New mustache bushing updates?

[AK260]

That’s a shame - there’s a part of me that feels there HAS to be one that fits - but better minds than mine have already looked. :(

 

I only have rubber left on one of my serrated washers. I’m about to cut up a rubber compression rod bush to make one. I did originally with a poly one of the same and it got rid of clonking when hard on the power and hitting bumps / holes in the road. But now I have the moustache bar off, I can better make something out of rubber. Will post up any success once I get around to it.

 

[Zed Head]

You could pour your own.

https://itwperformancepolymers.com/products/devcon (type urethane in to the search box)

https://www.flexsealproducts.com/

 

[AK260]

You could pour your own.
https://itwperformancepolymers.com/products/devcon (type urethane in to the search box)
https://www.flexsealproducts.com/
 

Now that would be very cool if it would stand the stresses!!

[Captain Obvious]

I firmly believe there are other options for rubber moustache bar bushings out there but the problem is figuring it out.

The original bushings pressed in (lightly), and then were swaged over for permanent retention. I bet a workable solution would be to use a new bushing of "similar, but slightly smaller OD" than the original and press the new one into the remains of the old bushing. Kinda like what you do with poly, but do it with a new rubber bushing instead.

All that needs to be done is for someone to find that "similar, but slightly smaller bushing".

I saw some pics of Miata diff mount bushings that looked interesting... Anyone have a Miata that could measure some bushings?

[Zed Head]

7 hours ago, AK260 said:

Now that would be very cool if it would stand the stresses!!

I can't remember who it is (anybody?) that is reproducing the small rubber parts but he would probably have the experience to make an attempt at it.  

Here's another good link.  Understanding how to create a good mold, following instructions, and knowing what can screw things up (moisture, contaminants, etc.)  are the key.

https://www.fibreglast.com/product/introduction-to-urethane-casting-resins/Learning_Center

[Zed Head]

Here's a start along the lines of what CO has been suggesting, the google search below.  It might be distasteful to many, because it seems "hacky," but a person could fill the void of an undersized bushing with metal-filled "space-age" epoxy (AKA JB Weld) and probably have a nice solid bushing assembly.

https://www.google.com/search?q=motor+mounts (browse the images)

https://www.jbweld.com/product/steelstik-epoxy-putty-stick

https://www.jbweld.com/products

 

[EuroDat]

We are talking about replacing the original bushing with something that has similar characteristics. We know the PU aftermarket bushings transfer a lot of diff noise to the body so making any bush out of PU doesn't seem to has any advantage.

I have made PU insulators for the fuel lines and other stuff for my own 280Z, but getting it to hold to the metal components enough to take the stress would be hard to achieve.

It would need to be a part from another car with a similar purpose. For example the original positon for the bolt was in the vertical position, otherwise it would probably fail quickly due to stress it was not designed for.

 

[ToolBoy]

I have used 2 part polysulfide rubber on teak boat decks and understand it's also used to glue up lap joints on the exterior skins of commercial jet fuselages because of its strength and flexibility. Probably too soft for this application? 

[Zed Head]

1 hour ago, EuroDat said:

We are talking about replacing the original bushing with something that has similar characteristics. We know the PU aftermarket bushings transfer a lot of diff noise to the body so making any bush out of PU doesn't seem to has any advantage.

I think that the commercially available replacements bushings were all made from a hard (high durometer) PU just because it was easy and cheap.  Probably chosen for a single application like the smaller front control arm bushings then they just started looking around for any rubber part that could be replaced, using the same material.

You can get PU in super-soft to brick hard.  An 80A would be pretty soft but firm.  PU's are very versatile, you can't discount all PU's because somebody in the past used them for the wrong purpose.    You just have to pick the right one.

https://www.polyglobal.co.uk/a-guide-to-shore-hardness/#:~:text=Polyurethanes are most commonly used,maintain their profile under pressure.

[Zed Head]

Here's a biased article from a company that makes PU products.

http://harknessindustries.com/rubber-polyurethane/#:~:text=Polyurethane has higher abrasion%2C cut,has better load bearing capacity.&text=Finally%2C polyurethane looks better than,better than its rubber counterpart.

[Captain Obvious]

6 hours ago, Zed Head said:

a person could fill the void of an undersized bushing with epoxy

I was picturing making a metal sleeve with an OD such that it pressed into the original outside shell (which you would leave in the moustache bar just like for a poly install) and an ID that would accept a smaller bushing pressed into place. I don't think I would trust epoxy there.

The thicker the sleeve, the smaller the bushing could that be used. I would want to keep it as close to stock as possible, but just something available instead of unobtainium!

[Zed Head]

2 minutes ago, Captain Obvious said:

 I don't think I would trust epoxy there.

No offense intended to anyone that has posted on this topic.  But some of these things just need to be experienced to be understood, I think/guess.  Carving up a piece of solid metal leaves an obviously strong part behind, made of metal.  But, if you go out and buy a piece of Steel Stick, or one of the other metal-filled epoxies, and try it out you'll understand how strong it can be, if prepared properly.  "Epoxy" is a nebulous word, the variety is large.

The same goes for polyurethane.  Rubber is used in the automotive industry because it's cheap.  If you've ever worked for a company that supplies automotive parts you'll understand how every fraction of a penny matters to the automakers.  They'll spend hundreds of thousands on engineering staff to design a part made from the cheapest materials.  Because the volume of parts is so high.  Making rubber parts cost quite a bit in tooling also.  Rubber parts are not poured, they are formed via pressure from rubber sheet or other solid form, and cured using heat.  I don't think that anyone is going to reproduce the rubber parts, in rubber.

I'm just posting options.  But nobody can really discount them off-hand without taking a closer look.

When I was messing with my mustache bar I bought some big rubber washers from the local hardware store and stacked them up to take up the space that the worn out scalloped washer used to fill.  AK260 could try that instead of carving up a PU bushing.  There are endless ways to get the big old chunk of mustache bar steel to stop moving around, clunking, but still avoid transmitting sound.