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Discussion Starter · #1 · (Edited)
Hi all,

My '86 SPG restoration is finally moving along. The engine is out, awaiting a thorough inspection and refresh. That's only one component of this project, though. Here's what else I'm looking at (for now):
  • Wiring harness repairs
  • Suspension overhaul
  • Brake overhaul
  • Steering rack replacement
  • Welding two small holes in passenger side floor pan
  • Paint job
I want to tackle the suspension and steering components with the engine out of the way. The interior is also out as I had to remove some surface rust on the floor pans, meaning now is the time to deal with the two holes.

Because I expect I'll have a bunch of questions down the road, I thought it'd be best to create a single project thread as opposed to several miscellaneous threads.

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Here goes...

1. I need to replace all suspension bushings and ball joints, tie rod ends, etc. What do you guys recommend as far as sourcing? For bushings, I'd like to stick with rubber. Is Saabits the way to go? Any thoughts on quality? I'd prefer to avoid PPS.

2. I want to swap out my springs and shocks as well. I was looking at Lesjofors but then noticed that Saabits carries an SPG replica spring. Any experience with these? I'm guessing they would provide a slight drop on my '86?

3. For shocks, I'm looking at Koni Reds. I remember reading that they were a good pairing with Lesjofors springs, and can imagine that they would work equally well with the SPG springs (?). I'm after a reasonable amount of comfort, granted the new springs would probably stiffen the ride somewhat.

Now, switching to the floor pan repairs (photos below)...

4. There are two small holes in the passenger side floor pan, roughly 2" in diameter. I was recommended 3M Panel Bonding, which I think would be an elegant fix given the small size of the holes and relatively flat surface area. Any objections to this route from experience?

5. I had to remove the rubberized coating on the floor pans (front seat area only) to remove some surface rust. For those of you who've done the same, what have you used to replace that material?

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I appreciate the help - hopefully more interesting questions down the line.
 

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I ordered my rubber bushings from Skandix - I don't think there are any US-based sources for non-PPS rubber ones. I couldn't find any. :/

My guess on springs is that everything is just a guess... SPGs were a half inch lower 35 years ago. Who knows what sort of toll time has taken on springs at this point. I've read good things about the saabbits springs - it's probably what I will do on my '79.

IIRC Koni Reds and Bilstein HD have almost exactly the same damping. IDK if it's true, but the Bilsteins on my current SPG give a ride similar to Reds on my old SPG, so I'm inclined to believe they're about the same.

I can't help on panel bonding, but I'll be interested to see how that goes for you. A friend repair a similar bit of damage with rivets and had good results.

I think the coating is just for NVH... I'd be inclined to NOT try and replicate it but instead use some modern solution that's less likely to trap moisture. That goes double for the foam sound deadening!
 

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Discussion Starter · #3 · (Edited)
Wow, it's been such a long time, I completely forgot about Skandix. Do they manufacture their own bushings? A few are listed as SAAB, but no specified brand otherwise.

Thanks for the input on the springs and shocks.

As far as the floor pan coating, I was looking at DupliColor Professional Undercoat Sound Eliminator the other day. Says it's rubberized and corrosion proof. Probably nowhere as thick as the original material, but I hear what you're saying about keeping it thin. Any particular product ideas?

Also, what would you sub the foam with? Mine has been out of the car for over two years now and it still feels moist o_O
 

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I just removed all of my interior on my new to me 1991 900S vert in preparation for replacing the heater control valve as well as re-dying the carpets (Tan). I too found some of the factory coating delaminating from the floors, presumable from moisture. Fortunately only surface rust. This was wire wheeled and then coated with POR15. I have had great result with this in the past. if, and that is a big if, I put something over the POR15 it may be a sound deadening mat by Noico. I already have it and it seemed to stick well to the floor boards of my 1969 Triumph TR6. This will provide a little sound barrier and be thicker than anything sprayed on.

The foam padding is the worst, it holds water as good as a kitchen sponge. My thoughts on this are to replace the original foam, which is open cell and absorbs water, with equally thick closed cell foam, that doesn't readily absorb water. The foam can be ordered in different thicknesses and different levels of firm/soft. I am thinking of using a medium thick vinyl glued to the new foam with a quality 3M spray adhesive to replicate the OEM "rubber" backing.

With my car being a convertible I always assume water will somehow find its way into the car and collect in the floorboards. Another "trick" I use is to source the rear trunk body plugs used in the W123 and W126 chassis Mercedes. The are down in the spare trunk well. These extend a good 1" to 1 1/2" below the body and have three vent holes in them. The holes allow water to drain out, but the length of them prevents road spray from getting in. I drill 1" holes at the lowest point in each footwell and install the plugs. Careful not to drill into any fuel or brake lines and avoid the frame stiffening rails. This allows any water a way of draining, but doesn't let water in. These drains and foam that doesn't readily absorb water should help prevent water from collecting in the floor boards.

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I used Noico on the door panels of my SPG



It made a HUGE difference in interior noise. I've considered adding it to other side panels, but a) it weighs a lot (it has to...) and b) I'm not super motivated.

I did use it to insulate the doghouse cover in my motorhome, where it sits directly over the engine. Without it, there's just some fiberglass and carpet keeping engine noise out. It does a stellar job, and the heat from the engine doesn't seem to affect it much. There is a big air gap, tons of air flow, and the rubber does soften a bit, but it hasn't gone anywhere in two years.

I'm happy with the Noico and I would use it again. However, I'm not sure I'd use it on a floor, where it needs to support weight. The butyl is very soft, and any weight will push it away and tear the foil. I would use something designed specifically for floors.
 

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Something else I will also add is that we found in the race car when you remove the thick padding under the carpet the distance between the floor and the pedals becomes very uncomfortable.
 

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And why I would, a closely as possible, replicate the thickness of what came from the factory. That or buy a set of Coco mats. They are plenty thick to make up the difference.
 

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Discussion Starter · #8 · (Edited)
This was wire wheeled and then coated with POR15. I have had great result with this in the past. if, and that is a big if, I put something over the POR15 it may be a sound deadening mat by Noico. I already have it and it seemed to stick well to the floor boards of my 1969 Triumph TR6. This will provide a little sound barrier and be thicker than anything sprayed on.
Ah yes, I remember seeing a good amount of floor pan repairs finished with POR15. Thanks for the tip. And those Noico mats look great. My first thought when I looked them up was what jvanabra did on his doors. Have you checked how they've held up over time on your Triumph's floor boards?

The foam padding is the worst, it holds water as good as a kitchen sponge. My thoughts on this are to replace the original foam, which is open cell and absorbs water, with equally thick closed cell foam, that doesn't readily absorb water. The foam can be ordered in different thicknesses and different levels of firm/soft. I am thinking of using a medium thick vinyl glued to the new foam with a quality 3M spray adhesive to replicate the OEM "rubber" backing.
The factory foam insulation seems to be a controversial topic. Some argue that it's better if it's absorbent because otherwise the water just sits between the pad and the floor. However, my floor pans almost rusted out with the factory padding so I can't really side with this theory. A nice work-around is what you've suggested with body plugs and closed cell foam.


Something else I will also add is that we found in the race car when you remove the thick padding under the carpet the distance between the floor and the pedals becomes very uncomfortable.
Great point; very easy to overlook. Something like this with a glued-on vinyl pad like MSG suggested might replicate the original:

 

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You would need foam at least 24" wide and 120" long to re-make the originals. The one thing I am unsure of is the softness of what is out there compared to how soft the OEM pads are. The softness/firmness is the Compression Deflection 25% and I "feel" the factory foam is pretty soft.

Yes, The factory foam absorbs water so it doesn't puddle, but the OEM foam holds the water forever. I have mine out and in a dry warm room and they are still wet/damp after a week. The holes with the drains are what I feel are a good solution. A way of letting the water drain and a foam that doesn't absorb water.
 

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This is the Mercedes drain plug I was referencing.

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Discussion Starter · #11 ·
Looks great! I noticed that you installed the drain plug over the Noico mat. Makes sense as any water seeping through the carpets will likely reach the mats before the floor. Any chance that water could get underneath the mats, or does the full surface of the mat adhere to the floor?

How many plugs did you install on each side? Also, is this the part?


Thanks.
 

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I don't quite understand the fascination with floor pan drain plugs, they are never truly useful. Offroading or post flooding are really the only time they are used, essentially if you're using a drain plug you already need to pull all of the carpeting from above to dry it anyway.

For sound deadening on the doors/firewall/trunk Dynamat or an equivalent product is very good. Overall it still adds weight but it ia thin, works very well & is fairly easy to cut & place where desired
 

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Yes those are the plugs. I install one in each footwell.

Consider this, without the drains the water will stay in the floorboards until it eventually evaporates. I'd rather try and give the water a way to drain off, but if you do keep the original foam padding then the drains don't do much good as the foam holds water like a sponge. And the argument can be said that the car shouldn't leak water and while that is true, a 30 year old convertible with a not so new top may not be as weatherproof as when the car left the factory. I just figured why not while the carpets are out anyway to be re-dyed.
 
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Climate probably also plays a part here... tracking rain moisture inside is a lot different than snow moisture. The sponge issue with the factory stuff is not a problem where I live but it's clearly not a universal truth.
 

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With the sound deadening mat the key is as clean a surface as possible and then stick it down and roll it on. The dimples on the mat are designed to disappear when the mat has been sufficiently rolled/pressed down firmly. They make special rollers for this and they work great.

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Yes those are the plugs. I install one in each footwell.

Consider this, without the drains the water will stay in the floorboards until it eventually evaporates. I'd rather try and give the water a way to drain off, but if you do keep the original foam padding then the drains don't do much good as the foam holds water like a sponge. And the argument can be said that the car shouldn't leak water and while that is true, a 30 year old convertible with a not so new top may not be as weatherproof as when the car left the factory. I just figured why not while the carpets are out anyway to be re-dyed.
My point is that you don't need drain plugs because if you ever need to use them, that large an amount of water means you should be removing the entire carpet to dry it. At that point a shop vac can be used, followed by a couple of hand towels to dry the bare floorboards.

Just my $.02 on creating an extra installation step & potential place for water to ingress for no real benefit.

I have a 20 yr old convertible, I am fully aware that tops may leak & drains may clog....it's a painful endeavor to get everything dry & avoid mold for sure. I never even considered using the drain plugs when I had a significant amount of water for thr reasons I stated above. YMMV
 

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Discussion Starter · #19 ·
All great points. Mine's obviously not a convertible, so I will weigh the pros and cons of adding a drain when I do the floor.
 

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Discussion Starter · #20 ·
Changing subject....

Can anyone confirm that flat-nose SPG panels were finished in Anthracite Gray 176 as in later years?
 
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