Front Brakes - what am I doing wrong?

twilightprotege · Post by **twilightprotege** » Wed Jun 04, 2008 9:49 pm

I'm replacing the rotors and pads on my 87 RX and no matter what i try I cant push the piston on the front caliper back to allow for room for the new pads to fit over the rotor. Tried everything i can think of, plenty of force, D-clamp and all. Am I missing some trick that I dont know about? Rears were no problem (pushed back by hand), just cant move the front. Would it be something to do with the hill assist thing? Help!

DavesB4 · Post by **DavesB4** » Wed Jun 04, 2008 9:57 pm

I have an idea that these do not simply "push in". You actually need to "screw" them in. I seem to remember that there are some cutouts which fit the factory tool and which simply winds them in.

Someone please correct me if I'm wrong.

PeeJay · Post by **PeeJay** » Wed Jun 04, 2008 10:00 pm

My series are screw in, can't remember about the L series, I don't think they were. I've found undoing the bleeder nut a tiny bit help alot.

AlpineRaven · Post by **AlpineRaven** » Wed Jun 04, 2008 10:06 pm

Yep thats correct you actually need to screw it in, there is a notch on the piston, all you need pliers and turn it clockwise until it reaches to the end... if you're screwing it "out" then you're going wrong way (fluid will leak!)

With rear disc is to be pressed in with clamp.

For Liberty above is different, front is push in and rear is same as front.

Cheers
AP

AlpineRaven · Post by **AlpineRaven** » Wed Jun 04, 2008 10:07 pm

PeeJay wrote:My series are screw in, can't remember about the L series, I don't think they were. I've found undoing the bleeder nut a tiny bit help alot.

If you loosen the bleeder - you will need to bleed whole system.
Cheers
AP

twilightprotege · Post by **twilightprotege** » Wed Jun 04, 2008 10:23 pm

figured it would be something easy. will give it a bash tomorrow night. i tried losening the bleeder and that didnt work either (bleeding the whole system anyway). so strange that they push out but require screwing in. i assume it's something to do with the handbrake being on the front wheels. anyway, thanks guys.

AndrewT · Post by **AndrewT** » Thu Jun 05, 2008 11:15 am

Yeah they definitely need to be screwed back, that got me the first time too.
I believe they actually gradually unscrew rather than just push out as you slowly wear the pads down.

twilightprotege · Post by **twilightprotege** » Thu Jun 05, 2008 12:15 pm

they cant gradually unscrew - there's a tab on the pads that'll stop that - the tab sits in a gap on the piston

AndrewT · Post by **AndrewT** » Thu Jun 05, 2008 2:11 pm

Ah my mistake. Subaru mystical witchcraft then

YouTube · Post by **El_Freddo** » Thu Jun 05, 2008 6:28 pm

twilightprotege wrote:so strange that they push out but require screwing in. i assume it's something to do with the handbrake being on the front wheels. anyway, thanks guys.

Thats exactly the reason why you need to screw them in. It got me the first (and last) time I swapped the front pads. I still need to get a new rubber boot for one of the calipers cos I pinched it

You'll know for next time

Bennie

tex · Post by **tex** » Thu Jun 12, 2008 1:45 pm

ditto had me stumped I read the service book three times then figured it out and I used a pair of needle nose pliers in the indentations. But I take it these things have something to do with the front park brake.

Subafury · Post by **Subafury** » Thu Jun 12, 2008 2:12 pm

loosening the nipple and then pushing/screwing in clockwise should help. else there is such a thing as disc pad spreader tool which do this job.

Reg Brumbys · Post by **Reg Brumbys** » Thu Jun 12, 2008 2:26 pm

Yep got me to the first time - very frustrating until I figured out what it was. Next time I didn't touch the break pedal or the handbreak when I had the calliper off and it didn't move the piston and slipped straight back on.

steptoe · Post by **steptoe** » Thu Jun 12, 2008 11:01 pm

A lot of cars need the piston screwed in, it may just be easier on the piston seal ??

dibs · Post by **dibs** » Fri Jun 13, 2008 6:43 pm

hi guys
i rang a m8 first he was unsure

if at first you dont succeed (like me) read the workshop manual (like me )

2nd side i did that quick my employe didnt beleave i did it lol

but now i gota bleed the suckers

dibs

Busdriver · Post by **Busdriver** » Sat Jun 14, 2008 12:09 am

The piston is pushed out by pressure of the brake fluid when the brake pedal is pushed, it does not turn. The oring retracts the piston by virtue of its square profile and being twisted and springing back into shape after the pedal is released. The handbrake mechanism pushes the piston out by rotating a spiral gear in the guts of the piston and does not turn the piston either. Due to the handbrake levers limited stroke it relies on the piston being close to the pad, that is why you have to wind it back in, it stays out after the pedal is pushed.
In this respect it exactly the same as rear disc brake calipers on Falcons and Magnas and lots of other cars with the handbrake on the rear and rear disc brakes have been for years.

Morcs · Post by **Morcs** » Mon Jun 16, 2008 5:30 pm

Hand Brake works on a rachet type of a rangement.

SUBYDAZZ · Post by **SUBYDAZZ** » Thu Jun 19, 2008 10:26 am

If it won't wind in it might be stuffed.

To make a tool for the job get a 24mm or so socket and grind away two opposite sides down about 3-4mm leaving two tabs. Then you can slot the tabs into the slots on the piston and wind it in with a ratchet or breaker bar as required.

Matatak · Post by **Matatak** » Thu Jun 19, 2008 6:22 pm

SUBYDAZZ wrote:If it won't wind in it might be stuffed.

To make a tool for the job get a 24mm or so socket and grind away two opposite sides down about 3-4mm leaving two tabs. Then you can slot the tabs into the slots on the piston and wind it in with a ratchet or breaker bar as required.

or jsut buy a tool.

they have multifit ones prolly like 10 bucks

Fatz · Post by **Fatz** » Wed Mar 11, 2009 4:00 pm

This got me last night..
i think it should be made a sticky or something...