DavieGravy Posted March 18, 2011 Share Posted March 18, 2011 I raplaced my brake pads and turned my rotors. During the brake job, I made the mistake of pressing on the brake pedal while the caliper was off the rotor and one of the pistons came out. I put it back in but a piece of the surrounding rubber fell off. After putting it all back together, there's no leaking brake fluid and I topped the fluid level off, but the brake pedal won't stay firm. If I push on it a few times it firms up, but then if I let off it it goes back to the floor. What should I do here? Did I ruin the caliper where the piston came out? Link to comment Share on other sites More sharing options...
johnceggleston Posted March 18, 2011 Share Posted March 18, 2011 you have air in the brake line. you need to bleed your brakes. Link to comment Share on other sites More sharing options...
DavieGravy Posted March 18, 2011 Author Share Posted March 18, 2011 How do I do that? Link to comment Share on other sites More sharing options...
Olnick Posted March 18, 2011 Share Posted March 18, 2011 You might not have ruined it. You'll need to go back in, pop the piston out and inspect it carefully. If it's scratched or gouged or if there is pitting due to rust/corrosion you will need to replace the caliper. If it's smooth and shiny you can get a very inexpensive caliper rebuild kit that includes a new rubber seal. You will need to bleed the brake lines afterwards. Good luck. Link to comment Share on other sites More sharing options...
DavieGravy Posted March 18, 2011 Author Share Posted March 18, 2011 sdfff Link to comment Share on other sites More sharing options...
DavieGravy Posted March 18, 2011 Author Share Posted March 18, 2011 I'm not really interested in rebuilding the caliper if it isn't leaking anything. I realize it may fail 7 years down the road, in which case I'll pick up a used one at the junk yard for 5 bucks. I'm really interested in how I get this air out of the system. I tried loosening the bleed bolt, pushing fluid through it and topping the reservoir up before it got below the low mark, but it's not helping. That damn peddle won't stay firm. I don't understand what's going on here. I've ran cars completely out of brake fluid before, filled them back up and they were fine. Why is this happening? Link to comment Share on other sites More sharing options...
Setright Posted March 18, 2011 Share Posted March 18, 2011 Well, if the above aren't the causes, then I expect you may have damaged the seals on the piston in the brake master cylinder. It went to the floor, right? Meaning the piston sweeped an area it doesn't normally contact, and the cylinder could be rough or corroded and therefore ripped a piston seal. Master cylinder rebuild....it's not rocket science Link to comment Share on other sites More sharing options...
DavieGravy Posted March 18, 2011 Author Share Posted March 18, 2011 Popping the thing that compresses against the brake pad out of a caliper can ruin a master cylindar? Link to comment Share on other sites More sharing options...
naru Posted March 18, 2011 Share Posted March 18, 2011 Bleed the brakes before worrying about that slim possibility. http://www.dummies.com/how-to/content/how-to-bleed-your-brakes.html Link to comment Share on other sites More sharing options...
Allpar Mod Posted March 18, 2011 Share Posted March 18, 2011 (edited) I'm having a bit of issue seeing how a likely caliper issue equates to a master cylinder also. There's two decent ways to bleed brakes. One requires a helper, the other getting a hand held vacuum pump like a Mityvac or similar. First, get some clear plastic tubing that will fit tightly over the end of the bleeder screw. Get a jar and put about 1" of brake fluid in it. Submerge the other end of the tube coming from the bleeder screw in the jar. With the helper, have him/her press down on the pedal and at the same time, crack the bleeder screw. You hopefully will see air bubbles along with fluid. Tighten the screw and release the pedal. Do this repeatedly until nothing but fluid comes through the tubing while being careful not to completely empty the master cylinder. Make sure to tighten the screw while the pedal is depressed so air is not drawn back into the system defeating what you are doing. Also. do not let the end of the tubing come out of the fluid jar or you will vacuum air back into the line again defeating your purpose. Repeat the process until the pedal returns to a proper firm tension. If it doesn't, then there may be a problem elsewhere like internals of a caliper or the master cylinder. Do both sides to be absolutely sure that air is or isn't the problem. My advice to you is to invest in a dedicated brake bleeder wrench made by a reputable tool company like Craftsmen, K-D, or off of the tool trucks. Sears also carries other makes of tools in their mechanic's section like Lysle and they are decent quality. They aren't expensive. Experience has taught me that there is way too much possibility of rounding out the head of bleeder screws with a regular box wrench, especially on ones on the car for several years and in corrosion prone regions. The pump takes the place of the helper. Edited March 18, 2011 by Allpar Mod Link to comment Share on other sites More sharing options...
idosubaru Posted March 18, 2011 Share Posted March 18, 2011 probably just air in the system, i'm not sure why you're not able to get it out. may need to bleed another line that's shared with that one, not sure how much air got in it, how much fluid was lost, how long it stayed open, etc. the piston has a dust seal around it that will hide leaks sometimes. Link to comment Share on other sites More sharing options...
Fairtax4me Posted March 18, 2011 Share Posted March 18, 2011 Improper bleeding would be my first guess. Go to a hardware store and get a section of clear 3/16" id fuel hose from the lawnmower / weed eater section. It usually comes in a ~2 foot length in a pack. Pop the end of the hose over the bleeder screw, loop the other end over something up just higher than the caliper, the lower spring loop or something, then point the other end into a container to catch the fluid. Be sure the end of the hose hangs down lower than the bleeder screw. Open the screw no more than one full turn. This will help keep air from being sucked into the caliper through the screw threads. Pump the pedal a few times until fluid starts to come out of the open end, then you can watch gravity pull the fluid through the hose, and along with it any air bubbles that may be in the line. Watch for large bubbles, keep an eye on the fluid level in the reservoir, and pump the pedal a few times here and there to help move out the big bubbles. If no more bubbles appear, close the bleeder, and move to the next wheel. Link to comment Share on other sites More sharing options...
Fuzpile Posted March 18, 2011 Share Posted March 18, 2011 (edited) Hello. I do not relish your position as I've been there. I doesn't make logical sense yet this is a different vehicle and the X-conn ,dual directional stuff is different. It would be helpful to know which corner but either requires a system. for the air has travelled thru it. Plz bear with me. The vacuum pump deal works ok yet it's awkward and the tubing slipping and the turning distorts the vacuum reading and it appears something has SHUT OFF -which it has. It was supposed to. If you recall some vehicles required a manual reposition of this valve, Subie does it different. Whatever corner you already bled, go bleed Right Front then LR then LF then RR. I need tell you I thought this procedure ineffectual as I would test the brakes and keep level up during each one. It was always the same until the last one where around there the bleeder broke off:eek: I had to loosen the Banjo bolt, pry a 2x4 against the seat cushion so it would depress the pedal further. It worked. Like new brakes yet they were still old. No more bananas Edited March 19, 2011 by Fuzpile Link to comment Share on other sites More sharing options...
davebugs Posted March 18, 2011 Share Posted March 18, 2011 I have a motive PRESSURE bleeder. Much better than standard "bleeding" or using a sucky toy. Air doesn't suck well - it just expands. They have a screw on adapter for the Subaru Brake resevoir. I have like 6 adapters and "universal" adqpters. I believe mine was 80-90 bucks. May be money well spent now that you're in this predicament. This way you're "pushing" the fluid and air bubbles, rather than trying to pull them. I've loaned mine locally to VW and Subaru guys who have done htis the old fashioned way and got into a jamb like this. Link to comment Share on other sites More sharing options...
Fuzpile Posted March 18, 2011 Share Posted March 18, 2011 Oh yes..Recently there was an entire thread about this and the adaptors to different m/c. That should be archived, it was SO good. (prolly is FAQ) You were right there davebugs I just didn't think that far to where he needed it now. It makes perfect sense. Except still there is that Order, I think. Link to comment Share on other sites More sharing options...
DavieGravy Posted March 21, 2011 Author Share Posted March 21, 2011 I turns out that I was loosening the bolt that holds the brake line in, not the bleeder bolt. I had a friend help me bleed the brakes and it fixed the issue. Thanks to everyone for the help. Link to comment Share on other sites More sharing options...
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