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Polyurethane Bushings for Early ('65-'67) Chassis

Contributed on Registry forum by McGuillc, 2/28/01

Sometimes it seems as though the performance aftermarket wishes all of the really early ('65-'67) Porsche 911/912's would just go away and die quietly. Many parts (for the front suspension, for example) are EXTREMELY difficult to find and expensive as hell if they ever are. Some parts, like new bushings (of any type) for the front control arms are just flat not available - from anybody.

This was a roadblock in the restoration/upgrade of my '66 912 for quite a while - I even went so far as to inquire about having custom bushings made by a company that specializes in custom urethane products, and that idea died a quick death when the cost was estimated at over $400! After asking a few questions, looking at a few cars, and doing a little research, I decided to try and modify a new set of bushings that were manufactured to fit the '68 and later 911's. No one could give me exact measurements (not even the bushing manufacturer!?) but they didn't look all that different. Guess what? They're not. Don't get me wrong. It's not like they just slipped right on, they're just different enough not to (kinda like Schwinn bike parts used to be just different enough not to fit on other bikes when I was growing up). The rear bushing O.D, at 50mm (2.0") actually fit into the crossmember just fine. It's the bushing's I.D that's wrong for the early A-arms - it's too small.

A trip to a machine shop had them opened up to the 38mm (1.5") that fit perfectly on the A-arms. The front bushings were too big - both I.D. and O.D. At first I thought of using some type of bushing to take up the space between the O.D. of the A-arm and the I.D. of the poly bushing, but what was I going to do about the O.D.? Have it turned on a lathe down to the size that would fit into the recess of the suspension pan and the clamp underneath? While I pondered this, I kept looking a the parts. Then it hit me. What I needed was a way to reduce the I.D. AND the O.D. at the same time, and as far as I could tell (and measure), by the same amount.

Hmmm...I whipped out the Dremel, stacked TWO cut off discs together on the chuck and cut the bushing from front to rear, leaving a small gap in the side wall (0.075", to be exact.) Success! With a hose clamp squeezing the cut in the bushing back together they now fit perfectly over the front A-arm AND into the front clamp which bolts to the suspension pan at the front of the car. The new bushing measurements ended up being 35mm (1.395") for the I.D. and 50mm (1.985") for the O.D. I reasoned that since this is not a continuous rotation application, the A-arms only pivot a few degrees for full suspension articulation; the cut in the bushing wouldn't hurt anything. Besides, when clamped around the A-arm, the cut closes up to nothing anyway. I hope this encourages any other early 911/912 owners to try this simple modification for their cars. Just because the aftermarket won't supply the parts we need doesn't mean we have to do without.

Contact 911S Registry WebMaster
All pages copyright © 2000, 2001 Early 911S Registry
Information and images contained in this website may not be published, broadcast or otherwise distributed without the prior written authorization of the Early 911S Registry.
The Porsche crest is a registered trademark of Dr.Ing.h.c.F.Porsche AG.

Home Welcome Membership Publication Early S Boutique Member's Pics Photos Classifieds Events Links Contact Us Message Board Technical Info		*Early 911S Registry* A website devoted to early 911S Porsches
		Tech Info to share
		Polyurethane Bushings for Early ('65-'67) Chassis Contributed on Registry forum by McGuillc, 2/28/01 Sometimes it seems as though the performance aftermarket wishes all of the really early ('65-'67) Porsche 911/912's would just go away and die quietly. Many parts (for the front suspension, for example) are EXTREMELY difficult to find and expensive as hell if they ever are. Some parts, like new bushings (of any type) for the front control arms are just flat not available - from anybody. This was a roadblock in the restoration/upgrade of my '66 912 for quite a while - I even went so far as to inquire about having custom bushings made by a company that specializes in custom urethane products, and that idea died a quick death when the cost was estimated at over $400! After asking a few questions, looking at a few cars, and doing a little research, I decided to try and modify a new set of bushings that were manufactured to fit the '68 and later 911's. No one could give me exact measurements (not even the bushing manufacturer!?) but they didn't look all that different. Guess what? They're not. Don't get me wrong. It's not like they just slipped right on, they're just different enough not to (kinda like Schwinn bike parts used to be just different enough not to fit on other bikes when I was growing up). The rear bushing O.D, at 50mm (2.0") actually fit into the crossmember just fine. It's the bushing's I.D that's wrong for the early A-arms - it's too small. A trip to a machine shop had them opened up to the 38mm (1.5") that fit perfectly on the A-arms. The front bushings were too big - both I.D. and O.D. At first I thought of using some type of bushing to take up the space between the O.D. of the A-arm and the I.D. of the poly bushing, but what was I going to do about the O.D.? Have it turned on a lathe down to the size that would fit into the recess of the suspension pan and the clamp underneath? While I pondered this, I kept looking a the parts. Then it hit me. What I needed was a way to reduce the I.D. AND the O.D. at the same time, and as far as I could tell (and measure), by the same amount. Hmmm...I whipped out the Dremel, stacked TWO cut off discs together on the chuck and cut the bushing from front to rear, leaving a small gap in the side wall (0.075", to be exact.) Success! With a hose clamp squeezing the cut in the bushing back together they now fit perfectly over the front A-arm AND into the front clamp which bolts to the suspension pan at the front of the car. The new bushing measurements ended up being 35mm (1.395") for the I.D. and 50mm (1.985") for the O.D. I reasoned that since this is not a continuous rotation application, the A-arms only pivot a few degrees for full suspension articulation; the cut in the bushing wouldn't hurt anything. Besides, when clamped around the A-arm, the cut closes up to nothing anyway. I hope this encourages any other early 911/912 owners to try this simple modification for their cars. Just because the aftermarket won't supply the parts we need doesn't mean we have to do without.
		Contact 911S Registry WebMaster All pages copyright © 2000, 2001 Early 911S Registry Information and images contained in this website may not be published, broadcast or otherwise distributed without the prior written authorization of the Early 911S Registry. The Porsche crest is a registered trademark of Dr.Ing.h.c.F.Porsche AG.