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Brake Bleading?

MarkG

By MarkG
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MarkG Enthusiast

MarkG

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I recently changed pads on my wife's car and I guess I did not get enough of that anti-squeak stuff on because the brakes are still squeaking.  Well, my problem is that I can not get the caliper off with the new pads on.  I am assuming I need to blead the brakes to releive some of the pressure off the piston so I can remove the caliper.  Changing pads no problem, but I have never blead the brakes before.  I know you have to be careful not to get air in the line but is this something better left to the pro's or is it that difficult?

 

Thanks for the help,

 

Mark

varmint2506 Enthusiast

varmint2506

Posted
Posted

You should not have to bleed to get the caliper piston to move back.  How did you get the piston back to install the new pads? I generally use a C clamp to squeeze the piston back. If the breaks are tight up against the rotor, you may have a caliper problem. You should be able to take a big screwdriver and pry against the pad TAB to push it back to. Dont pry against the pad itself. I had a similar problem on my pickup. One of the front pads started rubbing so bad it smoked. Turned out the caliper piston was rusty and was sticking.

 

If you have air in the system you would notice a soft pedal.

MarkG Enthusiast

MarkG

Posted
  • Author
Posted

I usually use a C clamp but that is once I have the old pads off and the caliper off.  Now the new pads are on and the caliper is much tighter.  I took the caliper bolts off and the caliper is loose but it will not come off because the piston is tight against the pads.  I was assuming I would have to relieve the pressure on that piston but maybe I will try a srew driver and see if I can pry the piston back.

 

Thanks,

 

Mark

CMNTMXR81 Senior Enthusiast

CMNTMXR81

Posted
Posted

Varmint beat me to it.  You introduced no air into the system via simply changing the pads, therefore no bleeding is necessary.  That is unless you have that soft 'squishy' pedal feeling.  At one time, with GM trucks (but I think it was isolated to S-Series) that you had to crack the bleeder screw when pushing the piston back to eliminate any crud in the lines from plugging a screen in the line.  Effectively, opening the bleeder screw let it flow out instead.  If that is required then you'd need to bleed.

 

When bleeding, always start at the wheel farthest from the master cylinder.  If bleeding all 4, that'd be the right rear.  If bleeding only two, it'd be the right front.  If you don't have a vacuum pump, then you'll need a second person to pump the brake pedal.  Actually, they'll need to push the pedal firmly to effectively squeeze out the fluid.  I'd highly recommend getting one of those hand held vacuum pumps.  They're only like $25 at a local auto parts store.

 

On a side note, when using that C-clamp to push the piston back in the caliper, open/uncap your resevoir.  Essentially you're pushing the fluid back through the system.  Therefore is you don't uncap/loosen the cap it'll swell in the resevoir and potentially expand it.  You  can tell by the white stretch marks in the plastic.

carguru Senior Enthusiast

carguru

Posted
Posted
:) Totally agreed that no air was introduced to the system, but if it has been more than a couple of years since the fluid was new, might be time to replace all of the fluid anyways.  Just my $0.02 :)
MarkG Enthusiast

MarkG

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Okay.  The no air introduced, no need to blead thing makes perfect sense, I should have thought of that.  However, I still have the problem of getting the caliper off.  I think Varmit mentioned using a screw driver to try and pry the piston back.  Will that work?  I don't want to screw up the pad.

 

Thanks for the help,

 

Mark

CMNTMXR81 Senior Enthusiast

CMNTMXR81

Posted
Posted

If it'll push the piston back, I'd do it carefully.

 

This is one of those situations where there isn't a specified procedure in a book, but more or less one of those "if it works, do it" type of procedures.

varmint2506 Enthusiast

varmint2506

Posted
Posted

How many miles are on the ride? Sounds like you may have a lip on the outside of the rotor. The breaks wear away at the rotor but do not touch all the way to the outside. Hence a lip is formed. I have seen rear drums hard to get off because of this. The shoes in the rear are self adj., so when the drums wear down the shoes will compensate.

 

If you have a lot of miles on the ride you and have not had the rotors turned, you may want to have that done.

 

The front pads should have a tab that sticks out through the caliper. I use a big screwdriver or pry bar to spread those tabs out. This should push the piston back enough to get the caliper off. Dont pry between the pad and the rotor.

 

Just my second 0.02 :thumb:

MarkG Enthusiast

MarkG

Posted
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Posted

Thanks for all the suggestions guys.  I will have to see what I can tear up when I get home this evening.  

 

Varmit, are you referring to the tab on top of the caliper?  I noticed last night there was a hole in the middle of the caliper and there was a tab in there.

 

Thanks again.

 

Mark

MarkD Senior Enthusiast

MarkD

Posted
Posted
You may have tried this, but I usually try to "rock" the caliper with it still on the disk to get a little play once I have taken out the bolts.  I also recommend taking off the reservior cap before trying anything.
varmint2506 Enthusiast

varmint2506

Posted
Posted
Varmit, are you referring to the tab on top of the caliper?  I noticed last night there was a hole in the middle of the caliper and there was a tab in there.

The center of the caliper should have a open slot and the pads have a tab or notch that fits into that slot. This along with other locking points keeps the pads in the caliper. I pry againts those.

 

Im sure this varies between models.

 

MarkD has a good idea! :thumb:

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