Parking brake not holding with Brembo brakes and thicker brake lining - Pontiac G8 Forum: G8 Forums - G8Board.com
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post #1 of 18 (permalink) Old 05-14-2015, 10:04 AM Thread Starter
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Parking brake not holding with Brembo brakes and thicker brake lining

Good morning folks! The G8 GT I recently picked up has the CTS-V Brembo upgrade along with the thicker parking brake shoe linings made to work with the larger rear rotors. I don't know the history on the car other than the brake upgrade was done fairly recently. I tightened the parking brake adjuster using the torx bolt in the center console. I tightened the bolt all the way and I'm still getting no engagement when pulling the parking brake handle all the way up.

My mechanic friend looked at this issue last week for me and told me I needed a new wheel cylinder adjuster, but I want to confirm that this is in fact my issue. I popped the right-rear rotor off last night and removed the parking brake shoe. I'm not sure how to confirm if the adjust is shot or not. I was able to easily remove both ends of the adjuster that contact the brake shoe, with fingers. I can see that end that points toward the rear of the car is expanding out when the parking brake handle is engaged, but apparently not enough to make contact with the hat on the rotor.

One thing I didn't do that I should have done is loosen the torx bolt in the center console up completely, but I instead tried rotating the toothed side of the adjuster that faces toward the front of the car and I couldn't determine how rotating it was pushing the opposite side out further. I'm wondering if I'm missing any parts now. Any idea how to determine if the wheel cylinder is in fact needing replacement? Thanks!

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post #2 of 18 (permalink) Old 05-14-2015, 12:00 PM
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You need to tighten the shoe via the adjuster and fit it to the rear rotors.
It needs to fit the rotor pretty snug.

The problem is the Camaro/V rear rotors don't have the adjustment hole in them so you need to put the rotor on and off many times until you can get the shoes to fit tight.

The G8 rotor has an adjustment hole. The Camaro has the adjustment hole in the backing plate, where the G8 does not.

Hope that helps some.
-Greg

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post #3 of 18 (permalink) Old 05-14-2015, 12:12 PM Thread Starter
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Excellent info, thank you Greg. Yeah I was checking all around for an access hole on the back side of the rotor dust cover, and ended up fighting to try to adjust it and put the rotor back on like you said. The shoes kept moving all over the place as I tried to center them into the rotor hat and it was getting dark so I gave up for the night and put everything back together haha.

2008 Pontiac G8 GT (sold)
D1SC Procharger - Alky Control Methanol Injection - Comp Custom Blower Cam
FAST 102 Intake Manifold - RCR-built 6L80E - Yank 3200 Converter - Camaro SS 3.27 Diff

2005 Pontiac GTO (for sale)
Twin 6265 Precision Turbos - Forged LY6 6.0 - Flowtech Custom Cam
Perfomabuilt Level II 4L60E - Vigilante 3400 Converter - Lots More!
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post #4 of 18 (permalink) Old 05-14-2015, 01:44 PM
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With the wheels removed (and 2 lug nuts reinstalled upside down an tight) on the rotors to secure them in place, remove the P/B access port/plug on the rotor an rotate it so that access hole is positioned over the adjusting nut. For sure you need to back off the cable adjuster (you previously worked with) to eliminate any influence on the shoes. Then using a screwdriver, start rotating the adjuster nut (to expand the shoes) until you can lock the wheel up. Then rotate the adjusting nut the other way 3 to 5 clicks (or until there is no dragging from the shoes when rotating the rotor). Do the same for both sides, then replug and reinstall the wheels. Now adjust the P/B cable to get a positive brake lock action in the 4 to 6 click range.
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post #5 of 18 (permalink) Old 05-14-2015, 02:56 PM Thread Starter
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Thanks for your help once again Gopherit, I really appreciate it! I'll definitely have to wait till I can get a floor jack under the differential to get both rear wheels off the ground (so I can rotate the access hole in the rotor to the right position and remove the tension from the adjusting bolt so I can try things again.

2008 Pontiac G8 GT (sold)
D1SC Procharger - Alky Control Methanol Injection - Comp Custom Blower Cam
FAST 102 Intake Manifold - RCR-built 6L80E - Yank 3200 Converter - Camaro SS 3.27 Diff

2005 Pontiac GTO (for sale)
Twin 6265 Precision Turbos - Forged LY6 6.0 - Flowtech Custom Cam
Perfomabuilt Level II 4L60E - Vigilante 3400 Converter - Lots More!
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post #6 of 18 (permalink) Old 05-14-2015, 03:35 PM
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What gopherit posted will not work with the Camaro rotors as there is not a access hole in them.

You will need to back off the adjuster nut on the brake handle then fit the rotor on and off as I posted. You can also use a set of dial calipers if you have some large enough.

1998 Pontiac Grand Prix - 11.24 @ 121
2009.5 G8 GT (Liquid Red)
GXP fascia conversion, GXP diffuser

2009 GXP M6 (MSM) #405 586rwhp/495tq

TVS2300, CTS-V Fuel System, Cam 222/230 116 lsa, Stage 4 Monster Clutch, American Racing 1 7/8 headers, rear Brembo's [email protected]
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post #7 of 18 (permalink) Old 05-14-2015, 03:55 PM
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That just shows that I best not post anything on a given thread, *if* a modification has taken place in that area. Too may things are changed from what they originally were.
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post #8 of 18 (permalink) Old 05-14-2015, 11:05 PM Thread Starter
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Thanks for the info guys! Yeah the variables can be a pain in the ass. I can't even tell you exactly what rear rotors the car has... I'm just assuming they are Camaro or CTS-V. A few unknowns

2008 Pontiac G8 GT (sold)
D1SC Procharger - Alky Control Methanol Injection - Comp Custom Blower Cam
FAST 102 Intake Manifold - RCR-built 6L80E - Yank 3200 Converter - Camaro SS 3.27 Diff

2005 Pontiac GTO (for sale)
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Perfomabuilt Level II 4L60E - Vigilante 3400 Converter - Lots More!
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post #9 of 18 (permalink) Old 05-15-2015, 08:39 AM
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Quote:
Originally Posted by MEAN GTO View Post
Thanks for the info guys! Yeah the variables can be a pain in the ass. I can't even tell you exactly what rear rotors the car has... I'm just assuming they are Camaro or CTS-V. A few unknowns
If you are using caliper adapter brackets they are the Camaro/CTS-v rotors.

1998 Pontiac Grand Prix - 11.24 @ 121
2009.5 G8 GT (Liquid Red)
GXP fascia conversion, GXP diffuser

2009 GXP M6 (MSM) #405 586rwhp/495tq

TVS2300, CTS-V Fuel System, Cam 222/230 116 lsa, Stage 4 Monster Clutch, American Racing 1 7/8 headers, rear Brembo's [email protected]
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post #10 of 18 (permalink) Old 06-02-2015, 11:20 AM Thread Starter
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Thanks Radrace.

So I took the car to the dealership to have them adjust the parking brake. They did it once and said it held on an incline in the back of the dealership. I picked up the car, drove it 25 miles home, and then tested it out and it wouldn't hold.

I took the car back, they adjusted it again and inspected the wheel cylinders and found nothing wrong. This time I tested it before leaving the shop and it DID hold. Drove it 25 miles home and once again, it will no longer hold. Any ideas here?? The tech did adjust things properly (loosen adjusting bolt in center console, adjust the brake shoes out, tighten the adjusting bolt in the center console). Thanks!!

2008 Pontiac G8 GT (sold)
D1SC Procharger - Alky Control Methanol Injection - Comp Custom Blower Cam
FAST 102 Intake Manifold - RCR-built 6L80E - Yank 3200 Converter - Camaro SS 3.27 Diff

2005 Pontiac GTO (for sale)
Twin 6265 Precision Turbos - Forged LY6 6.0 - Flowtech Custom Cam
Perfomabuilt Level II 4L60E - Vigilante 3400 Converter - Lots More!
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post #11 of 18 (permalink) Old 06-02-2015, 01:46 PM
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Quote:
Originally Posted by MEAN GTO View Post
So I took the car to the dealership to have them adjust the parking brake. They did it once and said it held on an incline in the back of the dealership. I picked up the car, drove it 25 miles home, and then tested it out and it wouldn't hold.
Don't know if this applies to a G8 or not, but here goes. Many years ago, most cars had self-adjusting rear drum brakes. If the automatic mechanism rusted up, you could manually adjust the brakes and they would work properly for a little while. Does anybody know if the G8 has an automatic self-adjusting mechanism on the rear brakes?

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post #12 of 18 (permalink) Old 06-02-2015, 02:56 PM
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^^^^ My take, is that any car that comes with rear disc brakes, would either have a mechanical device built onto the caliper, and when the brake handle is pulled or a brake pedal is pushed, the cam action (at he caliper) would force the pads tight to the rotors, and allow them to pull away when the handle or pedal is returned to its off position. Others (like the G8), use the spreading shoe design. I doubt any of them have the components added in, that would *auto adjust* those shoes (as time and use go by). I'm sure I will never even need to adjust those shoes (using its mechanical adjuster method) on this car, unless I choose to make them work as regular brakes from time to time (an wear the shoe thickness down). I also feel that these parking brakes have next to zero ability to assist in regular braking.


Its almost like "MEAN GTO" is lacking the shoe material thickness needed, or the wrong total diameter of the shoes currently installed in there, for proper parking brake action. Especially if a manual adjustment only lasts for like 1 or 2 cycles.
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post #13 of 18 (permalink) Old 06-02-2015, 08:18 PM Thread Starter
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I agree GOPHERIT, I'd be using the parking brake like you-- as a parking brake. Once it is adjusted to hold, I shouldn't be creating any wear on the linings of the shoes. Butttttttt...... one of my parents' prior Ford SUV's had an auto-adjusting parking brake, using the expanding shoe design like we have. To do the "auto" adjustment, you would simply engage the parking brake and drive the vehicle in reverse a few feet and that supposedly adjusted the shoes out futher somehow. It was either their '97 Explorer or '98 Expedition I'm pretty sure, if it wasn't their '97 F-150.

I was also speculating that maybe the shoe lining thickness was getting too thin. I'll try to take a visual and maybe even measure the thickness if I can tomorrow, without taking the caliper and rotor off.

2008 Pontiac G8 GT (sold)
D1SC Procharger - Alky Control Methanol Injection - Comp Custom Blower Cam
FAST 102 Intake Manifold - RCR-built 6L80E - Yank 3200 Converter - Camaro SS 3.27 Diff

2005 Pontiac GTO (for sale)
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Perfomabuilt Level II 4L60E - Vigilante 3400 Converter - Lots More!
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post #14 of 18 (permalink) Old 06-02-2015, 09:24 PM
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Get 2015SS rear rotors and problem solved. No squash brackets required and you can use original G8 parking brake shoes.

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post #15 of 18 (permalink) Old 06-03-2015, 09:32 PM Thread Starter
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Thanks Taz! I just finished reading the 12-page thread on that 2015 SS rear rotor upgrade. If that solves my problem I'll gladly spend $300 on the rotors, remove the Squash brackets, and swap the original parking brake shoes back in. Though I'd hate to spend that money and find out I still have the same problem, I think it would be worth trying. Otherwise I'm sure I can sell the rotors for a few dollars less than I paid if it ends up not working. I'll keep you all posted when I get back to MD next week and get around to ordering parts.

2008 Pontiac G8 GT (sold)
D1SC Procharger - Alky Control Methanol Injection - Comp Custom Blower Cam
FAST 102 Intake Manifold - RCR-built 6L80E - Yank 3200 Converter - Camaro SS 3.27 Diff

2005 Pontiac GTO (for sale)
Twin 6265 Precision Turbos - Forged LY6 6.0 - Flowtech Custom Cam
Perfomabuilt Level II 4L60E - Vigilante 3400 Converter - Lots More!
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post #16 of 18 (permalink) Old 03-24-2016, 07:36 PM
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I just installed rear Brembos using 2015 SS rotors and my parking brake no longer works. Worked fine before the upgrade. Hoping these adjustment tips will take care of it.
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post #17 of 18 (permalink) Old 03-24-2016, 07:37 PM
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Geez, I just now realized how old this thread is!
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post #18 of 18 (permalink) Old 03-25-2016, 11:58 AM
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Quote:
Originally Posted by Gabhart View Post
Geez, I just now realized how old this thread is!
LOL, I have done that so many times.

Nothing wrong with reviving an old thread though. The answers were never provided on how he solved his troubles and you have the same problem with the suggested fix.

I would say that you did your due dilligence and searched. Looking for answers befor posting up a new thread is the way to go!

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