maydog Posted May 12, 2005 Report Share Posted May 12, 2005 Greetings, After my engine replacement headache several weeks ago, I have felt that there is something wrong with my brakes. It is hard to explain but I will try. I remember having to let up on the brake pedal gradually when coming to a stop, now I feel as if I have to push harder as if the braking force is not sufficent the closer I come to the stop. The pedal is not what I would describe as squishy / spongy, but does not feel overly firm when the engine is running. The pedal does not sink to the floor with constant pressure applied; I can, however, push it to the floor easily using extra pressure with the engine running. With the engine stopped the pedal becomes quite firm after a few pumps. The brakes still stop the car very quickly in a quick stop type of manuever. All 4 of the brake rotors are hot after driving. Last week I removed all the pads and scuffed them up, cleaned the rotors and bled the brakes. The problem is still there. I do notice that the brakes grab much more after I really heat them up - I have ceramic pads up front and semi-metallic in the rear. This weekend I plan on bleeding the master cylinder. Are there any other quick checks I should be doing? Is there a good test of the booster, for example? Thanks in advance md Link to comment Share on other sites More sharing options...
jackc Posted May 13, 2005 Report Share Posted May 13, 2005 Did you / they have to open the brake system in the course of doing the engine? Link to comment Share on other sites More sharing options...
maydog Posted May 13, 2005 Author Report Share Posted May 13, 2005 I dont know, they did do a few goofy things during the replacement. I did bleed the front brakes last week, but I had the hands free bleeding tool hooked up wrong so I cannot tell if the bubbles were due to my error or theirs. It does not appear that the hoses were disconnected from the caliper. I am going to redo the bleeding and include the master cylinder this time. Could this brake feeling be caused by having the pads worn down? My pads are worn, but there appears to be plenty of meat left before the wear indicators would rub. Link to comment Share on other sites More sharing options...
franey Posted May 13, 2005 Report Share Posted May 13, 2005 YOU may have a bad brake booster, or the check valve going into it is bad, new check valve is cheap. A bad booster is , you are pressing on brakes and you are still rolling you press harder and you get this hard feel from the pedal and you slowly stop. ALSO check the vacume line to the booster and make sure it is not losing vacume. since you had the engine out you may have a screwed up vacume line to the booster. Link to comment Share on other sites More sharing options...
maydog Posted May 13, 2005 Author Report Share Posted May 13, 2005 I tested the check valve it seems to work fine. The pedal never feels hard when the engine is running. As I said, I can fairly easily push the pedal to the floor with a little extra effort - once the car is already stopped. I get a fair amount of resistance if I press down quickly in an emergency stop. I read that to check the booster, one is supposed to depress the pedal multiple times with the engine off to use up any saved vacuum. Then press down on the pedal and hold it down while starting the car. The pedal should sink from the pressure (which mine does). A pedal that stays hard is indicative of a bad booster. Does this sound right? Link to comment Share on other sites More sharing options...
jackc Posted May 13, 2005 Report Share Posted May 13, 2005 A hard pedal is what I'm used to seeing when the booster is bad. Air in the lines or a master cylinder going bad are where I'd go on your problem. Do a full bleed on the system. On mine, I had to run about a pint of fluid out of each wheel before I could be certain all the air was out. But in the end, I did have to replace the master cylinder. My symptoms were similar to what you're describing. Link to comment Share on other sites More sharing options...
JoeM Posted May 13, 2005 Report Share Posted May 13, 2005 Definately do a complete bleed of the brake system. Get all of the old fluid out and replace with new. This is the cheapest way to start troubleshooting... Link to comment Share on other sites More sharing options...
jhall Posted May 15, 2005 Report Share Posted May 15, 2005 maydog, Did you have a look at the brake lines near the master cylinder and other places in the engine compartment? If they pulled the engine a dropped in another, they may have banged a line and crushed it slightly. Also, DO check the booster hose to make sure it's connected well with no cracks. Link to comment Share on other sites More sharing options...
maydog Posted May 16, 2005 Author Report Share Posted May 16, 2005 I did a full system bleed over the weekend ( master cylinder and all 4 corners), I did get some air out but nothing seemed to change much. I also did some more checks of the booster, brake lines and other componets everything seems tip top. I have had some others drive the car and they think the brakes are fine. Maybe I am just nuts - maybe I will replace the rear pads since they will be needing replacement soon enough. That really seemed to help out the Aurora when the brakes felt a bit soft. Link to comment Share on other sites More sharing options...
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