Full Cobra Brake Upgrade Issues (02+ GT)

[Quickshift_02GT]

98Snakebite helped me install a full Cobra brake setup over the weekend and were having problems with it. We installed the complete front kit, and a seperate rear kit that used the stock GT rotors. I used the stock PBR pads for the ront, and then ordered a set of Hawk HPS pads for the rears since they didn't come with them.

The install went fine for the most part, we ran into a few issues and took a lot longer than expected. Everything is installed correctly and mechanically functioning great.

The problem is with the stopping power. When the pedal is depressed it feels like it moves down 1/2" or more without any grabbing at all. Beyond that, it's a really mushy, soft feeling when the pedal is depressed. It doesn't have any kind of a sharp "bite" to it like the pads are really grabbing onto the rotor. It takes quite a bit of effort to make it stop suddenly, or a long distance to stop normal.

My friend did some research and found out that it could be due to the ABS system after talking to Ford Racing. They said that an ABS Diagnostic utility is needed to cycle the ABS system and get the air out of it. Even though the rest of the system has been bled properly. They had said this was usually the primary cause in a case like this.

So...I took it to the Ford dealer this afternoon and told them about the problems. They said they would flush the brake fluid and refill it, then do the ABS Cycle to cure the issue. I went back and got the car and drove it home a few minutes ago, and it STILL is the same. It might be very slightly better, but definitely not even remotely as good as stock GT brakes. It still has that really mushy soft feeling and the threat like it's not going to stop when I want it to. At this point, my 06 Impala LT stops WAY better than my GT with full Cobra brakes.

I called the Ford dealership and they want me to take a ride with the service tech on duty that worked on my car earlier today so that I can point the problem out to them. I'm not sure where to even begin, especially if they can't see it plain as day. Quite frustrating, when all you have to do is drive the thing to figure it out. Especially after giving them $114 already to do the simple flush and ABS cycle.

I'm curious what your thoughts are guys, I'm in the hole quite a bit of cash with a car that has no stopping power.

 

[duner]

I wonder if they actually did the service. I had the brakes torn apart on my Cobra many times and never had to cycle the ABS. I just did a proper bleed of the system. It sounds like you still have air in the system.

Do you have Speedbleeders installed?

 

[98Snakebite]

I am of the opinion that there is still a air bubble trapped in the ABS/traction control unit. From what I discovered this seems to only happen in 02 and up. Has anybody else heard of this or have any advice? Grrrr.

 

[98Snakebite]

Duner: We didn't install speed bleeders, but we did bleed an entire quart through it before going to the dealer. While the calipers were disconnected, the MC resevoir managed to suck some air. It seems that if air is introduced between the mc and the abs unit, the air moves to the abs system and gets lodged there until a scan tool is hooked to the diagnostic port and the abs system cycled while bleeding. The weird thing is that FRPP said that the calipers should be able to be disconnected without drawing down the mc.

 

[duner]

I'd say the dealer needs to keep at it then since it's not fixed. I imagine the ABS bleed proceedure is a PITA. Maybe they had a noob working on it.

I agree that the system still needs to be burped.

 

[tarch]

when i installed mine it had a lot of air in the system, because i let the brake fluid container drain to the bottom... then you have to bleed the master cylinder or something along those lines... i remember bleeding something around there... also make sure there are no leaks... i had a leak and looked for it for the longest time

 

[Scooby5.0Doo]

oh brakes gotta love them so easy yet if you get one thing out of sequence or do somthing wrong how easy it can go to never never land in a hand basket

 

[98Snakebite]

Hey Matt I found out that there is a bleeder on the engine side of the master cyl. Open it, depress the pedal, close it, and release the pedal. Repeat until bubbles stop coming out. See if Greg across the street can help you out. If not I will come on up and we can finish this thing. Or, if you choose to go back to the dealer, tell tem what to do and really frost their asses.

 

[gospeedgo]

oh brakes gotta love them so easy yet if you get one thing out of sequence or do somthing wrong how easy it can go to never never land in a hand basket

 

[Quickshift_02GT]

I took it back to the dealer last night and they rebled the system a second time. It didn't feel a whole lot better afterward on the way home again, but it DID feel different.

I left later last night and put about 25 miles or so on it, just driving it around a bit and trying to get a feel for the brakes. It feels as if it's getting better with time and that I possibly just need to let the mating surfaces wear in a bit for them to have more grip.

Just before bringing the car home last night, my final impression is that the brakes HAVE improved finally. I have a big trip coming up with the Stang on Friday depending on the weather, it should be a good test and break-in period.

Thanks again everyone for the help, especially Snakebite for taking the time to do the research and come over here and help me out on this project. I can't thank you enough. :SNSign:

I'll be sure to fill everyone in on how they feel in a couple days.

 

[Quickshift_02GT]

Hey Matt I found out that there is a bleeder on the engine side of the master cyl. Open it, depress the pedal, close it, and release the pedal. Repeat until bubbles stop coming out. See if Greg across the street can help you out. If not I will come on up and we can finish this thing.

I never messed with this yet, nor asked them last night (got home after it was posted). Perhaps it still needs to be done? Not sure, the brakes do seem a lot better.

I may try this anyway, I'll either talk to Greg or ask my g/f to help me out (hopefully she can handle depressing a pedal).

I'm thinking about taking off the rear wheels tonight and painting those rear caliper finally. Should be easy and quick. Well, easier than our weekend project anyway!

 

[Scooby5.0Doo]

when i installed all new rotors and pads on my bmw which is an auto so nothing but the brakes slow you down. I about poped out a brick trying to stop the very first time. pedal was hard so that was not it. it was the fact that i was getting feedback that the brakes were working but i was not slowing down i had to press harder then when im at the track slowing down from 110 to 40 and i was only going 20

 

[Quickshift_02GT]

Hmm...

Your saying that higher end brakes like this work much better at higher speeds?

If that's true, that would explain some things. It feels like I have to step on it a little bit more to get it to stop at low speeds (0-35mph or so) than at high speed. I cranked it up to about 75 last night and tapped it, and it feel dramatically different than at low speed. Then it felt like it was grabbing pretty good at low speeds after that, then went back to normal. I'm guessing because the surfaces started heating up and these brakes work better with a little bit of heat?

Anyway, that's the main reason I feel that the brakes are better than before since when I took it out last night I could feel a difference at higher speeds. Could it also be because these are more of a "progressive" type brake setup? 98Snakebite gave me the quick and dirty about it, but I'm not sure I understood fully since I had never really dealt with them before.

But I'm guessing that still falls in place with more effort at low speed, and better stopping at high speed and being able to "modulate" the brakes better for track use?

Anyone care to walk me through the details?

 

[gospeedgo]

He is stating there is a break-in period. Hopefully you broke them in properly....there is an actual procedure for this.

 

[Quickshift_02GT]

Ah, well I hope I did it properly too...

What is the correct procedure?

I haven't done any hard stops at all. Just did some basic stop and go city driving. Got it on I5 once and tested them, but not really too hard at all. Just checked to see if there was a difference in pedal effort.


http://www.zeckhausen.com/bedding_in_brakes.htm


...something like that?

 

[gospeedgo]

its right on Hawk's website:
http://www.hawkperformance.com/motorsports/faqs.php#Q5

Q: What is the proper procedure for braking in new brake pads?
A: Brake pad break-in procedure.

1. After reaching medium speed engage brake pedal to slow car without coming to a complete stop. Release pedal quickly and do not drag brakes. Repeat four or five times.
2. At higher speeds engage brake pedal to slow car without coming to a complete stop. Release pedal quickly and do not drag brakes. Repeat five times.
3. At or near race speed engage brake pedal to slow car without coming to a complete stop. Release pedal quickly and do not drag brakes. Repeat three times. Allow a few seconds between brake engagements while car is in motion.
4. Do not hold brake pedal. Park car for approximately 20 minutes or until brake rotors are completely cool to the touch.
5. If during the above steps the brake pedal becomes soft or brake fade is noticed, park the car immediately for approximately 20 minutes. Do not hold brake pedal.

Important reminders:

* Do not attempt to use badly worn or damaged rotors with new brake pads.
* Do not drag brakes while car is moving during break-in procedure.
* Do not engage pedal while car is stopped at any time following the break-in procedure.
* Upon completing the procedure, allow the brake system to completely cool before racing.
* Applying the pedal a few times before the start of the race will allow the brake pads to heat up before attempting to reach race speeds.
* Clean a used rotor surface with fine sand paper or steel wool, rinse with water, dry and install before bedding new pads.
* Some forms of racing don't allow time for the proper break-in procedure to be performed. However, it is still very important to attempt to perform at least the core of the procedure: slow heat build up and complete cool down.

Top

Q: What can happen to my brake pads if not bedded properly?
A: Proper break-in will assure that small amounts of heat are introduced to the brake pad. Brake pads that are brought up to temperature too fast and not properly allowed to cool down may quickly become glazed and not perform as originally intended. The pads' rubbing surface reaches extreme heat levels during racing use. The surface needs slow temperature increases to help prepare the pad. Large amounts of heat all at one time can cause the brake pad rubbing surface to become somewhat liquefied and coat the pad surface with a glaze. This will dramatically reduce stopping performance as certain ingredients in the friction compound break down and cause glazing of the rubbing surface of the brake pad.

 

[Quickshift_02GT]

I did not do this. The new brakes have maybe 35 miles on them of stop and go.

Is it too late to "bed them in"?

 

[gospeedgo]

I did not do this. The new brakes have maybe 35 miles on them of stop and go.

Is it too late to "bed them in"?

Have a look then?

Q: How can I tell by looking at the brake pad if my pads have been glazed over?
A: When a brake pad glazes over the friction surface develops a cloudy or glassy looking coating. It is possible to remove the glazed surface by using sand paper to grind away the damaged layer and expose a new layer that will require the proper bedding procedure.

 

[98Snakebite]

Matt I should have told you about this. I was more concerned with getting the air out. If there is still air in them you can't bed them in anyway. I have ridden with you and if you always drive as gently as you did when I was with you, your pads are probably still fine. Try burping that MC. I got a link here for you on how to do it. If this works, go bed them in as above.

http://www.veryuseful.com/mustang/tech/brakes/bleeding.html

Here is the exerpt:

Master Cylinder Priming 4.6L

CAUTION: Use only bleed screws on the engine side of the brake master cylinder (2140). The hydro-boost bleed screw, located near the dash on the hydro-booster casting, is for the booster cavity filled with power steering fluid, not brake fluid.

Connect a clear waste line to the bleed screw closet to the booster first and the other end in a container partially filled with recommended brake fluid.
Open the bleeder screw, have an assistant push the brake pedal down slowly through full travel, close the bleeder screw, then return brake pedal slowly to full released position. Wait five seconds, then repeat operation until air bubbles cease to appear.
Repeat Step 2 for bleeder screw farthest from hydro-booster.

 

[Quickshift_02GT]

The brakes, to me, look in great condition still. The old GT rotors we pulled off were glazed bigtime, they had almost a mirror finish type look. These new Cobra rotors have a sort of grainy look to them as if there is tiny bits of brake pad material embedded in it. The rear ones have a different look, like a stringy, grainy type but not glazed or anything.

I took pictures, perhaps you guys could make better sense of them and tell me where I stand at the moment. The two front ones are fairly clear, but the rear pics didn't turn out so well. Both rear rotors look like the example in the picture though.

Front Left

Front Right

Rear

Rear Close


Thanks for the assistance with this guys, I really appreciate it.