# Pistons not retracting



## 20B_envy (Mar 16, 2006)

I was out mounting my pretty, newly pcoated Girling 60s to my brand new front power discs and when I got to the drivers front I had it all bolted up and bled it then when I got finished bleeding it I tried to turn the rotor to see if it would give like it should have and it was extremely resistant and the pads were gripping the surface pretty good. 
So I took it off and took a look at it and the pistons weren't fully retracted. I put a few blocks of wood in between the pistons and the end plate and hit the brakes a few times now they're out farther and won't retract; so much that I can't put them back on the rotors and pads. Is this normal or should I take it off and dis-assemble again?


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## 20B_envy (Mar 16, 2006)

Just because I'm such a noob, I'm leaving this post here... and getting a piston retracting tool asap


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

Why do you need a piston retracting tool? Thought that was only necessary for rear brakes.


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## 20B_envy (Mar 16, 2006)

As far as I know, no piston retracts on it's own.


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

They have to just a small fraction, enough to have clearance on the rotor. Sounds like there is something going on with your caliper. Maybe a burr or some pcoat inside the bore. Retracting tools are typically used to retract the piston a long distance (I have never used a retracting tool ever).


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## 20B_envy (Mar 16, 2006)

Yeah, they need to travel some distance... I don't understand though because the insides were pretty clean.
What could I use to strip the inside walls if I wanted to?


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

I would inspect it and if you found any foreign material/burrs, you might be able to hit it with a small hone. I really sure what to tell you.


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## 20B_envy (Mar 16, 2006)

Also, is powdercoating supposed to chip?


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

Not easily. How bad is it chipping?


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## 20B_envy (Mar 16, 2006)

ha well... when screwing in the carrier mounting bolts the carrier hole began to chip, both sides, front side and back side on both carriers ... and then I managed to knock a couple small chips out of the front of the one caliper. it's almost chipping like paint... and it looks like there's a white base coat underneath...


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

The quality of prep work highly affects the strength of the bond. They will typically either sand blast or chemically treat the base metal prior to pcoating. You might be seeing the sandblasted surface. The spots that coming off easy are spots that are really smooth, ie, not a good mechanical bonding surface. If really white, then maybe they didn't pcoat and used primer and paint.


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## 20B_envy (Mar 16, 2006)

That's what I'm thinking, in which case I'm pissed.


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

Hum...I would say take one and try to sand off a section. Maybe where the carrier meets the spindle. Something else you can try. Aircraft paint stripper has a hard time removing pcoat (know this from experience). If you got some of that, try it on an inconspicuous location. If the coating comes off easy, you got screwed.


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## 20B_envy (Mar 16, 2006)

I should go back and bitch, see if there's a warantee


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

Well, make sure it is pcoat or not. It will chip. It isn't like it becomes part of the metal. It is just a higher strength coating than paint.


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## 20B_envy (Mar 16, 2006)

Yeah, I mean I can see white underneath and it's not the media blasting and it chipped pretty easily... like when I screwed the caliper mounting screw it stripped it down to the white.


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## quattrofun5 (Aug 17, 2006)

*Re: (20B_envy)*

As far as I know, no piston retracts on it's own.
 
This is true in that the piston won't move if you push it unless you drain the fluid out of your system (unless you are Hercules or something). On the front brakes, you only need a big c-clamp to push the piston back - rear brakes have an actual tool for them because the piston needs to be turned to retract it.


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

Any luck yet? Did you talk to the shop on the pcoat?


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## 20B_envy (Mar 16, 2006)

I haven't been able to get them on the road to run them since I've been out of town for a week and I've got 2 more weeks out here. 
When I get back I'll be installing the USRT smartshift kit and getting this hog back on the road. 
Will update when completed.


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

Well, keep us up to date with what you find. About to take this venture.


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## SLVVR6 (Dec 19, 2000)

*Re: (SLVVR6)*

Any updates on the issues you were having? Getting ready to tear into mine.


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## 20B_envy (Mar 16, 2006)

Just broke my bench grinder the other night.. burnt out the motor. Still working on the shift linkages but everything else as far as the brakes are put together and seem to be working correctly.

The only thing I'm worried about is my pass side caliper/rotor... it seems to be grabbing with no brake pressure applied. After I install the USRT kit and bed the new pads I'll let everyone know what happens. 
SLVVR6 rebuild them right and install them correctly and you'll be golden. I came across a stupid wear and tear problem that set me back a couple weeks.


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

So any advice on rebuilding them right? What was the wear and tear item?


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## 20B_envy (Mar 16, 2006)

Be careful removing and installing the pistons, make sure you coat the seals and pistons and caliper walls with new brake fluid prior to re assembly. 
This set was in surprisingly good shape. There was hardly any rust on the caliper walls inside or on the outside of the pistons, that's how your brakes seize. There will be rust inside the pots, I left it alone. 
Don't bang on anything if it's not seating, use angles. When removing the pistons, using the air method worked the best for me. 
The wear and tear item had to do with my shift linkages. I broke the long shaft that links the shifter knob to the linkages on and around the transmission. It's a brick wall that I'm at right now, car's been on stands for months.


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

I pulled one of them apart yesterday and they are in really good shape as well. No rust on either the pistons or calipers (inside bore). they came apart really easily. I will be sending them to a place to get pcoated. One question I have is they will be sand blasting my calipers. Should I slide the pistons back into the caliper to prevent blasting of the inner walls or should I not even worry? The pistons technically don't ride on the caliper wall, but on that square shaped seal. Any thoughts? Do you know what your shop did to prep the calipers/carriers? What wheels are you going to run?



_Modified by SLVVR6 at 6:56 PM 4-28-2008_


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## 20B_envy (Mar 16, 2006)

They did the same media blasting on mine for the prep work. Not a big deal really... 
I'm currently in the market for 16s or 17s... but the 15s I have now work fine... maybe like 5 mm clearance. It looks pretty tight in there.


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

So would you recommend sliding the piston back in for blasting and have them remove them when they coat and mask off the bore?


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## 20B_envy (Mar 16, 2006)

I left it out, they might charge you for disassembly before prepping them if you leave it in. I just kept it apart to be on the safe side and the shop I went to took care of blocking off the bore.


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## SLVVR6 (Dec 19, 2000)

*Re: (20B_envy)*

Great...I have a co-worker who knows this guy really well and will most likely hook me up.


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