Reducing Brake Drag
I thought I had read, I believe here, a tip for getting better fuel economy was to reduce brake drag. Well that makes perfect sense to me, but in a disc brake or even drum brakes, how do you do this?
I was looking at the brakes on my Grand Prix yesterday and I just dont see how you would go about doing this. The piston in the caliper is designed to push on one pad which brings that pad in contact with the rotor and pushing that all into the opposite side pad and clamping the two together to low things down. When the brake pedal is released, the piston retracts and releases the pressure. However I can see where it would perhaps not pull it back enough to stop brake drag on the rotor.
But I just dont see how it can be made to pull back any further than it would on its own. Furthermore, what effect will this have on braking performance? Thanks in advance for any assistance.
Comments
Re: Reducing Brake Drag
Perhaps cryo them?? That is suppose to be good for pads and rotors.
Re: Reducing Brake Drag
That is in the works while I got the car up on stands to do tranny work. Which reminds me. I read a post somewhere that you were cryo'ing your tranny. Care to share any insight into that? Im particularly interested if the frictions can be treated? Have you treated any of the frictions and/or the torque converter? If so, what were the results?
My Grand Prix is up on stands at this time awaiting me to get around to yanking the tranny and engine so that I build up the tranny and have some of the engine, primarily the valve train upgraded and cryoed.
Re: Reducing Brake Drag
Just an idea off the top of my head... round the leading corner of the pad slightly, then it should "fly" over the disk on an air cushion instead of touching.
Edit: might benefit from some bottom edge rounding also, since air will flow outward.
Re: Reducing Brake Drag
[quote="RoadWarrior"]Just an idea off the top of my head... round the leading corner of the pad slightly, then it should "fly" over the disk on an air cushion instead of touching.[/quote]
Thats an interesting idea. I can do that. And once they are cryo'd along with the rotor (though my research shows you only need to do one, primarily the rotors) the pads should last long enough that that is not such a hassle to do, though even without cryo treament its still not a big hassle.
Re: Reducing Brake Drag
Wear a mask when you do that.
Yes I cryoed my tranny. Mine is a manual. No torque converter. So far I just did the case and all the parts inside. I will do the pressure plate and flywheel for sure. Still thinking about doing the clutch. It is not together yet, so I can not comment on how it is working yet.
Re: Reducing Brake Drag
[quote="ssheen"]Wear a mask when you do that.
Yes I cryoed my tranny. Mine is a manual. No torque converter. So far I just did the case and all the parts inside. I will do the pressure plate and flywheel for sure. Still thinking about doing the clutch. It is not together yet, so I can not comment on how it is working yet.[/quote]
I would greatly appreciate any insight, experience, etc. on your work. If you do the clutch I am interested in knowing about that as well since it has friction material on it. Can you share what it has cost you to get all the work done so far and where you had the process performed at?
Re: Reducing Brake Drag
Realised a problem with that though, wet braking performance might suck. :(
Re: Reducing Brake Drag
The rounding of the pads may effect the overall performance as there is less surface area. All be it a small percentage, hopefully.
I had mine done at a local outfit in Leduc, Alberta, called MCT. He charged me 150$ for my tranny and center section of the turbo.
Re: Reducing Brake Drag
[quote="ssheen"]I had mine done at a local outfit in Leduc, Alberta, called MCT. He charged me 150$ for my tranny and center section of the turbo.[/quote]
Thank you. Thats not a bad deal at all. I can hardly wait to get all the stuff I want cryo'd done and everything back together. Im eager to see if there are any mileage gains and the affect on wear. Im hoping my oil analysis results will come back showing the improvement.
Re: Reducing Brake Drag
Did you do a before OA? You doing your block, pistons, rings etc??
Re: Reducing Brake Drag
[quote="ssheen"]Did you do a before OA? You doing your block, pistons, rings etc??[/quote]
I have several OA's on my vehicle. But right now Im too chicken to break down the motor to do the block, pistons and that stuff. I have Comp Cam lifters, Comp Cam hardened push rods, Comp Cam roller rockers and springs, new viton valve seals, retainers and locks. Ive also should have some heads here shortly and I will probably go with some Si valves and get all that treated. Im also, as mentioned going to do as much of the tranny as possible and I have the supercharger off and will redo all the bearings in it and have it treated.
If I could get my hands on a spare block I would probably do it completely, but I just dont have the experience or the confidence at this point to break a known good and low wearing block and have it completely treated.
Re: Reducing Brake Drag
Ignorance and blind enthusiasm FTW :D
Re: Reducing Brake Drag
Back on topic... Don't your brake setups have springs that pull the pads apart so they are not contacting the rotor?
Re: Reducing Brake Drag
Good thing to check, lot of us don't bother with new front brake hardware kits when stuff "looks okay" but any clips and springs could be a bit weak with age.
Further thinking on getting a little air under the pad at speed... maybe some small angled slots would work in the leading edge, dremel or saw in at about 45 degrees, then there's still most of the sharp edge to squeegee most of the water off in wet conditions.
Re: Reducing Brake Drag
My brake doesnt have a spring return set up. On the caliper side, there are clips that connect the pad to the piston, on the other side the pad floats.
I have a dremel and a cutting too that is about 3/16" wide that I bet would perfect for cutting those slots, so I will probably look at trying that. I like that method as it would seem a better way also to make sure that any water is cleaned off when it is needed.