it wasn't braced up with subframe connectors and strut tower brace, etc.
    This is the most correct response IMHO.

    I've had the same issue (351w).


    Sent from my iPhone using Tapatalk
    Ed

    "The Dude abides."

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