My seats haven't had a full load in several years (it's a 72). The early cars had stititching on the seats, as opposed to moulded seams on the newer cars. Thus far I've had no problems with the stiching, but fear the worst. I, personally , have never encountered a product that REALLY softens the surrounding vinyl Areas, so the stitching remains usable. I worry that the first 6 months of road use will find the stitching causing the vinyl to tear.

Anyone dealing with this?
Pat

Geez Pat, I was planning on asking you this same question, due to your chemistry background!

I want to refurb. my OE NLA Beige vinyl & repair the bolster tears with decent older material cuz none of the new stuff matches, which my upholstery is otherwise in excellent condition - so far!

FWIW - I'm having the same problem on the driver seat on my DD 85 BMW 325e too - but not the pass nor rear seats - all the same age, so use seems to affect how pliable they stay.

I guess I await the answer too, on how to re-soften & keep the vinyl pliable.

Would it be possible to reinforce the stitching from the inside with some sort of tape or sealant to take the pressure off the threads? Tents use a type of sealant tape to strengthen the seems. A seam sealant is usally applied as well. So, maybe a product like seam grip from the inside might solve your problem. Be abit of a project, but might work.

hat might help the seams Tod, but the vinyl getting stiff over time is the bigger problem, as well as being the danger at the seam stitching (same concern with the later heat-seamed seats BTW).

What's needed is something that can be applied to the vinyl leatherette and basketweave/perforated/etc. to return it's pliability and flexibility so it won't tear at the seams, nor crack & tear at the "field" or open areas between seams, at bolsters, etc.

I've been through the same situation. I have a car that was almost not driven from 1976 till 2010. The vinyl looked perfect but I could tell it was a bit cooked from the sun (there was a small tear in the car cover).
I tried to softener the vinyl many vinyl and leather oils. I even tried facial cream
After about 6 months of occasionally driving the car, the vinyl gave up at the seams. Only the plastic cover of the vinyl cracked, leaving the fabric layer intact.
I conclude that adding more support under the vinyl will not help.

I have a relatively rare brown vinyl interior but I was able to identify a replacement material of the same color. I'm going to recover the seats.

I don't think you can "rejuvinate" vinyl like you can leather. You can protect it from age, sun heat, ect. but not go in reverse. I think it's true of most synthetic products.

ATMO,
Mark

Mark is correct. Unfortunately.

The plasticizers in early vinyls are nice & supple when new, but "gas-off" as the vinyl is subjected to heat & sun. Hence, the fog on the windows that we used to have. It was a bit slimey & difficult to remove without streaking. Back in the 70's, manufacturers of plasticizers included various forms of organic materials, mostly pthalate compounds, to maintain the suppleness of vinyl compounds. They did the job for a "normal" period of time, but were easily leached from the vinyl with heat. In short, they are almost surely gone from most 914 vinyl interiors - not all, but most.

I really knew the answer to the question I posed originally, but hoped someone may have come up with a solution to restore the suppleness. The threads aren't the problem - it's the vinyl.

"Back in the day", that is the late 70's, Armorall promoted its product (ther was only one then) as the antithises of vinyl degredation. Many of us bought into it. As it turns out (surprise!) the product does nothing, with the exception of providing a slimey/dust magnet surface.

Tip: never, ever use Armorall on your seats! And, never get near an autocross with that crap on your seats! Think seatbelts will save you? Try fresh Armorall on vinyl seats at an autocross.....nail the brakes hard & kiss the pedal cluster! Yep - stupid me. Did it. But that was about 79. Stay away from that product!
Pat

I head good things about a product called 303. Originally used as a protectant for marine applications, the concours guys seem to be using it on rubber/vinyl on their cars. Non slip non gloss product. Might be worth a try.

I've used it on the FG pop-top of my Westy to good effect, but hadn't tried it on my BMW seats at all.

I may try it on the worst crusty parts of the "extra" beige backpad I got to use the better areas to repair my seats (since that color leatherette is NLA & not matchable with newer fabrics out there).

I'll try some applications & see if it works at all & report back later. I also have some Vinylex that I can try.

I can do so in various test areas of the more faded stuff (e.g.: more weather & sun deteriorated areas), as I'll be using the more protected areas behind where the seats sit for my repairs.

Let me know if there are any other treatments worth a test at "Tom's Consumer Reporting"!

There must be something out there which can rejuvenate & replace the lost plasticizers Pat refers to above, even if organic compounds!?
If my Dad the petro-chemist were still alive, I'd ask him, but alas.....he passed in 12/08!

Tom, vinylex won't do it. It doesn't penetrate the fabric well. There are alot of highend product companies like Griots, Wolfgang, and the list goes on and on that might have some conditioners that would be applicable. Can try their catalogs, can test glyserin, can also google it or try some muscle car forums. I'm sure it's come up there before. Anxious to hear your results.

Yeah, I know what you mean - Vinylex seems more like a shiner coating like the old ArmourAll, than a penetrating conditioner product. In fact, that's why I hadn't tried the 303 on the vinyl before.

There's also P21, Einzeit (sp?) & some other products sold by the Porsche suppliers that may be worth a try.

I'm open to anything that works & preserves my existing NLA leatherette/basketweave - otherwise I'm in for an expensive full re-upolstery with something that still won't look like my OE stuff!

You want your steak rare and it's already well done - aint goin hapen. Just like Por-15 won't rejuvenate your rusty metal back into shiny steel.

Actually Mark, we're not talking about bringing T-Rex's skin back from the stone!

Mine is still pretty pliable after sitting in the garage for the past 26 years, mostly being garaged, car-ported & covered for the 10 prior to that that I owned it, 7 for the PO/OO - even where I have the shittage-in-the-back-pocket tear on my D-seat bolster & smaller ones elsewhere from when it was my DD `75-85.

Click to view attachment Click to view attachment

I think Pat's are in similarly good condition, but without my tears to repair (ergo the extra backpad I got in the matching OE leatherette).

I'm just going to test on the other backpad in the worst areas, so I don't f-up the good areas which I need, plus it will be working on something more far-gone, so it should work on a relatively pliable material - if it works on the crud - whatever the treatment is.

Oxidized metal & POR15/etc. are a different animal than plastics/vinyls & leathers due to their organic make-up. Not saying it will work, but something could to keep it pliable so it won't get crispy & tear at the seams, etc.!

Certainly there are well preserved original upholstery 914s out there who've managed to keep their vinyl pliable and in good shape, so that's what we're looking to find.

I'd be really & pleasantly surprised if glycerin did anything positive. It works really well in rubber items - for preserving them. If the runner part is in bad shape it won't help much, but will extend the life of the part until Mikey makes a new one!

Just a thought, everything we have that has been soaked in straight mineral oil gets soft. Might want to try soaking a scrap in some to see.

Wish I had some scraps! May try it anyway.
Pat

I'm sure there is plenty of old seats around..

Pat, I'll add mineral oil to my experiments with scraps off that extra backpad.

Thanks Tom - I'll be surprised if it does any good along the seams, but it's worth a shot.
Pat

Jeff,
The last thing I need is another piece of crap around here. My wife's always been supportive, but I suspect she is near the end of her rope! Case in point - I bought a package of 4 yellow top injectors (which I have no use for), with all rubber pieces (new) and 4 new elbows for under $22. Could care less if theinjectors work, though chances are 50% that Witchcraft can make them work. The only thing I needed was the injector elbows (new), so the rest went into a bucet of "will sell someday". My garage and basement are so sull of mostly new parts for a 914 that isn't running (but should be) that if I brought a raggety seat here I think she may explode!

She's been very supportive for well over 40 years, but if I don't get Fritz on the road soon she may have me committed.
Pat

Pat maybe one of the guys that do alot of car parting can send you down some old crusty fabric samples. Maybe Bruce? It will take up no room, and you'll be able to do your testing Wife is happy, Pat is happy, and Fritz will be happy.

Would be great to have about 20-25 1"x 1" samples, in various conditions. I'll pay the postage. Have some compounds/mixtures in mind, but you never know with old vinyl - some compounds can destroy the backing. Don't really think there's much hope for seriously degraded materials, but those in decent condition may have a life left.

Send me samples guys. Let me cook some brews!
Pat

I researched a lot about this in the past and also talked with some chemical eng.
The problem is that plastic coating of the vinyl shrinks over time, mainly from heat. There is nothing we can do about it except freezing the car.
At the same time, since it shrinks, the density grows so it also becomes harder (less elastic).
On the other hand, the backing fabric works in the exact opposite direction: the fabric loosens up and becomes soft.
Those 2 phenomenas lead to the point where only the plastic supports all the mechanical forces and it will brake.
Assuming that the vinyl didn't shrink too much due to its age, the only thing you can do is to glue it on a new fabric that has little (or no) elasticity. Contact cement works nice for this application.
I tried to do this to an old seat. The problem is that the old seat cover becomes a "seat saver" cover over the new one. It is more difficult to do then to redo the entire seat and the results are not so comfy. If you miss one stitch, it will brake right there since all the forces will concentrate on that point.

I'm not so certain that these seats cannot be rejuvinated. Unlike your ChemE friend (I am a retired chemist, accountant, financial administrator)I'm of the opinion that the phthalates that made the the vinyl supple originally can be re-introduced through other means.

Need those samples guys!
Pat

I conferred with an environmental attorney today, regarding my planned introduction of a phthalic anhydride gel spray to be applied on the underside of 914 upholstery. I'd found a supplier in China (yes, that's right) who could provide it.

I was informed to walk quickly away from this idea, as there are not only environmental concerns with the compound, but to have it made in China opened me up to quality concerns.

So, at this point, my involvement is at an end. Do not send samples, because I have no better ideas.

To give a very basic course of the process.....

Back in the day (70's & earlier) compounds involving phthalic anhydride were reacted with forms of alcohol to produce a compound that was called a plasticizer, to be used in upholstery among other things. Plasticisers, when applied to upholstery backing, kept the upholstery supple. But, as the plasticizers ages they break down under high heat (interior summer heat) & attempt to revert to the original form, releasing phthalate gasses (those fogs you used to get on the insides of the windows) and drying out the vinyl. Of course, the weakest point of the drying issue is where the seat stitching (early 914's) and molded seams (later 914's) is found. Dries out - becomes brittle - fails.

The interesting part of this is that upholstery kits you can get for 914's have been manufactured almost exactly the same! Why the use of phthalic anhydride compounds is OK with them is beyond me.

One of the environmental concerns of this compound is that it has been shown to reduce the size of rats testicles! Think about that after your next drive.....if you're a rat! I don't buy it.

Nonetheless, I close this project. Too bad. I think it had some merit.
Pat

Pat,

As you pointed out, they're still made that way (vinyl fabrics), so you may want to get a second opinion on the enviro. concerns from an enviro. eng. & enviro. attorney on it.

However, you may be better off patenting the process & compound, then getting a big US mfgr. to make it with expertise and infrastructure in this area, then you get the royalties, & they get the mfg. headacches, distribution & liability defense issues. Maybe Einzeit, P21, McGuires or one of the auto care mfgrs. would take it on, from your patent(s)?

Maybe too soon to give up!?

Let me know if you change your mind & want the fabric samples after all.

Tom
///////

Hey Pat,

Your avatar just gave me an idea about some other solution for my seats.
Could you please point me to the character in the picture...

No Tom.

Look, the greenies are just looking for any example to sue. At this point in my life I have little willingness to fight them.
Sorry, I'm done with this project.

Huh?! Splain please!

Okay Pat, just thought I'd suggest another way to do it, that doesn't put you directly in the enviro liability line of fire, but understand your concerns.

I've spent over 40 years in the development industry dealing with it, so understand the difficulties.

PS - Thanx for taking a run at it for all of us too!
Sounds like you did a lot of work on it already before stopping.

Tom,

Though I personally think they're unfounded, the concerns over use of pthalic anhydride are a hot topic right now. I just will not put myself, and my miserable amount of security in the line of shark attorneys. Somehow, the availablility of new seat covers (using the aforementioned compound) doesn't raise concern. I'll leave it at that!
Pat

Pat, maybe a pair of "driver" seats is what you need? Use the pristine originals for special events.

For now, I'll just wait to hear the riiiipppp, if it ever happens.

No more room for anymore spares! Though I'll always take "new" parts.

I'm such a whore for new parts, though I would like to have a new fuel pump (hint, hint)
Pat

i am a custom upholsterer and have been in the trade for 25 years. there is no way you will be able to 'soften' up vinyl. if the stitching is brittle or weak, it will break. you can take another bite on the seam, and that might hold for a bit. check out my site for resume santanainteriorsdotcom

Understand your points, but would rubbing Lanolin into the stitching help?