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> How do you get Pistons Out for Front Brake Calipers
kbrunk1
post Sep 3 2012, 09:50 AM
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Haynes and Climer books say you clamp one side (one piston) then use air to push out the other side.

I have a small compressor. I am assuming you closed both bleed valves and then apply air to where the hydrolic line comes in.

When I do this I can not get the piston to come out.
Do you have to get a threaded fitting and then apply air pressure?
I was just pressing a "riggged tape tip nozzle" and most likely am not getting sufficient air pressure.

Right side caplider brakes seems to be fine (move in and out easily when clamped) and I was just going to put a kit in because it is so old. The Haynes book says to not split the caliper unless you have to.

The other front caliper seems to have a stuck piston because when clamping it it will not move. I am soaking in brake fluid and will see.....

Any help here?
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IronHillRestorations
post Sep 3 2012, 10:04 AM
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That is the correct procedure. If you have some extra fittings you can make an adapter that won't leak air. A small compressor may not have enough PSI to pop the piston out. Be careful doing that as it can come out of there with enough force to remove a finger.

If you think it's corroded in there, brake fluid won't cut it. You need a penetrating oil like PB Blaster or WD40.
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Brian_Boss
post Sep 3 2012, 10:26 AM
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If you use the search feature, Eric Shea has posted a lot of good info on this.

The threads on the caliper fluid inlet are close enough to 1/8NPT and that is what most air blow guns have on the tip. Remove the tip, insert pipe nipple, thread into caliper for air tight connection.
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Bartlett 914
post Sep 3 2012, 10:44 AM
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QUOTE(Brian_Boss @ Sep 3 2012, 11:26 AM) *

If you use the search feature, Eric Shea has posted a lot of good info on this.

The threads on the caliper fluid inlet are close enough to 1/8NPT and that is what most air blow guns have on the tip. Remove the tip, insert pipe nipple, thread into caliper for air tight connection.

Worse comes to worse, use a grease gun. Fill the caliper with oil. any oil will do. Install a grease fitting and use some old cheap grease in a grease gun. Pump this and it will come out. I did not use a grease fitting. I screwed directly the grease gun in the caliper so if the fitting doesn't work, try that.
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kbrunk1
post Sep 3 2012, 11:46 AM
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QUOTE(Bartlett 914 @ Sep 3 2012, 11:44 AM) *

QUOTE(Brian_Boss @ Sep 3 2012, 11:26 AM) *

If you use the search feature, Eric Shea has posted a lot of good info on this.

The threads on the caliper fluid inlet are close enough to 1/8NPT and that is what most air blow guns have on the tip. Remove the tip, insert pipe nipple, thread into caliper for air tight connection.

Worse comes to worse, use a grease gun. Fill the caliper with oil. any oil will do. Install a grease fitting and use some old cheap grease in a grease gun. Pump this and it will come out. I did not use a grease fitting. I screwed directly the grease gun in the caliper so if the fitting doesn't work, try that.


If it turns out to be corroded then do you have to split the capliper and then use a small drill honing device?

I am curious how the fluid gets to the other side when you split a caliper? When the caliper is put back together is simply a compression fitting or is there a seal of sorts?
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jcb29
post Sep 3 2012, 12:46 PM
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QUOTE
I am curious how the fluid gets to the other side when you split a caliper? When the caliper is put back together is simply a compression fitting or is there a seal of sorts?


There is a small hole drilled thru the spacer block with small rubber washers on either side.
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Brian_Boss
post Sep 3 2012, 12:59 PM
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Here is a thread with a lot of good info:
brake thread

Just noticed you're in Dallas too. Where in Dallas? I live near Whiterock Lake in East Dallas.

Brian
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wingnut86
post Sep 3 2012, 03:40 PM
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Grease gun works every time on stuck ones. Make sure you drop the caliper down inside a wooden box or some sort of metal can if possible. Helps to cut down on the "Skeet" effect and flying parts (IMG:style_emoticons/default/happy11.gif)

I used the word Skeet so that Eric & Dr. Evil would understand...
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Elliot Cannon
post Sep 3 2012, 04:05 PM
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The best advice you can get is from Eric Shea. (No matter what all the "yahoo's" back east may tell you he knows what he is doing). (IMG:style_emoticons/default/lol-2.gif) Read and follow his posts and you will be OK. (IMG:style_emoticons/default/first.gif)
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Eric_Shea
post Sep 3 2012, 04:20 PM
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For what you're up against, fluid will probably be the only answer. When using a fluid like grease or water, there will be no flying parts. Fluids don't compress so they usually just plop out of the bore without much fanfare. Watch the video and you can see how it's done:


https://www.youtube.com/watch?v=WxN_iFv3CB4


I don't recommend honing bores any more. This leaves a fresh steel against fresh steel surface. If the car sits for any period of time, you will have this problem all over again but worse.

In for a penny, in for a pound. I "always" recommend do it yourselfers find a local plating company and finish the job right. The plating process will clean up the caliper and add a protective layer of zinc back into the bore. Yellow dichromate is the stock color and the fasteners are black zinc.

E.
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euro911
post Sep 3 2012, 08:17 PM
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Nice clip (IMG:style_emoticons/default/thumb3d.gif)

You make it all look fast and easy ... you know, like those weekend morning Home & Garden TV shows (IMG:style_emoticons/default/dry.gif)
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kbrunk1
post Sep 3 2012, 08:26 PM
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QUOTE(Eric_Shea @ Sep 3 2012, 05:20 PM) *

For what you're up against, fluid will probably be the only answer. When using a fluid like grease or water, there will be no flying parts. Fluids don't compress so they usually just plop out of the bore without much fanfare. Watch the video and you can see how it's done:


https://www.youtube.com/watch?v=WxN_iFv3CB4


I don't recommend honing bores any more. This leaves a fresh steel against fresh steel surface. If the car sits for any period of time, you will have this problem all over again but worse.

In for a penny, in for a pound. I "always" recommend do it yourselfers find a local plating company and finish the job right. The plating process will clean up the caliper and add a protective layer of zinc back into the bore. Yellow dichromate is the stock color and the fasteners are black zinc.

E.

Eric - when you do this do you also yellow dichromate the piston?
Thanks

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wingnut86
post Sep 3 2012, 08:31 PM
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Elliot is just jealous because the word Skeet was invented back East, er, some parts further South (IMG:style_emoticons/default/biggrin.gif)

(IMG:style_emoticons/default/huh.gif)

Eric?

"Plop"?



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kbrunk1
post Sep 3 2012, 08:52 PM
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QUOTE(kbrunk1 @ Sep 3 2012, 09:26 PM) *

QUOTE(Eric_Shea @ Sep 3 2012, 05:20 PM) *

For what you're up against, fluid will probably be the only answer. When using a fluid like grease or water, there will be no flying parts. Fluids don't compress so they usually just plop out of the bore without much fanfare. Watch the video and you can see how it's done:


https://www.youtube.com/watch?v=WxN_iFv3CB4


I don't recommend honing bores any more. This leaves a fresh steel against fresh steel surface. If the car sits for any period of time, you will have this problem all over again but worse.

In for a penny, in for a pound. I "always" recommend do it yourselfers find a local plating company and finish the job right. The plating process will clean up the caliper and add a protective layer of zinc back into the bore. Yellow dichromate is the stock color and the fasteners are black zinc.

E.

Eric - when you do this do you also yellow dichromate the piston?
Thanks

On the rear calipers do you perform a rebuild kit on the parking brake stuff.
Is your video for a 914 brake?
thanks - great video! (IMG:style_emoticons/default/smilie_pokal.gif)



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wingnut86
post Sep 3 2012, 09:35 PM
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You send him complete ugly ones, or those with missing pieces.

He then sends you back some gorgeous unita that ahould be framed, e-brakes too if needed.

Upgrades are recommended, as all his work is better than OEM.

IMO

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Elliot Cannon
post Sep 3 2012, 10:11 PM
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QUOTE(wingnut86 @ Sep 3 2012, 07:31 PM) *

Elliot is just jealous because the word Skeet was invented back East, er, some parts further South (IMG:style_emoticons/default/biggrin.gif)

(IMG:style_emoticons/default/huh.gif)

Eric?

"Plop"?

Born in McKeesport and raised in Clairton Pa. (IMG:style_emoticons/default/laugh.gif) GO STEELERS!!! (IMG:style_emoticons/default/first.gif)
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Eric_Shea
post Sep 3 2012, 10:52 PM
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We use a vibratory polisher on the pistons. Then we paint the top with a grey heat paint. No... Do not plate the pistons.

The video shows a 914 caliper in the opening sequence. The build is a M-Caliper. So technically, yes, a 914-6 caliper.

Rear rebuilds are totally different. The pistons screw out with the adjusters. Do not use fluids on the rears. We generally do not rebuild arms unless they're needed. The kits to do so are more expensive than good core calipers. The handbrake arm itself resides in a cavity with just a wiper seal.

Can do though...
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get off my lawn
post Sep 4 2012, 03:45 PM
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Using air pressure can be dangerous, a small cannon.
The safer way is to get a small cheap grease gun, screw it onto the caliper, fill with brake fluid, and pump. As long as you get most of the air out the piston won't shoot out or pinch your finger off.
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pilothyer
post Sep 5 2012, 03:36 AM
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Grease gun and water........no muss no fuss (IMG:style_emoticons/default/biggrin.gif)
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stugray
post Sep 5 2012, 04:09 PM
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I had a flat piece of 1" teflon laying around bigger than the caliper.
I split the caliper halves and drilled two holes into the teflon plate perpendicular to each other (one out the side, one out the top that intersected).
The hole on the side of the plate I tapped & threaded to screw in a air fitting.
The second hole was positioned where the hole was in the caliper half and clamped down with the o-ring gasket in place.

I put a wet shop towel over the caliper (and one under the piston) and turned up the pressure until - POP.

It would be a pain if you didnt have all that laying around, but took me all of 20 minutes to figure it out and pop out all 4 pistons.

Stu
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