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Can you push caliper piston too far back in??

Mossyoakglock

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SILVERADOSC540 Senior Enthusiast

SILVERADOSC540

Posted
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Don't get too excited yet. Make sure you have brakes and drive it for a day. Most feel soft at first. Look online, I'm sure that there are do it yourself videos will reflect that. I'm not positive, but I think everything is fine.

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Mossyoakglock Senior Enthusiast

Mossyoakglock

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Got home today after work and checked everything out. Took the brakes apart and pressed the brake pedal to try to get the pistons to move. Well, only one piston was pushing out, the other wasn't moving. I could get it to move out a little but not like the other one. I also noticed a small tear in the boot on the piston that wasn't moving much.

 

Is the caliper going out?

 

If it is bad, do you think I should rebuild the caliper or get a new one? The rebuild kit is $8 from O'Reilly's and the caliper is $117

 

Rebuilding looks pretty easy and I have a compressor so popping the old piston out shouldn't be a problem.

LeoS41280 Enthusiast

LeoS41280

Posted
Posted

The sealing surface in a caliper isn't the bore. It's the outside of the piston. Calipers are very easy to repair if it only needs seals and a piston. Make sure the bleeder screw is free. Be very careful using compressed air to push out the piston. Use a wood block to stop the piston as it comes out. Assembly lube is a must when reassembling.

2007SierraSLT Enthusiast

2007SierraSLT

Posted
Posted

Mine did the same thing when I did mine the other day, I disconnected the hose off the vacumn booster and reconnected it and it got better after that... Went out to check my pistons after i seen this, piston was hauling even on both ends when pedal was pushed so I guess their good anyway haha

Mossyoakglock Senior Enthusiast

Mossyoakglock

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Mine did the same thing when I did mine the other day, I disconnected the hose off the vacumn booster and reconnected it and it got better after that...

 

I'll try that. It can't hurt.

 

I finished building my own pressure bleeder last night so I'm going to flush the lines this weekend to get any air out that might have gotten in there. Plus it can't hurt to replace the fluid anyways since it's 5 years old.

Mossyoakglock Senior Enthusiast

Mossyoakglock

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Mine did the same thing when I did mine the other day, I disconnected the hose off the vacumn booster and reconnected it and it got better after that...

 

Probably a stupid question but did you do this with the truck running or off?

2007SierraSLT Enthusiast

2007SierraSLT

Posted
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Probably a stupid question but did you do this with the truck running or off?

 

Running then I shut off the truck put it back on and started it back up

Mossyoakglock Senior Enthusiast

Mossyoakglock

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So I replaced my front left caliper today and bled the brakes twice. There were no air bubbles what so ever so I'm sure that I got all the air out of the system. I used a pressure bleeder.

 

I went to test drive it and still have no pedal pressure. With the truck off I could pump the brakes 3 or 4 times and they would be solid as a rock and hold. When I would drive I could pump the brakes and about the 3rd pump it would return to normal pedal pressure and hold until I stopped. Once I let off the brakes to accelerate and brake again, there would be no pressure.

 

I checked all lines and the master cylinder and there are no leaks anywhere. When I pressure bled, I used 10 psi and it held there all day long.

 

What else could be the problem? Master cylinder?

 

I'm taking it monday to the dealer so they can bleed the ABS system and fully flush the lines. When I compressed the piston when changing my pads could I have pushed air into the ABS system?

Mossyoakglock Senior Enthusiast

Mossyoakglock

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I did a few tests on it and everything seems to be functioning fine (other than the soft pedal). With the truck off I can pump the pedal a few times and with each pump the pedal gets more and more firm and rises each time.

 

If I press the pedal and then start the truck, the pedal drops to the floor. This makes me think that the brake booster is functioning properly.

 

I still cannot find any leaks anywhere which makes me think that I somehow got air in the ABS when compressing the pistons.

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