Hyundai Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
30 Posts
Discussion Starter · #1 ·
Brakes were working normally but I decided to check the front left brake pads because I was hearing a noise coming from the front left. The only thing I did was compress the pistons to inspect the brake pads. Now the pedal goes all the way to the floor when I apply the brakes.

With the engine off I can pump the brakes to a firm condition. As soon as I turn the engine on the brake pedal will go all the way to the floor with little effort.

If I pump the brakes I do not see the piston move on the caliper I was working on.

When I try to bleed the system a very limited amount of brake fluid comes out. Indicating to me that fluid is not getting to the caliper.

Anyone know what is going on?
 

·
Registered
Joined
·
349 Posts
If you simply compressed the piston and forced the fluid back up into the master cylinder and reservoir, then you probably knocked some debris loose or damaged a seal somewhere along the line, or possibly in the master cylinder itself.

Start with using a vacuum bleeder on the wheel where the piston does not move. Just make sure that the reservoir does not run dry.

And in future, do not simply compress the pistons in the caliper to retract them. Open the bleed valve. Flow in this system needs to be one way IMO.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #3 ·
Start with using a vacuum bleeder on the wheel where the piston does not move. Just make sure that the reservoir does not run dry.
I'll start with that. It was cold, about 27 F. I don't know if that would have caused the problem. I never had this problem before.

Thanks.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #4 ·
I tried to vacuum bleed both front calipers. I was unable to get any significant fluid out of either side. Next I'm going to replace the master cylinder.
 

·
Registered
Joined
·
1,978 Posts
I would first spend more time bleeding lines.
It appears you have air in the system causing the soft pedal.
Master cyclinders generally last longer than calipers; you may even have a seized caliper causing some of the problem.

Try a clear piece of plastic tubing so you see the air bubbles coming out if the bleeder screw; old school simple methods sometimes work fine.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #6 ·
Tried "old school" with the engine off and with the engine on. Basically no fluid comes out.

Would a bad caliper cause the symptoms my Santa Fe is experiencing? As soon as the engine is turned on the pedal goes straight to the floor.

How did the air get in there in the first place? All I did was to rotate the caliper up and then compressed the pistons.

A couple of years ago the other caliper was stuck and I replaced it. I didn't have any trouble bleeding it "old school", as you say. Basically, now it does not bleed. It's like the fluid is not being pushed when the pedal is depressed.

FYI I'm still considering replacing the caliper.

As far as I can tell the is no fluid leakage.

Another thought has occurred to me. What if the ABS unit got damage when I compressed the pistons? Is that possible and would it exhibit the same symptoms my car does?
 

·
Registered
Joined
·
8,613 Posts
ABS pumps/modules are usually open valves that close when commanded to cycle the brakes on and off. It should not have been damaged. Sounds to me like you blew out the Master Cylinder.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #8 ·
Just finished replacing the master cylinder and bleeding all four corners. The only part I replaced was the master cylinder. After replacing the master cylinder I had no problem bleeding any of the calipers using the "old school" method. I did not use my new vacuum bleeder. The problem appears to be solved. I guess when I compressed the pistons I blew out the master cylinder. In the future I'll open the bleed valve before compressing the pistons. Based on my recent research this appears to be the new procedure when the pistons are compressed, especially if you have ABS. I learn something new everyday.

Thanks for all the advice and encouragement. I'll update if a problem recurs with the brakes.
 
1 - 8 of 8 Posts
Top