Rear Brake Dragging

While many owners report a pedal drop it is not normal and is no longer there if a careful bleed of the system is done. The recurring 12k or 24 month flush is very important with the linked brakes system. I have had pedal drop - mine seemed to come with it when I first bought the bike and I did not know it was not normal until I bled it out at the first 12K service. Sometimes it returns 8 or 10,000 miles after a flush and replacement and I bleed it out at at the next +/-12,000.
 
Well, I did a short 140 miles today, and the bike ran like a dream...... the braking was smooth, steady, sure..... when I got home, the rear rotor was warm, but not unusually so. I've reconsidered and decided that even if I have to rebuild or replace the SMC once a year, and exchange the fluid and bleed the system once a year, that isn't too high of a price to pay for a bike that performs the way my ST does.... and besides, I know how to do it all now. Shouldn't be as traumatic as the first time, huh?

(also, the dealer in Quincy, Wa, who had a 2005 Goldwing with 25K at $14995, didn't wanna talk any deals with me...... "I can sell that Wing almost immediately, but I have trouble selling ST1300s..... it's a good bike, but nobody seems to want them....." So be it, you and me, ST, you and me for another 100K!)
 
OK Guys, I"m in the club

My '08 ABS 15k miles rear pads tightened up so much wheel wouldn't turn. Honda warrantied SMC, brakes, disk-Thank you Honda!- Dont know how water got in there, but I'm watching it from now on. I happened to have an excellent mechanic with a good connection to Honda. YMMV.
Did I mention Thank You Honda!
 
GoferitST said:
OK Guys, I"m in the club

My '08 ABS 15k miles rear pads tightened up so much wheel wouldn't turn. Honda warrantied SMC, brakes, disk-Thank you Honda!- Dont know how water got in there, but I'm watching it from now on. I happened to have an excellent mechanic with a good connection to Honda. YMMV.
Did I mention Thank You Honda!
Click to expand...

I am shocked you got it replaced. I was waiting for the parts on backorder. Today the entire assembly finally came in. I gave up on waiting on the rebuild kit.
 
My '05 with approximately 22K has developed the dragging rear brake problem. Now that I know what to be looking for, I will post the results of my investigation. Thanks to those who've already posted!

Later....

LndCrsr
 
Very interesting thread. Curious, the brake lock/drag issue seems that no year or ST type is immune, linked or ABS, even after the apparent 08 "groove" design update. Is that right? How many total ST's I wonder, as a percentage, have experienced this issue?

My 04 is OK right now but I'm fast approaching 20K miles and haven't done a thing with my breaking system. A bleed and brake cleaning is in my near future. Thanks to st-owners.com website. I love this community.
 
My rear brake locked up a few weeks ago, I only noticed by seeing that the fuel consumption gauge on the computer was reading 6.8 litres to the gallon instead of its usual 10-11 at my cruising speed of 80mph. Upon releasing the throttle as someone has already stated it was like I had thrown out an anchor!! There was smoke coming out of the rear calliper bleed nipples.

The rear disc and virtually new pads were completely shot. I took the opportunity to completely overhaul the braking system and I replaced the centre rear piston and fitted new seals to the rear calliper, there was evidence that the center piston had seized. Upon overhauling the smc I found that the self lubricating bearing on top of the front left calliper was seized as was the smc ( The drain hole was blocked and there was a lot of dirt and rust behind the rubber boot ) ,to make matters worse the lug on the left fork leg where the bearing had seized was fractured at the thinnest point. I took the parts to my local dealer who is very honest and easy to talk to. He stated that he had seen the problems several times on ST`s that he has serviced over the years and that these problems were quite common, including the fractured lug!! We had a discussion about a logical fix for the seizing smc problem.

I felt that the self lubricating bearing once seized would prevent the smc from operating at the correct angle and that perhaps the drain hole could be enlarged, he ( My dealer ) agreed. Anyway I had the lug welded and built up so that the week point is now twice as thick and I replaced the self lubricating bearing with a replaceable copper sleeve. If this does not last I will get the stainless bush reduced in diameter and I can then replace the copper sleeve with a stainless one. I drilled the drainhole out to 3.5mm this should also help and thoroughly coated the rubber boot inside and on its outer edges with grease. ( As someone else has suggested a small tie on the middle of the boot should also help )

In my view the self lubricating bush seizes and prevents the smc from operating at the correct angle which along with the dirt and rust which accumulate behind the rubber boot compounds this. This then causes the rear brake to gradually lock on and can seize the centre rear piston. So far everything now works correctly and smoothly.

Regards,

Mike
 
I purchased a used '07 that had not been ridden for quite a while. When I first started riding I noticed that my rear brake was dragging. After reading this thread I pulled the rubber boot away from the SMC and squirted a little non-petroleum lube http://www.jigaloo.com/ca/e_products_jigaloo.php onto the cylinder and worked the SMC back and forth. It freed up the piston and the problem disappeared. I now do this after washing the bike and when checking tire pressure etc.
 
ottawa st

Good idea, but check that top bush, the bracket which fits around it is supposed to be free to move. The calliper moves up and down in an arc and if the bush is seized the bracket will be fixed to the fork leg and the operating rod to the smc will be working at a fixed angle, not good and in my opinion will compound the seizing problem. If it has seized be careful if you remove the stainless bush because it is very easy to fracture the lug on the fork at its thinness point, that is, if it has not already fractured. ( I hope not!! )

Apparently rust ( Not quite the right word, but you know what I mean ) forms behind the impregnated copper sleeve and the alloy of the lug, this action can seize the bush and then fracture the lug at its weakest point. This is from my local dealer.

Regards,

Mike
 
Hi OttowaST

I also have an 07. I think Im seeing symptoms (hot rear disk, discolored fluid, poor gas mileage). However the rear wheel isnt locked-up so Im hoping I can use the jigaloo and go into maintenance-mode and abstain from the smc rebuild.

Question - with all parts attached to the bike ... when lifting up on the left caliper how much is that piston supposed to move? a few millimeters? several centimeters?

Thanks in advance
Phil

OttawaST said:
I purchased a used '07 that had not been ridden for quite a while. When I first started riding I noticed that my rear brake was dragging. After reading this thread I pulled the rubber boot away from the SMC and squirted a little non-petroleum lube http://www.jigaloo.com/ca/e_products_jigaloo.php onto the cylinder and worked the SMC back and forth. It freed up the piston and the problem disappeared. I now do this after washing the bike and when checking tire pressure etc.
Click to expand...
 
p3210 said:
Hi OttowaST

I also have an 07. I think Im seeing symptoms (hot rear disk, discolored fluid, poor gas mileage). However the rear wheel isnt locked-up so Im hoping I can use the jigaloo and go into maintenance-mode and abstain from the smc rebuild.

Question - with all parts attached to the bike ... when lifting up on the left caliper how much is that piston supposed to move? a few millimeters? several centimeters?

Thanks in advance
Phil
Click to expand...

I can get no more than about 1/16" inch or less than 2 mm travel in the SMC when moving it by hand but wouldn't take this as what a SMC will have. I have no air or water in my SMC but plenty of bikes that need a fluid change do and they might have more play or movement. A flush really needs to be done by the book with the linked system or the bore of the SMC collects moisture and mucks up.
 
Thanks Dave!
Good info - maybe there's still hope for me and my SMC.
I just ordered the speed bleeders; hope to flush out the discolored fluid this weekend.
Thanks again
Phil
 
Make sure to remove the left caliper at the appropriate time and tilt it up so the SMC is flushed and bled of all old fluid and accumulated stuff. You will love your new brakes!
 
Shadowfax has been dragging his hind quarters since I met him but now the center piston has siezed following months of rain and winter road brine.

Judging by the 'corrosion' in the aluminium around the pad pin's far end and the state of the pin (unusually corroded and difficult to pull) I'm guesing I need to remove the caliper and overhaul it.

In fact, I've ordered an eBay used one to fit to solve 4 issues:
1. I've not removed the rear wheel before (bought a 27mm 6-side socket :)) and at tyre change the splines were dry of moly)
2. I'll know if the SMC is to blame for the sieze (by illimination)
3. I'll be able to practice overhauling a caliper without time pressure (then sell and claw some pennies back)
4. I'll know if part of my dragging problem is a warped caliper bracket because the pad wear has always been very uneven like the pads touch at an angle
​
There's little evidence of lubrication in the boots, either. Given the seals were replaced in November 2008 (some 50,000+ miles and 3 winters ago) this isn't a bad time to redress the issue ;)

It's also time to re-look at the SMC. Since my STealer went bankrupt I've managed to find a decent parts supplier in Southampton. For now, some silcone lube might be an idea.

It's thanks to you lot and threads like this that I have the confidence to do this stuff. In the same spirit I'll report back if I find anything interesting / unusual to add.

Cheers, all.
 
FYI - I added the jigaloo, bled all the lines (I tilted the smc - thanks) and then took the bike out for a spin.
Rear rotor was still hot; rear wheel was not spinning freely.
I read more posts on this forum.
I cleaned the rear caliper pistons with brake cleaner and a Q tip (I read about road gunk binding up the pistons) and the next time I rode I pressed hard on the rear brake peddle 2-3 times (I read that it frees up the SMC).
The rear rotor is now compfy warm instead of hot and the rear wheel spins easier. I dont know if it was binding pistons or the SMC. Hopefully the jigaloo and the new fluids will keep this issue from re-occuring... but I'll have to keep an eye on it.
Thanks to all for keeping this forum so informative.
Phil
 
A quick way I found to check the SMC is to place the bike on the centre stand and rotate the rear wheel by hand while pushing up on the SMC to compress the piston. (you don't have to push up very far to compress the piston) This mimics what happens when you apply the front brakes. You should be able to move the SMC with only a small amount of pressure and you should feel the rear brakes being applied. When you release the SMC the rear wheel should once again spin freely.
 
After some searching, I read on this forum how to test the SMC solo. Currently the SMC seems to be working OK. Thanks!
 
Up and running but the rear brake is only 60% effective - maybe more air to bleed or a cyclinder isn't working - investigate tomorrow. SMC seems to move okay but quite old looking. Future project regardless.

On the dragging, I'm now convinced the caliper bracket was warped on Shadowfax - the new bracket and caliper run far more true it seems, barely any drag at all: just a squeeky rub where the disk might have a slightest warp, and that only seems to be from the pads sitting +/- 2mm (1/16in) higher on the disk so just catching the wider outer disk lip. (Perhaps this is affecting its effectiveness where it can't bite on the disk?) I'm sure the pad will wear in and I'll be checking disk 4mm run out soon anyway.

Oh, when working on rear brakes 2 important lessons learned:

1. When bleeding with left caliper tilted off the disk, re-insert the pads if you needed to remove them to clear the disk BEFORE commencing bleeding (2nd time I've done this - oops - may need to go in the original article for idiots like me?)

2. When road testing for 10-miles, remember to replace the rear fender and licence plate or the LEO won't know who they're chasing!!! (DOUBLE Oops).
 
You must log in or register to reply here.
Back
Top Bottom