hatchsub Posted October 16, 2009 Share Posted October 16, 2009 Ok so i last weekend i put in the rear disks on my subaru. They work fantastic...so well in fact that they work better than the fronts. I can lock the rears but not the fronts. At first i was attributing that to my pitiful front disks. They were BAD. I just redid the front brakes with new rotors, pads and calipers so that i could get vented rotors. That didnt solve the problem though it did make it a lot less noticable. Am i missing something here? Do I need to get an adjustable proportioning valve like i did on my camaro when i went to 4 wheel disk? Or do i just need to grab a disk/disk prop valve off a turbo EA82? Anyone else run into this problem? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 16, 2009 Share Posted October 16, 2009 (edited) Yep - that's exactly what happened to me on my Brat. I installed the proportioning valve from the same car the disc's came from and the problem vanished. I've been telling people for years that you need the proportioning valve but they don't beleive me. I did a skid test on wet pavement and did a 180 into the oncomming lane without the valve - rear brakes lockup and the back of the car passes the front. With the valve it was perfectly straight. I wish it were simple to install the valve but it's not. You have to redo all the lines under the back of the car. Unless you do two aftermarket valves that just go inline with each brake. GD Edited October 16, 2009 by GeneralDisorder Link to comment Share on other sites More sharing options...
TheSubaruJunkie Posted October 16, 2009 Share Posted October 16, 2009 There has been talk about installing a valve with the disc conversion to eliminate this problem. It will work. But, did you do a thorough bleed job after you did all this brake work? I would maybe bleed the entire system one, or two more times... also break in the front disks and see if that helps. Link to comment Share on other sites More sharing options...
Turbone Posted October 16, 2009 Share Posted October 16, 2009 (edited) Ok so i last weekend i put in the rear disks on my subaru. They work fantastic...so well in fact that they work better than the fronts. I can lock the rears but not the fronts. At first i was attributing that to my pitiful front disks. They were BAD. I just redid the front brakes with new rotors, pads and calipers so that i could get vented rotors. That didnt solve the problem though it did make it a lot less noticable. Am i missing something here? Do I need to get an adjustable proportioning valve like i did on my camaro when i went to 4 wheel disk? Or do i just need to grab a disk/disk prop valve off a turbo EA82? Anyone else run into this problem? What about the brake fluid? Did you flush it and install new stuff? Heres a good write up on disc brakes and info on breaking them in. http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml Edited October 16, 2009 by Turbone Link to comment Share on other sites More sharing options...
The Dude Abides Posted October 16, 2009 Share Posted October 16, 2009 Having did the rear disc swap recently i did notice a tremendous difference between the drum and disc brakes. But ive slamed on my brakes and have been unable to lock them up. Theyve had a full bleed as well. Now if this is strictly a ea81 thing then thats a possibility because my ea82 doesnt seem to need it. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 16, 2009 Share Posted October 16, 2009 All EA82's have proportion valves - so you already have one and it's very similar to the disc brake cars. EA81's never had discs or valves. So yes - it is an EA81 specific problem. GD Link to comment Share on other sites More sharing options...
hatchsub Posted October 16, 2009 Author Share Posted October 16, 2009 Im almost sure that all the air is out of the front brakes but it could still have a bit of air in there. Im pretty sure i just need to put an adjustable prop valve in there but before i do ill drive it around for a bit and break in the front brakes a bit as well as bleed them out again. I did bleed the brakes enough that there is no old fluid in there. Hell i even bled the master cylinder. Gotta love the bleeder valves on the MS. I wish my camaro was that simple. Link to comment Share on other sites More sharing options...
ruparts Posted October 17, 2009 Share Posted October 17, 2009 Ok so i last weekend i put in the rear disks on my subaru. They work fantastic...so well in fact that they work better than the fronts. I can lock the rears but not the fronts. At first i was attributing that to my pitiful front disks. They were BAD. I just redid the front brakes with new rotors, pads and calipers so that i could get vented rotors. That didnt solve the problem though it did make it a lot less noticable. Am i missing something here? Do I need to get an adjustable proportioning valve like i did on my camaro when i went to 4 wheel disk? Or do i just need to grab a disk/disk prop valve off a turbo EA82? Anyone else run into this problem? hi, you did not mention which vehicle was the doner car for the rear brakes, but there are at least 3 different rear caliper variations used on EA-82 vehicles, the caliper piston diameter that is. they all fit the same and same pads, so you would not notice it, xt6 is smallest and wag-sedan is largest, if you are using the smaller piston calipers you can reduce the effective rear braking force some by using the larger piston version caliper. this might be easier than fitting valves inline and worth a try first, they are a direct fit and pads everything. might be the difference you need to lighten up the rear clamping force just a little. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 17, 2009 Share Posted October 17, 2009 I was only aware of two piston diameters although I hadn't considered the XT6, but yes that is true. I used the calipers from an '89 FT4WD GL-10 turbo sedan. At any rate I still had a severe mis-proportion to my braking and had to install the valve. Unfortunately, for a lot of folks, getting the rear disc assemblies is hard enough - shopping around for different piston size calipers isn't really feasible. When you find a good set you take it, and if that means you need valves to make them work then so be it. GD Link to comment Share on other sites More sharing options...
hatchsub Posted October 17, 2009 Author Share Posted October 17, 2009 Unfortunately, for a lot of folks, getting the rear disc assemblies is hard enough - shopping around for different piston size calipers isn't really feasible. When you find a good set you take it, and if that means you need valves to make them work then so be it. GD That basically sums it up right there. I have NEVER seen a 2wd EA82 turbo anything in the yards where i live. When Skankinpickle offered up the set of rear disks i jumped on em since i doubt ill find another set for a long time. I have no clue what they are off of. As for the valve, i saw two ways of doing an adjustable prop valve which i would like to discuss. One involves two prop valves on each of the rear lines in the engine bay. Looks like subaru made it easy for me even by having some fittings right before the lines go into the firewall. This would probably be the easiest way for me but more expensive since it involves two valves instead of just one. The other way i was thinking would be to put an adjustable prop valve right below the master on one of the two lines coming out of the master cylinder. This brings up the question of whether or not that will work however. Also which line is which coming out of the master (front line for the rears and rear line for the fronts like most cars?) and would it work to have the stock valve and an adjustable right in front of it. Link to comment Share on other sites More sharing options...
bratman18 Posted October 17, 2009 Share Posted October 17, 2009 Hmmm, I have rear discs on my Brat and the fronts still lock up before the rears. I did not use the proportioning valve. I guess I just got lucky again. Link to comment Share on other sites More sharing options...
Yo'J Posted October 17, 2009 Share Posted October 17, 2009 I like the Idea of putting the valve in the engine bay. Tell me more! It does seem like it would be way easier to install, like in a legacy. I'm sitting on installing a prop. valve until I can get to my ej swap which means my brat has to be a dd (rear wheel bearings and a tranny possibly a steering column we'll know after I get rubber$$$$) Link to comment Share on other sites More sharing options...
hatchsub Posted October 18, 2009 Author Share Posted October 18, 2009 That basically sums it up right there. I have NEVER seen a 2wd EA82 turbo anything in the yards where i live. When Skankinpickle offered up the set of rear disks i jumped on em since i doubt ill find another set for a long time. I have no clue what they are off of. As for the valve, i saw two ways of doing an adjustable prop valve which i would like to discuss. One involves two prop valves on each of the rear lines in the engine bay. Looks like subaru made it easy for me even by having some fittings right before the lines go into the firewall. This would probably be the easiest way for me but more expensive since it involves two valves instead of just one. The other way i was thinking would be to put an adjustable prop valve right below the master on one of the two lines coming out of the master cylinder. This brings up the question of whether or not that will work however. Also which line is which coming out of the master (front line for the rears and rear line for the fronts like most cars?) and would it work to have the stock valve and an adjustable right in front of it. Night bump. Anyone got suggestions about this? Link to comment Share on other sites More sharing options...
mcbrat Posted October 19, 2009 Share Posted October 19, 2009 you'll need 2 valves if you do it in the engine bay. the soob brake system is "dual diagonal", but you could re-plumb in a number of ways, but by using 2 valves, you'd keep the original dual-diagonal set-up... Link to comment Share on other sites More sharing options...
hatchsub Posted October 19, 2009 Author Share Posted October 19, 2009 (edited) Dual-diagonal? Sorry but could u explain to me how that works? I was under the hood and tried to figure it out and couldnt really lol. So with this system there is not one line coming out of the master for the rears and one for the fronts like my camaro? I did see two lines coming out of the master but they dont get divided up like that? EDIT: Just looked it up on car dictionary. Thats an interesting setup. I didnt realize that they had a brake system like that that hooked up the front brakes with the rear brakes diagonally across. So im assuming that is the main reason that i cant just use one adjustable prop valve on one of those lines coming out of the master. I can however put one prop valve on each rear line in the engine compartment? Ok. got it... i think lol. Edited October 19, 2009 by hatchsub Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 19, 2009 Share Posted October 19, 2009 Yeah - it's going to be easier to just do two aftermarket adjustable valves near each wheel. That's what I'm going to do with my Brat. Installing the stock valve assembly is a chore and creates a plumbing nightmare unless you want to spend the money on new hardline, a tubing bender, flaring tool, ferules, etc. And if you have never bent hard steel tubing before - best you don't make this your first project. Makeing it pretty and getting the bends right and the lengths correct.... there's a learning curve to it. GD Link to comment Share on other sites More sharing options...
hatchsub Posted October 19, 2009 Author Share Posted October 19, 2009 (edited) Ive done it before when i did rear disks in my camaro (not redoing all the hardline but some) and i was anything but thrilled when i thought i would have to do it again. Its a pain. Anyways i think ill go the route of 2 valves on the rear lines in the engine bay since subaru was nice enough to have fittings already there for me. Edited October 19, 2009 by hatchsub Link to comment Share on other sites More sharing options...
hatchsub Posted November 25, 2009 Author Share Posted November 25, 2009 Figured I would bump this one up and let everyone know what i ended up doing. I got two aftermarket adjustable prop valves off of ebay and installed them in the engine bay. Now i make it sound alot easier than it really is. Since the prop valves had standard threads and the brake lines on the suby are metric i had to cut and flair 4 lines. Awesome. It took me awhile of swearing and breaking the stupid 3/16 adapter tool twice to get it all done and leak free. Bled the lines and then took it for a spin on full power and kept turning the rears down until the car will put me through the windshield but not lock up the rears. Link to comment Share on other sites More sharing options...
renob123 Posted November 25, 2009 Share Posted November 25, 2009 Figured I would bump this one up and let everyone know what i ended up doing. I got two aftermarket adjustable prop valves off of ebay and installed them in the engine bay. Now i make it sound alot easier than it really is. Since the prop valves had standard threads and the brake lines on the suby are metric i had to cut and flair 4 lines. Awesome. It took me awhile of swearing and breaking the stupid 3/16 adapter tool twice to get it all done and leak free. Bled the lines and then took it for a spin on full power and kept turning the rears down until the car will put me through the windshield but not lock up the rears. Thanks for the update. I was following this thread a month or so ago. If you had to do it again, would you just get a couple metric valves and save yourself some swearing, or do they not exist? Jacob Link to comment Share on other sites More sharing options...
hatchsub Posted November 25, 2009 Author Share Posted November 25, 2009 They dont really exist that i know of. There are fittings that come with the prop valves that you tighten into the valves. I went down to napa and tried to get metric conversion fittings but i guess they dont really make those. Most people who put adjustable prop valves on cars are dealing with standard threads on muscle cars and such and not having to run into the problems that i ran into. I would have loved not having to mess with the stock lines but now that its done its done. Link to comment Share on other sites More sharing options...
silverhelme Posted November 25, 2009 Share Posted November 25, 2009 Try Summit Racing. They have at least one made by Titan that is metric. Kind of expensive though about $105 each. This all is good info for when I do the rears on my Brat. I currently have all the parts I just have to find the time. Link to comment Share on other sites More sharing options...
hatchsub Posted November 25, 2009 Author Share Posted November 25, 2009 Yea not going to spend over 200 just to save myself a bit of grief lol. I spend 35 a piece on the prop valves and they work just fine. Link to comment Share on other sites More sharing options...
mcbrat Posted November 25, 2009 Share Posted November 25, 2009 Yeah - it's going to be easier to just do two aftermarket adjustable valves near each wheel. That's what I'm going to do with my Brat. Installing the stock valve assembly is a chore and creates a plumbing nightmare unless you want to spend the money on new hardline, a tubing bender, flaring tool, ferules, etc. And if you have never bent hard steel tubing before - best you don't make this your first project. Makeing it pretty and getting the bends right and the lengths correct.... there's a learning curve to it. GD yeah, when I put all new brake lines on my '82 with Toy axles, that was fun. at least the Toy and Soob both use Inverted Flare 10mm fittings.... Link to comment Share on other sites More sharing options...
SubieDaddy80 Posted November 25, 2009 Share Posted November 25, 2009 It amazing how much I can learn by just reading the threads! This was great info for later when I do my swap! Link to comment Share on other sites More sharing options...
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