Sticking Brakes

[LETZRIDE]

So this annoys me and it seems to be a common problem on F-body cars and I want to know what we can do to fix it.

If I jack my car up and spin my front wheel it rotates maybe 5 full turns and stops indicating there is quite a bit of friction present on the brakes. My car has always been like this, and I even replaced the two front calipers last year.

Recently my front driver side brake has had the sliders start to seize up, so I bought new sliders and some stupidely expensive lube at Autozone that was chromoly based I believe, it was around 25$ or so (versus everything else that was 10-12$)
I have to say, Ive never seen a slider on any car move in and out so smoothly and frictionless before, so I'm happy there.

But at the end of the day, it only helped out a little bit.

NOW, when I push the piston back in the caliper and bolt in onto the car, it's like I have frictionless brakes. I give the tire a little spin and it goes for 2 minutes!!

I took a video: http://www.youtube.com/watch?v=A2m37GrDyk0
That is how the car should act...so how can we get our brakes to stop rubbing the rotors and have our wheels freewheel like the above video rather than turn 5-6 times?? Do you know how much gas mileage/horsepower we're giving up with that friction??

If all 4 of our wheels have this much friction, I bet you could free up .1 at a minimum at the track just eliminating this friction...

[EarlR]

Re: Sticking Brakes

Actually, there should be a very light amount of contact between the pads and rotors all the time, that's perfectly normal. And not just with F-bodies, but all cars. If you didn't have that, every time you pressed the brake pedal you would have to take up the slack between pads & rotors on all 4 wheels, and would end up with a pedal that went most of the way to the floor. It may be a little worse on some cars, and depending on how worn/warped the rotors are it will even vary between cars of the same model.

[LETZRIDE]

Re: Sticking Brakes

Actually, there should be a very light amount of contact between the pads and rotors all the time, that's perfectly normal. And not just with F-bodies, but all cars. If you didn't have that, every time you pressed the brake pedal you would have to take up the slack between pads & rotors on all 4 wheels, and would end up with a pedal that went most of the way to the floor. It may be a little worse on some cars, and depending on how worn/warped the rotors are it will even vary between cars of the same model.

I understand that portion. But it should be nowhere near to the extent of a difference between freewheeling like it is in the video and only getting 5-6 turns of the wheel.

My buddy has an LS1 that freewheels similar to the video I posted above, and it does that normally anytime you jack the car up and spin the wheel. His car stops beautifully, yet has way less friction than many of the F-bodies out there. Unfortunatly, his Grandfather built the car and has since passed away, so I have no idea what was done to make it like that

[EarlR]

Re: Sticking Brakes

I understand that portion. But it should be nowhere near to the extent of a difference between freewheeling like it is in the video and only getting 5-6 turns of the wheel.

My buddy has an LS1 that freewheels similar to the video I posted above, and it does that normally anytime you jack the car up and spin the wheel. His car stops beautifully, yet has way less friction than many of the F-bodies out there. Unfortunatly, his Grandfather built the car and has since passed away, so I have no idea what was done to make it like that

My guess would be that everything is in near-perfect condition; the caliper pins are sliding freely, the calipers were probably (properly) rebuilt, the rotors are true, etc. Now that you've brought it up though, I'll have to try that on mine this weekend, and see how it does. I have new pads to put on the front anyway...

BTW, are those aftermarket calipers on your car?

[LETZRIDE]

Re: Sticking Brakes

They are the rebuilt ones from Autozone.

How hard is it to rebuild the piston? Im thinking of getting new seals and doing a mini rebuild.

The chromoly lube or whatever it is I used on the new sliders that cost me 25$ for a small container is 100000000x better than the silicone stuff I had used before. I've never seen a slider move so freely and smoothly before

[EarlR]

Re: Sticking Brakes

They are the rebuilt ones from Autozone.

How hard is it to rebuild the piston? Im thinking of getting new seals and doing a mini rebuild.

The chromoly lube or whatever it is I used on the new sliders that cost me 25$ for a small container is 100000000x better than the silicone stuff I had used before. I've never seen a slider move so freely and smoothly before

Ah, ok, the paint makes them look like maybe an aftermarket piece. The calipers aren't that hard to do, if you are mechanically inclined. I did my fronts last year, the hardest part is getting the boots back on. I just disassembled them, ran a brake hone inside the cylinders, hit the pistons with a brass wire wheel, cleaned everything up really well and re-assembled with new o-rings & boots.

One other thing that occurred to me; maybe your friend's grandfather ground the pad ears just a bit so they would slide a little easier in the brackets. If the pads are a tight fit, it won't matter how easily the caliper moves because the pads won't. I've never done that, but I have had to grind pads in the past that were too tight to even go in the brackets.

[LETZRIDE]

Re: Sticking Brakes

I have grinded the pads where I see they make contact with the bracket so that they can slide easier with less friction.

I think I am going to try rebuilding the piston

[EarlR]

Re: Sticking Brakes

Interesting - I tried the 'spin the tire' game this weekend, and my wheel only does about 2-3 turns before it stops. Clearly there is some friction there, but this was also on old pads/rotors so I am curious to see what it's like with new (didn't get a chance to put the new ones on) pads, and also with no brakes.

They say the NASCAR guys will purposely push the pads back when qualifying on a super speedway where they don't use brakes, and tell the drivers not to touch the brake pedal until they are done with their laps. I always thought that was a little overboard; I guess not.

[LETZRIDE]

Re: Sticking Brakes

Im telling you, it's wayy too much friction...think about the guys in stock classes that run with as little oil as possible to the point of, you have to shut the car down at the end of the track or the pump goes dry...all to gain hundreths...if the friction from oil makes a difference...that brake friction for sure makes a difference.

Now, some cars freewheel like my video naturally, like my buddies LS1 camaro. I'm not sure if it has aftermarket brakes though, unfortunately his grandfather built the car and passed away, so all info has been lost and I rarely see the car anyways...I'm dead set on finding a way to get atleast 15-20 spins out of the tire

[bigbrian442]

Re: Sticking Brakes

Google Residual Pressure Valves.

[LETZRIDE]

Re: Sticking Brakes

From what I am reading, wouldn't those be the opposite of what I want?

[bigbrian442]

Re: Sticking Brakes

They are part of the factory braking systems.

[LETZRIDE]

Re: Sticking Brakes

ahh...where? Likely would have been located in the ABS block no? I deleted that and replaced it with a prop valve, how does that make a difference?

[bigbrian442]

Re: Sticking Brakes

They are in the Proportioning valve too.

[LETZRIDE]

Re: Sticking Brakes

So does that mean the prop valve is going/is bad? I'm not quite sure I follow