SAAB c900 Alternator Bushing Replacement

Now that we have popped the alternator out of Grona, we can replace the bushings on the mounts and put the old alternator's pulley onto the new alternator.

It's a lot easier removing the alternator from the mounting bracket when it's out of the car.

Put it in a vise and undo the bolt with a 16mm socket.

Here's the bracket and the mounting bolt.

As for the pulley: it's been a while since I took one of these off. I know they can be difficult to remove.

I used on old leather belt around the pulley in the vise so as to not put vise marks on it.

The pulley was quite tight in the vise, but I couldn't budge the nut with my trusty 1/2 inch drive breaker bar.

The nut is a 22mm, by the way.

The pulley just wanted to turn. I'm not too surprised. I had Plan B ready.

Plan B is using an impact gun to get the bolt off. Took 5 seconds to loosen it.

Check out the impact gun/wrench. It's a Ridgid cordless one - uses an 18 volt battery. According to the specs, it has 325 lb-ft of torque! Of course an air gun has more, but this is much more portable.

Cordless tools have really come a long way. That thing packs some real power.

Here's the bolt after removal.

I want to start taking Grona's suspension apart and replace all the bushings now that I have this cool impact gun.

But first things first. I need to finish this job.

The alternator with the fan, spacer washer and pulley removed.

And all of the parts - the alternator mount, the adjustment arm, and the alternator pulley, spacer washer, and fan before they have a bath.

First I push out all of the old bushings. Two in the bracket. You can see how chewed up they are. I'd guess they're the originals - at the end of their service life.

25 years is pretty good I'd say.

The bushing for the engine block end of the adjustment arm is in 2 halves.

It's in bad shape too.

I took some environmentally safe degreaser to all of the parts. They came out pretty clean.

Now you can read the SAAB part number cast on the alternator mounting bracket - 7511843.

In case you needed to know.

Took some fine steel wool to the insides of the brackets to clean up the area where the new bushings will go.

I always figure, when you have it all apart, go ahead and do it right.

Well, it's the Queen's Award, innit?

I have some Powerflex poly bushings for the mounts. They're stiffer than the stock rubber bushings - should help keep the infamous c900 alternator wobble under control.

The bushings are made in England (where most of the world's race cars are built). And if you look closely, you'll see they won the 2013 Queen's Award for Enterprise International Trade.

Good thing, that.

You get a small tube of PTFE/Silicone assembly grease with the bushings...or is it 'bushes?'

Apply it to the outer and inner surfaces of the bushes before installing.

Powerflex make three levels of bushings: yellow, rated at 70 on the Shore A Durometer scale (about 25% stiffer than stock) purple, which are 80A (30% stiffer), and black, which are 95A (80% stiffer). The latter are for race applications.

The new bushings slide right in easily.

Love that purple color. Too bad they'll be mostly invisible when the alternator is back in!

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UPDATE Dec 7, 2018: I don't recommend poly bushings for the alternator. Mine were destroyed after a couple months. They seem like a good idea, but they will go bad very quickly. Stick with the factory rubber bushings instead.
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The top bolt hole on the alternator mount is where the alternator ground lead goes. I cleaned it up to ensure a good connection. You can see it's a bit shinier than the other two holes.

I wasn't 100 percent sure the higher-output (115 amp vs. 80 amp stock) alternator was going to be a direct fit.

Fortunately, it is.

The shot on the right is a comparison between the two - the stock 80 amp Bosch 124x on the right, versus the 115 amp Bosch 129x on the left.

The cases are virtually identical. The only slight difference is that the location of the B+ terminals is rotated slightly, but it's no problem at all to install.

The other thing to be aware of is the ground bolt. On the stock alternator, there is one longer case screw that the ground bolts on to (see the image). On the 129x, there is a threaded hole that I used for a ground - I'll show that in a minute.

Here's a picture of the pulley ends of the alternators - exactly the same case shape.

After reading up on this on the interwebs, I was reasonably sure it would be a straightforward conversion. I just couldn't find any pictures to confirm the sizes of the alternators. Pictures! I need pictures!

Now I have one.

This is the static supressor mounted on the back of the alternator. You can see it's just a 2.2uF/100 volt capacitor.

I just took it off the old alternator and put it on the new one. Exact same location.

The screwdriver is pointing to bolt I used for the alternator case ground on the 129x. It's a 5mm thread - I used a 10mm long bolt to go there.

I probably could have used that longer case bolt from the old alternator, but the new one is so clean that I didn't want to put the old bolt on!

Note also that the supressor is installed as well.

Now we just put the spacer, fan, and pulley on the new alternator.

Funny picture - the lens focal length (24mm) makes it look like the ratchet is bigger than the alternator!

Now everything's ready to be installed in the car.