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Guest Message by DevFuse

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rear disc conversion ... interchange alert

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11 replies to this topic

#1 baccaruda



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Posted 08 September 2003 - 12:43 AM

So. when does it take all ************ day to do a rear disc brake swap? ($10 to anyone who can figure out what that ***'ed out word is :P )

When the backing plates don't fit over the rear knuckles! The middle of the knuckles was too narrow.
I had to go to the HW store and get some grinding bits.
Drilled a bunch of smaller holes 1/4"-ish apart all the way around, grabbed the tabs with the vise grips and wiggled them off. good thing that middle section is just aluminum! Then I ground it down and rounded the rest of the way. Not cosmetically perfect but it went on OK.

Anyone know what's up with this? I got these rear backing plates from a guy I know, no fault of his, but I don't know what they came from. Maybe a 2WD? did any 2WDs come with rear discs?

If anyone knows what cars have these smaller, not-quite-as-universal rear backing plates, it might be nice to make a note in the swap article in the USRM so we don't choose that car to pull our rear backing plates from.. unless that's what they're going on as well :D
BTW the botl holes lined up fine, the inner diameter was too small though.

#2 calebz


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Posted 08 September 2003 - 12:46 AM

My 88 turbowagon was 2wd with rear disc.. was under the impression that it would fit a 4wd(except the hub)

I watched Zap do the rear disc swap on Bob.. took about 30 minutes.. and thats because he broke a bolt and stopped for a beer!

#3 PoorManzImpreza


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Posted 08 September 2003 - 12:55 AM

I'm betting the word is 'motherF*****G'

Kaz ;-)

#4 baccaruda



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Posted 08 September 2003 - 01:06 AM

Caleb, you're saying that the backing plates I had were 2WD?
30 minutes.. yeah, it all went really smoothly except for the whole NOT FITTING thing. Don't worry, I made sure there was beer on hand as well. Ahhh Newcastle, how do I love thee? let me count the ways.. one two three four five six! :drunk:

Did you all know that an 8" (mayb 9") adj. crescent wrench's handle works great as a rotating-the-piston-back-in tool for rear calipers? I have the multi-cube thingy for the fronts but the rears are the hollow cylinder type of piston. I haven't sprung for the pro style retractor kit yet. Maybe :santa:'s listening? hint hint
Thankfully, the front calipers had almost-new pads in them so I didn't have to deal with the multi cube too much to retract them again. I hate that thing, it's probably designed to slip off every 5 turns :madder:

Oh, and halfway through the process, the old Black and Decker drill I borrowed from Dad broke.. the set screw that holds the .. uhh.. drill bit grabby part, to the output shaft was gone so it popped off the drill halfway through. had to call Dad and make him deliver another drill (he used to own a HW store / shop so he has a few laying around :D ) .. delays delays delays! DAMN YOU MURPHY, YOU AND YOUR INSUFFERABLE LAW!

Kaz.. not even close :D

#5 TheSubaruJunkie



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Posted 08 September 2003 - 01:31 AM

You need to find out what car those came from. There is no reason to modify anything on your car as long as you got the right parts.

I believe the 2WD and 4WD backing plates are the same. Are you sure those are from a Subaru?? maybe a Legacy or something.


#6 baccaruda



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Posted 08 September 2003 - 02:08 AM

I'll call him tomorrow. If I have time I'll go look at the dealer's parts book too. The only thing I can think of would be that they're 2WD. I even test fitted them inside the wheels as they were obviously off the car for all this, and they cleared OK.

Maybe a non-turbo GL10? :cornfuzz:

#7 TheSubaruJunkie



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Posted 08 September 2003 - 02:22 AM

EA82 only has 2 types of Rear Disc's... 2WD and 4WD. Ive never seen rear disc's on a non-turbo Subaru, but they were an option as far as i know.


#8 GLCraig



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Posted 08 September 2003 - 02:45 AM

Rear disks were standard on all XTs regardless of being turbo or not. If the backing plates were from a legacy, there would be a bunch of extra holes for the E-brake components.

#9 TheSubaruJunkie



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Posted 08 September 2003 - 03:00 AM

e Brake Components????

How very interesting. I wonder if we could use a legacy rear backing plate and caliper, and rig some sort of rear eBrake setup for our EA81 and EA82's.


#10 edrach


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Posted 08 September 2003 - 07:49 AM

2WD and 4WD backing plates are different. I forget the difference but that's the only part that won't interchange when doing the swap from drums to disk.

#11 MilesFox


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Posted 08 September 2003 - 12:51 PM

i put rear discs on mine, the only fitment issue was a little rust needed to be brushed off.

the 2wd backing plate being smaller sounds like the problem. because the 4wd rear knuckle hosed the bearings, thus being larger than the 2wd rear knuclke that has a spinlde insteead.

aside from that i know you can use the caliper and rotor(after swapping hubs) from a 2wd.

the rotors on the trashagon came off a 2wd gl-10(you know, one of the 2wd blue with blue interior gl-10's that jim keeps coming up with):temper:



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Posted 08 September 2003 - 08:59 PM

It's my understanding that the backing plates from the 2wd and 4wd are the same. The only difference is the hubs because we need the hubs from a 4wd car. But hey, What do I know, Mine are still sitting on a shelf.....

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