poor-mans rear subframe bushing upgrade idea...

[Dackelone]

I was watching MotorTrend's Hot Rod Garage Ep. 37 #Bonemaro project and I got an idea when they used some 3M Window Weld urethane to make some upgraded motor mounts. I got to thinking why couldn't you use this product to harden the factory 1er rear subframe bushing mounts!?!?

I think ideally, one should still drop the subframe and use a small hose to strategically inject the urethane from the TOP and from the bottom of the RSB's. This idea seems so simple, I am surprised no one has thought of it for our cars.


Watch this video from 09:07, where they use 3M's Window Weld urethane to beef up the stock GM/Chevy motor mounts...

3M 08609 Window-Weld Super Fast Urethane Black Cartridge - 10.5 fl oz.
http://www.amazon.com/3M-08609-Windo...3M+window+weld

[anglocanadian]

I think you will find the urethane in the centre of the bushing will take forever to cure , if ever !
Its intended to be used in thin layers, 2 part silicone (as used for prototype moulds) would cure properly.
Neither would would be as rigid as the Whiteline inserts

[houtan]

If you're taking the time to lower the subframe, just rent the tool from harold and install whitelines replacement two piece bushings. With the tools, the bushings come out very easy.

[2002ish]

The same thought went through my mind when I saw that video.

[tracer bullet]

The idea has been done for many years for motor mounts for various cars. It never seems to work as well as the real thing. The window weld looks good at first but over time detaches and breaks down leaving you where you started. That's what I've always seen anyhow.

[mr.fabulous]

OLD cars get that treatment because parts are NLA. But if you're taking a 1er that far apart, just renew the bushings.

[kong24680]

Solid bushings or go home bro!

[vtl]

I had seen someone pouring polyurethane in some Audi A4 transmission mounts that had big voids in the rubber. Made sense for that platform as the aftermarket solutions were stupidly expensive for just a single mount. But in this application (E8x/E9x) doesn't make sense IMO

Nolathane poly bushings only cost me around $165AUD. Yes, inserts and gap filling means you wouldn't have to pull the old bushings out, but honestly its not that hard removing them. First time I installed these bushings I used hand tools to pull them out.

The Nolathane bushings are pretty much the same as the Whiteline 2 piece bushings. The same company owns both the brands apparently. They press in by hand unlike the M3 bushings and don't require the subframe to be dropped as much

I made my own bushing removal tool with some PVC pipe and threaded rod:

http://www.1addicts.com/forums/showthread.php?t=1158856

I've installed it on a few cars. Sometimes the bushings come out super easy, sometimes its a royal pain. WD40 helps massively

[bNks334]

This is really common in the Honda crowd. I did it on my civic. You can buy the stock bushings on ebay as a kit for dirt cheap and fill them with some 85 durometer polyurethane from home depot... way cheaper than spending $300 on new bushings.

However, as other people pointed out, the higher durometer poly will separate from the softer internal rubber it's filled. The home made bushings will fail over time and you'll be looking to do the labor all over again in a few years

[Solo_M_Tech]

I have the M3 bushings and Im considering going to Solid. Maybe this summer it will happen.

As for the window weld treatment. The window weld isn't what you want. You want to find a 2 part urethane epoxy designed to cure to rubber and cures solid. It is available and most online speed part retailers have it. It's been done in the drag racing world for decades with sucess. Though I don't think it would be a smart solution to the RSFB on our cars, since it takes 3 days to cure 100%, and the rubber has to be clean and dry to adhere properly.

[tjswarbrick]

I just found the 95A durometer black/race Powerflex inserts at ECS for just a few bucks more than yellow street inserts.

If the stock ones really are as easy to remove as people say, and the subframe doesn't need to be fully dropped, I'm willing to go 2-piece poly replacements (would go yellow in that case, or Whiteline.) But I'm wondering if using the hard black inserts would make it moot.

[uberschnell]

inserts should be the poorest anyone goes. They are cheap and easy to install. The urethane/window weld wont fix the up/down movement which the inserts do.

Or go full replacement, I did mine in my driveway.

[Freon]

I've done this on a previous car for motor mounts. It can work. It's easy and cheap.