Rear Differential Bushings Write-Up w/Part Number :) 90-94

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kimokalihi
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Rear Differential Bushings Write-Up w/Part Number :) 90-94

Post by kimokalihi »

I decided to do a little write-up on these bushings because I had such a hard time finding them.

What's the point of them you ask? They are much stiffer than the OEM bushings and they significantly reduce the rear differential's ability to rotate when torque is applied via the driveshaft. This gives you more torque (throttle response) to the rear wheels and also helps eliminate a lot of the dreaded "clunk" in most older subarus. There's many companies including whiteline and turn-in-concepts that sells these bushings but they're only for 2002+ which won't fit 1st gen legacys.

The bushings are not sold in the USA to the best of my knowledge. I stumbled across them by accident over on eBay UK. They're made by PowerFlex and they're list as "(PFR69-123) Rear Diff Mount, Early RA & UK WRX Models" but they also fit our cars because we have the same rear diff mounting bracket.

http://www.powerflex.co.uk/product-deta ... /1817.html

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Only the 93-94 GC Impreza uses this bracket. 95-01 Imprezas have bushings directly in the subframe with no bracket. In 2002+ Subaru went back to the bracket but used smaller bushings and the bracket was no longer offset like ours.

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So here's what $80 will get you.

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Tools required to get the job done:

17mm Wrench
17mm Socket
Extension
Swivel Adapter
Hammer
Impact Gun (speeds it up but not required)
Hack Saw
Punch
2 Extra 17mm Nuts
Wire Wheel Ginder (cleans everything up while off the car; optional)




Jack your car up using blocks under the front tires and set it down on jackstands. Shake car and jack stands to make sure it's sturdy before crawling underneath.

Screw the 2 extra 17mm nuts onto the ends of the studs on the back of the rear diff. This allows you to get a wrench on the inner nuts and loosen the studs without the nut coming off. Then use your 17mm wrench to remove the 2 studs as pictured below. Make sure to support the diff with a jack before removing them all the way.

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Remove the two bolts holding the bracket in the subframe. The right side bolt hits the axle so the diff must be lowered to gain clearance to pull the bolt out. I thought to myself,"Why did these idiots put the bolt in through this end if it hits the axle when you try to take it out!" Then I tried putting it in through the other side and realized it hits the gas tank. :roll:

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Once both bolts are removed yank the bracket out and you're left with this.

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I tried using a press to remove the bushings which are housed in a metal sleeve which also has to come out and that was a major PITA and got me nowhere. Then I got the idea that I could cut the bushing out and use a hacksaw to cut the sleeve and punch it out. It worked really well. Take your hacksaw blade off and insert it through the hole in the bushing and cut both ends off. Remove the bushing and proceed to cut two slices almost all the way through the sleeve. Then use a hammer and punch to remove the piece in between. This relieves pressure of the sleeve and allows it to come right out. This is a good time to clean the bracket up nicely inside and out. Wire wheel got all the dirt and grease off easily. Careful not to remove the paint or it will rust.

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Use the supplied grease to lube up the new bushings and metal bolt sleeves and pop them into the bracket.

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Hard part is over. Get back under your car and jam the bracket back into the subframe starting with the left end and then insert the right side and line up the bolt holes. Insert the bolts into each end. Reinstall the diff studs before torquing anything so it's easy to get them in. Then tighten them all up really nicely by hand and go test drive your car, hopefully with much less drivetrain clunk! Killed the remaining clunk leftover after replacing my trans crossmember bushings, rear diff outrigger bushings, subframe locking bolts and driveshaft carrier bushings.

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Last edited by kimokalihi on Fri Oct 14, 2011 6:39 am, edited 2 times in total.
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SiCkSTi04
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Re: Rear Differential Bushings Write-Up w/Part Number :)

Post by SiCkSTi04 »

I'll have to purchase a set from them. Excellent write up Sir :)
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silver03
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Re: Rear Differential Bushings Write-Up w/Part Number :)

Post by silver03 »

Terrific write up! Is it worth it? Were yours toast?
kimokalihi
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Re: Rear Differential Bushings Write-Up w/Part Number :)

Post by kimokalihi »

Thanks. No they were still good to go but much more flexible than these. Much more. I could flex them by hand and you'd never be able to do that with these.
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Re: Rear Differential Bushings Write-Up w/Part Number :)

Post by Legacy777 »

Nice write-up Kimo!

It's amazing the difference in color of the bushings between your first pictures and the later ones.

So did it add much more NVH compared to what you had with all the other stuff?

Do you have bushings for your laterial & trailing links?

Looks like I'll be picking a set of these bushings up.



Oh and yes....cutting those old metal collared bushings out is the only way. I dealt with that for the trailing link and rear a-arm bushings. It super sucks!
Josh

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Legacy777
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Re: Rear Differential Bushings Write-Up w/Part Number :)

Post by Legacy777 »

Just picked a set of these up off of ebay UK
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
kimokalihi
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Re: Rear Differential Bushings Write-Up w/Part Number :)

Post by kimokalihi »

Thanks Josh. They actually pm'd me over on NASIOC and asked me to put the write-up on SLI too. Awesome. I did not notice any added NVH. My NVH is pretty bad already lol. I'm sure if you only added these and not the other bushings and locking bolts I have you would notice a difference but I think it thins in comparison to the subframe locking bolts.

I don't have any suspension bushing upgrades yet except of course the rear whiteline swaybar bushings.
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Re: Rear Differential Bushings Write-Up w/Part Number :) 90-

Post by coffeeman885 »

These went in quite easily after using the hacksaw bushing removal thing. I will know how much they help after the race this weekend.
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kimokalihi
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Re: Rear Differential Bushings Write-Up w/Part Number :) 90-

Post by kimokalihi »

Hack-saw for the win!
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Re: Rear Differential Bushings Write-Up w/Part Number :) 90-

Post by crisco »

me likey
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Re: Rear Differential Bushings Write-Up w/Part Number :) 90-

Post by nortonjefferson »

Would anything for a 93+ Impreza work? Beat rush makes a whole bracket for the rear diff. I have an 02 lsd automatic (4.11FD) wrx rear diff I would like to throw on my car but while I'm at it id like to put new bushings or even a whole bracket back there. When I shift hard or leave hard from a stop I get a horrendous clunk. I found this https://www.rallysportdirect.com/part/t ... upport-bar but don't know if it will be compatible? Any help would be much appreciated!
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Re: Rear Differential Bushings Write-Up w/Part Number :) 90-

Post by Legacy777 »

It looks like that bracket has the same offset as the stock one....so I would think it would work, but someone else would have to comment on whether they know for sure it would work.

I suspect the clunk you are hearing is from the outrigger hitting the chassis. You want these bushings.

http://www.whiteline.com.au/product_det ... 1&sq=20699
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
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Re: Rear Differential Bushings Write-Up w/Part Number :) 90-

Post by nortonjefferson »

Legacy777 wrote:It looks like that bracket has the same offset as the stock one....so I would think it would work, but someone else would have to comment on whether they know for sure it would work.

I suspect the clunk you are hearing is from the outrigger hitting the chassis. You want these bushings.

http://www.whiteline.com.au/product_det ... 1&sq=20699
Thanks josh!! I went all out and just bought the brace on a whim. Haven't installed it yet but the offset matches the diff on our cars just fine! I'll comment on results when I put it in.
White 1993 L Wagon AWD 5MT-FXT lift, 27” MTs 380xxx miles
White 1991 L sedan AWD 5MT-(Robtune 550 DOHC Ej22t swap coming together) 187xxx miles
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Re: Rear Differential Bushings Write-Up w/Part Number :) 90-

Post by Legacy777 »

Sounds good! If you still have problems/noise, get these bushings I linked to. You should be able to find local retailers in the states or online.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
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