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Rear Disc Conversion for Gen 1's


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i've been driving on them since sunday night... i have yet to really test them. the roads were a little slick with snow this morning so i tried slamming on them a couple times... they didn't lock up if i was carefull... the fronts lock up before the rears however...

 

running stock brake booster and the braking is a little more even... instead of the whole car just leaning forward when i slam on the brakes it more kinda sinks down...

 

but ya, i wanna get on some gravel and try slamming on them a few times and see what happens...:D

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Sweet.

 

If the fronts still lock first, sounds like you'll have a workable setup when all has tested out. You'll have to put a couple hundred varied miles on it and report back as to their performance. I'd definately be interested in hearing.

 

Regards

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Hodaka Rider

So, did it take you guys long after I left?

 

we finished at around 8... and i was wearing short and a t-shirt in near freezing weather...:-p

 

If the fronts still lock first, sounds like you'll have a workable setup when all has tested out. You'll have to put a couple hundred varied miles on it and report back as to their performance. I'd definately be interested in hearing.

 

the roads were all wet on my way home so i found myself a nice little empty street and went up to 35mph and stood on the brakes... front drivers side locked first... (closest to the brake booster and the 200lbs pile of me sitting on that side...?)

 

none of the others locked... i'm hoping to get on some gravel tonight... i put in used pads and rotors but they still need a little breaking in... i can feel the brakes getting tighter/better evertime i drive it... i'll report back after a few hundred miles...:) (so far i'm at about 60-70)

 

after these all check out i'm upgrading to ea81 vented rotors for the front...:D

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I did this swap too on my 78 Brat. I did it at least a year ago. I have not had any problems. Although I had a different way of how I did things and it did not involve a torch. I achieved a proper fit with just a grinder. It only took me about 2 hours from start to finish to get the job done. Fairly quick and easy too! I have noticed that the back rotors are getting little to no use on them though. I have been driving it regularly and the back rotors never seem to really get the rust off of them like the front ones do. The front ones stay nice and shiny like they should but the back ones do not. Not sure why though. Maybe I just need to bleed the brakes out again. Stops fine so I guess that is all that matters right?:brow:

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The issue you are having with your rear disc brakes is the combination valve that your subaru came with. when using rear drum, and front disk, your vehicle requires 2 types of valves. The rears (drum) get a proportioning valve that limits the pressure to the rear to a lot less than what disc brakes require. The front disk brakes get a metering valve (sometimes), that delays the pressure to the front wheels. The idea behind that is that the drum brakes just take a tiny bit longer to actuate because they have return springs. You want the rears to apply fractionally first, to keep the rear end behind ya.. long story short... you need to remove that combination valve and connect that mess of brake lines right there so they are split diagonally. You should then feel the actual full force of using rear disc brakes.

 

NOTE: apparently modern research has show that using rear drum brakes actually work better than rear disc brakes for heavy truck vehicles (heavy truck meaning 1/2 ton). For lighter vehicles that are more front weight biased tho, 4 wheel disc is the way to go. (such as our tinker toy subarus)

 

-Mike

(just thought I would throw a little info out there, no real thoughts either way)

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