rivercreek
Member
- 101
- 1
- 18
- Location
- Berryville, VA
Thought I'd share a seeminglyunusual problem and it's fix I discovered on my A3 steering system. Symptom:Truck felt as though there were detents in the steering box, for lack of abetter way to describe it. Most noticeable while turning the wheel at speed(over 20-25mph) - tight spots in the steering. More strangely, inconsistentlocations as well (not necessarily always at 2,4 6 oclock). Truck was difficultto drive in a straight line on a crowned road or smoothly through curves. If asmall correction L or R took the wheel past a detent, truck would swerve,requiring steering corrections topping several of these detents. I haveunintentionally stumbled onto an animation that shows with remarkable accuracythe action required to keep this truck going straight down the road (Minus theshifting, of course - and minus the smile as well). Ispent quite a bit of time researching both SS and Google for answers, andwasn't able to find anything that addressed my specific problem. Workingbackwards, I narrowed the culprit to the power cylinder (pneumatic cylinderattached to tie-rod). After pulling the air lines, bolts, fittings, etc., Iproceeded to dump app. 1/2 cup of nasty white goopy crap out of both sides ofthe cylinder. (Air dryer was not working properly when I bought the truck, it'ssince been repaired, along with both of my air tanks that had rusted through.)Manual efforts to pull the cylinder apart for cleaning were unsuccessful, and Iended up using air pressure. Note: USE CAUTION! I had read of others' warningsabout doing this and did it with some apprehension. I plugged the hole for thedrain plug with a finger while using a rubber tipped air gun on the air hosefitting to prevent over-pressurizing the R side of the cylinder and blowing ahole through my wall or perhaps worse. With just the pressure I was able tohold with a finger, that ram came out of there with MUCH more force than I had anticipated. I had read in several places that the cylinder cap was threaded, mine was not.Perhaps they made different types, I don't know. Once apart, I was able toimmediately see what was causing the binding, and it was not at all what Iexpected. It wasn't the rubber packing binding inside the cylinder at all, onceapart, the packing moved smoothly back and forth. The problem was that the ramitself was binding inside the cylinder cap. I had to use a mallet to beat thecap off of the ram. What I found was that I had some corrosion on the inside ofthe cylinder cap due to the water intrusion. In the center of the cylinder cap,there is a brass bushing that the ram passes through. Corrosion had gotten inbetween the (fairly thick) aluminum cylinder cap and the (thin) brass bushingand was actually compressing the bushing against the ram. Naturally the steel ramis much harder than the brass bushing, therefore there wasn't ANY sign of thison the ram at all. Nothing at all that could be seen without taking thecylinder apart. The fix was fairly straight forward, just took a dremel toolwith a fine sanding wheel and slowly ground out the brass bushing, checking thefit as I went. Only took a couple minutes. The only other thing I did (which Icannot say for sure is necessary or not) was to add an o-ring on either side ofthe rubber packing between the rubber packing and the large washer. It lookedto me as though there may have been a lip of some kind on the center hole ofthe packing that had been chewed up pretty well, my intent was to replace thisas best as possible. I did this only because of what you see in the picture Itook of the packing ring (the bubbles under the surface). In any case, once Igot everything back together and buttoned up, the steering was BEAUTIFUL. Nomore detents, no more jerky steering, smooth as silk. One last thing -according to Air-O-Matic, these cylinders, packings, o-rings are NOT supposedto be lubricated. According to the old service manual I found (which didn'thelp me a bit in this diagnosis or repair), you are not supposed to use anysort of oil, penetrating oil, grease, etc. on these units. Supposedly they aredesigned to work dry. Well, I'm certainly no engineer and perhaps I wascompletely wrong in doing so - but I used Parker O-Ring Lubricant on EVERYsingle o-ring and packing in the whole unit. I know that there are a number ofother members who have used MMO with significant results, and I just can't seehow dry rubber sliding on dry metal is a good thing. Anyway, I guess Parkercan't be any worse than MMO.. Hope this helps some other poor soul out therewho has spent as much time as I did trying unsuccessfully to troubleshoot thisstrange problem. Hopefully photos will attach properly..
