Top is Falling Apart

REAL Speedsters (Porsche) had a steel top bow with a rubber insert. The top would be glued to the top bow, not the rubber. Replica cars have a fiberglass bow. The installation is about the same. The rubber goes in after the top is glued in pace.

I can't imagine anyone trying to hot glue a top on!  I have installed several tops. If you're not able to do that you'll need a good top shop.

Most of us have Hartz canvas tops...I believe.

Look for Alan Merklin. I suspect he's installed more Speedster tops than anyone else here.

@Alan Merklin may use something better, but I had very good luck with DAP contact cement in the red can.   Available at most DIY box stores.  There are step-by-step instructions for convertible top installation in the Resources section of this site (which Alan and I wrote).  

Hot melt glue won’t last (as you already found out).  

The original FF/CMC front header bar was laminated fiberglass.  It does delaminate over time.  I replaced mine with one from (old) VS.  It fits better and appears to be butyl (can't see any laminations).  It fits much better without grinding for a better fit. Sounds like maybe Gorilla Glue was used?  The original FF/CMC tops were indeed vinyl - don't believe Haartz cloth was offered (may on later Street Beast?)

Many replica tops are made of vinyl, especially older CMC/Fiberfab.

Good old DAP contact cement works.

Quick instructions: Take it all apart at the header, then stretch it as much as possible over the installed and clipped-on header. I used LOTS of blue wide masking tape on the windshield. 

Mark it on the inside where the top meets the header with chalk.

Remove all, coat the top AND the header with contact cement. WAIT the required time. Stick them together, and fold the excess into the header. Re-install your rubber strip.

It helps to do this on a warm and sunny day, especially when stretching the vinyl.

Cheers.

All I can add is to sand/scrape the old glue off the header.  You want the header  contact surface roughed up and dirt free.  Not sure how to get it off the vinyl's canvas backing - maybe plastic putty knife.  I would NOT use a solvent as it may destroy the vinyl.

Clean the old adhesive from the header bow with lacquer thinner onto a rag .  Rough up the area of the header bow groove that will have the adhesive applied to it.              3M Super 90 Adhesive is applied on both the top material and the header bow with a narrow brush allowing a few minutes for it to tack up then press the top material onto the header bow groove. Push a piece of rubber hose into the header bow groove to keep pressure on the material for an hour of so until the adhesive dries.

Ahhhhhhh.........

The old "Rubber Hose" trick!   

Will lacquer thinner hurt the vinyl top material?  It’s all gooped up too. Everything is just sliding around. 

The lacquer thinner will slowly turn the glue into an emulsion (it thins out) but should not effect the vinyl, but to be sure, try it on a small area on a corner, first.  It might take a few tries to get rid of all of the old glue - It can be tenacious stuff.  

I did as Alan suggested using the same adhesive. Again, he knows what he is talking about.

Wolfgang mentioned up above that the original FF/CMC header is made of laminated fiberglass.  Having modified several of them for myself and others, I’m not so sure.

I’ve cut into and drilled several of them and they don’t act like laminated fiberglass.  They act a lot more like someone came up with a mold and poured runny Bondo into it and let it cure.  None of them looked like they had much machining from the mold to the final, useable part (a nice way of saying that they were pretty “rough”).  Usually, when you cut through laminated fiberglass the cut shows Frosty clear or amber/white.  When you cut through the CMC header the cut might show solid white or blue or gray.

??????

Every one I worked with needed to be modified slightly for the windshield frame slot to actually fit the shape of the windshield(s) and no two seemed the same.

Not saying they are better or worse than anything else, just like a bunch of other CMC stuff - Just a little Weird.

@Marshall posted:

Will lacquer thinner hurt the vinyl top material?  It’s all gooped up too. Everything is just sliding around. 

I’ve never dealt with these tops so I don’t know, but a lot of vinyl has a mesh-cloth like backing. I would use caution and, like the disclaimer always reads: Test on a small patch out of the way. 
FWIW: GoofOff adhesive remover works as well or better than thinner, and is easier on the fabric. 

Greeting again,

Some photos regarding my top.

It was much cooler this morning.  I noticed that the exposed glued areas had changed from the consistency of honey to being much more stable.  I attempted to pull and reattached the two previously glued pieces.  There was some "stick" but not enough to hold the pieces together.  

The bow, as several of you called it, appears to be black plastic?  Almost a heavy black rubber but harder.  The channel is filled with a rubber gasket.  The bow is rather flexible.  It rises in the middle when clamped down.  It will not remain pushed in.  Am a missing a metal piece that would stiffen the bow and keep it aligned?  An additional clamp to the left or right of the mirror would accomplish the same thing but there isn't one.

Any thoughts?

Marshall

Another question related to the top.

Attached is a close up of the latch.  It appears to have three adjustment indentations.  When I latch it now it is very loose.  Can I tighten this up somehow so it's tighter?

Marshall

If you look at the hook portion of the latch it is threaded and a few turns in should tighten it. Others have added a third latch to tighten the center and others have done something even easier. They've added a spring steel clamp shaped like a "D" that gets snapped in place when the top is up. I'll see if I can find it in a previous reply and post it for you.

****EDIT****

Found the link:

https://www.speedsterowners.co...ft-top-clamps?page=1