Can't Adjust Venting Clearance On Rear Caliper, WTF? Options

[Spoke]

I'm setting up restored rear calipers and the passenger side outside piston will not move when I try to adjust the venting clearance.

What do I need to do?

Also, the inside venting clearance adjuster doesn't seem to want to move. Looks like I'm taking the caliper off to check it out.

[laflaur]

Bump for a similiar,yet different problem.
This thread came up on search first,so..
I went out this morning to hook up the ebrakes on my car. It is a factory six with the original calipers, spacers and ventilated discs.The brakes had the correct venting clearances already, so I hooked up the cables to the arms, actuated the ebrake handle up and down ,checked the calipers,and the left rear is clamped down tight,both inside and outside pads.
The facory book says readjustment(venting) may be necessary,so I tried to back off the outside pad(counterclockwise) with the adjusters and the pad still wont budge.
I unhooked the cable from the actuating arm and still nothing,still clamped tight.
Any help would be great,
Thanks,John

[pilothyer]

laflaur..............I am thinking that you should turn the outer adjuster clockwise to retract the outer piston, and then the inner adjuster counter-clockwise to retract the inner piston.

[Eric_Shea]

I tried to back off the outside pad(counterclockwise) with the adjusters and the pad still wont budge.

What Jerry said.

turn the outer adjuster clockwise to retract the outer piston, and then the inner adjuster counter-clockwise to retract the inner piston

Here's a little bit that helps me remember:

Imagine screwing a wood screw into a block of wood but... the screw remains stationery. Turn it clockwise and the block of wood comes toward you.

Imagine that "outside" piston in the same relationship. Turn the adjuster "clockwise" and the piston will retract, coming in towards you and off the rotor.

Both adjusters have a right hand thread pattern for economies of scale. This way ATE could use the same pistons on both caliper 1/2's. The internal adjuster is "Smack Dab in the Middle" of the handbrake arm so they used a gear to drive that adjuster. Meaning; it will now turn in the opposite direction due to the gear.

Again, same right hand thread pattern, same pistons... gear driven so it must go in a counter-clockwise direction to pull that piston off the rotor.

IMPORTANT: Gents, our adjusters have a small 4mm hex to adjust them. These get stripped "often" because 1. Fluids haven't been changed regularly or 2. The lock nut was not loosened before attempting to adjust the caliper.

Here's some things to consider when attempting to adjust your calipers:

1. Change your brake fluid before attempting to adjust the calipers. New fluid has a cleansing property. Maybe even run a quart of el cheapo fluid through your system and then move on to the good stuff for a final bleed. Use small Vise-Grips on your bleeders if they haven't moved in a while, "then" use a 7mm open end.

2. Move your hand brake arm back and forth to free the inner piston in the bore before adjusting. The arm should actuate the piston in the bore by roughly 1/8". Back the lock nut off the outer adjuster a tad and tap the outer adjuster (tap not beat). Be carefull not to go too far and jam the nut against the clip that "should" be there. The objective here is to get old, stuck pistons to move before you start to adjust them. If you can do this with a two step flush process (el cheapo fluid first) the fist fluid should help wash away some of the deposits.

3. Once you have all your pistons free and operating off the adjusters the way they should you can adjust to .004" on the high side of the runout. The high side may be different for the inner and outer pads. Basically; have them bind and back off a hair (literally) until the rotor spins freely. Then install and adjust your cables so you have a tight handbrake.

[laflaur]

Thanks for the replys,I moved the outside adjuster clockwise and counterclockwise,then lefit and came back and the piston had loosened up. I will do #2 of Erics post right now and then adjust the handbrakes. BTW,I think it is because I have driven the car very in frequently lately that the piston bound up.
Thanks again,
John

[JawjaPorsche]

There you go! Drive more frequently! (IMG:style_emoticons/default/beerchug.gif)

Thanks for the replys,I moved the outside adjuster clockwise and counterclockwise,then lefit and came back and the piston had loosened up. I will do #2 of Erics post right now and then adjust the handbrakes. BTW,I think it is because I have driven the car very in frequently lately that the piston bound up.
Thanks again,
John

[laflaur]

Gonna!
That is why I am going through ,bleeding brakes, lubing cables ,adjusting shifters,wheel bearings,etc,etc.
Thanks again!

[rhodyguy]

great write up eric. always fun when "lefty loosy, righty tighty" doesn't apply and you don't know it.

k