The Goodyear Air Spring Affair

Back in 2017 I replaced Gigi tyres and one thing I did forget to do was to clean the dirt/rust between the drums and the rims on the front wheels… This in the industry is known as a mistake, because you always ended up with a wheel wobble at around 40km/h especially while braking…

Because of the weight of the wheels and the drums, I always said that the day that a job on the front axle would have come up, would have been the day that I fix that as well..

In January this year while looking at Gigi’s front Air spring I realised that the rubber was starting to perish and perhaps it was time to combine the two jobs.. While replacing the bellow was a new job for me, Paul, having previously replaced the bellows in his bus, warned me of how hard it was to actually shape the rubber into the correct size,so to be able to inflate them and to seal on the piston..

Armed with this strategic new piece of information, I decide to acquire the help of my mate Charlie,to perform this task.. Charlie on the other hand was convinced that there are no two Air spring in the market that will behave the same, when the time of replacement is upon them.. As one bellow has now failed,it was now the time to get dirty and down to business..

Perhaps it is better explain now, that what people normally call Airbags are actually called Air springs as, that it is what they are replacing, the actual metal spring.. The Airbag are actually the one inside the car that protect their occupant in case of a collision..  A google search will quickly show you what I mean..

When you replace the rubber part only then it is called the bellow. The rubber does come in three possible shape depending on the installation requirement..

You have the single bellow (what I used this time), then you have the double or triple bellow…

As we can see it is easy to tell which is which…

And while on the subject, it is nice and also interesting to know of the why the industry has moved away from first springs, then coils to now rubber. There are several reasons and they are all good, and here is a list of why you should consider driving on air spring instead of spring coils, leaf spring or torsion bars:

• Ride Quality
• Adjustable ride height
• Adjustable comfort
• Improved handling
• Better cornering speed
• Better and adjustable carrying capacity
• Less weight
• Less vibrations

They are also safer as they tend to keep the wheels firmly on the ground, no matter what, and this alone is probably the best reason for why they have become so popular in most modern cars as well.. If you are still driving on leaf spring, do yourself a favour and at least add one of the Air Spring kit available to improve spring performance… Once you have ridden on Air Spring it is hard to go back to the metal to metal form of suspension…

While waiting for Charlie to show up, as the man has no idea what so ever of what punctuality actually is or mean, I decided to try myself to remove the bellow from the mount.. You can see in the picture that the bottom part of the bellow it is easily removed from the piston/bell (different names again for the same part), but there was no way to remove it from the top, and for a good reason.. On the top, hidden inside the bellow there is a flange holding the bellow in place..

Once you open one and take it apart it become obvious how the system works..

So in the meantime I decide to tackle the other ugly job or cleaning the dust/rust from the hub and the inside of the drum.. If you don’t like brake dust, this job is not for you, so make sure to wear both goggles and a protective mask if you are tackling this task!

Also the actual drum is frigging heavy, so pay attention where your fingers are while removing it or reinstalling it on the hub… A little grinder tool with a sanding disk,is the best option for this job.. Beside the huge amount of dust, this job is actually quite simple and it should be performed every time you take the front wheels off the hub, as inexorably dust and rust will dislodge and create a gap between the hub and the drum..

This is also an excellent time for checking out brake shoes, retention spring and the s cams.. You could also take advantage of the extra space around the hub while you are there and grease all those nipples that are normally in the dark when the wheel is mounted on the hub.. I was impress and relieved to see that my shoes have still plenty of meat on them and they should last quite a while,especially considering the most of the braking is actually done by the retarder..

At around lunch time Charlie managed to show up 😁 and in a jiffy we were able to remove the bellows from both side..

To remove the bellow,you start from the top by first removing the air hose connection, then the actual air hose elbow, and finally the large 30mm retaining nut,plus the other 18mm nut hidden behind the frame.. Then to remove the bottom piston you have another two 18mm bolts.. Now your setup may vary and it could be different as Charlie did confirm that there are so many variation for Air Spring setup going around Australia.. You may have plastic piston (more common now on new trucks) and you may have three to four bolt instead of two…

Once the entire setup is out as in top retaining bellow and bottom piston, you can easily take the three things apart…

On the top there are two nuts with o-ring that retain the inner retaining flange. Once they are removed you will need to extract the retaining flange from the inside of the bellow as it need to be used again with the new bellow..

You can see the top outside plate that has a bit of superficial rust and the spanner sitting on one of the two nuts..Make sure to clean the best you can every bit of that plate and to remove any rubber residual from the bottom piston as well, so to give the new bellow a good chance to seal once it is inflated..

Now there is an easy way and an hard way to do this job.. The hard way is to put the bellow back on the piston first and then mount the entire assembly back on the chassis.. We did this on one side and it took an extra half an hour to align the holes with the threaded bolt insert..

Then on the other side I had the idea to mount the piston back first onto the chassis and then install the bellow, and this took only a few minutes.. So as far as I can tell that’s the easiest way of doing it.. Also when you try to pull the flange out it helps if someone or something stand on the bellow end rim to make the hole a bit wider as the flange is obviously larger than the rim itself.. Don’t be afraid to use some o-ring grease to aid the bellow rim to seat in his position on the bottom piston either, but don’t put anything on the side of the piston as that will attract dust and possible small stones..

The last picture does shows what happen to the bellow when the vehicle is raised off the ground.. Because the 4 way valve is off,it create an internal vacuum making the bellow shrink.. This could be a problem in the long run as the rubber could be pinched between the piston top and the top flange of the bellow..

Finally a big Thank You to Charlie for taking the time to come down and help me out with the Air spring.. I hope this short pictorial it may help other people doing their own Air spring in the future…

As usual stay safe and travel as much as you can..