Author Topic: Tips for removing brake piston  (Read 792 times)

Online Scout63

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 2682
  • Location: Orleans, MA USA
Tips for removing brake piston
« on: November 30, 2021, 08:29:25 PM »
Any good tips for removing a stuck brake piston from the caliper?  They are Brembo F08s.  I usually use a little compressed air while assembled, which moves the less stick one out, then disassemble, put my finger over the hole and use compressed air again to try to get the other piston out.  It just gives me the willies thinking my finger is so close to the piston. Is there a better way?
Ben Zehnder - Orleans, MA USA

Offline nc43bsa

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • Posts: 1353
  • Location: Mooresville NC
Re: Tips for removing brake piston
« Reply #1 on: November 30, 2021, 08:37:48 PM »
Screw a grease fitting in place of the bleed screw, pump the caliper full of grease.

Use a small C-clamp to hold the non-stuck piston in place.
1990 MilleGT

Offline ridingron

  • Gosling
  • ***
  • *
  • Posts: 232
  • Location: Florida
Re: Tips for removing brake piston
« Reply #2 on: November 30, 2021, 08:51:54 PM »
Quote
  Screw a grease fitting in place of the bleed screw, pump the caliper full of grease.

Use a small C-clamp to hold the non-stuck piston in place. 

+1

I would try to pump them out with the master cylinder first. Then go with the grease gun. It is amazing to me how much pressure a grease gun can generate. Of course you're left with a bit of a mess to clean.

Online Antietam Classic Cycle

  • Gaggle Hero
  • *****
  • *
  • Posts: 14141
  • Happily stuck in the past.
    • Antietam Classic Cycle
  • Location: Rohrersville, Maryland
Re: Tips for removing brake piston
« Reply #3 on: November 30, 2021, 08:56:03 PM »
When using compressed air to remove the piston, I wrap an old towel around the caliper half several times, so that when it does come out, it won't go flying across the shop.

Heating the alloy caliper half will help if the piston is an original steel one.
Charlie

Wildguzzi.com

Re: Tips for removing brake piston
« Reply #3 on: November 30, 2021, 08:56:03 PM »

Online Scout63

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 2682
  • Location: Orleans, MA USA
Re: Tips for removing brake piston
« Reply #4 on: November 30, 2021, 10:13:07 PM »
Thanks everyone.  I think I might use a c clamp and rubber to block the fluid passage as well.
Ben Zehnder - Orleans, MA USA

Offline Canuck750

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 2138
  • Location: Edmonton, Canada
Re: Tips for removing brake piston
« Reply #5 on: December 01, 2021, 12:50:16 AM »
Sometimes the steel piston is so corroded that no measure of pressure, compressed air or grease will budge it. As a last resort I weld the tip of an old bolt to the centre of piston and let it cool. Attaching a wrench to the bolt head I then turn the bolt / piston out, works every time.
48 Guzzi Airone, 57 Guzzi Cardellino, 65 Benelli 200 sprite, 66 Aermacchi Sprint, 68 Gilera 106 SS, 72 Eldorado, 72 Benelli 180, 74 Guzzi 750S, 73 Laverda SF1, 74  Benelli 650S, 75 Ducati 860GT, 75 Moto Morini 3-1/2, 78 Moto Morinii 500

Offline smsw

  • New Egg
  • *
  • *
  • Posts: 99
  • Location: Cleveland, O
Re: Tips for removing brake piston
« Reply #6 on: December 01, 2021, 08:02:10 PM »
Sometimes the steel piston is so corroded that no measure of pressure, compressed air or grease will budge it. As a last resort I weld the tip of an old bolt to the centre of piston and let it cool. Attaching a wrench to the bolt head I then turn the bolt / piston out, works every time.
If a steel piston is that far gone, isn't the caliper's aluminum also toast?

Online Scout63

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 2682
  • Location: Orleans, MA USA
Re: Tips for removing brake piston
« Reply #7 on: December 01, 2021, 08:45:57 PM »
I don’t think it’s very far gone. The other piston popped right out with pretty good fluid still behind it.  The caliper body looks good with nice paint.  The bleed screws came right out. I was feeling a little timid and put it down for another night.  Expelling brake pistons with air is up there with seating tire beads for causing anxiety.
Ben Zehnder - Orleans, MA USA

Online n3303j

  • Ron Cichowski
  • Gaggle Hero
  • *****
  • *
  • *
  • Posts: 1600
  • Location: Eastern Massachusetts
Re: Tips for removing brake piston
« Reply #8 on: December 02, 2021, 09:06:51 AM »
If a steel piston is that far gone, isn't the caliper's aluminum also toast?
The caliper bore only guides and secures the piston when braking. As long as the piston is a slip fit in the bore the caliper will function as intended.

BUT: The seal between the caliper and the puck is maintained by the square sectioned "O" ring. It is imperative that the surfaces between the "O" ring and the caliper body are smooth enough to seal. Being protected by the "O" these surfaces the surfaces of the groove are usually in excellent condition.
'98 MG V11 EV
'96 URAL SPORTSMAN
'77 MG 850T3 FB

Offline Gino

  • Hatchling
  • **
  • *
  • *
  • *
  • Posts: 192
  • Location: Scotland
Re: Tips for removing brake piston
« Reply #9 on: December 02, 2021, 10:53:24 AM »
I had an issue with a Kawasaki last year and made this video, may help

https://youtu.be/1GAg5IHcCBo

Gino

Online Scout63

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 2682
  • Location: Orleans, MA USA
Re: Tips for removing brake piston
« Reply #10 on: December 02, 2021, 08:49:00 PM »
I had an issue with a Kawasaki last year and made this video, may help

https://youtu.be/1GAg5IHcCBo

Gino

Thanks Gino.  I’ve heard about that but never seen it done.

I used a small c clamp and a bit of inner tube to block the inner port, wrapped a towel around it like Charlie suggested, and a little compressed air popped it out.
Ben Zehnder - Orleans, MA USA

Offline Gino

  • Hatchling
  • **
  • *
  • *
  • *
  • Posts: 192
  • Location: Scotland
Re: Tips for removing brake piston
« Reply #11 on: December 03, 2021, 05:59:40 AM »
Thanks Gino.  I’ve heard about that but never seen it done.

I used a small c clamp and a bit of inner tube to block the inner port, wrapped a towel around it like Charlie suggested, and a little compressed air popped it out.

Hi Ben
Compressed air works if its not too bad but sometimes if its too bad its worth keeping the grease trick up your sleeve
Gino

Online Scout63

  • Gaggle Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 2682
  • Location: Orleans, MA USA
Re: Tips for removing brake piston
« Reply #12 on: December 03, 2021, 07:20:21 AM »
Roger that Gino.  You make it look so easy.
Ben Zehnder - Orleans, MA USA

***Wildguzzi Official Logo High Quality 5 Color Window Decals Back In Stock***
Shipping in USA Only. Awesome quality. Back by popular demand. All proceeds go back into the forum.
http://www.wildguzzi.com/Products/products.htm
Advertise Here
 

20 Ounce Stainless Steel Double Insulated Tumbler
Buy a quality tumbler and support the forum at the same time!
Better than a YETI! BPA and Lead free.
Advertise Here