Braking issues

Update, one month later: my rear brakes seem to have jammed tight. the last time I rode (just a mile or two), there was a periodic squeaking sound. Sprayed all brake assemblies with slightly soapy warm water, then generous amounts of non soapy warm water. Two weeks later, I can't wheel the bike around, even if someone is helping me! I can ride around the parking lot, but I can feel the engine struggling against the brakes. Brakes holding so tight I can't even get the rear wheel to move enough for me to get it up on the centre stand!

I'm too nervous to ride to the mechanic (3 miles away) unless that's my only option. It's also going to be quite expensive for me to get the brakes serviced there.

Help!
 
Does the 1100 have an SMC? That would be my first guess as to the cause here. If not, then the mechanic might have put the pads in incorrectly (or sprayed the rubber parts w/ brake cleaner).
 
SMSW said:
Does the 1100 have an SMC? That would be my first guess as to the cause here. If not, then the mechanic might have put the pads in incorrectly (or sprayed the rubber parts w/ brake cleaner).
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What's a SMC?

Until the current situation. the brakes have been stopping effectively enough (other than the slight judder on firm braking). The last time, the mechanic just said he cleaned the brakes without fully servicing them - he said taking them apart would be a lot of work and he didn't charge me for it so I'm sure he didn't open them up. Doubt he even took them off their mounts, TBH.
 
Secondary master cylinder. Its a caliper on the front wheel, left side. When the brakes are applied, the center piston grabs the disk, the caliper moves a few mm towards the direction of rotation of the wheel, moving against a piston which forces brake fluid to the rear wheels. Its part of the linked braking system.
 
SMSW said:
Secondary master cylinder. Its a caliper on the front wheel, left side. When the brakes are applied, the center piston grabs the disk, the caliper moves a few mm towards the direction of rotation of the wheel, moving against a piston which forces brake fluid to the rear wheels. Its part of the linked braking system.
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Checked the ST1100 service manual, the brakes section makes no mention of a SMC/linked braking (except for the ABS/TCS model, which isn't mine) so I'm assuming there isn't any.
 
krist0ph3r said:
Checked the ST1100 service manual, the brakes section makes no mention of a SMC/linked braking
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Guess not. If you go to articles in the blue bar at the top of this page, click on it, then 1300, the first one is SMC rebuild. There is a picture of it at the top of the article.
 
The ST1100 ABSII (1996 and on) has an SMC. Not sure about the ABSI (1995 and before).
 
OK... Non-ABS ST1100, rear brake dragging badly.

Probably pistons not retracting because of corrosion collecting behind the seals. Crack the bleed valve open and see if that lets you freely rotate the wheel. If so, you can ride it to your dealer without using the rear brake, or take it apart and rebuild it yourself.

If it’s still binding you’ll need to force the pistons back into the caliper enough to release the wheel (big screwdriver). You may be able to pry out one of the pads, then you can remove the wheel and get the caliper off to inspect/service/rebuild.
John
 
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John's covered it.
Take the panniers off.
You'll have good access to caliper.
Place a bit of pad or cloth between caliper and knee and push inwards on the caliper body. It should move enough to allow enough space for the wheel to turn. It may take a bit of pressure.
Ride to dealer using only front brake.
Good luck.
Upt'North.
 
thanks for all the advice, I rode slowly to the mechanic yesterday morning, first few minutes felt like the engine was struggling, and all sorts of scrubbing sounds from the rear pads... improved after about a mile. turned out the rear caliper wasn't sliding smoothly but wasn't fully jammed, the front (which I thought was fine, but couldn't check as I couldn't even get it on the centre stand with locked brakes) was even worse! spent £70 to get everything opened and freed (front pistons had what seemed like surface corrosion or heavily baked on dirt).

purchased a can of brake cleaner spray to help me keep things moving from now on. mechanic said there's not much else that can be done myself when roads are salted and wet (which is all the time in Belfast in winter) - do you guys agree? spray on pistons after every time I'm out on dirty roads? is there any other part I should spray on (the thing that the calipers slide on? I'm assuming that's greased already now, and not sure if the cleaner spray will dissolve that)

also, watching the guy check the rear brake, he had to loosen the axle nut and left exhaust to get at the brake - is that the best way to do it? do I need a torque wrench when tightening the axle nut if I happen to loosen it?
 
jfheath said:
I've never had to use brake cleaner, and I used my Pan on UK roads throughout winter, for commuting. But I changed tyres every 5000 miles and the brakes got a very good clean up and service each time the wheel came off. But in between time, they just did their job. Looked filthy, but they worked well.
Once pistons were cleaned, I used plenty of rubber grease on the outside of the pistons. The grease attracts a lot of muck, but it just wipes off, and present no problems for the seals.
The slider pins and pad pins got the same attention. Not too much grease on the slider pins as that can create an air lock and air pressure pushes the caliper across to warm the disc up !! (But I really overdid it. A healthy smear is adequate).
I'd clean up the pads too, and the grooves between the pads, and poke out the debris in the disc surface drain holes.

I think that regular maintenance is better than brake cleaner.
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cool! one difference is that I don't commute, I ride around town every couple of weeks to keep her running and just do longish rides when the opportunity presents itself, so my brakes are sitting without much use for quite a while. would that change things re cleaning/getting stuck?

I have also been using soap/water spray (reusing household cleaner spray bottles) without undoing anything, and it doesn't seem to do the job. do you take the calipers off and clean/grease them? or is it something that can be done without undoing any bolts? I wouldn't want to be undoing bolts every other time I ride the bike
 
If everything has been cleaned and lubed you should be good.
Don't get spraying anything in there, just clean it off with a cloth and a little light oil on non braking surfaces if you feel the urge to make it shine. But don't rub any lube off.
If the calipers are cleaned every tyre change you shouldn't have to do much else.
Obviously I would avoid riding it on salt covered roads as much as possible.
Good luck.
Upt'North.
 
krist0ph3r said:
cool! one difference is that I don't commute, I ride around town every couple of weeks to keep her running and just do longish rides when the opportunity presents itself, so my brakes are sitting without much use for quite a while. would that change things re cleaning/getting stuck?

I have also been using soap/water spray (reusing household cleaner spray bottles) without undoing anything, and it doesn't seem to do the job. do you take the calipers off and clean/grease them? or is it something that can be done without undoing any bolts? I wouldn't want to be undoing bolts every other time I ride the bike
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With the wheels off and pads removed, carefully extend the caliper pistons with the lever/pedal. A block of wood in the caliper will keep them from going too far out. Note that the pistons have no stop, so you can push them all the way out if you're not careful. Then, using a flat shoestring soaked in brake fluid, wrap it around the pistons and clean the outer surface. Then use a c-clamp to gently and slowly squeeze the pistons back in, a step at a time. This is about the best you can do without taking anything apart, outside of wheel and pad removal.
 
N.B. - Do not spray your calipers with “brake cleaner”. That’s basically acetone which will swell your pistons’ seals so they don’t retract. Brake cleaner is used to remove grease (any contaminants) from metal parts like your rotors, and brake pad surfaces (while removed from calipers!).

John
 
John OoSTerhuis said:
Yeah, me too, I sew... have a parachute rigger license. Then I somehow conflated bobbin into thimble, which is somewhat like a caliper piston. DOH! And not at all familiar with floating rotors (or that they are on ST1300s); hence, my ‘embarrassed’ emoticon.

OK... back to your regularly scheduled program. :)

John
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Well the 1300 does run like a sewing machine! :biggrin: Russ.
 
jfheath said:
Since I usually work on them at wheel change time, the caliper bracket has to be lifted out of the way anyway. That means taking out the stopper bolt as well. With the brake caliper and bracket removed like that, it is simple to separate the two parts on the rear caliper. I do not disconnect any of the fluid lines - just work with the lines connected - being careful not to put strain on where the hose and banjo union are crimped together. I find I am riding much less at the moment, so I just keep an eye on things to ward off corrosion when the bike is just sitting in the garage.
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Hi John. Good morning from sunny Scarborough! I'm just in the process of fitting a new SMC to my 2006 ST1300A. The new SMC comes with plastic inserts on the two places where the brake lines attach. They are clearly there to keep out dust, dirt and foreign objects whilst the SMC is stored, and need to be removed before the unit is fitted. But looking closely inside the entry port which will have the "through" banjo attached, it appears as though there may be a thin plastic membrane at the bottom, although I can't be sure as I don't want to go poking around too hard in there. Do you know whether there is in fact a membrane of some sort at the bottom; and if there is, does it need to be removed before fitting the unit? I'm puzzled as I don't understand what would be its purpose given the brake line attachments already have plastic inserts to keep out dirt.
 
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