Mr. Yale,

. . . I’m happy to say that I have installed the air bags and am quite pleased with the performance on my Volvo 770. I installed them myself without any special tools, just a 1/2 in. drill and normal wrenches in about 4 1/2 hours - about an hour of which was spent deciding where to locate the valve and gauge on an already quite full dashboard. I had only about nine inches of air tubing left over after the installation so I suggest including a couple more feet with the kits. I had three problems with the front end of my truck which are now solved. One of which was solved by fitting the truck with a heavier duty steer tire load rated for 7,300 lbs. The other two, the harsh front end ride, and overloaded shackles were solved by the addition of the Donvel Steer Axle Stabilizers. In a world where advertisers seem willing to say just about anything regardless of the truth, making all sorts of wild claims, few of which actually hold up in the real world, it is refreshing to see that the claims made in Donvel’s literature do, in fact, hold up to be true, even to a rather skeptical tough sell such as myself.

With little experimentation I am literally able to dial out most of the shock to my dashboard caused by horrendous concrete joints and breaks in the surface such as I-40 and I-30 in Arkansas among others. With an opposite setting I can dial out a lot of trailer back slap from wavy roads. Also, quite a bit of the wander from road ruts has been eliminated. But one advantage that may seem to be only a concern to some is that on my Volvo the front end is so seriously overloaded right out of the factory (12,420 bobtail) that I was unable to successfully get grease into the shackle pins without jacking the weight off them - a job that is more difficult than suspected on the road where few shops have a jack capable of jacking from the tow hook tubes, the only way to jack the frame, not the axle. The way I formerly had to do it was insert a bottle jack between the leaf spring and the frame and jack them apart. This is precisely where the Donvel air bag is installed already so all I have to do is inflate them to accomplish the same thing - only without all the sweat and greasy clothes! Now all I have to do to successfully get grease into the shackles is to inflate the air bags to 100 lbs. just before going into the grease shop! I can also easily grease them between services quite easily with my own low pressure portable grease gun.

The long term benefit of taking some of the weight off the shackle pins and bushings should be, of course, much longer wear for the bushings. I must also add that the first class air fittings used (push on) really added to the ease of installation. Good choice. Thanks. You may reprint all or part of this letter for your advertising purposes without compensation as long as you remain true to the original intent.

Sincerely,
D. W. Bowling

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