Lowering your Swing Axle
- Written by Steve Phillips for HotVWs Magazine -
In this article I would like to discuss the pros and cons of lowering your swing axle. What is a swing axle? Swing axles came in the early bugs, ghias, type 3 up to 1968 and buses up to 1967.
The good news about swing axles is they’re strong. The bad news is they only have one swivel point per side so the rear tire goes up and down at a radical angle. From the factory the angle was set so just sitting, the bottom of the tires were slightly in. That way when the car gets weight in it or hits a bump and moves up it will be flat on the bottom and moving up farther be out at the bottom. Though it’s not the best for cornering. That is why companies sell rear camber compensators. This keeps the unloaded tire from “tucking”. In other words the bottom of the tire from angling in. Too much tuck and guess what? The car rolls over. Those of you wanting to raise your baja, be careful not to go too far. If yours is just sitting there and has too much “tuck” then it will be easier to roll the car over. If you want more height safely then you should look into the later IRS suspension. That’s a ton of work to convert a swing axle suspension to IRS but well worth it in the long run. If this is what you’re wanting to do then dig up one of my old articles on the best suspension for an off road car. On buses, raising a swing axle bus is pointless. For one, they come from the factory damn near as high as it will go. Two, and more importantly, with the reduction boxes the weight transfer when you let out the clutch goes up instead of down. If you do this the bus is going to be more unstable than it already is from the factory.
Now let's look at lowering swing axles on everything but a bus. I see it every day. Cars seem to get lower and lower every year. I too like the look of a lowered car, but here is what you need to keep in mind. When you slam the car, you're only riding on the inside of the tires. You don’t have the full width of the tire on the pavement. “So what, I get a deal on tires” you say. Ok that’s not a huge deal. What is a huge deal is the rear axle bearing. Look at this, the transmission shares oil with the axle bearing. When you lower the back so much that the tubes are pointing up, the axle bearing will no longer have oil. Oil in bearings is a good thing. When the tubes are pointing up, any oil that was in the bearing is now going to run down the axle tube and into the transmission. Not bad on the transmission but now the axle bearing is dry so to speak. Oil from the transmission can no longer get to the axle bearing because the last time I took a physics class oil doesn’t run up hill. I'm sure a lot of you are going to say you’ve been running your car like that for years. Well the good news is the factory bearings are good bearings. Or maybe your car never goes on long trips. I personally have had bearing failure out on the road. Not an easy fix alongside the road. What is the fix here? I love my bug slammed. Well the only way is to have your suspension adjustable, like air bags. I'm not an airbag guy, but this is a good way to have both. When you’re going on that trip to the show you can raise the car so as the axle tubes are pointed slightly down. When you get to the show then let the air out and bam you're on the ground looking cool. Another way is to do a transmission raise. This is not an easy option. You’re talking about a mountain of work. Body mods, pan mods, on and on. I have seen guys greasing the outer bearing and this is like putting a bandaid on a broken bone. It does help, but when the bearing gets hot all the grease melts out and runs down the tube. It doesn’t hurt but doesn’t really cure the problem either.
Let's talk about early buses. I'm not a fan of lowering the rear if you have reduction boxes. Here is why. Again oil doesn’t run up hill. The gears in a reduction box act like oil pumps so you will pump all the oil out of the boxes and let it run down the tube into the transmission. You have four bearings in those boxes which means four chances to burn one up. There are some good ways to get that lowered look on a bus without burning bears. One is to do what's called a rear swing kit. This gets rid of the reduction boxes and will lower the back 3 ½” with factory camber. Now you can go lower than that, but keep in mind what I said about the axle tube angle. If you slam slam it then you will have the same problems as the other cars I mentioned earlier. Again if you have to have it that way, maybe look into air bags or an IRS conversion.
In conclusion here I'm not saying you shouldn’t slam your car, but if you’re going to do it you should try to do it right and not end up with bearing issues, major tire wear, and other safety concerns.