: Annoying brakes



Johnny Kaka
06-02-13, 01:33 AM
Hi everyone, I posted a few weeks back about my brakes. prior to exchanging the front pads, I had the following problems - 1 - vibrating brake on the right side. (especially when heated up). - 2 - a few months back, the brakes started becoming increasingly spongy and the vibrating got worse.

I changed the front rotors and bled the brakes. Unfortunately the brakes are still spongy (possibly worse). I only bled once with a 1 man bottle. I'm gonna try again tomorrow with a helper, but I have the nagging feeling that something else is wrong.
Any ideas as to what it could be? ABS? I checked the booster vacuum and it seems to work fine. Not sure what to do next and I'm getting more and more nervous about my brakes.
Thanks everybody.

cadillac_al
06-02-13, 09:01 AM
Does the pedal firm up when you pump the brakes? (air) or is the pedal traveling further than it should, almost to the floor every time like a bad master cylinder?

Johnny Kaka
06-02-13, 11:59 AM
The pedal firms up when I pump, but not to the point of braking well. They firm up somewhat, and the brakes are a little better when I do. But still pretty weak.

----------

I forgot to mention that the pedal felt increasingly firmer while bleeding, but lost all pressure once I started the car to test the brakes. What does that indicate?

amunderdog
06-02-13, 12:00 PM
I would be looking at the Master cylinder.
Often the will leak into the booster.
"When a brake master cylinder begins to go bad or fails, you will notice a soft or squishy feeling when you press down on the brake pedal. When constant pressure is maintained on the brake pedal (like when you keep your foot on it at a stop light), the brake pedal will begin to sink to the floor as the brake fluid leaks internally in the master cylinder".
http://www.trustmymechanic.com/auto-repair/3665/brake-master-cylinder-symptoms/

Johnny Kaka
06-02-13, 12:01 PM
The master cylinder was changed about 3 years ago. Could it fail that quickly? How hard is it to replace?

deVille33
06-02-13, 01:08 PM
It could, if you replaced it with an inferior MC. When it comes to brakes, I get the best quality product I can. I do not like to use the brake products you get at Auto-Zone, because they are often Name brand seconds. I prefer original GM or a brand I trust like Eichlin, EIS. Raybestos makes some good brake products, but they also distribute seconds I do not prefer.

Johnny Kaka
06-02-13, 02:39 PM
What is the significance of the pedal only being mushy when the car is started? How can I tell if the bleed is being done right when the car is off?

cadillac_al
06-02-13, 09:57 PM
Now you're seeing things the way I do. I don't have good luck bleeding brakes without the engine running. I always end up starting the car to bleed brakes. Once in a while I will splurge on some Speed Bleeders because sometimes it's hard for me to find a competent brake pumper.

deVille33
06-04-13, 11:39 AM
Now you're seeing things the way I do. I don't have good luck bleeding brakes without the engine running. I always end up starting the car to bleed brakes. Once in a while I will splurge on some Speed Bleeders because sometimes it's hard for me to find a competent brake pumper. Right. You have to find a brake pumper with experience or one that can hear, will pay attention and follow your instructions, no playing their ipod, texting, or too spaced out. lol. :histeric:

Johnny Kaka
06-06-13, 04:23 PM
How about a vaccuum bleeder kit? Is this better?

deVille33
06-07-13, 10:20 AM
Either approach to bleeding works well. Sometimes I use a pressure bleeder, but it is a pain to set it all up. The 2 man pump and bleed uses less equipment. I have used vacuum, but it can be frustrating and difficult to make determinations as to what is going on.

csbuckn
06-07-13, 11:30 AM
^I agree. I've did vacuum and 2 person, the 2 person bleeding has got better results for me.

Johnny Kaka
06-12-13, 08:38 PM
I didn't even have to start the bleed again to find fluid leaking out of the back of the rear drum. Could this be the rear wheel cylinder? This is what I'm thinking. I'm also thinking of bringing it into the shop to have it done. How likely is it that the rear cylinder is shot? I found no other leaks coming from anywhere.

rodnok01
06-12-13, 11:57 PM
It can only be brake fluid or gear lube. More than likely you have found the problem. Wheel cyl not hard to change if you can get the lines loose. Start spraying with pub blaster and use quality line wrenches. Replace both rears while you're at it. If one is leaking the other is probably not far behind and they're cheap anyways.

deVille33
06-13-13, 11:47 AM
A bad cylinder will do all you described. Because of it's position, it will allow air into the system and give you that squishy feel, and low pedal. As rodnok01 says, better to replace both. If it has been leaking a long time, it may have saturated your brake shoes, so consider replacing the shoes and possibly the hardware. Now, another issue, with a better brake at the rear, the line pressure allowed the system will make evident deficiencies in the master. The brakes may work well right after replacing the rear cylinders, but be aware, that the master may fail due to the improved line pressure in that part of the system. :lildevil:

The Ape Man
06-13-13, 02:17 PM
Right. You have to find a brake pumper with experience or one that can hear, will pay attention and follow your instructions, no playing their ipod, texting, or too spaced out. lol. :histeric:

One time my ex wife was pumping the gas pedal instead of the brake pedal.