Faulty Master? Please check me on this.. - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

4WDlifeform · 03-19-2023, 03:17 PM

Quick back story - Last summer, I broke a valve spring, had the car hauled back to my garage. Sat for maybe 7 months before I was able to fix the valvetran. Everything back together, engine runs great.

Took it out for a test run, the brake pedal goes nearly to the floor. There was braking available, but it was at the last 10% of the stroke. When I put the car away, the brakes were perfectly fine. It sat 7 months in a warm garage all winter, and now nearly no brakes...

I checked the calipers (brembo) and bleed an entire bottle through the system with a power bleeder, no air or debris came out of the bleeders. Fluid looked good. When the brakes do engage at the end of the stroke, braking feels balanced and reasonably strong before hitting the floor. I don't think it is calipers. Rotors and pads are maybe a year old, 5k on them at the most.

I am cammed, but never had booster issues. And, my understanding with bad boosters/low vacuum would be the opposite; a hard pedal and lost braking. It must be the master cylinder, right? Just boggled how a master can go bad by just sitting??

Thoughts? If it is a master, what am I getting into with ABS and bleeding? Should I just give her to a shop? I don't have tuner/controller to cycle the solenoids (if that is necessary?) Thanks in advance.

CamaroCracka · 03-20-2023, 07:50 AM

Your logic sounds right to me. If you're not losing fluid and the calipers are working, I would look to the master cylinder. Even if booster was shot, you would have some brakes.

If you have a clutch, it would be a good time to put in a separate clutch reservoir.

You can get a scan tool that does ABS for around $100 (Foxwell 630 or similar), or you can old school bleed them and then take it to a shop to have them bled with a scan tool. The scan tool basically runs the ABS pump to clear any air out of it while bleeding and you should get as much air as possible out before using the scan tool anyway.

4WDlifeform · 03-21-2023, 08:51 AM

Thanks for the check. I'll get a master on order, and post back with an update. The car is due for inspection, so I'll have a shop do a proper bleed when I take it in for her yearly. Thanks!

4WDlifeform · 04-24-2023, 08:55 PM

Quick update. Replaced the master, and still had a soggy pedal. I was able to limp it to the dealer, where they bled it with the computer. Brakes are back!

1JEWLDSSRS · 04-25-2023, 08:58 AM

Good job! Glad you got that problem fixed!!

KevinLo822 · 04-25-2023, 10:03 AM

It's strange that your master cylinder would go bad just from sitting for 7 months, but it's not impossible. Sometimes, internal seals can fail over time or with temperature changes, and that could cause the symptoms you're experiencing.

As for what you're getting into with ABS and bleeding, it really depends on the specifics of your car. Bleeding the brakes on a car with ABS can be a bit more complicated than on a car without ABS, but it's still doable. You may need a special tool to cycle the solenoids, but you could also try bleeding the brakes without cycling them and see if that works.

If you're not comfortable doing this work yourself, taking it to a shop is definitely an option. They'll be able to diagnose the problem and fix it for you.

03-19-2023, 03:17 PM	#1
4WDlifeform Drives: 2014 Camaro 1SS RS Join Date: Oct 2017 Location: Pittsburgh Posts: 75	Faulty Master? Please check me on this.. Quick back story - Last summer, I broke a valve spring, had the car hauled back to my garage. Sat for maybe 7 months before I was able to fix the valvetran. Everything back together, engine runs great. Took it out for a test run, the brake pedal goes nearly to the floor. There was braking available, but it was at the last 10% of the stroke. When I put the car away, the brakes were perfectly fine. It sat 7 months in a warm garage all winter, and now nearly no brakes... I checked the calipers (brembo) and bleed an entire bottle through the system with a power bleeder, no air or debris came out of the bleeders. Fluid looked good. When the brakes do engage at the end of the stroke, braking feels balanced and reasonably strong before hitting the floor. I don't think it is calipers. Rotors and pads are maybe a year old, 5k on them at the most. I am cammed, but never had booster issues. And, my understanding with bad boosters/low vacuum would be the opposite; a hard pedal and lost braking. It must be the master cylinder, right? Just boggled how a master can go bad by just sitting?? Thoughts? If it is a master, what am I getting into with ABS and bleeding? Should I just give her to a shop? I don't have tuner/controller to cycle the solenoids (if that is necessary?) Thanks in advance. __________________ 2014 SS RS Cammed, 4.10s, Tuned, Long Tubes, NPP, CAI

03-20-2023, 07:50 AM	#2
CamaroCracka Drives: 2010 Turbo LS3 Join Date: Dec 2009 Location: Palm Bay, FL Posts: 2,731	Your logic sounds right to me. If you're not losing fluid and the calipers are working, I would look to the master cylinder. Even if booster was shot, you would have some brakes. If you have a clutch, it would be a good time to put in a separate clutch reservoir. You can get a scan tool that does ABS for around $100 (Foxwell 630 or similar), or you can old school bleed them and then take it to a shop to have them bled with a scan tool. The scan tool basically runs the ABS pump to clear any air out of it while bleeding and you should get as much air as possible out before using the scan tool anyway. __________________ 2010 SS - On3 kit with downpipe cutout, CTR 78/80, CompCam 239/251 620/632 122+4, E85, Z28 suspension and ZL1 diff with Outlaw axles. Gen6 ZL1/1LE brakes. 2011 Vert - 416/w 230/236 .612/.602 115lsa, 1LE suspension w/32mm rear bar. Z28 diff. ZL1 brakes.

03-21-2023, 08:51 AM	#3
4WDlifeform Drives: 2014 Camaro 1SS RS Join Date: Oct 2017 Location: Pittsburgh Posts: 75	Thanks for the check. I'll get a master on order, and post back with an update. The car is due for inspection, so I'll have a shop do a proper bleed when I take it in for her yearly. Thanks! __________________ 2014 SS RS Cammed, 4.10s, Tuned, Long Tubes, NPP, CAI

04-24-2023, 08:55 PM	#4
4WDlifeform Drives: 2014 Camaro 1SS RS Join Date: Oct 2017 Location: Pittsburgh Posts: 75	Quick update. Replaced the master, and still had a soggy pedal. I was able to limp it to the dealer, where they bled it with the computer. Brakes are back! __________________ 2014 SS RS Cammed, 4.10s, Tuned, Long Tubes, NPP, CAI

04-25-2023, 08:58 AM	#5
1JEWLDSSRS Drives: 2011 SS-RS Join Date: May 2011 Location: FLORIDA Posts: 11,417	Good job! Glad you got that problem fixed!! __________________ TSP STAGE 3 CAM,231/246 @112 LSA 614/641 LIFT, CIRCLE D 5C-4200-4500 CONVERTER,LOD INTAKE.CORSA EXHAUST. DSS 1 PC DS. PEGASUS SOLID CRADLE MOUNTS. 486RWHP/475RWTQ.LOTS MORE.

04-25-2023, 10:03 AM	#6
KevinLo822 Drives: 2012 Camaro ZL1 Join Date: Apr 2023 Location: Denver Posts: 4	It's strange that your master cylinder would go bad just from sitting for 7 months, but it's not impossible. Sometimes, internal seals can fail over time or with temperature changes, and that could cause the symptoms you're experiencing. As for what you're getting into with ABS and bleeding, it really depends on the specifics of your car. Bleeding the brakes on a car with ABS can be a bit more complicated than on a car without ABS, but it's still doable. You may need a special tool to cycle the solenoids, but you could also try bleeding the brakes without cycling them and see if that works. If you're not comfortable doing this work yourself, taking it to a shop is definitely an option. They'll be able to diagnose the problem and fix it for you.