Adjusting Pistons for Brake Rub on Formula C1 (Turbo X)

mattbytes

Member
Looking for pointers on adjusting the pistons on the Formula C1 hydraulic brakes. My problem is the brake pads are still rubbing agains the rear disc. I've had some moderate success trying to fix it, but there is still some rubbing. I have tried to reset the pistons but the problem is, when I push one piston back in, the other piston comes out slightly. I haven't found anything out there that addresses this. Sounds like I need to do some bleeding but I'd like to see if anyone has experienced this before. From what I've gathered, space between pads and disc are pretty narrow to begin with on Formula brakes.
 

ronin2000

Member
Did you loosen the 2 bolts holding the caliper in? I normally loosen them up, adjust as needed, give a squeeze then check again. Finally tightening them up. Normally have to adjust them when I take the front wheel off and something bumps the brake lever while in transit.
 

Douglas Ruby

Well-Known Member
There is a special plastic tool that should have come with your Turbo. It is a Formula specific "wedge" which is inserted into the empty space between pads when the wheel is removed. This will force the pads far enough apart to allow space for the disc and keep the pads from squeezing back in accidentally when the wheel is out. It also has a thicker wedge at the end for forcing pads even farther apart. You then pull the tool out, reinsert the wheel. Loosen the two caliper bolts and then squeeze and/or pump the brakes until the pads are gripping with the caliper bol;ts loose. While the pads are still gripping, tighten the caliper bolts. Everything should be equalized once you loosen your grip on the brake lever.
 

mattbytes

Member
There is a special plastic tool that should have come with your Turbo. It is a Formula specific "wedge" which is inserted into the empty space between pads when the wheel is removed. This will force the pads far enough apart to allow space for the disc and keep the pads from squeezing back in accidentally when the wheel is out. It also has a thicker wedge at the end for forcing pads even farther apart. You then pull the tool out, reinsert the wheel. Loosen the two caliper bolts and then squeeze and/or pump the brakes until the pads are gripping with the caliper bol;ts loose. While the pads are still gripping, tighten the caliper bolts. Everything should be equalized once you loosen your grip on the brake lever.

No wedge included. I need to take it back to the LBS.
 

Allan47.7339

Active Member
I use a Park tool but the other way is use the old pads and carefully wedge a screwdriver to force the pistons back in place. I had to replace the pads before the commute this morning.
 

reoutput

Member
When I installed new pads I needed to "burp" out a bit of fluid from the lever.

Do not fully remove the bleed port screw! Loosen till a bit of the fluid starts to form a drop and squeeze the lever a bit. This should give you enough clearance to get the pads to fit without rubbing. If you don't know where the bleed port screw is, just take it to the shop, quick and easy fix...if they're not busy :)
 

mattbytes

Member
I tried a piece of wood to wedge the pistons apart and I had it with no rubbing. I took it out around the neighborhood and braked hard a few times. Sure enough when I got back the pad started rubbing again. I think I have it as good as it's gonna get until the pads start wearing a little. I may try the bleed suggestion if it gets worse. Thanks!
 

Douglas Ruby

Well-Known Member
I tried a piece of wood to wedge the pistons apart and I had it with no rubbing. I took it out around the neighborhood and braked hard a few times. Sure enough when I got back the pad started rubbing again. I think I have it as good as it's gonna get until the pads start wearing a little. I may try the bleed suggestion if it gets worse. Thanks!

Matt, after wedging the pistons apart, did you"
  1. Loosen the mounting screws (the two that hold the caliper to the fork);
  2. Pump the brake to get the pistons both squeezing the same amount.
  3. Squeeze the lever brake tightly to hold the caliper in position
  4. Then tighten the two screws to fix the caliper in a centered position
  5. then release the brake?
After separating the pistons, you need to recenter the caliper so that when you release the brake, both pistons release an equal amount. If you just wedge the pads and pistons apart, one side or the other will return further than the other and there will still be brake dragging.

Doug
 

mattbytes

Member
Thanks Doug. This is the rear brake so I did all the above but in different order.

1. Remove the caliper completely from the frame
2. Remove the brake pads from the caliper
3. Pumped the brakes to get pistons even
4. Use a piece of wood to reset the pistons as far back as I could get them (they still stuck out just a slight bit. Without the bleed suggestion, I think this is the best I can do)
5. Reinstall brake pads
6. Reinstall caliper
7. Adjust caliper by squeezing tightly and tightening two screws
8. Loosen the two screws to adjust the caliper ever so slightly
9. Slightly Bend the rotor with a wrench to reduce the rubbing even further

So this worked so I thought until I went around the block and perform some break tests. It's still rubbing at a small section but it's acceptable.
 

jwb

Member
One thing I noticed about the Formula brakes is that the rubbing isn't coming from the pads, it's coming from the edge of the disc rubbing on the caliper body. There's a little notch worn into the caliper on mine. To prevent this I need to very carefully center the caliper.
 

jwb

Member
Probably not a bad idea with new disc and pads, but with bedded pads a really poor idea!
 

John Fuller

New Member
Looking for pointers on adjusting the pistons on the Formula C1 hydraulic brakes. My problem is the brake pads are still rubbing agains the rear disc. I've had some moderate success trying to fix it, but there is still some rubbing. I have tried to reset the pistons but the problem is, when I push one piston back in, the other piston comes out slightly. I haven't found anything out there that addresses this. Sounds like I need to do some bleeding but I'd like to see if anyone has experienced this before. From what I've gathered, space between pads and disc are pretty narrow to begin with on Formula brakes.
I just purchased a used Turbo X that had only been ridden 55 miles. Test rode it and all was fine. Rear brake level didn't have nearly the travel of the front, but still worked. Carried the bike home on my Thule rack and when I tried to ride it around the neighborhood,the rear brake level had zero travel. rear caliper was clamped hard on the disc. I could hardly pedal the bike in turbo mode. Rear disc became extremely hot. Is there a way to adjust these brakes? I looked on the internet but can only find info about bleeding the brakes.
 

J.R.

Well-Known Member
I just purchased a used Turbo X that had only been ridden 55 miles. Test rode it and all was fine. Rear brake level didn't have nearly the travel of the front, but still worked. Carried the bike home on my Thule rack and when I tried to ride it around the neighborhood,the rear brake level had zero travel. rear caliper was clamped hard on the disc. I could hardly pedal the bike in turbo mode. Rear disc became extremely hot. Is there a way to adjust these brakes? I looked on the internet but can only find info about bleeding the brakes.
I don't have the same brakes as you, but all the hydro brakes I've owned have a reach adjustment screw on the inside of the lever, similar to this:
images.png
 

John Fuller

New Member
I don't have the same brakes as you, but all the hydro brakes I've owned have a reach adjustment screw on the inside of the lever, similar to this:
View attachment 17161
I tried adjusting that before my first post, but the rt. Brake level could not be made to budge. After allowing the bike to sit and cool off for about an hour, the real wheel would spin and I was able to ride the bike. The rear brake , however is unusable. I plant to take the bike to my local Specialized dealer tomorrow to see if they can figure it out.
 

Charlie Rohlfing

New Member
Looking for pointers on adjusting the pistons on the Formula C1 hydraulic brakes. My problem is the brake pads are still rubbing agains the rear disc. I've had some moderate success trying to fix it, but there is still some rubbing. I have tried to reset the pistons but the problem is, when I push one piston back in, the other piston comes out slightly. I haven't found anything out there that addresses this. Sounds like I need to do some bleeding but I'd like to see if anyone has experienced this before. From what I've gathered, space between pads and disc are pretty narrow to begin with on Formula brakes.
Disc brake pads are supposed to lightly rub the disc in normal operation. That's how ALL hydraulic discs work. Is that the rubbing you are talking about? The pads do not retract away from the disc when you let off the pressure, they just lightly touch.
 

mattbytes

Member
I noticed over time that as my pads wore the issues I reported went away. I no longer have the rubbing issue. However it was a PITA early on. I tried several different methods of adjusting with limited success. Best to take it to the dealer and let us know how it goes!