Polybushes
Posted: Tue Nov 19, 2013 9:10 pm
I have just refurbed the rear beam on the Rocco (MK2 1.8 GTS) everything has been refinished or replaced and the last part to fit before I refit it to the car is the pivot bushes VW Part no. 171 501 537. These aren't available from VW or Heritage anymore so I have been reluctantly thinking about using Polybushes. I'm confused though about how they could ever work properly - This is my thinking :
I am happy to use Poly bushes on the ARB as they work in exactly the same way as the original bushes i.e. by "squashing" with a negligible rotational movement.
The bushes on the pivots however rotate mostly with a bit of "squashing" too. The original OEM rubber bushes are bonded to a steel sleeve and into a larger steel sleeve, both sleeves are clamped tight and the rotation is achieved within the flexibility of the rubber. Nothing moves against anything else, no wearing surfaces, no lubrication. The movement is all as a result of the torsional quality of the rubber, all good. The only downside is that eventually, after many years, they perish.
But as far as I can find out, Poly bushes in this application are not bonded to the inner or outer sleeves and therefore must rely on rotation to work ? Either in the outer sleeve, around the inner sleve, or both ? They assemble with grease but even so surely something is going to be wearing against something else and, surely they will stick before they break free and move even when they are new ?
I researched on the internet and came up with this http://www.netbug.net/blogmichael/?p=103 which seems to make perfect sense.
Is this wrong ? Can anyone explain how a polybush would operate properly in this application ?
I am happy to use Poly bushes on the ARB as they work in exactly the same way as the original bushes i.e. by "squashing" with a negligible rotational movement.
The bushes on the pivots however rotate mostly with a bit of "squashing" too. The original OEM rubber bushes are bonded to a steel sleeve and into a larger steel sleeve, both sleeves are clamped tight and the rotation is achieved within the flexibility of the rubber. Nothing moves against anything else, no wearing surfaces, no lubrication. The movement is all as a result of the torsional quality of the rubber, all good. The only downside is that eventually, after many years, they perish.
But as far as I can find out, Poly bushes in this application are not bonded to the inner or outer sleeves and therefore must rely on rotation to work ? Either in the outer sleeve, around the inner sleve, or both ? They assemble with grease but even so surely something is going to be wearing against something else and, surely they will stick before they break free and move even when they are new ?
I researched on the internet and came up with this http://www.netbug.net/blogmichael/?p=103 which seems to make perfect sense.
Is this wrong ? Can anyone explain how a polybush would operate properly in this application ?