Front brake issue- not releasing on 91

popinjay said:
ST 1100 is an excellent motorcycle, but is too sensitive for the brake system.
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Not true... its like with many other things around:
neglect it and face trouble
maintain it accordingly and live happy ever after
 
Crack the banjo fitting at the front MC, if the wheel spins more freeer, the MC is holding pressure. If no change, crack the banjo's at both calipers. If you see a difference after doing that, you probably have a pinched or collapsed brake line.

If still no difference, you have at least one sticky caliper.

If I was closer to Holland, I would swing over to assist, but sorry I'm not. Got a trailer ?? I'm about 70 miles from Holland.

BTW, I have set of used brake lines that are in decent shape.
 
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Jim Van- you may be on to something there. To recap- I rebuilt front master cylinder (Honda kit with new piston), and bore looked good actually, but considering the age, it was overdue I suspect. Cleaned out MC and weep hole looked perfectly clean, but I ran some electrical wire around in it several times, hoping I would find something.

Put it all back together, same pads as before, and pads are still not retracting to allow me to spin wheel freely. I can turn wheel a tiny bit, but it still has a fairly tight grip on the rotors. No, there is not a pinched line, I checked carefully (I can hear those responses coming again).

Is there any sort of modulator valve built in anywhere? In regard to the collapsed brake line, it "seems" like I am not getting a lot of brake fluid through, but I did get a lot of air bubbles out when bleeding the RF, and then it became pretty clear. Now it appears I started with the wrong one, but I bled LF next (remember this is non-ABS and all that fancy stuff) so I assume it should be somewhere close to normal. Right now it is spongy and the wheel will hardly turn. It was getting late, so I decided to quit before I started getting mad at it.

But really... this is getting ridiculous. My thinking is there is a bad component somewhere that I have missed, as all my work has not really changed anything very much. I think I will try cracking each of the banjo nuts on the calipers and see if that makes a difference. I vaguely recall when I started all this that both sides were refusing to retract together, and calipers on both sides appear to be OK (one I replaced when I first started this process). So I do not suspect calipers, as they retract nicely when I remove the pads. I guess if I get to cracking the nuts on both sides and the wheel turns easily, then I have narrowed it to something upstream eh? :)
 
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Nope, long hours at work and apparently working Saturday, so it will be a little bit. Driving me nuts that the bike is not on the road though, as you imagine! Riding the KLR is getting a little old (and slow!). I'll be sure and report back asap, possibly this weekend. Thx!
 
So... I cracked open the bleed nipples (should have done banjo bolts, but I forgot which was suggested) and it made no difference, wheel is still 90% locked. Brake fluid flowed out of course, so a "pressure release" regardless. I pulled the pads from LF caliper, no change. So pulled RF pads and of course, wheel spins freely. I pulled the replacement RF caliper off, as I suspect that is the source of the problem, but then again... I did replace it once, and both pistons seemed to retract freely when I installed it.

My theory for now is that both original and replacement RF calipers are sticking, and a rebuild is the only answer. So, will order up a rebuild kit and see what happens. Anyone have any other ideas? Keep in mind, I had no problem getting pads out nor prying pistons back in, and then I pushed them back further with a pump pliers once removed. The only clue is that the pistons seems a little bit reluctant to retract when I had the pliers on them, and the caliper is a bit dirty looking. Otherwise, everything seemed fine. I just hope the caliper rebuild (which I have never attempted) is as easy as the master cylinder.

I knew things were going too well with this bike! :)

Thx for the continuing advice! Got to get her on the road for the Midnight Ride here in August!
 
I have had a line that is delaminating from the inside do this a few times ,the rubber inner liner will separate and get a flap going where fluid goes through it easily but restricts the fluid going back after a few minutes or some time they will release . This is really done most times if the line gets kinked off at some point in its use .Checking is by usually replacing the lines as needed .Since the right caliper seems to be the problem I would replace this line as a start but since they are 20 years old it might be needed to replace all the front ones . Hope this helps ,not meant to be a parts replacer but to give some help to find this problem .
 
Thanks gmtech! I was thinking of something like this, but not sure where to look or if it was even feasible. I swear that it freed up a couple of times too, as I had it when I first pulled it from storage (could not back it up easily) but then rode it for a day or so. Next day, did it again so I quit riding it.

Calipers may be fine, a bit dirty and would probably benefit from a rebuild, but this may be the root of the problem. I wonder how common it is?
 
Just a note to close this thread... ST is back on the road, finally! My KLR, which is only 7 years old, once again has electrical issues, so I finally got myself to finish the ST. The issue was I could not get the pistons out, as compressed air was not doing it, so hooked the calipers back up again and pumped them out, after leaving one of the brake pads out so they would come out further. The rest was easy, new seals in left caliper and simply cleaned up the right caliper with brake cleaner and fine steel wool on the pistons. I still had one piston that I could not get out, so used one from my extra caliper, as of course they fit. Per Jim Van's advice (thank you!!!) I used dielectric grease on the pistons and bores and they slid right in nicely. And the best part it, it stops perfectly again AND the things finally retract! Also rebuilt master cylinder, so I should be good there for some time, although I may put new seals in left side eventually. Now on to the rear caliper, as that has been slowly getting spongier, but I am at least able to get a few weeks of riding in here before the nasty stuff starts. Thanks again for the advice!
 
I have found this thread very helpful, as within the last few days my right front caliper is not releasing properly also. Brake is dragging just lightly enough to make it hard to move in and out of the garage.

I have already cleaned and re-greased the caliper slides, and pin hanger, Honda part #45215-ML7-922. No grease on the pin hanger, just cleaned them. They were a little sticky, but now slide easy on the brackets. But still have the right side pads not retracting properly. Left side is fine, when after using the front brake hard, and releasing the left caliper has a little movement on the bracket. You can actually see the pads retract from the disk, the right side does not, and is still tight against the disk.

Also complete fluid change done last fall for front, rear brake & clutch.

I have ordered new piston and dust seals for both front calipers. I have the Honda front brake MC rebuild kit on hand, and will do them as soon as the seals come in.

Gary.
 
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Forkbrace pinched my brake hose clamp just under the triple clamp. It looked OK but sure enough, that was my issue. Thanks to John Oosterhuis and this thread, my bike is back in business.
 
RedMotion said:
Forkbrace pinched my brake hose clamp just under the triple clamp. It looked OK but sure enough, that was my issue. Thanks to John Oosterhuis and this thread, my bike is back in business.
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So why with the bleeder open did you experience "automatic" braking? No brake fluid to heat up, if it did, it would bleed out.
 
I only experienced the automatic braking when the bleeders were closed; be it by applying the brake or through it heating up from the friction on the discs. Once I opened up the bleeders, no lock-up.
 
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