About half a year ago when my friend and I were changing my pads/rotors I noticed that on the drivers side caliper, on one piston, the rubber accordian looking thing (boot?) had like a 1" tear in it. Sorry for my lack of technical terms I'm not really sure what it's called. Would that affect braking performance? Sometimes when I get on the brakes real hard (normally at high speeds, hasn't happened lately at low speeds) it feels like the peddle either stiffens up or almost as if something was on the rotor. I'm not really sure how to describe it.

Also the brakes feel very spongy. There is almost no resistance until about halfway down and then I have to mash it hard in order to bring the car to a stop. It will stop when I want it to, but I have to press the peddle really hard, not like any other car I've driven. Would that have anything to do with the caliper? Or is that brake line related and would I have to get stainless lines?

 

They do have rebuild kits available for the stock calipers (most auto parts store will have them), they usually included all new boots for the pistons, pins, etc.

The stock LS1 calipers do have a tendency to spread. Mine did this. I ended up going with C5 corvette calipers. They bolt right up to the stock knuckles and can use fbody brake pads/rotors. For me the C5 calipers had much better feel and stop MUCH better over the stock spread Ls1 fbody calipers.

 

I read up a bit on the rebuild kits and from what I gather they are kinda hard to find and expensive. So the C5 calipers can just bolt straight up to the fbody? Do the c5/z06 use the same calipers? Where would be the cheapest place to get them?

 

If that's the case with the rebuild kits you may be better off just changing the entire caliper then. I used C5 Z06 Calipers on mine, they fit under Z28 16" wheels. The only difference between the C5 Z06 and regular C5 calipers is the color. Z06 is red whilst the regular C5's are just natural finish... They bolt right up to the factory components. As i said previously Fbody pads and rotors can still be used with the C5 calipers. If you decide to upgrade to the C5 rotors you can buy the caliper brackets from various companies that relocate the caliper to allow the use of the larger C5 rotor.

If your changing the caliper you should probably buy new crush washers for the brake line blocks and new brake pad clips. Again, these can be bought at any auto parts store.

 

I would start with the basics like some fresh fluid and a good bleeding. The fluid over time will absorb water (hydrophilic) and needs to be replaced as part of routine maintenance. (the tear could help to be slowly increasing the absorption of water) If you do any type of track or autocross, I would use a higher temp fluid like an ATE super blue. If not, DOT 5 or similar will be sufficient, whatever higher grade stock fluid will work just fine. Do a full fluid replacement, and bleed the brakes at all four corners. If you aren't aware, you start with furthest to closest. Passenger rear, Driver rear, passenger front, drivers front, and then repeat to be sure all the air is out. That may solve your mushy pedal and it needing to go so far down. If that doesn't do it, I would just go with the stock caliper. The C5 is overkill in my opinion unless you're doing heavy track time or lots of autocross. Even then, it's debatable on the need for a C5 caliper on our cars. They're the same size, number of pistons, and everything except the C5 is cast differently for better longevity (less spread). The stock calipers work very well and with fresh fluid, pads, rotors, and everything stock working as it should, the car will stop incredibly fast. The stock system is actually quite good when properly set up.

It should go without saying, but if you do replace the calipers, you'll need to bleed the brakes again since you are introducing air into the system.

FWIW, I autocross my car regularly so I have Russell stainless lines, ATE super blue fluid, stock calipers, brembo blank rotors in front, power stop blanks in back, and Z26 power stop pads F&R. With the stock calipers and this set up, its flat out amazing how fast it stops. It's well under 100' feet from 60. I was actually shocked how fast it stops.

Good luck. Post up when you figure out what it is.

 

Yea I'll bleed the lines soon. **** the rebuild kit I don't have the tools/time/knowledge to do that and C5 calipers as nice as they are are too expensive. I just found this:

http://www.autopartswarehouse.com/se...0)&No=0&Npp=10

I'm looking at the top A1 caliper, says driver side front which is the one that has the torn seal. It is re manufactured, but it says it has a limited lifetime warranty which covers defects in material or worksmanship. Would this be ok to buy? For $55 that's not bad at all. And it says if I send my core in they will refund me $61...am I reading this right? I will actually make a few dollars buying this caliper? Also there is one a little further down the page that says bolt on ready and is $30 more, where this one is friction choice, what does that mean?

 

The way that core charge works is you'll pay $55 + $61 = $116 per caliper initially. However, when you send them your old caliper (which they will recondition and sell to others) you will get $61 back once they receive it.

It looks like the difference between the $55 caliper and $90 caliper is the $90 one comes with pads. Just looking, I would say this is the only difference between the two.

Through GM Parts Direct, it looks like the F-body caliper and the C5 (base and red Z06 caliper) and even the base C6 caliper (all of which are interchangeable) are all about $120 each, brand new—note that this is about the same price as the rebuilt caliper if you did not send in your core. I am pretty confident that the only difference between these calipers is aesthetics and the C5 and C6 calipers are each a little stronger than the F-body caliper.

Whatever you do, I would definitely bleed the brake system, and use a quality DOT 3,4, or 5.1 fluid (NOT DOT 5, which is silicone-based and will NOT mix with 3, 4, or 5.1). Many people on LS1Tech use and recommend ATE Super Blue (DOT 4) for its relatively high wet boiling point, and that is what I am going to use as I do my C5 conversion. It's about $12/liter from The Tire Rack. There's really no reason not to use high-quality components (at least OEM quality) when working with the brake system.

 

Ohhh ok that makes sense. I had briefly looked around online for C5 calipers and the ones I saw were like $190... I'll try GM parts direct. And I'll pick up some ATE Super Blue.

 

Yeah, it's exactly as FancyFarm explained it with the core. I would also look around at some local parts stores like NAPA for a good caliper. It might be cheaper than getting "gen-u-wine" GM parts. I still don't think a C5 caliper is required, but if they are all the same price for you, go for it.
It will be cheaper to buy local than shipping them too.
I bought the ATE super Blue from Summit and it was a little cheaper than tire rack. Got it the next day too. I bought two liters, but I only needed one for sure to do the complete rebuild with new lines, bleeding them twice and everything.