Original Dash beginning to crack-advice?

[MM569457]

I just noticed a small “bugsplat” crack forming on my original dash.

what can I do to prevent further damage to this dash? The rest of the dash is pristine.

[psdenno]

1 hour ago, MM569457 said:

I just noticed a small “bugsplat” crack forming on my original dash.

what can I do to prevent further damage to this dash? The rest of the dash is pristine.

 

Decades ago when my dash started to crack, I drilled a small hole at the end of the crack.  I was an aircraft maintenance officer in the Air Force at the time and knew that procedure worked well on C-130s when sheet metal cracked.  So, I gave it a try.  The dash is still in my Z.  The crack eventually got bigger over the years.  But, the "stop drill" procedure worked for years.  Good luck with whatever you decide to do to save the dash.  They all have a "Best By" date.

[cgsheen1]

I would also highly recommend you start using only Meguiar's Hyper Dressing on your vinyl, rubber and plastic parts. 

[26th-Z]

I did an internet search and read a few things to confirm what I already knew.  The chemicals in the polymer evaporate out and the material becomes brittle over time.  Heat will make the material pliable, something in the 200 degree range, boiling water temperature, but the material will return to its same brittle state when it cools down.  There is no way to infuse the material with what has evaporated out over the years.  There are some really good products to protect and slow further damage, the Mequiar's being one of the top five, but that's about all you can do.

[Namerow]

I experienced the same issue and outcome when attempting to soften some Z parts made from rubber. With age, they had become rock hard.  An overnight soak in the recommended 'rejuvenating' chemical (acetone, IIRC) did a beautiful job and I thought my problems were solved.  Unfortunately, the parts reverted to their previous, hard-as-a-rock state within 24 hours.

[Mark Maras]

 As I recall in a previous discussion and a verifying experiment of my own, the trick to softening and keeping rubber (I don't know if it works on vinyl) soft was wintergreen oil. I soaked a destroyed hard rubber firewall grommet in acetone and wintergreen oil. It softened the grommet and left it soft for months after, at which point I was convinced and trashed it. I also seem to remember the go-karting world using w. oil on tires.

[87mj]

I realize this is sort of an old post but at some point, I thought the general consensus was to use petroleum jelly on the dash?

[dutchzcarguy]

Petroleum jelly on the dash?? tell us about that... i never heard of it..  i never heard a good (read: cheap!) solution for a cracking or cracked dash..  Mine (240) has a cracked dash with a cracked dashcover on it ! Hahaha...  🤣  that's what you get after 51 years..

Although my 280zx that was all it's time in the Dutch weather and warm garage.. it's dash is pristine! (after 43 years)

[Marty Rogan]

10 hours ago, dutchzcarguy said:

Petroleum jelly on the dash?? tell us about that... i never heard of it..  i never heard a good (read: cheap!) solution for a cracking or cracked dash..  Mine (240) has a cracked dash with a cracked dashcover on it ! Hahaha...  🤣  that's what you get after 51 years..

Although my 280zx that was all it's time in the Dutch weather and warm garage.. it's dash is pristine! (after 43 years)

I got my '70 Z in 1998.  It had a small crack in the dash that had been repaired reasonably well.  I have used petroleum jelly on it ever since and it has not had any further cracks.  Vinyl is a petroleum based product.  Although I have no scientific proof, I believe the petroleum jelly replaces at least some of the oils that have out-gassed over the years.  My dash has stayed fairly soft.  I do put a white towel on the dash to protect it, if I ever have to leave it parked in the sun.

[DatsunZGuy]

I am fortunate to have an uncracked dash and even a working clock on my '72.  My dilemma is wanting to keep my dash protected, but not resort to a cap or fabric mat that would require any adhesive or Velcro applied directly to the dash.  The solution I went with was to purchase some black plastic grommets and long black sheet metal screws.  I burned a few holes in a carpeted dashmat with a soldering iron and then used the grommets and longer screws in place of the fasteners used to keep the windshield defrost vent cover in place.  It turned out well.  The mat remains securely in place while driving and nothing is stuck directly to the dash itself.       

[dutchzcarguy]

13 hours ago, Marty Rogan said:

petroleum jelly replaces at least some of the oils that have out-gassed over the years. 

Yes, that could be.. My 240z dash is gone but i surely could use the jelly on my 280zx dash to keep it in perfect condition! thanks again!