Brake piston retractor tool

[ironmanalishi]

Just had a lengthy session, trying to push back my pistons(sram code r) when fitting new pads…they did seem quite stiff…...in the end, I managed to get a mini g cramp in the calpier to retract the pistons….did the job although, it was a fiddle, using a spacer to stop the clamp marking the paint on the outside of the callipers….

does anyone know if there’s a cycle specific (like a wind in /out affair on a threaded bar as some use in motorcar applications) tool to do this in future please ? I don’t like the look of the “spatula” type ones as it seems to me they would apply excessive force to the calliper mountings…..

here’s a link to the park tool, that I don’t like the look of, before anyone possibly suggests…Park Tool PP-1 Hydraulic Brake Piston Press | Tredz Bikes

thanks in advance!

 

[RustyMTB]

Nothing exists as far as I'm aware. You won't damage calipers or their brackets with a spatula tool in any event. A better approach is to clean & lube extended pistons so that no grit or dirt gets between the bore & the piston causing it to seize or score & pistons should retract with moderate pressure provided they're level when pushing.

If you get them off even a tiny degree they will give the problems you describe.

 

[Sophie777]

Just had a lengthy session, trying to push back my pistons(sram code r) when fitting new pads…they did seem quite stiff…...in the end, I managed to get a mini g cramp in the calpier to retract the pistons….did the job although, it was a fiddle, using a spacer to stop the clamp marking the paint on the outside of the callipers….

does anyone know if there’s a cycle specific (like a wind in /out affair on a threaded bar as some use in motorcar applications) tool to do this in future please ? I don’t like the look of the “spatula” type ones as it seems to me they would apply excessive force to the calliper mountings…..

here’s a link to the park tool, that I don’t like the look of, before anyone possibly suggests…Park Tool PP-1 Hydraulic Brake Piston Press | Tredz Bikes

thanks in advance!

I think you can leave the old pads in place, insert the tool between the old pads, and push on the old pads to push back the pistons. This way I think your pistons would be protected.

 

[ironmanalishi]

I think you can leave the old pads in place, insert the tool between the old pads, and push on the old pads to push back the pistons. This way I think your pistons would be protected.

ta for this…..leaving the old pads in place and gently prizing them apart with a large flat bladed screwdirver(by turning it when it’s between the pads) used to do the trick on my last bike ….didn’t do the pad surfaces much good but they were usually toast by this time…..the bike had only done 500 miles so I’m doubting there’s any crap in between the piston mating surfaces…..however they really did not want to retract fully…until I reported to the g-cramp solution…..

 

[Mikerb]

I use the Park Tool "spatula" type tool together with a flat plastic covered handle of ( in my case) a wire trimmer tool. The plastic covered handle goes against the piston so it is protected and the width of that plus the "spatula" means that leverage by the spatula begins straight away. Note if the leverage angle is any larger you will not be a ble to keep the piston at the correct angle to retract.

The trick to pushing the piston back is that the piston must be kept parallel to the calliper and that means keeping the plastic covered handle parallel to the side of the calliper and then applying leverage with the spatula at a point that is on the centre of the piston. If you cause the piston to be at any angle other than its natural position dictated by its seal, it will not push back into the calliper. Get it right and it takes very little force to push the piston back.
So it is about using whatever tools you choose to accurately apply force that keeps the piston at its natural orientation.....not about brute force.......indeed if you use a lot of force you are likely to damage the piston or its seal.

Since the pistons actually spend all their time partly out of the calliper and only a few mm on either side from the pads it is worth using IPA and a cotton bud to clean and then lube the exposed parts of the pistons before trying to push them back.
Having done that, I then use a brake block (r3pro product) that allows one piston at a time to push out, and clean/lube them properly.

 

[steve_sordy]

Remove the bleed screw on the lever assembly, the pads will move easily then.
Because that will probably push out some brake fluid, bunch some paper tissue around the lever assembly.
I did this trail side when fitting some new pads, so I just refitted the bleed screw and carried on. The brakes were "on" in an instant, so I could have lost a bit more fluid without ill effect. I bedded the pads in as usual and the instant "on" soon reverted to normal.

 

[Mcharza]

This is perhaps one of the best instructions on how to clean and adjust the brake caliper.
I personally use a plastic tire lever to press the pistons in. It's an old Pedro's lever.

 

[RiderOnTheStorm]

I've used this Sram tool to push back the pistons. Worked well for me and doesn't damage piston or caliper surfaces. Hope this helps.