Baer brakes installed and working

[Aurora40]

Rather than continue a 4+ page thread, I thought I'd start a new one. I bled the brakes today with the assistance of my wife. At first the pedal still felt a bit soft, but I wanted to break them in to see if that helped.

To bed the brakes, there's a neighborhood boulevard I use. It's maybe 7 suburban blocks long. I'll go about two blocks speeding up to 45-55mph, then hit the brakes fairly hard down to about 10mph. Then when I get near the end, I make a U-turn and do it again. I probably hit the brakes about 7 times or so like this when I noticed they went extremely soft. I could push the pedal to the floor and not activate the ABS.

At first I thought "what crappy brakes", but then thought maybe they were too hot. So I took a long spin around my town to cool them down. Then I didn't try bedding them anymore, but did speed up to ~60mph and hit the brakes hard. I could activate the ABS easily.

So apparently they just faded from use. I was a bit surprised though that this happened. FWIW, the fluid I used was Valvoline synthetic, but not their "SynPower", I couldn't find that anywhere. Maybe I need better fluid? Or maybe it's just these stock rotors? In messing around with them so much, they sure are thin. Even the Aurora has obviously thicker front rotors, to my surprise. Though only 12" in diameter. I didn't expect bedding the brakes was that hard on them though.

All told the brakes don't seem that different. The pedal feels similar in that it moves a little before anything much happens, but then they come on a little less progressively. They feel good, just not much different.

However, here is what I am now wondering about. The brake bias. When I got home, after a reasonable drive (3-4 miles of highway) of no/little braking, the fronts were hot. Heat was wafting out of the wheel. The rears, I could rest my hand on the caliper or the rotor no problem. So do I need to do something to adjust the bias?

[Jeffvette]

Rather than continue a 4+ page thread, I thought I'd start a new one. I bled the brakes today with the assistance of my wife. At first the pedal still felt a bit soft, but I wanted to break them in to see if that helped.

To bed the brakes, there's a neighborhood boulevard I use. It's maybe 7 suburban blocks long. I'll go about two blocks speeding up to 45-55mph, then hit the brakes fairly hard down to about 10mph. Then when I get near the end, I make a U-turn and do it again. I probably hit the brakes about 7 times or so like this when I noticed they went extremely soft. I could push the pedal to the floor and not activate the ABS.

At first I thought "what crappy brakes", but then thought maybe they were too hot. So I took a long spin around my town to cool them down. Then I didn't try bedding them anymore, but did speed up to ~60mph and hit the brakes hard. I could activate the ABS easily.

So apparently they just faded from use. I was a bit surprised though that this happened. FWIW, the fluid I used was Valvoline synthetic, but not their "SynPower", I couldn't find that anywhere. Maybe I need better fluid? Or maybe it's just these stock rotors? In messing around with them so much, they sure are thin. Even the Aurora has obviously thicker front rotors, to my surprise. Though only 12" in diameter. I didn't expect bedding the brakes was that hard on them though.

All told the brakes don't seem that different. The pedal feels similar in that it moves a little before anything much happens, but then they come on a little less progressively. They feel good, just not much different.

However, here is what I am now wondering about. The brake bias. When I got home, after a reasonable drive (3-4 miles of highway) of no/little braking, the fronts were hot. Heat was wafting out of the wheel. The rears, I could rest my hand on the caliper or the rotor no problem. So do I need to do something to adjust the bias?


Bob, when I bed brakes. I do progressive stops. 30-5, 30 -5, 50 -5, 50 -5, 80-5 and then a 100-5. After the last one I cruise around for a good distance and then park the car with out using the pads to come to a complete stop and then park the car overnight. I have very little time between braking as well, just use the acceleration and then back on the brakes.

What size are the pistons in the 6SP kit? You may be supplying much more fluid to the front and not pushing enough to the rear, and a bias spring, may not be able to compensate for that. I had to change my brake MC when I added the 4 piston rears to my car.

[Aurora40]

According to Baer's website, the piston sizes are: Front 6-piston diameters are 1.625 / 1.375 / 1.1875 inches.

[USAFPILOT]

With a fixed caliper...what is going to happend if you warp a rotor? I dont know much about brakes...but I thought all calipers could move a bit.

[Jeffvette]

According to Baer's website, the piston sizes are: Front 6-piston diameters are 1.625 / 1.375 / 1.1875 inches.


Bob, you are definitely do not have enough fluid volume from the master. You will always have a somewhat soft pedal.

[Jeffvette]

With a fixed caliper...what is going to happend if you warp a rotor? I dont know much about brakes...but I thought all calipers could move a bit.


You will not have any issues if you warp a rotor and the caliper is mounted correctly. You will have enough run out room for any warping. An ideally you will be running a thicker rotor with a 4-6 piston caliper. Only way to get a 1.25 or 1.5 inch rotor to warp is severe thermal shock.

[Aurora40]

Bob, you are definitely do not have enough fluid volume from the master. You will always have a somewhat soft pedal.
Great... :rolleyes: Though the pedal isn't really any softer than stock. What I do notice is initial application is softer than if you let up and depress the pedal again. Perhaps due to the runout knocking the pads further back on the one rotor.

Do you think a bias spring will at least get the rears doing their share? Then it wouldn't be so bad. Right now though it feels weirder than stock. The car pitches forward more it feels like, I really think the rears are doing next to nothing.

[tf95ZR1]

Bob, you definitely do not have enough fluid volume from the master. You will always have a somewhat soft pedal.


I HATE not having enough fluid and a soft pedal.
Doesn't that come with age?
Oh wait, that's something else.......

Seriously, what/how did you upgrade your master for
your bigger brakes? Do I remember a Camaro master
or something?

And pressure is pressure, so why can't the existing system handle the larger calipers by just adding more fluid to fill the volume?

[Jeffvette]

I HATE not having enough fluid and a soft pedal.
Doesn't that come with age?
Oh wait, that's something else.......

[-X

Seriously, what/how did you upgrade your master for
your bigger brakes? Do I remember a Camaro master
or something?

I used a MC for the 98-02 Camaro. Has to modified to work though. And after that you need to cut the inner fender piece that attaches to the hood for it to clear the reservoir.


And pressure is pressure, so why can't the existing system handle the larger calipers by just adding more fluid to fill the volume?


Piston size in the current MC. It's designed to push a certain amount of fluid, if the caliper is requiring more than the MC can supply, than you got issues.

[Starman]

Your car is a 90, in 92 they upgraded the master cylinder to fix the soft pedal. In my 91, stainless brake lines at all 4 corners really helped. I also run the DRM bias spring with GS front calipers. With the larger rear tires, the ZR-1 can take more rear bias than a stock C4, something GM either missed or did not dial in enough.

Pads can also make a big different in pedal feel. I have stock pads in the Vette, but my pickup had the same soft pedal issue with the same factory fix - the following year. Ceramic pads and stainless lines helped a lot.

[Aurora40]

I have stainless lines, Hawk HPS pads on the rear (had on the front but now it is whatever Baer supplied). That is interesting about the M/C. Is it worth the effort/cost to swap to the '92+ master cylinder?

[Aurora40]

Piston size in the current MC. It's designed to push a certain amount of fluid, if the caliper is requiring more than the MC can supply, than you got issues.
Hey Jeff, I appreciate all the help. I am wondering if you or maybe someone else can explain something?

In my mind, the way the brakes would work, is you have to push more pedal to send more volume to the fronts in order to push the pads back that knock-back amount and get them working. In my mind, that would mean that you are also sending a lot more fluid and pressure to the rear since you've moved the pedal more? Is that faulty thinking?

[Starman]

I was not specific enough, the booster and master cylinder are different. A lot of work and expense for not a big change if your current units work right. Of course if you have a big volume change with your Baer calipers, you might actually need the newer setup. Got to remember that the whole system is a matched set, albeit poorly on the 90/91s.

I would work with Baer or ? about what pad they have that will give you a firmer pedal. I've always used matched pad front and rear on all vehicles.

[Aurora40]

I just figured I should update this. I installed the DRM bias spring a few months ago. Wow what an otherwise easy job made a super pain by the reluctance of the new spring to compress...

The car didn't really feel much different in daily driving. The pedal is still fairly long, in that you have to press it a decent distance before the brakes begin to activate, but they feel firm as they are applied. I think it feels better under more aggressive braking, but it's really hard to say. I wish it were easier to quantify the braking through each stage.

On full-force stops, the fronts still do the brunt of it, and can be locked up easily. Though the total stopping seems more aggressive/violent when doing this, so I assume the rears are contributing more.

I don't know, I guess on the whole, I'm not unhappy with the brakes. If nothing else, they are a little lighter... I'm not sure they've been improved in any meaningful way, though. Or maybe they have and my butt-dyno is poorly calibrated...