changing rear brake pads **HELP**

alky89 · 17-04-2010, 04:34 PM

hi guys,

need some help... i started changing the rear brake pads on my 04 LR zetec but i ran into a spot of trouble. the problem is retracting the caliper piston. i'm under the impression that i need to turn it like a screw to push it back in but i cant get it to budge. i also tried using a clamp to push it back in, like on the front calipers but that didnt work either and i didnt want to force it.

if it helps, the end of the piston had a maltese cross kind of shape sticking out. the reason i thought it might have been a clamp/push type is because the end of the piston doesnt seem to rotate. the wear on the brake pad backing plate showed that the cross shape on the piston stayed still and simply pushed. this was confirmed when i manually moved the handbrake.

at any rate, i'm stumped. anyone done this before? i'd really appreciate the help.

cheers,
adrian

DragonMesh · 17-04-2010, 07:11 PM

i had to hit mine with a hammer a few times, then with a clamp it should go in.. also do you have the brake fluid reservoir open that should help?

edit: yea you have to turn it as your pushing it in

alky89 · 17-04-2010, 08:10 PM

yeah reservoir was open. how did you do yours? just with pliers? and do you remember which way to turn it? oh and did you open the bleeder or just leave everything alone except for the reservoir?

cheers

marg99 · 17-04-2010, 08:19 PM

A web search suggests the rear disc brake pistons screw in with a "special Tool " that fits in the cross groves in the piston. This is probably the case if your parking brake works on the rear disc pads. Possibly the same tool for the mid 1990's falcon before they started putting the parking brake back as a drum brake under the disc rotor.

alky89 · 17-04-2010, 08:42 PM

yeah i think i'll need the tool. either have to buy one tomorrow or borrow one off my mechanic on monday and explain to him why i didnt just take the car to him in the first place...

i've been some googling and people have had some success with needle nose pliers but the shape of the piston in this car (stupid contoured cross shape) means i cant get a good grip and i have the skinned knuckles to prove it.

DragonMesh · 18-04-2010, 08:32 AM

hmm im not sure all i know is that mine was a ********** to get back in. shouldnt need bleeder valve open tho

alky89 · 18-04-2010, 11:48 AM

ok cool. thx for clearing that up. i think i'll just get the tool. too much trouble without it. was your piston end that funny cross shape as well?

my67xr · 18-04-2010, 12:59 PM

u can buy a tool from your local auto parts store, theres 2 types, 1 is about $15, the other ed falcon style is $40

alky89 · 18-04-2010, 01:59 PM

ok they didnt have the big "proper" tool so i bought one of those little cubes with the tabs that stick out into the indents on the piston. (like this- http://static.summitracing.com/globa...-w80621_cp.jpg). i put it on the end of a ratchet and it lets me turn the piston but it wont move in or out. does this mean i need to push down harder or is there something else wrong?

my67xr · 18-04-2010, 04:11 PM

the piston is threaded, as u turn the piston clockwise it will slowly go back in (passenger side, not sure on drivers side, possibly anticlockwise??)

alky89 · 18-04-2010, 05:13 PM

i mucked around with it a bit more and i found if i turned it anticlockwise it would extend but when i turned it clockwise it wouldnt go back in. same on both sides so im pretty sure it aint broken (fingers crossed). i think i need to apply more pressure to it as i turn it in. for that i'll need the real tool which will have to wait for tomorrow when i can grab it off my mechanic.

alky89 · 19-04-2010, 11:41 PM

VICTORY!!! i managed to get the new pads in without resorting to the mechanic. i used a big G clamp to press the little cube piece down while i turned it with a screw driver stuck in through the side. once the clamp was on there applying some pressure it was easy.

Watto_Cobra · 16-08-2014, 03:01 PM

Old thread but saved me some hassle. I couldn't figure out out to get the piston back in until I did a search on here. Ended up remounting the calliper with no rotor on. Used needle nose pliers to push in and turn.

Thanks for putting me onto the "wind the piston in" idea.

Bourbon Ute · 17-08-2014, 10:23 AM

FYI wind in style pistons retract quicker if you both twist clockwise and push using a caliper tool at the same time
Large multigrips also work well.

pajoda · 17-08-2014, 05:42 PM

always found long nose pliers work fine, even easier if you crack the brake line, If I am doing pads I do fluid at the same time anyway