Poll: How many have changed the brake caliper seals on their ST's?

Have the brake caliper piston seals been changed on your ST?

  • 1. Not changed

    Votes: 27 56.3%

  • 2. Changed for suspect sticking pistons.

    Votes: 16 33.3%

  • 3. Changed for a leak.

    Votes: 0 0.0%

  • 4. Changed just as preventive maintenance.

    Votes: 5 10.4%
  • Total voters
    48

Oldschool1

Joined
Oct 19, 2009
Messages
199
Location
Nor Cal
Bike
2005 ST1300A
Just curious how many people have thought it was necessary to change the seals on the brake calipers when they were not leaking?

Really looking at the seals after aging and potentially getting corrosion or "gunk" behind the seals as a source of piston friction that don't allow them to retract properly.

Seems at an age of up to 19 yrs i would think this may be common?

Responses:
1. Not changed
2. Changed for suspect sticking pistons.
3. Changed for a leak.
4. Changed just as preventive maintenance.
 
I didn't "change" the piston seals, but I bought a refurbished rear caliper from a member here. All the guts were included, except I had to add my own brake fluid.
Wasn't sure which way to answer, so I went with #1.
 
My 2010 had an issue after replacing the tires and brakes at one point. I rebuilt the SMC, the rear MC and the rear caliper seals and replaced the rear caliper bracket. I really don't know for sure just which one was the cause of the rear brakes not retracting, but rebuilding all of those solved my problem!

That was a lot of years/miles ago, and I haven't had any issues since with them.
 
Last edited:
The calipers on my 1991 were rebuilt by the shop I bought it from. Those on the 2006 were rebuilt by the dealership my brother bought it from. Both get inspected every year and neither shows any alarming indications. So I'm unsure which I should check since, yes they were changed but not by me, and I have no idea why they were changed...likely cracks/leaks but who knows.
Last calipers I rebuilt were on a 1976 CB360 and a 1978 GL1000, both back in the 1990's. Originals were hard and made no attempt to retain fluid. All were still working fine after 20 years.
Same with our autos. 13 years and 180k miles, 10 years and 76k miles, 5 years and 36k miles. Each was inspected at a local shop this year, the older one got new pads and rotor resurfacing...no leaky or cracking seals.
I am absolutely impressed with the progress of elastomer design since I began working on vehicles in the early 1960's.
 
I replaced them on my 1991 ST1100 as my brakes would lock up when bike sat for weeks. Didn't solve it though. I replaced them on my 2007 ST1300 due to rear brake dragging. Also turned out to be a different issue (improperly mounted glide pin).
 
My 1998 failed the MOT test for rear brakes binding, although you could not feal it on the road, showed up on the brake tester rolling road.
Decided to go the whole hog and stripped front & rear, renewed all seals & pistons & replaced all hoses with hell braided brake lines.
On strip down there was not a lot of corrosion to be honest, just a lot of crud in rear caliper causing pistons to stick.
Probably would have been ok with a good clean up & new seals but decided to do the lot for peace of mind.
Voted Sticking Pistons!
 
Getting ready to replace pistons and seals for the front brakes on my 2000 ST1100. Brakes won't release and are sticking pretty bad.
Just a little over 180,000 miles.
 
Oldschool1 said:
Just curious how many people have thought it was necessary to change the seals on the brake calipers when they were not leaking?
Click to expand...
Even while this is ST1300 related (whilst the thread took a turn by now...) I don't fully understand the grounds of that poll...
Like many other items on a motorcycle/atumotive those rings are wear parts... consumables... there is no service plan/roster...
Once I feel definite resistance while pushing on the calipers to retract the pistons prior wheel-removal, I know the overhaul is due... period.
Doesn't matter if its a CB500, NT700, my ST1100 or a car...
 
GreenZR said:
Getting ready to replace pistons and seals for the front brakes on my 2000 ST1100. Brakes won't release and are sticking pretty bad.
Just a little over 180,000 miles.
Click to expand...

This happened to me in my Jeep Wrangler... literally 2-3 minutes away from home on the very curvy country road (3 90° curves left) ... as I approached the 1st curve, I applied the brakes, then released, but the Jeep kept slowing and I could smell "something burning".

I pulled over and waited 5 mins - the front disc calipers released enough so I could get home. Turns out the pistons are phenolic and froze up (I suspect they expanded). Needless to say, new calipers on the front, along with new pads and rotors and flexible brake lines.
 
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