where the hell is the return spring for the front caliper on a Lanos?? i have took off the caliper many times and i know that it doesn't have a spring to return the piston back when the driver's foot is off the brakes.
the only thing i can think of is the piston oil seal working as a spring, after all it is the only thing attached to the piston and flexable enough to produce a "spring effect"... am i right??
also does this mean that a sticky caliper got a stiff oil seal?? (assuming all other parts are functioning normally).
it is kinda embarrasing to clame to be a car maintenace expert and not knowing about this issue so please help.
I just did a full brake change yesterday, Brembo Rotors, Bendix Pads, fully synthetic fluid. So I think I may know what you are talking about.
There are (2) return springs, and they are at the top and the bottom of the caliper. You know when you change the pads, and you have to loosen only one of the screws and the entire caliper pivots upward? Well, I believe that that screw is exactly where one of the return springs is, and the other one is identical to it only at the top of the caliper. It is a little confusing, they are covered with rubber.
i know what you are talking about as i took off both the top and bottom 14mm bolts and removed the whole caliper off its braket then removed both upper and lower rods, rubber protection off the bracket to clean and regreas the whole thing up.
their is no springs under the rubber... it is just a cover for the metal rods to prevent dirt and shit from getting in between the rod and bracket guids and corode it.
i removed the rods from the guids in the bracket and it just slides in thier with no "springing" force whatsoever.
the amazing fact is: when you push the caliper to the side before you do a pads change job, the caliper doesn't go back to its normal position unless you pump the brakes a few times... this justifies my theory that thier is no "conventional" spring their and the springing effect got something to do with the brakes piston.
mmamdouh wrote:
the amazing fact is: when you push the caliper to the side before you do a pads change job, the caliper doesn't go back to its normal position unless you pump the brakes a few times... this justifies my theory that thier is no "conventional" spring their and the springing effect got something to do with the brakes piston.
anybody got any idea??
MMamdouh
My forenzas the same way... makes it easy for a pad change
IDK, yesterday, I had the entire caliper off, I pushed it together and it sprang back to its normal length, this was all by hand, no pumping. No I'm not going insane , I did this to check the life of the springs and I pushed it together and it went back apart, no problem. The "springiness" seemed to be coming from where the 14 mm bolts were.
BosnianLanos wrote:IDK, yesterday, I had the entire caliper off, I pushed it together and it sprang back to its normal length, this was all by hand, no pumping. No I'm not going insane , I did this to check the life of the springs and I pushed it together and it went back apart, no problem. The "springiness" seemed to be coming from where the 14 mm bolts were.
thats because the upper pin compressed some air while you were putting it back and the grease made an air tight gasket... i get that all the time during the greasing job... some times the pin moves out till it barly hangs on the caliper bracket.
i took the pin out and looked into that port... it got nothing inside it, also if you cleaned the pin and the guid very well and tried that test again you will get no spring effect at all 'cause now air got a way out between the guide and the pin.
the calipers should be a floating design to permit equal force distro across the pad. that being said, there sould be no way to effectively place a retaining spring on the pads to return them to a normal position. the spring would destroy the floating effect. the friction between the rotor and the pad should be enough to push it away... that's how the willwoods on our fsae car work anyway.
Audacityracing wrote:i'm taking a stab cause i have no idea on this...
the calipers should be a floating design to permit equal force distro across the pad. that being said, there sould be no way to effectively place a retaining spring on the pads to return them to a normal position. the spring would destroy the floating effect. the friction between the rotor and the pad should be enough to push it away... that's how the willwoods on our fsae car work anyway.
you are quite right on the money, the brake calliper piston have no spring in it. the piston works using brake fluid pressure. the pressure pushes on the back side of the piston when you step on the brake and when you release the brake, the fluid pressure goes down, returning some of the brake fluid back to the reservior just like an hydraulic system. the pad is then pushed back by the rotors. the pads are only pushed back a very small distance maybe 1mm or 2mm from the rotors.
that seems pretty much logical to me also this means that a sticky caliper got problems in floating but i think the 2mm clearance is too big... i recon it is much smaller than this as i couldn't see any gap between my pads and rotors but it is big enough to make the rotor spin freely.
as for the sticky caliper... i would take it apart and totally clean it (brake parts cleaner or kerosene, or perhaps a part washer). check for dirt and stuff and change any gaskets and rings that look worn. on our willwoods, the o-rings on the pistons have a tendancy to get dry and crack and then they prevent the system from operating right. just a thought anyway...
due to the fact that we lack professional products in here, i will end up with just a can of WD 40... can i use that for the cleanup process?? will it hurt the rubber piston seal?
i have no idea how that would effect the rubber... but if you take apart the entire caliper and soak it in wd-40 (yeah... that would be like 30 minutes of just spraying inot a jug) i bet you'd get pretty similar cleaning results. you really just need to inspect and look for anything like dirt or debris and check for worn or busted seals. it should be fairly obvious if you need to clean or replace something (i'd bet money that brake dust has gotten on the piston and prevents it from returning to it's normal position)
so please help.
, I did this to check the life of the springs and I pushed it together and it went back apart, no problem. The "springiness" seemed to be coming from where the 14 mm bolts were.
