Should I make replacement Polyurethane bushings for the 521?

[ConnortheWeller]

I'm working on repairing an old datsun 521 I picked up and I'm having a little trouble finding replacement steering bushings. I've got a small machine shop and a molding machine that can run polyurethane. If I were to make replacement bushings would that be something anyone would be interested in buying? or am I missing a source that already exists?

[datzenmike]

The idler arm might have bushings but probably metal, but the rest of the steering are ball joints. A lot of the suspension have rubber bushings. 

 

I don't recommend poly over rubber. It's too stiff and non compliant. Rubber can grip two moving parts and twist with movement. Poly might grip one surface but not the other causing squeaks, chafing and wear. Rubber is excellent for vibration isolation where poly is not. Poly is good for racing applications where noise and vibration are not an issue and where there is regular inspection and replacement.

 

I do recommend poly on sway bar links but not the bushings that hold the bar.

 

 

Someone here will have a source for 521 rubber parts. 

 

Always wondered if you could make them out of rubber on a lathe.

[mklotz70]

Exactly which bushings are you trying to find? 

[]2eDeYe]

I was just going to suggest talking to mklotz of bluehands.... 😄

[datzenmike]

Speaking of Beelzebub.....

[ConnortheWeller]

4 hours ago, datzenmike said:

The idler arm might have bushings but probably metal, but the rest of the steering are ball joints. A lot of the suspension have rubber bushings. 

 

I don't recommend poly over rubber. It's too stiff and non compliant. Rubber can grip two moving parts and twist with movement. Poly might grip one surface but not the other causing squeaks, chafing and wear. Rubber is excellent for vibration isolation where poly is not. Poly is good for racing applications where noise and vibration are not an issue and where there is regular inspection and replacement.

 

I do recommend poly on sway bar links but not the bushings that hold the bar.

 

 

Someone here will have a source for 521 rubber parts. 

 

Always wondered if you could make them out of rubber on a lathe.

I'd prefer to make them out of buna rubber but I'm not super familiar with the process for manufacturing with it.  I was worried about the noise with poly bushings but it sounds like if they are greased correctly you can mitigate this, although I have zero experience with them. 

 

Part of my reason for asking is that if there is actually a need for 521 bushings it would be a great little niche for company to help out with while helping keep more old datsuns on the road (or at least easier to keep on the road).

 

can you machine buna rubber? I've never heard of that, would be super cool if you could though.

[ConnortheWeller]

3 hours ago, mklotz70 said:

Exactly which bushings are you trying to find? 

all of the bushings to rebuild the front and maybe even the rear suspension. I've looked around a but there doesn't seem to be a very dependable/affordable source besides a few ebay listings for new old stock.

[ConnortheWeller]

1 hour ago, ]2eDeYe said:

I was just going to suggest talking to mklotz of bluehands.... 😄

I'm not familiar with either, can you point me in the right direction?

[ConnortheWeller]

Just now, ConnortheWeller said:

I'm not familiar with either, can you point me in the right direction?

oh duh he commented above nevermind

 

[paradime]

6 hours ago, datzenmike said:

 

Always wondered if you could make them out of rubber on a lathe.

 

I've only lathed wood so I'm no rubber expert, but I would think it's wildly impractical due to tooling and centrifugal distortion. Maybe a CNC with a rubbadublade? In this application, I think the molder the better. If you didn't have a reference piece, you could lathe the mold pretty well though.

[datzenmike]

Can you print rubber like compound?

 

No matter what you do you need an original or the dimensions.

[mainer311]

Rear leaf spring bushings might come in handy.

[wayno]

All that stuff is different, left to right, shock/sway bar bushings, Bushing upper link, and leaf spring bushings.

 

 

 

 

[mklotz70]

All the buna I've dealt with has been for gaskets.  The softer it gets, the harder it would be to machine.  Urethane cuts pretty easily with a polished insert designed for aluminum.  Doing it on a wood lathe would probably be a bit scary.  If your hand held tool took a bit too much bite, it could screw up the part.....at a minimum. Machining urethane can be fun...

The rear shackle bushings come up on ebay now and then. 

 

The UCA to dogbone bushings are still cheap and easy to get, they just don't last long at all....which is why I started making a urethane version years ago.

http://www.bluehandsinc.com/320520521620drum-urethane-uca-bushings.html

 

The LCA inner bushing should still be available, but it's pretty rare that they're bad enough to justify the nightmare of replacing them.  Info at the bottom of this page...

http://www.bluehandsinc.com/ball-joint-infoparts.html

 

The tension control rod bushings can be replaced with the sway bar end link bushings....which are cheap and easy to get.  I would not use urethane for these since they can cause the TC rod to snap.  It's down the page a bit, but you'll see how the urethane bushings need to be "softened" so they don't snap the rod.  DimeQaurterly did a great write up many years ago which is where I got the info for this modification.