I know what keeps the caliper pistons from retracting on my bike..

Joined
Sep 10, 2011
Messages
2,211
Location
West Michigan
Bike
'98 ST1100
STOC #
8470
Dave, I was able to get one of these to add to my tools for the next Tech Event in the spring.

20171216_215331.jpg

Screenshot_2017-12-16-21-54-33.jpg
I use compressed air to remove the pistons. That way, the outside of the pistons won't be marred or damage by using a tool. And I can save some $$ by not buying the tool - I'm retired and on a fixed income. First place a thin wooden stick across the pistons to protect the end of the pistons.

I know a guy who had some pistons frozen in the caliper. Compressed air wouldn't budge them. He removed the caliper, removed the pads, and pumped the brake lever to use hydraulic pressure to force the pistons out. Don't know how he managed to get the last piston out, tho. Maybe it was out far enough so some compressed air could finish the job. Or by using two thicknesses of wooden sticks could block the piston that was wasn't as tight to get the other piston out fully, first. You get the idea.
 
Last edited:

Andrew Shadow

Site Supporter
Joined
Jan 28, 2012
Messages
5,069
Location
Montreal
Bike
2009 ST1300A9
And if you use compressed air to remove seized pistons be sure to keep everyone's fingers out of the danger zone. Once the air in the caliper is compressed enough to blow the piston out it comes out with serious force. I know of someone who sliced the tip of a finger clean off this way because he didn't think that he needed to wait for me to show him how to do this.
 
Joined
Apr 23, 2017
Messages
101
Location
Nantahala
Bike
2008 ST1300 ABS
So I'm ready to do my rear caliper since on my tire change I realized that the rotor looked burnt and the pads were tight and dragging. I needed new pads anyways, but didn't expect the caliper to be screwed up. Not to mention I'm gonna replace all 4 bearings because they didn't feel to peachy. Now for the question: When I bleed the brakes out, is it gonna be a real PITA since I have the ABS? Should I start with the rear caliper first of go through the "whole 9 yards"?, and I saw a video that it takes about a quart of fluid to do it correctly?
 

ESB

STRIDER
Joined
Aug 5, 2008
Messages
277
Location
Oklahoma
Bike
'07 ST 1300
Have never had any trouble with grit & dirt seizing up any pistons on any calipers on my bikes.
How can a piston seize up?? They don't move very much at all, & the very slight runout of the rotors should be enough to back off the stackup to gain free and clear running.
Something else is exerting a clamping force while U'r riding.
 

jfheath

John Heath
Site Supporter
Joined
Mar 18, 2006
Messages
2,786
Age
69
Location
Ilkley, W Yorkshire, UK
Bike
2013 ST1300 A9
2024 Miles
000679
STOC #
2570
So I'm ready to do my rear caliper since on my tire change I realized that the rotor looked burnt and the pads were tight and dragging. I needed new pads anyways, but didn't expect the caliper to be screwed up. Not to mention I'm gonna replace all 4 bearings because they didn't feel to peachy. Now for the question: When I bleed the brakes out, is it gonna be a real PITA since I have the ABS? Should I start with the rear caliper first of go through the "whole 9 yards"?, and I saw a video that it takes about a quart of fluid to do it correctly?
Well there are lots of reasons for pads binding - which may or may not be due to pistons sticking. There are a whole load of other things to look at. A bit of searching around will reveal a load of stuff. But (and I am biased here) can I suggest giving two articles to illustrate whatever else you read. They are in the articles section, and at present they appear on the first and second pages. One is 'ST1300 - getting all of the air out of the brake system', the other is 'ST1300 Brakes - Avoiding the Pitfalls'. In both cases, download the pdfs - and for the first one in post 7, take a look at the video - don't just look at the pics - the pdf file has more info and better images.

Yes - you have to do the whole 9 yards - except it will be at least 45 yards by the time you have been round the system 5 times. Yes you have to do them in the correct order - it's not a case of being able to manage without doing that - its a case of chasing the air bubbles around the system to get them to a suitable bleed valve. And no, it's got very little to do with having ABS - the same procedure has to be followed for the ST1300 with or without ABS.

Its always a good idea to have plenty of fluid. Too much and you get the job done. Too little and you have to go shopping and it makes the job tediously longer than it is already. Leave yourself plenty of time, and start by removing the right hand middle cowl - you need to be able to get to that highest bleed valve (the PCV) which is near the right hand ignition coil, and it helps enormously if you can see it.
 

Andrew Shadow

Site Supporter
Joined
Jan 28, 2012
Messages
5,069
Location
Montreal
Bike
2009 ST1300A9
Now for the question: When I bleed the brakes out, is it gonna be a real PITA since I have the ABS? Should I start with the rear caliper first of go through the "whole 9 yards"?, and I saw a video that it takes about a quart of fluid to do it correctly?
Have a look through the below threads. They should answer all of your questions.

ST1300 - Brake Fluid Replacement.
ST1300 - Getting all the air out of the brake system.
ST1300 - Brakes- Avoiding the Pitfalls.
 
Last edited:

John OoSTerhuis

Life Is Good!
Joined
May 10, 2005
Messages
5,218
Location
Bettendorf, Iowa
Bike
1991 SSMST1100
STOC #
1058
How does a caliper piston seize? By enough corrosion buildup in the groove behind the fluid seal forcing the seal to grip the piston tighter and tighter until it doesn’t retract. BTDT x 2 [one event, one piston on each side, front calipers]

The other likely suspect for frozen/dragging single-action type brakes: caliper/bracket slider pins.

John
 

ST1100Y

Site Supporter
Joined
Dec 4, 2012
Messages
4,981
Age
59
Location
Vienna, AuSTria
Bike
ST1100Y, ST1100R
STOC #
637
How does a caliper piston seize? By enough corrosion buildup in the groove behind the fluid seal forcing the seal to grip the piston tighter and tighter until it doesn’t retract.
Yep...
And significant resistance when pushing them in by hand (i.e. for replacing brake pads, or prior of removing a wheel) is a sure sign that an overhaul/rebuild is in order...
Depending on conditions/annual mileage due like every 2~4 years... regular maintenance, nothing strange or astonishing there... :shrug2:
Some seize up while being grounded in the shed/garage for longer period, brake fluid is hygroscopic and draws humidity in... causing crystallization and bam! the square ring jams on the piston...
 
Joined
Jun 21, 2011
Messages
1,117
Age
70
Location
Ada ( Grand Rapids ) Michigan
Bike
'07 ST 1300 & '91 GW
STOC #
8421
When I bought my used '81 GL-500 SilverWing , in '92 , it had only 600 miles on it @ 11 years old ! Front caliper seized so much that you could barely turn the wheel by force . I only tore it apart , cleaned it , polished piston on a metal polishing buffing wheel , put it back together using the original seals , Still works to this day @ 37 years old , with current owner !
 
Last edited:
Joined
Apr 23, 2017
Messages
101
Location
Nantahala
Bike
2008 ST1300 ABS
The reason I mentioned the rear caliper first was because I know it's gonna get drained. I thought that doing it first would at least get fluid to it before I started on the steps of bleeding the system. Seems it would be allot of pumping to get the rear primed going through the front caliper (as per video I watched on YT). As for sticking/dirty calipers, I'm very familiar with that with it with all of the bikes I've owned. I'll let ya all know how it goes :)
 
Joined
Apr 23, 2017
Messages
101
Location
Nantahala
Bike
2008 ST1300 ABS
Pads installed. So what was making my pads freeze up was........I goofed up. Didn't see that the outside pad didn't hook in, in the slot in the front of the caliper. Once the rotor/wheel was stuffed, I didn't notice that it fell out, or I didn't make sure it was in. So....got that sorted out, pushed the pots in and installed the wheel with new pads. No need to rebuild this time. So a good thing, even though I learned the hard way on this bike.
 
Joined
Sep 10, 2011
Messages
2,211
Location
West Michigan
Bike
'98 ST1100
STOC #
8470
How does a caliper piston seize? By enough corrosion buildup in the groove behind the fluid seal forcing the seal to grip the piston tighter and tighter until it doesn't retract. BTDT x 2 [one event, one piston on each side, front calipers]

Snip ....

John
:plus1: ( Again, ESB )
 

jfheath

John Heath
Site Supporter
Joined
Mar 18, 2006
Messages
2,786
Age
69
Location
Ilkley, W Yorkshire, UK
Bike
2013 ST1300 A9
2024 Miles
000679
STOC #
2570
Didn't see that the outside pad didn't hook in, in the slot in the front of the caliper. Once the rotor/wheel was stuffed, I didn't notice that it fell out, or I didn't make sure it was in.
That is quite common on the rear pads. They will fit quite snugly resting below the slot and resting on the hub of the rear wheel, and they machine a very attractive go-faster groove in the hub (or so I am told).

I always check them at both ends once everything is secured. Just to be absolutely sure. Its difficult to see the outer rear pad is seated properly as the stopper bolt and the brake hose is in the way. Nevertheless, I once checked thoroughly as I pushed the pad pins in, tightened up and didn't check afterwards. Both front left pads fell out as I reversed the bike out of the garage. I still haven't got a clue how I thought the pins had gone through the holes.

On the later 2008+ 1300 the front pad spring on the right caliper can be a problem. The pistons have a different arrangement from the left caliper, and the pad spring can rock laterally as you push the first pad in, resulting in the piston pressing against the edge of the spring.
 
Top Bottom