1999 CH Mack. Making an RV out of a Single drive 1999 CH Mack

[Aussie Greg]

Hello all. I'm a first time poster here. So be gentle. 😃 I'm currently building a CH Mack for RV use only. Its a fairly long wheelbase single drive with rear Hendrickson Airbag suspension. It has a standard (fully rebuilt) front end 3 leaf parabolic spring set up. I'm chasing a softer front end for RV use but concerned with going outside of safety / engineering standards. I would dearly love to add airbag to the front end and this is very do-able here is Australia. My thoughts in adding air to an already fairly rigid sprung front end won't help me (Happy to be wrong :)) I see all these web based sset ups from the USA especially regarding long wheelbase KW's and Peterbilts and note they have airbags installed with usually 2 shock absorbers, but only run one leaf spring? To me this seems unsafe? One leaf breaks and it all turns to the brown stuff.

Ultimately I'd like to take out one of the 3 parabolic leaves (to soften the ride) and add the airbag to get the correct ride and height. As i'm only ever using this truck for RV use not haulage, i will run a consistent weight on the front end. The RV body will only be approximately 2 Ton so the steer won't be a whole lot different to running around in a commercial environment bobtail (Empty). 

Just reaching out for some feedback after telling my brief story. In Australia, we don't have the suppliers and resources you have in the USA so grateful for any ideas or thoughts. 

[Brocky]

Welcome to BMT!!!  Pictures are always welcome also!!!! Please start another topic in the Antique and Classic section.  What year and specs on the CH??? Being in the States I can not advise you on what the Aussie engineering and inspection people will have to say. I know they are stricter than what we have up here. Maybe Mrs Mack Paul can help you there?? You can PM him thru this website.

I drove a 2006 Freightliner for 5 years with a factory air ride steering axle. To be honest I never looked it over close to see how it was assembled, but am pretty sure it had at least one leaf spring. When I first got it, when you hit a bump it seemed like it wanted to wander, go where it wanted, a lot like when we first got radial tires on the steering and still had bias on the drives. After while I guess I got used to it?? This was a sleeper operation and I believe it rode a little better than the 9600 Inter I got out of???

[Vladislav]

Welcomer to the forum!

I have a couple of cents to toss in the ring regarding your ideas. 1st there was a guy on the forum who added airbags to the stock front axle of his 2nd generation Superliner. As long as I remember all 3 leaves rested in place and the bags were put in between the axle beam and bottom sides of the frame rails. 

The 2nd is I have a MH-model which normally (to my understanding) must have 3 leaves in each front spring as your truck. But that truck has only two leaves. I haven't checked the thicknesses yet so keep wondering of if springs of Vision-model (2 leaves) were used or just the 3rd leaf removed. But I have the truck driven for about 1600km when moved it to my place and found nothing extraordinar in riding. Ok, a cherry on the top of the cake - front shocks were not taking place there at all. 

Vlad