Regarding the alda and the shaft seal that dries out causing the alda to not work: the location of the alda is above the IP, on my 87 300D it's between the rear of the ip and the intake manifold. On other models is much easier to access. You need to take the alda off to check if it's sealed up. There is a 24 mm nut on the bottom that I think needs to be turned clockwise (if I remember correctly). Once this nut is loosened, you screw off the alda from this nut. To test it, just blow into the metal nipple where the rubber hose went in. Don't hold your finger over the base where the shaft is. If you blow and air immediately escapes, you have a bad seal, which will cause very poor power (especially at low rpms) and hard shifting in low gears because it messes with the vaccuum somehow. If your seal is shot, you need to take the alda apart, which can be difficult as the 4 screws are threadlocked into place. You need to put it in a vice, find a perfect fitting phillips bit, then put that bit in a socket (I think it's 1/4 inch) so you can get more leverage by using a rachet. You will more than likely strip the head of one or more of the screws. IF that happens, just take a drill and drill right though the screw, you can use a skinny bolt and nut to put it back together. So once you get the thing apart, you will see two metal saucer looking things. The one on top that's attached to the adjustment screw can be left alone (hopefully you didn't try adjusting it to the point where the screw came out of the saucer). The saucer on the bottom is the one that has the shaft attached to it. Pull it out, and you will see a little rubber gasket on the alda housing. Take this out (likely it will fall apart), and then match this up to a proper fitting O ring. I used a metric sized o ring. Then take a little grease to lube up the shaft, and put it back in place making sure the o ring stays in place, and the shaft moves freely. Now you will need to take a LITTLE bit of gasket sealant and put it around the rubber seal that seals up the two halves of the housing . Then put the two halves together, either with the original screws, or with bolts. They don't need to be crazy tight like they originally were. Now you're ready to put the alda back on and enjoy a full powered engine! You may need to adjust the alda after performing this, especially if it was adjusted out all the way prior to fixing the seal.

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87 300D - Running on Veggie oil; 260,000 plus miles; Original #14 head