RallyKeith Posted October 12, 2004 Share Posted October 12, 2004 Car as described in title. Cleaned out the resevoir and Bled all four corners of the brake system well and until I had bled through fresh fluid. Problem is, brakes seem to start to engage after normal pedal travel, but after that you have to press the pedal really far to get proper braking, and even then you don't get adequate stopping force. Tonight while diagnosing a misfire I had my foot on the brakes as hard as I could and pressed down on the gas. The brakes couldn't hold the car. What could be wrong? All the pads and linings have plenty of material. Yes, this is disc in the front and drum in the rear. Thoughts? Keith Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted October 12, 2004 Share Posted October 12, 2004 You sure you got all the air out of the lines? Does the pedal feel soft initially? If so, does pumping it again firm it up? Quote Link to comment Share on other sites More sharing options...
RallyKeith Posted October 12, 2004 Author Share Posted October 12, 2004 You sure you got all the air out of the lines? Does the pedal feel soft initially? If so, does pumping it again firm it up? Pedal doesn't feel soft. Pumping makes no difference either. I think I got all the air out. I'm trying to get the parts to convert this to discs in the rear in an effort to help the problem. Keith Quote Link to comment Share on other sites More sharing options...
RallyKeith Posted October 12, 2004 Author Share Posted October 12, 2004 Could the front rotors be too thin? What is the minimum thickness or how can I find that out? Keith Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted October 12, 2004 Share Posted October 12, 2004 How did you bleed the brakes? order, method, etc? How did the pedal feel before you bled the brakes? I don't think thin rotors would cause what you're experiencing. I'm not sure what the run out spec is for that car. You may want to call the dealer and see if they'll tell you. Quote Link to comment Share on other sites More sharing options...
RallyKeith Posted October 12, 2004 Author Share Posted October 12, 2004 Pedal felt the same before and after. I used standard operating procedure. Start at the corner fartherest away from the master cylinder and worked closer. That would be: Passanger rear Driver rear Passanger Front Driver Front I used the same vaccum bleeder that I've successfully used on 5 other subarus, including those with drum rears. Quote Link to comment Share on other sites More sharing options...
cookie Posted October 12, 2004 Share Posted October 12, 2004 On some cars the piston can move full forward and limit the stroke. If you bleed each line by pushing on the barke pedal do you get a powerful squirt from each? This is the kind of effect you can get if you install a master cyl without bench bleeding and it does not pick up. Quote Link to comment Share on other sites More sharing options...
Setright Posted October 12, 2004 Share Posted October 12, 2004 Could be a bad seal on a MC piston. Or, maybe one or more of the bleed screws on the caliper isn't tight enough, and brake fluid is slipping by? I say this because I found that mine (same brakes) were a pain to seal again. Next time I bleed, I will put new screws in! You might want to make sure the vacuum booster is working. Run the engine, switch off, pumping the brake should see it get firmer as the vacuum booster is "emptied". Quote Link to comment Share on other sites More sharing options...
RallyKeith Posted October 12, 2004 Author Share Posted October 12, 2004 Well, I may try a few things, but there are no external problems present such as lose of fluid due to a bad seal. I called my friends at the dealership to ask them about the minimum thickness and they gave me this thought. They have had several cars where aftermarket brake pads were installed and it gave the car a long pedal. The cheap pads that people had installed were a tight fit, and that didn't allow the pad to correctly seat agains the rotor. So the pedal would still start to feel like it was engaging, but extended travel was required to get the pads to work properly. I think I'm just going to rip everything apart, clean it up, make sure the pads fit no more than snug and re-bleed the system the old fashion way. Plus I really think I'm going to upgrade it to discs in the rear someday. Keith Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted October 12, 2004 Share Posted October 12, 2004 Keith, The proper bleeding sequence according to the FSM is Right Front Left Rear Left Front Right Rear. Subaru does it backwards for some reason. I've bled both ways, and for some stubborn air, the sequence in the FSM was the way I got it out. Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted October 12, 2004 Share Posted October 12, 2004 On some cars the piston can move full forward and limit the stroke. If you bleed each line by pushing on the barke pedal do you get a powerful squirt from each? This is the kind of effect you can get if you install a master cyl without bench bleeding and it does not pick up. can you elaborate on what you mean by the "piston can move full forward.." I've swapped around MC's and tried to bench bleed...it was for the most part unsuccessful IMO, yet successful in making a mess....I said screw it and just put everything together and bled it on the car. I don't notice any adverse affects from doing this.....? Quote Link to comment Share on other sites More sharing options...
cookie Posted October 13, 2004 Share Posted October 13, 2004 anything on a Subaru except my clutch. I am thinking of several master cyl units I have rebuilt in the past. Many of the later ones were dual circuit brakes and had two pressure lines coming out. Inside these were two seperate pistons sometimes seperated by a spring, sometimes the units were fastened together, and sometimes all one moving piston with two parts. Each would have its own seal for the piston. On ones that were seperated by a spring it was possible for the rear piston to go full forward and not give pressure to the line in the rear of the cyl. If the rear seal fails this is the failure mode which still gives you brakeing pressure to tow wheels, often on opposeing sides of the car. Bench bleed made it easier to see that the dang thing was putting pressure out of both lines before standing on your head to install it in the car and find out it did not work. On VW parts made in Brazil we had about a one in 10 failure rate of rebuilt masters and that was a pain in the butt. You often will get it to work fine without bench bleeding and if the customer was standing there in a hurry we skipped that step. Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted October 13, 2004 Share Posted October 13, 2004 I got ya now. According to the fsm, it is a dual circuit design, and it looks to have two independent pistons that are separated by a spring. There is also a spring in front of the first piston. Quote Link to comment Share on other sites More sharing options...
RallyKeith Posted October 13, 2004 Author Share Posted October 13, 2004 BTW, I just thought I'd add that the car brakes evenly left to right. The car doesn't pull in any fashion. Keith Quote Link to comment Share on other sites More sharing options...
RallyKeith Posted October 16, 2004 Author Share Posted October 16, 2004 Well, First off I lied. The car didn't pull when doing low speed stops. I got the car up to about 70mph today and slammed on the brakes and it did pull a bit to the left. Armed with that and what the dealer and you guys told me I went to work. Jacked up the front of the car and puilled off tghe right wheel. Behold! The upped slide pin for the caliper was seized. Would not budge, even when I heated the caliper in that area and hit on it with a sledga hammer. So I swapped out the entire caliper assembly, bled that circuit with my same little vaccum bleeder and pedal is where it belongs. Car still pulls to the left under heavy braking, so I think I may have to look at the other side, and possibly put new pads on. Anyhow, I guess I'd have to say that the dealer's suggestion was actually more correct and more helpful, since I honestly looked for something sticking first. Keith Quote Link to comment Share on other sites More sharing options...
cookie Posted October 17, 2004 Share Posted October 17, 2004 to see if all bits were free and lubed. I am sure you will free them all now. Quote Link to comment Share on other sites More sharing options...
RallyKeith Posted October 17, 2004 Author Share Posted October 17, 2004 to see if all bits were free and lubed. I am sure you will free them all now. Typically I've had problems with the lower sliders binding and not the top, so the lowers were all checked and lubed. Also, the caliper swiveled freely up to look at pads. Only after prying back the seal on the upper slider did I realize that in reality I was threading and unthreading the pin and it was in no way sliding. Also, the brake pads looked very new on both sides of the car, so I made the mistake of assmuing the car had been recently serviced in that manner and things like that wouldn't be an issue. (the car was bought 2 months ago from a reputible small dealership dealing mostly in Subarus) It wasn't like I blindly posted without having already looked at mostly everything, I just missed this. Quote Link to comment Share on other sites More sharing options...
cookie Posted October 17, 2004 Share Posted October 17, 2004 when they changed the pads, but you have salt back there and perhaps it just ruted quickly. Quote Link to comment Share on other sites More sharing options...
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