DIY poly rear diff bushings

[Bloodlust182]

Alright, so I decided to swap my solid aluminum rear diff bushings out for some poly ones.Since no one really sells poly rear diff bushings I decided to make my own like I did for my front control arm. I did not intend to make a write up, so I do not have pictures of actually cutting the stock bushings out. I don't own a press yet, so I just cut the center pins out by hammering a flat head through the rubber. I then used a sawz-all to cut the bushing sleeve out of the mount pieces. After cutting out a groove in the sleeve you should be able to push it out with a flat head and a hammer easily. You will end up with mounts that are like this:

http://i289.photobucket.com/albums/ll203/bloodlust182/20140322_133357_zps8bbd5b11.jpg (http://s289.photobucket.com/user/bloodlust182/media/20140322_133357_zps8bbd5b11.jpg.html)

I talked to Pauly P and he pointed me in the right direction for the size of the bushing. It turned out that 9.9484 (http://www.energysuspensionparts.com/proddetail.asp?prod=9.9484) fits very well. They are 18.99 for a pair, so we will need 2.

http://i289.photobucket.com/albums/ll203/bloodlust182/20140328_175338_zps51898516.jpg (http://s289.photobucket.com/user/bloodlust182/media/20140328_175338_zps51898516.jpg.html)

The only problem is the inner diameter on the pins is 9/16" but our bolt is about 3/8" To fix this gap I found some copper pipe couplings (2 per bushing so we need 8 total) at Home Depot at 79 cents each.

http://i289.photobucket.com/albums/ll203/bloodlust182/20140328_175355_zps588a1fff.jpg (http://s289.photobucket.com/user/bloodlust182/media/20140328_175355_zps588a1fff.jpg.html)



I didnt want to risk bending the copper when installing it so i used a spare 17mm bolt to center everything while hammering them in.

http://i289.photobucket.com/albums/ll203/bloodlust182/20140328_175617_zpsc23c3707.jpg (http://s289.photobucket.com/user/bloodlust182/media/20140328_175617_zpsc23c3707.jpg.html)

They fit very good.

http://i289.photobucket.com/albums/ll203/bloodlust182/20140328_175935_zpsa59d0d24.jpg (http://s289.photobucket.com/user/bloodlust182/media/20140328_175935_zpsa59d0d24.jpg.html)


Next, we will need to trim the bushing flange down. For the front 2 bushings I removed about 3/4 of the flange on my bench grinder

http://i289.photobucket.com/albums/ll203/bloodlust182/20140328_182350_zps414a9124.jpg (http://s289.photobucket.com/user/bloodlust182/media/20140328_182350_zps414a9124.jpg.html)


and about 1/2 for the rear bushings on the Y plate.

http://i289.photobucket.com/albums/ll203/bloodlust182/20140322_133410_zpsa257135d.jpg (http://s289.photobucket.com/user/bloodlust182/media/20140322_133410_zpsa257135d.jpg.html)

From here the bushings should slide easily into the mount holes. There is a gap between the 2 bushings, but I just fill it with grease and also grease the bushing prior to instillation too.

Here is one of the side mounts mounted to the diff/subframe

http://i289.photobucket.com/albums/ll203/bloodlust182/20140328_192257_zps42b4a81d.jpg (http://s289.photobucket.com/user/bloodlust182/media/20140328_192257_zps42b4a81d.jpg.html)

Y plate

http://i289.photobucket.com/albums/ll203/bloodlust182/20140328_192303_zps37ef870f.jpg (http://s289.photobucket.com/user/bloodlust182/media/20140328_192303_zps37ef870f.jpg.html)

With shipping, this cost me about $55 when all said and done. After listing up my solid bushings for sale I have received a few pm's asking why I was switching from solid aluminum to poly. I originally had a stock drive shaft with the Aluminum bushings. Surprisingly, the rear drive shaft dampener did a very good job keeping the rear diff quiet with the solid mounts. Shortly after installing the bushings my oem drive shaft u joint on the front yoke decided to go out. Decided to upgrade to a 2-piece aluminum/steel hybrid shaft I found for $450 shipped. Put the drive shaft in and I couldn't stand the whining from the drive train. With poly mounts now the whine is gone. Car feels solid when accelerating and is less harsh DD-ing.

[pipebomb]

1) How bad were your original rear diff bushings? Were they badly shot?
2) Were you able to wedge a metal bar down there and find play in the rear differential?
3) Were you previously clunking every time you let off the throttle?

Can you do a write-up on how you installed these rear diff bushings? Was dropping the rear differential necessary?
I have a set of new OEM rubber bushings that needs to go in. Debating if I should do it myself.

[green-lantern]

Can you post the sale link to the polly mounts?

[familyMAN]

Nice work! Too bad you didn't post this when I had my subframe out for AWS delete and diff swap.

[Bloodlust182]

1) How bad were your original rear diff bushings? Were they badly shot?
2) Were you able to wedge a metal bar down there and find play in the rear differential?
3) Were you previously clunking every time you let off the throttle?

Can you do a write-up on how you installed these rear diff bushings? Was dropping the rear differential necessary?
I have a set of new OEM rubber bushings that needs to go in. Debating if I should do it myself.


1. Bad
2. Didnt try.
3. Mine clunked every time I got on the throttle hard or shifted gears.

You do not need to drop the rear diff to swap the bushings out. I swapped out the mounts 1 at a time and had my jack supporting the diff. The only thing you need to disconnect really is the drive shaft to get the bolts out for the side mounts. If you are putting stock bushings back in; I recommend taking your mounts to a machine shop and having them press the bushings in if you do not have a press.


Can you post the sale link to the polly mounts?

It is hyper-linked to the part number. Just click on the part number and it should take you to where I bought mine.



Nice work! Too bad you didn't post this when I had my subframe out for AWS delete and diff swap.

Thanks, I wish I would have just went with poly bushings to begin with and made the w/u a few months ago =/.

[green-lantern]

It is hyper-linked to the part number. Just click on the part number and it should take you to where I bought mine.



OK thanks, didn't see that

[EvanH]

That's pretty cool. I'm curious of the durability of the copper.

[Bloodlust182]

The copper isnt really taking much of the beating from the drivetrain. It is just used to correctly center the bushings. The steel sleeve is pinched between the flanges on the subframe. I tighten the bolts fairly tight to keep everything from moving much.

[Elderloc]

Are those inserts hardened? I ask because it would be easy to make pins on a lathe. If they hardened would add extra step. Given that the poly is much more ridged does the thicker pin matter?

Will be interesting to see if 3SX gets the kits anytime soon, they bought the molds and are in the hands of a manufacture.

[Bloodlust182]

Thicker pin? I don't understand. The center of the poly(between the 2 pieces) could use a spacer, but I just fill it with grease.

[Elderloc]

I was thinking you could turn down the poly bushing on a lathe if you have one. Since you had to remove about 3/4 of the upper lip if you cut from the back and then trimmed off the top with a 45 degee chamfer like some other companies do to help with the sticking and loading.

Wish I hadn't sold my lathe, or eMachine shop worked in Poly I'd just get several sets cut. Can't believe no one will make these damn things there are 20k VR4 and RT or there. Oh well great write up things like this give me hope.

[fastfalcon94]

I tried to have a machine shop lathe my 90 shore poly down and they couldn't do it. They probably weren't using the right tools or something. They said they could have done mine with Delrin (sp?). I looked at it but it was an extremely hard plastic material that felt like metal so I decided against it. This same shop makes the Delrin bushings for Vermont Sportscar which builds the cars for the Subaru Rally team. I ended up making them work with a hand plane, a drill press, and a wood rasp.


https://www.youtube.com/watch?v=RFIX1dHVKs4

[Elderloc]

I have not worked with it in years but you do need to use the right speed, and a tool like a razor blade, or a hook tool. It's machined all the time for seals and other stuff.


https://www.youtube.com/watch?v=a10Z4vj7QI4

There are many other videos that show people milling 90a or other. It's done all the time, we did it CMI in the R&D labs when I worked there back in the early 90s.