No laughing matter I have replaced my master cyliner four times and my left front caliper three times and am still not convinced we have solved the problem. We bleed the brakes and they work for approx 4-6 weeks when the pedal gradually softens to the point of no resistance- never losing braking ability completely but reaction time is compromised and foot is on the floor. I trust my mechanic. He’s talked with Car Quest where the answer was supposed to be faulty caliper-air leaking. But I am not convinced. Anyone else encounter this problem yet. This has been a 2 yr long issue.
Are the rear brakes drums or disks?
I am sorry; I don’t know how to find out without bothering my mechanic. Could you explain your thought for both types?
You may like and respect your mechanic; but, he is in over his head. He is missing something each time he looks at the brake system. It’s time to let a new set of eye-balls (a brake shop mechanic) look at your brakes.
Everyone I speak with seems in agreement that there is air in the system somewhere. But I am hearing two different results-one it’s in the mechanical aspect of the brake system or the other it is in the hydraulic ABS system. Can someone verify the possibility that if air in the ABS system isn’t properly bled with a scantool then the soft pedal issue will continue. Or are these systems totally separate not affecting each one because the ABS kicks in when needed. I have experienced the ABS coming on when I thought it wasn’t totally necessary. Thank you!!
If it has rear drums then I am guessing it is rear brakes worn or out of adjustment. If it has rear discs then I am not guessing.
This can happen because I’ve expierienced it.
What can happen is the caliper piston seal can allow just a slight amount of air to enter the caliper when the brakes are released and piston retracts back into it’s bore. But air/fluid doesn’t leak out because the seal expands when hydraulic pressure is applied to it. So the seal acts like a check valve. Allows air to enter in one direction but doesn’t allow air/fluid to escape in the other direction. So each time the brakes are used and released just a small of air enters the caliper until enough air accumulates where it results in a soft pedal. You can bleed the brakes and get a firm pedal back. But as the brakes are used again the soft pedal returns.
The fix is to replace the calipers.
Therefore, the answer may be the right front caliper, which hasn’t been replaced.
My mechanic did mention all four calipers may eventually need to be changed when he first learned of the caliper issue. However, the front left is the only one he’s replaced. Is there evidence on these caliper piston seals? Are rebuilts okay? Would this speed up damage to the Master Cylinder? Or speed up wear and tear on the rear brakes; they were replaced early in this process. And what about the ABS system interfering? Our mechanic has been all over this car many times for many reasons. He is not making the kind of money he would normally by spending so much time on my car. He typically refurbishes classic, foreign and high end cars. We both truly want to solve the problem.
I hate to state something that would be harsh on your favorite mechanic but this is a pretty simple problem. Does your favorite mechanic have the ability to put your T&C on a professional diagnostic computer? I guarantee the brake problem is either in the anti-lock computer or one of the sensor components, or you have a faulty proportioning valve. A far shot would be something like the brake line for that caliper being replaced and it not being the right size or length. You may also want to find out if there is a difference in master cylinder and calipers between 2003 year model and, what is usually termed as, 2,3,4,5,6 of 2003 production T&C (2,3,4,5,6 being number of month), more easily thought of as a 2002 1/2 T&C. Nissan is really famous for this same year - different month problem.