Park Tool "Hydraulic Brake Piston Press" PP-1.2
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Park Tool "Hydraulic Brake Piston Press" PP-1.2
I've always reset pistons with some old pads inserted in the caliper, and I use a broad flat-blade screwdriver to press the pad to press the piston, figuring that this was the least likely way to do damage.
My kid, doing the same thing, just cracked a piston.
So I thought maybe I should get the park tool.
However, it looks like a $20 pretty version of the screwdriver. Moreover, there is the following disclaimer at the bottom of the page:
"NOTE: Wedge-style piston tools, such as the PP-1.2, are not intended for use with ceramic pistons in Shimano® road disc brake calipers."
Ok. I assume this means don't use our tool or your screwdriver to push the pistons back with the pads.
Where does that leave us? Is it better to use a plastic tire lever and press it in the center of the piston? (I assume touching the piston with the screwdriver or whatever directly would be far worse.)
My kid, doing the same thing, just cracked a piston.
So I thought maybe I should get the park tool.
However, it looks like a $20 pretty version of the screwdriver. Moreover, there is the following disclaimer at the bottom of the page:
"NOTE: Wedge-style piston tools, such as the PP-1.2, are not intended for use with ceramic pistons in Shimano® road disc brake calipers."
Ok. I assume this means don't use our tool or your screwdriver to push the pistons back with the pads.
Where does that leave us? Is it better to use a plastic tire lever and press it in the center of the piston? (I assume touching the piston with the screwdriver or whatever directly would be far worse.)
Last edited by Cyclist0108; 10-04-21 at 04:50 PM.
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p. 57 of this pdf shows "a flat-shaped tool" (unspecified, like a little ruler, I guess) straight through the caliper so you can push on the piston evenly.
https://si.shimano.com/pdfs/dm/DM-RADBR01-02-ENG.pdf
https://si.shimano.com/pdfs/dm/DM-RADBR01-02-ENG.pdf
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Pic assist:
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I would have thought it impossible to crack a piston while pushing against brake pads but I guess if you try hard enough you can indeed do that. I pretty much ALWAYS use the Park tool and press against the old pads. If that doesn't work I remove the pads and carefully push on the piston w/ the box end of a small combination wrench. I've have not ever cracked a single piston doing this and I work on a metric **** ton of disc brakes.
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Thanks for the reality checks.
It is possible the piston cracked for some other reason, but it did so shortly after he reset them.
It is possible the piston cracked for some other reason, but it did so shortly after he reset them.
#6
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The upside of the park tool is that it's way wider than most screwdrivers. You can crack a Shimano piston if you press the piston in sideways, which can happen with a narrow screwdriver that's not well centered in the middle of the pistons. That tool is convenient, but the better approach when doing pad changes is to remove the old pads and clean the pistons with isopropyl alcohol and a toothbrush or q tips and then press them in with a plastic tire lever. This helps keep the pistons moving over the quad seals with less friction from contamination.
A lot of people have skepticism over shop tools, but in a commercial environment a tool that costs, what, $15 at shop cost?, even a full retail $20?, sure beats cracking a piston working quickly, and also saving a few seconds on something you do often adds up pretty quickly.
A lot of people have skepticism over shop tools, but in a commercial environment a tool that costs, what, $15 at shop cost?, even a full retail $20?, sure beats cracking a piston working quickly, and also saving a few seconds on something you do often adds up pretty quickly.
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A guy could probably modify a cheap wood chisel from a yard sale.
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#10
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I bought the Park PP 1.2 and it works pretty well. Quite frankly though, if one had a quality flat-blade screwdriver with dulled edges you could do the job. That's how I had been bleeding brakes but the Park tool, as a one-trick pony tool, does provide more protection.
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They must mean not to push directly on the pistons w/ the tool. As long as you have some old pads to push against you should be fine. If a piston seems stuck I'll pull the brake lever a bit to get it moving then push it back in to the bore. Usually always works.
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#12
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The PP-1.2 is not a necessary tool, but nice to have. I always take the pads out and used a wide plastic tire lever (e.g. Pedros/Muc-off) to push the pistons back. Never cracked any pistons. I don't recommend flat head screwdrivers as they can be sharp and narrow. But I recently got the PP-1.2 (just because I had to buy something and it was there). It looks nice and makes me look like a pro in front of my friends as it adds another tools to my bike tool shed . It works well as it's wide and has a nice angle that fits perfectly on the piston. Unlike many other bike tools, this one isn't necessary at all, but if you have the budget, it's nice to have.
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#13
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Pedros lever is what I use directly on the piston, park tool if pressing in the pads. I clean pistons anytime they're dirty during a pad change or bleed with iso and a toothbrush I use just for this purpose. I also exersize pistons after every bleed until they move evenly and always set brakes up with evenly extended pistons. It is surprising how many brakes in the wild are set up with one piston pretty much fully in the caliper and the other extended. This meaningfully affects power.
In related news, just took a new personal bike for its first ride. Dura Ace hydraulic feels so, so excellent.
In related news, just took a new personal bike for its first ride. Dura Ace hydraulic feels so, so excellent.
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#15
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Really R7000 or better feels pretty similar, but it's night-or-day better than the Sram Force 1 on my road ebike, and also pretty noticeably better than some of the lower end non series Shimano road hydraulic setups. Campy hydraulic also is pretty fantastic.