Skip Fix
03-06-2013, 08:17 PM
Thought it posted but don't see it so I'll try again.
Ok putting the rear back in the 81. Freshened the rear and rear disc calipers. Getting new Bilsteins and front springs .Original shackle bushings not really too bad.Outer edges frayed but all the inner looks good, but figured I would replace them. Well that is where the dlilema on fit comes in.Hard to get a dial caliper up in the frame but the rear spring eye is 1.609". Frame might be a hair tighter.
So the OD on the factory ones is 1.575 GM #480902 but they have been squeezed in theere proabbaly since '81. MOOG has two numbers listed for our cars. Some MOOG K6560s(comes 4 to a box) that are the correct "thick" outer portion are only 1.543 and made of a pretty firm rubber they say is as stiff as urethane. The other MOOG number listed K6559(two to a box) has the incorrect thin outer is the same 1.543 and feels pretty sloopy in the the spring eye non compressed. NAPA number HB1136(two to a box) are the correct thick outer and are 1.566". Old Energy Susp. poly is 1.620 no way will it fit in the frame and maybe could pry the eye open some to fit in. Customworks Delrin is 1.570 and do. Global Frame aluminum1.585 and is a press fit, spring eye 1.633 and will also be a tight press fit.Weird deal is inner Delrin sleeve is 0.050 shorter on the frame and 0.065 shorter on the spring eye so ther is no clamping to spin on just the Delrin inner sleeve all the spinning is the outer Delrin washers on the aluminum sleeve and and shackle.
All two piece butt together on the center before the outer lip touched the spring or frame uncompressed,except the Custom works.
So as the rubber compressed I assume it swells and takes up the slack I feel uncompressed? Something poly sure can't do.
Anyone else used poly and how did they fit?
Ok putting the rear back in the 81. Freshened the rear and rear disc calipers. Getting new Bilsteins and front springs .Original shackle bushings not really too bad.Outer edges frayed but all the inner looks good, but figured I would replace them. Well that is where the dlilema on fit comes in.Hard to get a dial caliper up in the frame but the rear spring eye is 1.609". Frame might be a hair tighter.
So the OD on the factory ones is 1.575 GM #480902 but they have been squeezed in theere proabbaly since '81. MOOG has two numbers listed for our cars. Some MOOG K6560s(comes 4 to a box) that are the correct "thick" outer portion are only 1.543 and made of a pretty firm rubber they say is as stiff as urethane. The other MOOG number listed K6559(two to a box) has the incorrect thin outer is the same 1.543 and feels pretty sloopy in the the spring eye non compressed. NAPA number HB1136(two to a box) are the correct thick outer and are 1.566". Old Energy Susp. poly is 1.620 no way will it fit in the frame and maybe could pry the eye open some to fit in. Customworks Delrin is 1.570 and do. Global Frame aluminum1.585 and is a press fit, spring eye 1.633 and will also be a tight press fit.Weird deal is inner Delrin sleeve is 0.050 shorter on the frame and 0.065 shorter on the spring eye so ther is no clamping to spin on just the Delrin inner sleeve all the spinning is the outer Delrin washers on the aluminum sleeve and and shackle.
All two piece butt together on the center before the outer lip touched the spring or frame uncompressed,except the Custom works.
So as the rubber compressed I assume it swells and takes up the slack I feel uncompressed? Something poly sure can't do.
Anyone else used poly and how did they fit?