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TR2/3/3A Brand new brake caliper question...

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K

karls59tr

Obi Wan
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Installed the caliper...bled the brakes....good pedal...stops OK....it appears that one piston retracts fully but the outer piston does not return in completely like the inner one? Is this an issue? I'm using new pads and the rotor does not spin as freely as I would like but this just might be because the pads have not worn in yet. Was there a post describing the best way to break in new pads gradually?
 
brake calliper pistons should not retrsct when taking your foot off the pedal, there should be no gap between piston and pedal,
When you fitted the pads were they a nice slip fit into the caliper, did you use copperslip on the edges and back of the pad,
best way to brake in pads is to travel in second gear, dont take your foot off the gas pedal and left foot brake gently on and off,
 
If the brake caliper pistons do not retract when you take your foot off the brake pedal then you are not going anywhere because your brakes would be locked up.
 
As Nutmeg says, disks have a continuous contact on rotor. Sometimes rotor is harder to turn, but there is always contact. Car can still be pushed and roll down hill, but stops as soon as brake pressure is applied.
 
They do not retract...they relieve pressure on the disc when you take your foot off the pedal. If they visibly move back from the rotor, then the rotor has excessive runout (wobble). Technically they would be "pushed" back, instead of retracted.
 
There has been issues in the uk with the “rubber” dust protector “bellows” being to hard and pulling the piston back. Could this be it ?
As said above they shouldn’t “retract” but the pressure just relaxes. Excess play can appear with stub axle flex and we call that pad knock back after extreme driving.

in this instance I’d suspect the dust covers.
Try keeping the brake on hard - stick on the peddle for 24+hrs and see if that resets the rubber.
 
The tiny valve at the union where the lines split is supposed to hold fluid in the caliper lines so the pistons dont "relax" too much
perhaps you have an issue.
Also ,to beat a dead horse again, replace the old calipers with Wilwood units .Safety is not a thing you want to laugh off
for a couple of hundred clams. Just think of the luxury of getting ANY compound brake pad you wish! From high performance
to quiet street pads. Put your old bits under the bench for the day when the car goes off to a museum and is no longer driven.
Mad dog
 
NutmegCT said:
If I recall, disk brake pads should remain lightly in contact with the disk even when pedal is released.
Click to expand...
Yes the caliper piston must pull back slightly to allow the rotor to spin.
mctriumph said:
The tiny valve at the union where the lines split is supposed to hold fluid in the caliper lines so the pistons dont "relax" too much
perhaps you have an issue.
Also ,to beat a dead horse again, replace the old calipers with Wilwood units .Safety is not a thing you want to laugh off
for a couple of hundred clams. Just think of the luxury of getting ANY compound brake pad you wish! From high performance
to quiet street pads. Put your old bits under the bench for the day when the car goes off to a museum and is no longer driven.
Mad dog
Click to expand...
I put a used brake pad that still had a lot of meat on it on one side of the disc.....works great.
 
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