Soft brakes after bleeding on 2011 Silverado 1500

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Just replaced both the front calipers and brakes on friends 2011 Silverado 1500.

We bleed both drivers and passenger side with the car off. We went through alot of fluid. Air is no longer exiting the caliper tubing when bleeding. The brakes are still spongy. What am I missing?

I'm frustrated and tired.

Thank you!
 
Must be the feel of the new pads until they seat/bed in.
How did you bleed the brakes?...

1)Gravity?
2)Vacuum Pump?
3)Two man system? I don't do a 2 man setup anymore as the person inside the truck can/could be pushing the master cylinder piston too far(not realizing) and cause cylinder wall scoring. You really shouldn't push the brake pedal to the floor!

What type of brake pads did you use?
Did you stray from OE or OE-like? Meaning did you change from the factory friction material(Semi-Mets vs Ceramic) and brake coefficient of friction/CoF(FF vs GG)?...I don't like CoF-GG pads but most others here do so, I'm the oddball in this camp.
 
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Originally Posted By: barkingspider
Perhaps bleed the rear brakes, too


^^^Yes, this too however, I don't think(just me) that this is going to change the sponginess feeling since the brakes were feeling normal prior to the pad/rotor change.
 
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Originally Posted By: dja4260
Just replaced both the front calipers and brakes on friends 2011 Silverado 1500.

We bleed both drivers and passenger side with the car off. We went through alot of fluid. Air is no longer exiting the caliper tubing when bleeding. The brakes are still spongy. What am I missing?

I'm frustrated and tired.

Thank you!


Have you fired the engine up to get the servo working ?
 
Originally Posted By: NGRhodes
Originally Posted By: dja4260
Just replaced both the front calipers and brakes on friends 2011 Silverado 1500.

We bleed both drivers and passenger side with the car off. We went through alot of fluid. Air is no longer exiting the caliper tubing when bleeding. The brakes are still spongy. What am I missing?

I'm frustrated and tired.

Thank you!


Have you fired the engine up to get the servo working ?


Yes
 
Originally Posted By: Char Baby
3)Two man system? I don't do a 2 man setup anymore as the person inside the truck can/could be pushing the master cylinder piston too far(not realizing) and cause cylinder wall scoring. You really shouldn't push the brake pedal to the floor!


Had a few master cylinders go bad after bleeding brakes two man. The last one I had go bad had a big block of wood under the brake pedal during the two man bleed. Thought the block of wood would help but nope.
 
Originally Posted By: BigD1
Originally Posted By: Char Baby
3)Two man system? I don't do a 2 man setup anymore as the person inside the truck can/could be pushing the master cylinder piston too far(not realizing) and cause cylinder wall scoring. You really shouldn't push the brake pedal to the floor!


Had a few master cylinders go bad after bleeding brakes two man. The last one I had go bad had a big block of wood under the brake pedal during the two man bleed. Thought the block of wood would help but nope.


Yeah, I either gravity bleed or use the Mityvac.
I'll gravity bleed if I'm just inspecting/cleaning/lubing the brakes.
I'll Mityvac when doing a whole brake job. I'll turkey baste the master cylinder and start with fresh fluid.
 
It sound like the MC went dry and now there is air in the ABS, use a scan tool to trigger the bleeding.
If you don't have one a shop wont charge much to do that for you.
 
First thing I would do is gravity bleed the rear brakes. Its simple enough to do and you dont even need to pull the wheels. Just break the bleeder free and place a hose on it to a container, let it drip for 10 minutes or so (watching the level in the MC reservoir) Do the drivers side first then the passengers. Cheap and easy. If that doesnt do it I would drive the truck and try to get the ABS to activate a few times then rebleed the system (you could get a Tech tool to activate the ABS for bleeding but I dont have one so this is the shadetree method)

Its also possible that one of the new calipers isnt any good or that the pads arent moving freely in the calipers. If the pads are binding and wont slide freely in the mounts it will give you a mushy peddle.
 
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Why were the calipers replaced? I thought my front right caliper was frozen. Nope, it was the CRC grease recommended by the auto parts store. Do Not use standard brake grease on the calipers of that truck. The grease will get hot, boil, and harden jamming up the caliper bolts and slides. Use syl glide or a silicon based paste. Bad movement could cause spongy response.

You said replaced brakes, what does that include? (rotors, pads, etc). If it was just ceramic pads, old rotors, that may take a while for bedding to occur. The old rotor should come off and thoroughly cleaned to remove pad glazing and grease.

You're in Chicago. Go slip on something making the ABS flutter, try bleeding again.
smile.gif


You have a hydro boost system which means you rely on the PS pump for your power assisted brakes. Turn on truck and listen. Turn the wheel, step on the brakes. Hear any whining? May need to replace the PS pump. At least, turkey baste the PS reservoir a few times. this was my spongy brake issue. Not enough hydroboost pressure, faulty PS pump.
 
did you stick with Dot 3 or swap to Dot 4. I've swapped to Dot 4 a couple of times and found the brakes to be spongier after that. Swapping back to Dot 3 later firmed it up.

-m
 
I'm not sure if GM used the cranky Kelsey-Hayes/TRW ABS system on the GMT900s as they did with the GMT400/800 trucks - those do need a Tech II or a aftermarket scan tool with bidirectional capability to run the bleeding procedure.

If you don't have a scan tool and if the truck is 4WD, put it up on stands. Then start the truck up in any 4WD mode then hit the brakes. The ABS will cycle. Do this a few times and bleed again. Since you have new pads, I would avoid making sudden stops - which is why I can't recommend the hillbilly method which is driving carefully to an empty lot and wailing on the brakes to get the ABS modulator to actuate.
 
Originally Posted By: redhat
Your bleeders aren't pointing down are they?
X2 thinking that as I scrolled to the end. If you put the calipers on the wrong side, they will fit but are upside and impossible to bleed. Wild guess but easy to check. please post a follow.
 
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