Intermitant Spongy Pedal - Page 2

MrDobin · #16 (**permalink**) 04-18-09, 08:50 PM

Alright, let me recap so i get this. Dont wanna miss interpret. The park brake seems to be interferring with the rear brakes?. So adjust the lines?. Or I still in fact need to fool around with the rear brakes themselves?.

carnut · #17 (**permalink**) 04-18-09, 09:08 PM

No, not interferring but the parking brake works only if the caliper adjusters (in behind the caliper piston) are not siezed from lack of use. By lines, I presume you mean the cables. If the cables are adjusted correctly and the parking brake still wont hold the car in gear, you need new/ rebuilt rear calipers. I prefer you get "loaded" calipers from a supplier. By loaded, I mean rebuilts with pads installed. Much easier to install over the rotor and verify adjustment. Also as an aside, use organic pads, semi metallic will give you a lousy pedal feel. Front and rear pads, ideally, should be the same brand.

MrDobin · #18 (**permalink**) 04-18-09, 09:12 PM

Ok pardon if I sound clueless, just long day and not keeping with your wording.
So simply I need to repair the brakes themselves or the pistons, or the park brake line?.

MrDobin · #19 (**permalink**) 04-18-09, 09:13 PM

Ignore my last comment there, my browser goofed and didnt show your last comment. Thanks a bunch carnut.

carnut · #20 (**permalink**) 04-18-09, 09:16 PM

They all work together.#1 Replace calipers, #2 Adjust park brake cables, #3 Bleed brakes. Done correctly, you wont believe the difference! This car does not nose drive when stopping, it squats, assuming all 4 brakes are doing their job. And use the parking brake every time you shut down the car.

MrDobin · #21 (**permalink**) 04-18-09, 09:28 PM

Ah. Alrighty. Good thing I have people who will help for free. haha. Dont wanna pay a mechanic and not up for it myself really.

masterzelda · #22 (**permalink**) 04-21-09, 03:07 PM

Probably is the master cylinder; and corrosion build-up in your brake fluid. You also may want to visually inspect your brake lines. When they get worn; they can expand when you press on the brakes; but more than likely; you need a new cylinder; and a brake flush. I had an issue with water getting into the brake fluid of my Seville; and when it would get hot; I pretty much didn't have any brakes at all!

MrDobin · #23 (**permalink**) 04-21-09, 03:22 PM

Yea I don't think its the cylinder. There is a small chance, but currently front brakes are totally intact. Rear don't react to pedal even when just starting up the car. Brake lines appear intact as well. The key thing showing that makes me think it is what it is the calipers needing to be replaced is that even with the park pedal hard to the floor and the springs on the rear brakes contracted the brakes don't react. I'm going to bleed them today and see what I get. Depending on the outcome the answer will remain calipers or will end up new cylinder.

**Ranger** · #24 (**permalink**) 04-21-09, 05:09 PM

Parking brake is cable operated. Regular brakes are hydraulically operated. Two completely separate and independent systems.

MrDobin · #25 (**permalink**) 04-22-09, 12:54 AM

Yea. Tomorrow I am going to bleed the rear both sides to make sure it is in fact the calipers. I looked through some of your post regarding air in the system and given that my brakes dont sink to the floor and dont leak outwardly in the lines. This leaves the fact that the pedal will travel a little farther at times but not always. I plan on being ready to replace the calipers in any case but want to verify that the air in the lines isn't the issue holding the brakes up. Would I still need to replace calipers if the bleeding, adjustment, and new fluid added are done?. I assume the problem would return again but in the pistons or something if let be?.

**Ranger** · #26 (**permalink**) 04-22-09, 12:42 PM

You only need to replace the caliper if it is frozen. What you are describing does not sound like a bad caliper to me. If you have air in the system, the pedal will go low, but you can make it harder and bring it up by pumping it, thus compressing the air in the line. If the pedal slowly sinks to the floor with no external leak, then it's the master cylinder.

MrDobin · #27 (**permalink**) 04-22-09, 12:51 PM

Ok. Ill see what happens. Been busy and unable to bleed them. But I did try the pumping last night and noticed what you described as hardening. We had a similar deal with a 2001 escalade and they had to flush it out. How would air cause the back brakes to freeze. Wouldn't the pumping temporarily at least, make them operate? Or is the air making them unable to retract and adjust?.

**Ranger** · #28 (**permalink**) 04-22-09, 01:11 PM

Air in the system would not cause them to freeze. Rust would. Air would just make them less effective until you pump them up.

MrDobin · #29 (**permalink**) 04-22-09, 01:49 PM

Ah lovely. So new calipers are in my future it seems.

MrDobin · #30 (**permalink**) 04-23-09, 01:36 AM

Went looking around for parts and came to a decision that seems best all around and for the future of the car.

New master cylinder. Flush brake system. Calipers replaced. LATER. Rotors replaced.

Given that even if the calipers are my issue and air can be bled out of the lines to somewhat alleviate the issues I have. I am going to just take out all the stops. Got a full manual to guide me through. HOWEVER. Is there anything that you guys suggest or advise while doing these replacements?. I have no concern in my ability but I don't trust all I read and a first hand piece of knowledge can often go a lot farther. Will take any insight you think is needed/helpful. Thanks again everyone. Love this site and its a huge help. Saved me a bunch of cash on prescription tranquilizers and mechanics visits.