Trick to Pushing Back Rear Caliper Piston?

[Frank3]

Ok, what is the "trick" to pushing back in the '05 rear caliper piston when installing new brake pads? I attempted this while at the track this past weekend without success. I was told there is a trick to it on the Mustang rear calipers. One told me you have to rotate the piston back in and that there is a special too for it. All I know I tried everything I could think of without success. If you are in the know, how is this accomplished?

Thanks in advance...

[Roushinator]

I know on the pre-05's you have to use the special tool and rotate the piston back into position.

[FordFan]

Frank,
I've used the same tool on both the SN95 and S197. It's shaped like a cube and has different sides for different applications (Ford, GM, Chrysler). It attaches to the end of an 3/8th's extension from a socket, they should be available at any Auto parts stores in your area. I modded mine slightly with a grinder so it is less likely to slip while pressing inward and turning the piston. The best way I found was to remove the rotor and remount the caliper to the caliper bracket so you can get some leverage while turning the piston clockwise.

good luck,

[STU]

http://www.harborfreight.com/cpi/cta...emnumber=97143

[06Roush_st_3]

I have the cube thing and used it for my pad installs. I am not sure if you need it for the 05+ cars though.

I bought a brake caliper clamp from autozone for the next time though to test.

If you have to use the cube you use a 3/8" ratchet and turn clockwise to put them back in.

I have the hawk HT-10 pads on the Roush now, just use them all the time. now I have the Steeda Kit, and the hawk pads the brakes are really nice.

[DevilSun]

The "cube" is the devil's tool for doing brakes. I almost lost a hand using it. The item like STU posted is really what you want...the cube is horrible, but it will work. The trick, is, it doesn't push in, it screws in.

[Frank3]

Thanks for the quick feedback...

I see the Harbor Freight tool is not too expensive and Craftsman has one for a little more but only has one thrust bolt. I did try turning the piston but not while pushing on it. Maybe that is the trick...

Does anyone know if your need to rotate the left and right caliper pistons in opposite directions? i.e. right side clockwise and the left side counter clockwise or visa versa?

[Torqd]

I know on the pre-05's you turn the piston clockwise (like tightening a bolt) and push same time p.i.t.a. and thats with the cube thingy.

[FordFan]

Originally Posted by Frank3

Thanks for the quick feedback...

I see the Harbor Freight tool is not too expensive and Craftsman has one for a little more but only has one thrust bolt. I did try turning the piston but not while pushing on it. Maybe that is the trick...

Does anyone know if your need to rotate the left and right caliper pistons in opposite directions? i.e. right side clockwise and the left side counter clockwise or visa versa?

The "cube" will work fine and only cost $5. You turn the tool clockwise no matter what side of the car your working on. Like I mentioned, remove the rotor and remount the caliper on the bracket, the extention with the "cube" will pass thru the mounting bracket area. This allows you to use both hands to pushing on the rachet to keep the "cube" engaged on the piston while turning it.

I could do it faster then I can type these explaination-

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[Frank3]

Originally Posted by FordFan

The "cube" will work fine and only cost $5. You turn the tool clockwise no matter what side of the car your working on. Like I mentioned, remove the rotor and remount the caliper on the bracket, the extention with the "cube" will pass thru the mounting bracket area. This allows you to use both hands to pushing on the rachet to keep the "cube" engaged on the piston while turning it.

I could do it faster then I can type these explaination-

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is this the "cube"? http://www.partsamerica.com/ProductD...egoryCode=3479 I suspect so...

[FordFan]

Originally Posted by Frank3

is this the "cube"? http://www.partsamerica.com/ProductD...egoryCode=3479 I suspect so...

Yes- ok $10
I found that the tool works best if you take the side facing up in this picture with the 4 post (the side I've never used in 10 years) and grinded off 2 opposing studs. Then use that end to engage in the caliper piston.





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[Torqd]

Originally Posted by FordFan

Yes- ok $10
I found that the tool works best if you take the side facing up in this picture with the 4 post (the side I've never used in 10 years) and grinded off 2 opposing studs. Then use that end to engage in the caliper piston.





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Yep, thats exactly what I did.

[Frank3]

Alright, thanks all. I will give it a try this weekend.

Now, another question. Does the piston (or other internal part(s)) have actual threads on it that requires the truning motion to retract or is it just the turning motion while appling pressure that allow the piston to be retracted?

[STU]

Frank, yes there are threads inside the rear piston. Hard to find any Ford pictures but I did find some nice pictures relating to Lexus and Hummer. They will give you an idea of how the rear calipers operate.

http://www.autoshop101.com/forms/brake06.pdf

http://www.redhummer.com/myhummer/brakes/cutup.html

Hope it helps.

[Frank3]

Well I got the pistons pushed back and the new rear pad on. I used the "cube" and it worked ok. It did take a considerable amount of force as well as relieving the pressure by loosening the bleeder valve. I think if this is something you do routinely, the Harbor Freight kit or similar would be the way to go.

Thanks all for you help...

[06Roush_st_3]

I didn't use the release when I did mine on the rear.

it took me a long time to get it back in, and a lot of pressure.

[Frank3]

Originally Posted by 06Roush_st_3

I didn't use the release when I did mine on the rear.

it took me a long time to get it back in, and a lot of pressure.

Yeah, I cranked and cranked on it and it went so far and stopped advancing. When I cracked open the bleeder valve, it colapsed in within about 1 turn.

[06Roush_st_3]

Originally Posted by Frank3

Yeah, I cranked and cranked on it and it went so far and stopped advancing. When I cracked open the bleeder valve, it colapsed in within about 1 turn.

That is why I think the 05+ cars don't have to be cranked. you just have to push them in. otherwise why would one turn do the same as turning, and turning.

I haven't worked on the rear brakes on the 98 for a while but it didn't seem the same.

[Pony2]

Most rear disc systems with the parking brake built into the caliper(Shaft,lever,bracket and cable in backside)need to be "threaded" in. The piston has threads on the inside and as the park brake barrel rotates it forces the piston out to apply the brake. Most turn clockwise(looking at the piston from the pad side) HOWEVER some '08 ford trucks and the '08 taurus have 1 left and 1 right hand threaded caliper.
walt

[Frank3]

Originally Posted by Pony2

Most rear disc systems with the parking brake built into the caliper(Shaft,lever,bracket and cable in backside)need to be "threaded" in. The piston has threads on the inside and as the park brake barrel rotates it forces the piston out to apply the brake. Most turn clockwise(looking at the piston from the pad side) HOWEVER some '08 ford trucks and the '08 taurus have 1 left and 1 right hand threaded caliper.
walt

Not sure on this one without pulling it apart and taking a good look. All I know is that I pushed and turned and pushed and turned and it only went so far, maybe 1/2 way. Then when I released the pressure it collapsed all the way within one turn. Based on this, I would have to say that the mechanism is a spiral spring wrapped around a cylinder (piston) and the turning action is merely unwinding the spring (releasing the spring’s clamp if you will) enough to let the piston slide in. I have heard of some just pushing with great force without turning to collapse the piston and this supports this belief theory. I'll have to tear into it one of these days...

Anyway, thanks all for the help...