hobo-letta Posted July 30, 2006 Share Posted July 30, 2006 I have a 1973 RS 700 L with a Garrison Type Power Assist with a "SHIMMY" at very low speeds. Front wheels and steering wheel shake rapidly. At normal driving speeds the steering seems fine accept there is a lot of free play. Any HELP? Quote Link to comment https://www.bigmacktrucks.com/topic/1363-garrison-power-steering/ Share on other sites More sharing options...
Rob Posted July 30, 2006 Share Posted July 30, 2006 I have a 1973 RS 700 L with a Garrison Type Power Assist with a "SHIMMY" at very low speeds. Front wheels and steering wheel shake rapidly. At normal driving speeds the steering seems fine accept there is a lot of free play. Any HELP?It seems that you have loose front end parts, or a badly misaligned/bent front rim on the steer axle. The control valve for the steering mechamisim is trying to re-center the linkage and when it takes up the slop, it rapidly shifts the other way. Control valves are very close tolerance internally, and just a fraction of an inch movement (internally) will cause them to route hydraulic boost pressure in the direction it thinks you are try to turn the truck in. When the loose front end part shakes a bit due to clearance or wear, the control valve rapidly shifts direction. It doesn't matter all that much on a "long arm, short arm" type front suspension, but king pins are much more susseptible (sp?) to this behavior.Hope this helps.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/1363-garrison-power-steering/#findComment-6836 Share on other sites More sharing options...
hobo-letta Posted August 2, 2006 Author Share Posted August 2, 2006 It seems that you have loose front end parts, or a badly misaligned/bent front rim on the steer axle. The control valve for the steering mechamisim is trying to re-center the linkage and when it takes up the slop, it rapidly shifts the other way. Control valves are very close tolerance internally, and just a fraction of an inch movement (internally) will cause them to route hydraulic boost pressure in the direction it thinks you are try to turn the truck in. When the loose front end part shakes a bit due to clearance or wear, the control valve rapidly shifts direction. It doesn't matter all that much on a "long arm, short arm" type front suspension, but king pins are much more susseptible (sp?) to this behavior.Hope this helps.Rob Thanks for the information Rob. Quote Link to comment https://www.bigmacktrucks.com/topic/1363-garrison-power-steering/#findComment-6894 Share on other sites More sharing options...
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