New brake pads, pedal goes to the floor

[00pooterSS]

I've been a tech for 20 years and roughly 4 times in those years I've had a master cylinder go bad after compressing the calipers.

 

You said you compressed them with a c clamp, nothing wrong with that and it wouldn't have let air in. So it's not air.

 

I've came across many vehicles that were from the north or someone left the rubber caps off the bleeders and water got in and rusted them, you're not getting them out, been there too many times. When I'm in that situation and absolutely have to get fluid through, I'll break the brake line bolt loose at the caliper.

 

The way you did the brakes is perfectly fine and should not have caused any problems, I can almost guarantee you lost the master cylinder.

 

Don't worry about bleeding it at the wheels either, you can bench bleed the master and then after you install it follow the lines to their closest connection point after the master (should be the inlet lines at the ABS unit) crack the lines loose there and bleed it there so you don't have to keep fighting it at the wheels.

 

I've also bled master cylinders by only bleeding them at the cylinder itself, just by cracking the lines loose at the master and pushing the pedal and it works perfect. It works because when you loosen the lines they only loose a tiny amount of fluid from the tip of them, when you crack the lines at the master and push the pedal it pushes fluid into the line and out the fitting, and air rises to the highest point so if your line at the master is the highest point you'll be set.

[sdeeter19555]

Having lived in "the north" for 15 years, I learned twice a year to crack the bleeders and put a touch of anti-seize on the threads. Never a problem for me. Even in "the south", I crack them once a year.
 
 
[emoji4]

Same here...just drizzle ATF down the bleeder center and around the outside when rotating tires or servicing brakes in between replacement. 30 years of rust belt and never had one sieze...

2012 2500hd 6.0l CCSB 4wd

[Lee Nettnin]

12 minutes ago, 00pooterSS said:

I've been a tech for 20 years and roughly 4 times in those years I've had a master cylinder go bad after compressing the calipers.

 

You said you compressed them with a c clamp, nothing wrong with that and it wouldn't have let air in. So it's not air.

 

I've came across many vehicles that were from the north or someone left the rubber caps off the bleeders and water got in and rusted them, you're not getting them out, been there too many times. When I'm in that situation and absolutely have to get fluid through, I'll break the brake line bolt loose at the caliper.

 

The way you did the brakes is perfectly fine and should not have caused any problems, I can almost guarantee you lost the master cylinder.

 

Don't worry about bleeding it at the wheels either, you can bench bleed the master and then after you install it follow the lines to their closest connection point after the master (should be the inlet lines at the ABS unit) crack the lines loose there and bleed it there so you don't have to keep fighting it at the wheels.

 

I've also bled master cylinders by only bleeding them at the cylinder itself, just by cracking the lines loose at the master and pushing the pedal and it works perfect. It works because when you loosen the lines they only loose a tiny amount of fluid from the tip of them, when you crack the lines at the master and push the pedal it pushes fluid into the line and out the fitting, and air rises to the highest point so if your line at the master is the highest point you'll be set.

Thank you so much 00pooterSS, you have saved my day tomorrow. The lines in the engine compartment are in great shape and should come apart like they were brand new. I will get a new master and bleed like you said. You are my hero.   :-)

I will let you know how it goes.

[Lee Nettnin]

15 minutes ago, sdeeter19555 said:

Same here...just drizzle ATF down the bleeder center and around the outside when rotating tires or servicing brakes in between replacement. 30 years of rust belt and never had one sieze...

2012 2500hd 6.0l CCSB 4wd


 

Nice, I take it the ATF will loosen rusted bleeders?? Going to give it a whirl and maybe, just maybe the next time they are needed I can get them loose.

[00pooterSS]

37 minutes ago, Lee Nettnin said:

Thank you so much 00pooterSS, you have saved my day tomorrow. The lines in the engine compartment are in great shape and should come apart like they were brand new. I will get a new master and bleed like you said. You are my hero.   :-)

I will let you know how it goes.

Sounds good and glad to help. Definitely report back. 

 

My my only concern is you said the reservoir cap seal “was too big”. Every time I’ve seen that it was due to fluid contamination and the seal had actually swollen. It’s usually from someone pouring motor oil in the reservoir. Hopefully that’s not the case. If it is you may have other problems down the road and it could explain why you lost the master cylinder.

 

You could still do a full bleed/flush by breaking the brake lines loose at the calipers if need be. 

[Lee Nettnin]

4 minutes ago, 00pooterSS said:

Sounds good and glad to help. Definitely report back. 

 

My my only concern is you said the reservoir cap seal “was too big”. Every time I’ve seen that it was due to fluid contamination and the seal had actually swollen. It’s usually from someone pouring motor oil in the reservoir. Hopefully that’s not the case. If it is you may have other problems down the road and it could explain why you lost the master cylinder.

 

You could still do a full bleed/flush by breaking the brake lines loose at the calipers if need be. 

Thanks again, I will take a close look at the fluid. Now that you say that the rubber did feel swollen kinda real slippery and gooey. If  I don't feel good about the fluid I will try the brake line bleed. The only problem I see is I may be leaving a small amount of fluid in the wheel cylinders.

[DanJS10]

For what it's worth, I had an 08 Sierra 1500 and once after I completed changing brake pads the pedal went straight to the floor just as you described. Went to the dealership and they replaced the master cylinder and even the booster (both under warranty!!) as a precaution. Sounds like you're on the right path but I figured I'd throw in my two cents. Good luck.

[Lee Nettnin]

10 hours ago, DanJS10 said:

For what it's worth, I had an 08 Sierra 1500 and once after I completed changing brake pads the pedal went straight to the floor just as you described. Went to the dealership and they replaced the master cylinder and even the booster (both under warranty!!) as a precaution. Sounds like you're on the right path but I figured I'd throw in my two cents. Good luck.

 

10 hours ago, DanJS10 said:

For what it's worth, I had an 08 Sierra 1500 and once after I completed changing brake pads the pedal went straight to the floor just as you described. Went to the dealership and they replaced the master cylinder and even the booster (both under warranty!!) as a precaution. Sounds like you're on the right path but I figured I'd throw in my two cents. Good luck.

_{Thanks Dan.}

[00pooterSS]

14 hours ago, Lee Nettnin said:

Thanks again, I will take a close look at the fluid. Now that you say that the rubber did feel swollen kinda real slippery and gooey. If  I don't feel good about the fluid I will try the brake line bleed. The only problem I see is I may be leaving a small amount of fluid in the wheel cylinders.

 

Sounds like someone may have put oil in there. Flush the fluid out as much as you can as far away as you can. You could also pull the brake lines off the calipers and let them drip and keep topping off the master cylinder for an hour or so until you go through a jug of fluid. Or you could bleed them out of the other side of the abs unit or whatever. Hopefully the fluid just stayed in the master cylinder and didn't go further. Good thing about brake fluid is it doesn't circulate it just all kinda stays wherever it is so you may have lucked out.

 

13 hours ago, DanJS10 said:

For what it's worth, I had an 08 Sierra 1500 and once after I completed changing brake pads the pedal went straight to the floor just as you described. Went to the dealership and they replaced the master cylinder and even the booster (both under warranty!!) as a precaution. Sounds like you're on the right path but I figured I'd throw in my two cents. Good luck.

If they replaced the booster that means the master cylinder was likely leaking from the back side and into the booster. We replace boosters for that sometimes too. I've also rinsed them out with water and drained them out to save them.

 

 

OP check for brake fluid in the booster. You can run water in it with a water hose then drop a vacuum hose in it and siphon it dry and hopefully save it.

 

Water is the best thing for cleaning brake fluid, no chemicals needed.

[Lee Nettnin]

Well the bad news I cannot bleed the brakes...I tried and the master cylinder will not push any fluid to the wheel cylinders so I pulled off the master cylinder and sure enough there is fluid in the booster, just a small amount around the opening as I can't see any inside but thanks for the hint about using water and sucking it out as I had so little that should work fine. I also found that the fluid in the reservoir did indeed have water in it but I am not sure if it had any other oil, moot point anyway as I am going to bleed all the fluid out and replace with new, I just don't trust the fluid at this point and if someone  put DOT 5 in it, it really must be purged out. Also if someone put DOT 5 fluid in and that maybe why the gasket under the cap swelled up and maybe why the master cylinder took a dive off the deep end. Just for grins and giggles I tried to bench bleed the master and it would not output any fluid...It's dead Jim.  

[00pooterSS]

On 4/20/2018 at 7:38 PM, Lee Nettnin said:

Well the bad news I cannot bleed the brakes...I tried and the master cylinder will not push any fluid to the wheel cylinders so I pulled off the master cylinder and sure enough there is fluid in the booster, just a small amount around the opening as I can't see any inside but thanks for the hint about using water and sucking it out as I had so little that should work fine. I also found that the fluid in the reservoir did indeed have water in it but I am not sure if it had any other oil, moot point anyway as I am going to bleed all the fluid out and replace with new, I just don't trust the fluid at this point and if someone  put DOT 5 in it, it really must be purged out. Also if someone put DOT 5 fluid in and that maybe why the gasket under the cap swelled up and maybe why the master cylinder took a dive off the deep end. Just for grins and giggles I tried to bench bleed the master and it would not output any fluid...It's dead Jim.  

Glad you're getting somewhere. Let us know how it goes after you get the new master cylinder on there.

 

Again, you can disconnect/loosen the brake lines at the calipers to bleed the whole system, except the calipers, that'll at least get most if not all of the contaminated fluid. If someone topped it off with an improper fluid, it likely didn't make it all the way to the calipers/wheel cylinders. If you can't get the lines off at the calipers/cylinders, try where the rubber hoses connect to the hard lines a little further up.

[Lee Nettnin]

I would like to once again thank 00pooterSS, you nailed it. My master cylinder definitely went south. I cleaned out the booster with water to get out any brake fluid and sucked it all out with a vacuum. I installed the new master, retapped the one snapped off bleeder and installed a new larger one, and very carefully got the remaining ones out with a fire wrench. I let any fluid gravity drip out of the line then connected the master and bled out the lines, 3 times. I went for a test drive and the brakes work perfectly. Great advice and case closed.

[ExtraSlow]

I know your pain about the bleeders seizing, and it always makes me nervous when I need to mess with them.  Glad that things worked out eventually, although it's bad luck that you had to go through all that on what should have been a simple job.  

[davester]

You might also want to bleed your ABS system.  The "right" way to do it requires hooking up a computer to your truck to command it to go through a special purge cycle, but some people will instead do it the 'redneck' way and do some panic stops on a gravel road to activate the abs system several times.  After doing this, you then bleed all 4 corners again (starting from wheel furthest from MC to wheel closest to it).

[Lee Nettnin]

9 hours ago, davester said:

You might also want to bleed your ABS system.  The "right" way to do it requires hooking up a computer to your truck to command it to go through a special purge cycle, but some people will instead do it the 'redneck' way and do some panic stops on a gravel road to activate the abs system several times.  After doing this, you then bleed all 4 corners again (starting from wheel furthest from MC to wheel closest to it).

Thanks for the info. My scan tool does not cover ABS but I am working on getting the add ons for it. In the mean time I will hope things work out ok and the brakes will continue as they are now. I am retired and dont put many miles on it until camping season starts (if the warm weather ever gets here).