Author Topic: Stuck Caliper Piston  (Read 18190 times)

0 Members and 1 Guest are viewing this topic.

Gearhead57

  • Guest
Re: Stuck Caliper Piston
« Reply #50 on: July 06, 2009, 10:21:22 PM »
I put ice (dry ice is better) in the cup of mine. heated the other side up with the torch a bit and put 120psi of air into it. sent the piston right out.

Offline Toxic

  • Expert
  • ****
  • Posts: 1,204
Re: Stuck Caliper Piston
« Reply #51 on: July 13, 2009, 06:58:14 AM »
I used a full size, hand powered grease gun, but it did not take a lot of muscle to push it out.  Using a metric zerk to thread in is a great idea, no chance of messing up the threads. 

Where are you guys finding a fitting that fits?
I'm looking for a fitting for a 74 CB750 and I know the size should be 10mm with a 1.25 thread pitch.

I tried Lowe's and even some local bearing places and no luck.

Any help would be appreciated.

Offline Bob Wessner

  • "Carbs Suck!"
  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 9,921
Re: Stuck Caliper Piston
« Reply #52 on: July 13, 2009, 07:45:29 AM »
I used a full size, hand powered grease gun, but it did not take a lot of muscle to push it out.  Using a metric zerk to thread in is a great idea, no chance of messing up the threads. 

Where are you guys finding a fitting that fits?
I'm looking for a fitting for a 74 CB750 and I know the size should be 10mm with a 1.25 thread pitch.

I tried Lowe's and even some local bearing places and no luck.

Any help would be appreciated.


I unscrewed the tip off the grease gun. The remaining, threaded piece just fit. I wrapped a few turns of Teflon plumbers tape around the threads and inserted it with a slight twist, not much. It held well enough to pump the piston out.
We'll all be someone else's PO some day.

ev0lution7

  • Guest
Re: Stuck Caliper Piston
« Reply #53 on: July 13, 2009, 08:14:17 AM »
i idea is not to burry the grease fitting on the caliper if i remember right mine just seemed like it was barly on there but it worked!

Offline Toxic

  • Expert
  • ****
  • Posts: 1,204
Re: Stuck Caliper Piston
« Reply #54 on: July 13, 2009, 08:17:26 AM »
I've done exactly that and it worked great but now as I am about to do two more calipers I thought I would try to find the proper fitting.  I don't want to push my luck as it where and bugger up the threads.

But being in Canada I don't  have access to the vast resources in the USA.

If I can't find the fitting I'll do without and keep my fingers crossed.

razorbackid

  • Guest
Re: Stuck Caliper Piston
« Reply #55 on: July 14, 2009, 12:15:16 PM »
Man I should have read this topic a week ago.  I will try this tomorrow.  Have a stuck piston on a 1977 750k.  I got it partially out with a torch and banging the crap out of it.

Great tip.

Offline blake255

  • Full Member
  • **
  • Posts: 68
  • Look Out! I'm about to crank this thing!
Re: Stuck Caliper Piston
« Reply #56 on: July 15, 2009, 01:14:22 PM »
Toxic,

Take a look at an auto parts store.  If they don't have one, pm me and I'll mail you one.
1970 CB750 K0 Project 1
1969 CB750 Sandcast Project 2
1969 CB750 Sandcast Project 3
2009 Yamaha YZF R6

Offline tjjkc

  • Hot Shot
  • ***
  • Posts: 489
Re: Stuck Caliper Piston
« Reply #57 on: July 15, 2009, 03:45:33 PM »
I just took a spare 10 mm bolt drilled a #7 (13/64)hole,tapped with a 1/4 28(1/4 20 will also work) tap and put in a standard zerk...........took a couple minutes but had the stuff at home
1978 cb 550k......stock,my first re-build

83 GL650I..Silverwing


Loud pipes suck.......

Offline Toxic

  • Expert
  • ****
  • Posts: 1,204
Re: Stuck Caliper Piston
« Reply #58 on: July 16, 2009, 05:16:48 AM »
Toxic,

Take a look at an auto parts store.  If they don't have one, pm me and I'll mail you one.

Awesome offer thanks, I searched Lowe's as well as two fastner stores and a two bearing supply stores and nothin.

I did get it out without buggering up the threads which was my main concern so I'm good to go.

thanks for the offer though. 

Next time I'm travelling in the states I think I'll pick one up just to have.

I've done 4 calipers with the grease method.

rrjockey

  • Guest
Re: Stuck Caliper Piston
« Reply #59 on: November 14, 2009, 06:50:32 PM »
I've not tried the grease gun trick but, this little item has worked for me.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=44964

1) Place a block in the caliper to stop the piston from shooting out.
2) Remove the brake line fitting
3) Insert the rubber tip in the brake line hole with enought press to cause the rubber tip to seal the hole
4) With 90-120psi simple bend the rubber tip. This releases the air.

Sometime a little liquid wrench or WD40 on both side of the piston helps.

Offline lwitchey

  • Full Member
  • **
  • Posts: 28
Re: Stuck Caliper Piston
« Reply #60 on: November 16, 2009, 08:18:44 AM »
I have a $20.00 Harbor Freight Grease gun that I use. I have also found out that you can get a metric grease fitting to fit where the brake line goes in and tighten the bleeder up. I have never had a problem.
2000 Harley Fatboy
1978 Honda CB750K
1972 Honda CB750
1969 Yamaha R3
1968 BSA Lightning
1997 Kawasaki Lakota 300
70's 3.5 Bird Mini Bike

www.witcheyscreations.com

Offline rjz5400

  • Full Member
  • **
  • Posts: 5
Re: Stuck Caliper Piston
« Reply #61 on: November 28, 2009, 12:05:55 PM »
i hit mine with a hammer a lot and then alternately compressed and released the piston with enormous channel locks. i also hit it with a hammer, a lot all over in and around the outside in and the back. pretty much everywhere, hit with hammer!!!
i also pumped the brake and hit it with a hammer a LOT.
good part was i didn't have to buy anything, and after it slowly came out i removed the oring cleaned the #$%* out of evything with 600 grit. wiped wiped scraped the groove of the seal,  and it totally works.
total cost zero$
tried the airgun trick but i have a stripped bleeder and no grease gun anyway


Offline tbpmusic

  • Hot Shot
  • ***
  • Posts: 677
Re: Stuck Caliper Piston
« Reply #62 on: November 28, 2009, 03:17:18 PM »
I put ice (dry ice is better) in the cup of mine. heated the other side up with the torch a bit and put 120psi of air into it. sent the piston right out.

Where do you get dry ice???
"If you can't fix it with a hammer, then it's an electrical problem"

Bill Lane
 '71 CB450 Mutant/ '75 CB200/ '81 CM200/ '71 C70M/ '72 CL350
http://home.comcast.net/~tbpmusic3/450site.htm

Offline Yoshi823

  • Biker to the bone.
  • Enthusiast
  • **
  • Posts: 205
  • Never too old to be a biker
Re: Stuck Caliper Piston
« Reply #63 on: November 30, 2009, 04:58:14 AM »
Not too sure if you can get the part in the USA but over here in the UK we had a CB250N Superdream.The bleed nipple from this bike has a 10mm AF hex on it which makes it a lot easier to use.This fits all of the 750/550/500F&T/400F models.
I also suggest using a turn of PTFE tape around the thread of the bleed nipple a A) itstops air getting into the system when bleeding the brake and B) it stops the bleed nipple from seizing in the caliper body.
Bikes...they're in the blood.

Yamaha 2001 R1
Yamaha 1990 FZR1000R EXUP
KTM 2004 450 EXC RFS
Honda 1997 XR400R
Honda 1988 CB125T2

http://www.cb750cafe.com/bikes.php?cat=3&id=67

Offline City Boy

  • Hot Shot
  • ***
  • Posts: 650
Re: Stuck Caliper Piston
« Reply #64 on: November 30, 2009, 08:25:49 AM »
Hi guys.I use an old master cyl. attached to a short piece of handle bar and mounted in a vise.Mount to suspect caliper with some used banjo washers,fill with water, and a half assed bleed,all air does not need to be removed.The piston always walks right out and cleanup is easy and not toxic with the exception of residual brake fluid left inside.No waste of perfectly good grease either.    Rock On
'52 Kiekhaefer Mercury Rocket Hurricane KG4H
'70 750/Cobra 1000 Original Owner
'83 1100F

Offline hoodellyhoo

  • CB350F
  • Master
  • *****
  • Posts: 1,654
Re: Stuck Caliper Piston
« Reply #65 on: January 16, 2010, 11:20:29 PM »
Just used the grease gun method today (after trying a few other things) and it worked great. I couldn't find a zerk fitting in the correct pitch so went with one that was close and didn't tighten it much. Someone said something before about wasting grease but at $1.19 a tube (and most of it left), I'd say this is a good deal.
1972 CB350F(down for repairs)- http://forums.sohc4.net/index.php?topic=20822.0
196? S65 - Coming Soon!
1972 CB750K2 (father-son project)
1976 CB750K6- http://forums.sohc4.net/index.php?topic=96859.0
1976 CB750K6 (sold)- http://forums.sohc4.net/index.php?topic=62569.0

Offline Slams77

  • Enthusiast
  • **
  • Posts: 162
  • Naturally Aspirated
Re: Stuck Caliper Piston
« Reply #66 on: February 03, 2010, 04:49:06 PM »
I was totally stoked with the grease gun method.  Even though the threads were different sizes on the grease gun and the caliper, I turned the grease gun fitting just enough to catch the first thread in the caliper, and in less than two minutes the pad and piston came right out.  I did spray some pb blaster in the caliper a couple of days before hand, which may have also helped.

Offline Steel Dragon Performance

  • Full Member
  • **
  • Posts: 65
    • Steel Dragon Performance
Re: Stuck Caliper Piston
« Reply #67 on: April 03, 2010, 08:35:53 PM »
I used air. I used wood shims until the piston was all the way out.  The first time no wood , it was scary.

Offline Indiana John

  • Full Member
  • **
  • Posts: 14
Re: Stuck Caliper Piston
« Reply #68 on: April 04, 2010, 08:41:59 AM »
I had what I thought was a stuck piston in the caliper on my 550 a couple of years ago. Knew it couldn't be too bad as I had rehabbed it the season before and it had worked fine then. I decided to use the master cylinder to pump the piston out. It pumped a little hard at first, but then the pad popped out and it got real easy. I looked at the pad and saw a lot of rust around the metal backing plate. I cleaned all the rust off, pushed the piston back in with a C-clamp, polished the rust out of the inside edge of the caliper body and put a thin film of grease on the edge of the metal back on the pad and the inside of the caliper body. You don't want to use any more grease than needed, otherwise it can get on the face of the pad and the disc and cause trouble. Since doing this, I've had no more problems with that brake.
IJ

76 CB550
75 CB750
76 GL1000

Offline cobra2411

  • Enthusiast
  • **
  • Posts: 197
Re: Stuck Caliper Piston
« Reply #69 on: September 08, 2010, 09:13:44 PM »
Why didn't I find this thread weeks ago??? Why???

I had a stuck everything... I tried the air compressor and it was a no go... And not a sissy small compressor, a big 175psi shop compressor...

In the end I rebuilt the master and hooked it up and with the caliper heated with a propane torch I was finally able to pump the brake and have it come out.

Offline nckyle

  • Full Member
  • **
  • Posts: 3
Re: Stuck Caliper Piston
« Reply #70 on: October 04, 2010, 02:03:44 PM »
My caliper was froze to the wheel when I bought my bike.  Tried to unscrew the bleeder and it broke off from rust. Not sure if its better to try to find a new caliper or rebuild the one I have. I can maybe get the broken piece from the bleeder out. I'm just not just it's worth the trouble.

If a new caliper is the answer, does anyone know where I can find one for less than $200?

Offline roadkng48

  • Full Member
  • **
  • Posts: 8
  • 76 CB750
Re: Stuck Caliper Piston
« Reply #71 on: October 06, 2010, 09:10:25 PM »
Worked for days trying free a stuck piston on a bike that had been sitting  for years. Soaked it overnight in PC Blaster, tried air with no luck. Read this forum, used the grease gun method and two pumps and bang it was out. I manually cleaned grease out the best I could with rags, q-tips and acetone. Then I boiled the caliper in water for about 15 mins and all the grease was cleaned out. Thanks for all the users on here.

Offline seaweb11

  • 1st Mate &
  • Really Old Timer ...
  • ******
  • Posts: 6,153
  • Ride & Smile
    • Playground Directory
Re: Stuck Caliper Piston
« Reply #72 on: October 06, 2010, 09:44:39 PM »
I've had had success with air and a small air hose that just squishes into the bleeder hole and the air gun.

I learned a long time ago to reach into a big cardboard box for the final blow out ;D

Offline roadkng48

  • Full Member
  • **
  • Posts: 8
  • 76 CB750
Re: Stuck Caliper Piston
« Reply #73 on: October 08, 2010, 08:44:18 PM »
NCKYLE....I just went through the same problem with my rear caliper on my 76 750f. I carefully drilled the broken part out by stepping up drill sizes (3) to get to the threads and get the piece out. Be careful not to drill too deep because you will destroy the seat at the bottom of the hole where the bleeder seats to shut of flow. I ran a thread chaser down the hole to clean up threads. Spend sufficient time getting all the drilling scrap out of the hole. I used a small magnetic phillips screwdriver, Q-tips and finally flushed with air. It took about thirty minutes, but my caliper works well with no leaks at the bleeder. Total cost about $2 for a new bleeder.

Offline haggeo

  • Full Member
  • **
  • Posts: 99
Re: Stuck Caliper Piston
« Reply #74 on: October 15, 2010, 01:24:12 AM »
http://www.youtube.com/watch?v=CfDY5ghpqic

video of the grease gun method.

 

;