on my 06 st1300a my rear brakes do not seem to stop the bike as well as i think they should. i know that they shouldn't lock up but i can almost stand on them and it just bearly slows down. i also own a bmw k1200rs with abs, if i do the same with it, hold on tight. any thoughts? note the front brakes work ok. if any one knows of a dealer that knows something about these bikes please let me know. i live in exeter nh thanks tim
2006 st1300a the rear brake won't stop the bike
- Thread starter tim swisher
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I would start with a brake bleed. With linked brakes it should activate both front and rear brakes and stop you. The brake bleed process is well documented here so follow the steps and it should help.
why only the rear brakes, the front seem to work ok. my bmw is a 2003 and i never bleed the brakes. if you grab a handfull and stand on the pedal hang on.
There a quite a few variables involved here...
When was the last time the brakes were properly stripped and cleaned?
What state are the pads in?
If you spin the rear wheel and move the left front caliper up and forward to activate the secondary master cylinder, the rear wheel should stop and rotate freely again when the left front caliper is allowed to move back to its normal position. Does this happen?
Are your front pads evenly worn on both sides of each disc and on each side of the bike?
If you work through this and let us know whats going on, it may help to pin down possible problems.
When was the last time the brakes were properly stripped and cleaned?
What state are the pads in?
If you spin the rear wheel and move the left front caliper up and forward to activate the secondary master cylinder, the rear wheel should stop and rotate freely again when the left front caliper is allowed to move back to its normal position. Does this happen?
Are your front pads evenly worn on both sides of each disc and on each side of the bike?
If you work through this and let us know whats going on, it may help to pin down possible problems.
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The brakes on the 1300 are a very complex bit of plumbing.
The rear foot brake sends brake power through the ABS module, to a proportioning valve. From there it sends brake pressure to the front and rear calipers.
The front brakes use completely separate brake lines and different pistons on the calipers. Which is why it is entirely possible to have good brake function with the front brake leaver and not the rear. They really are completely separate even though they both actuate braking pressure on the same calipers.
This thread talks about replacing the brake fluid. Of course in doing this you have to do a flush. If the bike is new to you, I would do a complete replacement so you know where you are at with the brake fluid.
link
The rear foot brake sends brake power through the ABS module, to a proportioning valve. From there it sends brake pressure to the front and rear calipers.
The front brakes use completely separate brake lines and different pistons on the calipers. Which is why it is entirely possible to have good brake function with the front brake leaver and not the rear. They really are completely separate even though they both actuate braking pressure on the same calipers.
This thread talks about replacing the brake fluid. Of course in doing this you have to do a flush. If the bike is new to you, I would do a complete replacement so you know where you are at with the brake fluid.
link
If the above is truly the case, then you should be examining the rear brake system immediately to determine what is causing the system to malfunction. The Honda linked brake system is a pretty slick design that works very well.
Your description of little to no brake response when applying the rear brake pedal, appears to suggest that the rear brake master cylinder circuit is not functioning properly. This could be due to a number of different issues, the most common being:
- Air trapped in the brake lines. The air compresses when the brake pedal is applied, thus greatly reducing the brake pressure generated by the master cylinder.
- Low or no brake fluid. Low brake fluid may allow air to enter the master cylinder, which results in air becoming trapped in the brake lines, and/or starving the master cylinder of brake fluid, causing the master cylinder to become ineffective in building pressure.
- A worn out rear master cylinder. Though not very likely, a master cylinder where the piston to cylinder seals have become so worn as to prevent any pressure to be generated.
When operating correctly, the ST1300 rear master cylinder supplies pressurized brake fluid to almost every hydraulic brake component on the motorcycle, this includes both front brake calipers, as well as the rear brake caliper. In your situation, I imagine the issue has more to do with the rear master cylinder not generating proper hydraulic pressure.
As Mr Sennister has already suggested, bleed the rear brake system.
Here are two links that may prove useful as you delve into the Honda linked brake system:
- First a very good description of the linked brake system from the Honda Blackbird, which is very similar to the ST1300 linked brake system.
- Second is a color sketch of the ST1300 linked brake system, with a brief description of the three distinct brake circuits.
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The color sketch above is pretty good. I don't think I have seen that before. One thing that I would mention, just to clarify, is that the braking action on the front left caliper causes it to compress the SMC (Secondary Master Cylinder). This braking action is induced by not only the application of the front brake but also the rear brake. It is the rotation of the tire that causes the caliper to rotate up and compress the SMC. As shown in the diagram the rear pedal provides braking action to the middle pistons on all 3 calipers. So this is why you will have less braking power but it is more than enough to stop the bike. Because the braking action also compresses the SMC it actuates all 3 pistons on the rear caliper to some extent. While the brakes are pretty good on the 1300, the SMC is a pretty common point of failure for many of us. However the symptoms of that are a case where the rear brake is dragging which is the opposite of the issue that you are reporting. Sure the other items like brake pads and such should be checked, I am assuming that isn't the issue but it could be. If it were me I would start with a flush of the brake fluid and then work it from there.
Silver Bullet
Retired
My vote , Moisture in the rear system , you need to bleed and replace the fluid ! I just had the same symtoms on my 98 XLR 650 last summer , Wouldn,t stop if you stood on it and very mushy ! Bled out the milky old fluid and wow , back to solid braking ! Might be your problem or not , but worth checking ! Good luck !
MIKE
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Hi, and welcome !
I can't argue with what everyone else has said so far, but i'll add an alternative. Check the rear wheel and disks carefully. Run your hand or a spirit- damped rag over the surfaces.
You are looking for a thin layer of grease, which may be caused by the incorrect grease being used in the wheel bearings, or by a workman with dirty hands. Wrong grease or over- greased bearings will spin-dry their contents over the wheels and disc surfaces. The discs may clean themselves, but the pads will be well lubricated.
To cure, take the pads out, take the wheel out. Gently prise off the oil seals and clean out as much of the grease as you can. The bearings are sealed anyway, and most of the lubrication they need is trapped inside. The seals and the spacers need just a smear. Degrease the disc. Take a good look at the pads. They may need to be replaced, but sometimes it is adequate to clean them by rubbing the surfaces back and forth lengthways on fine wet and dry laid on a smooth flat surface.
Hope you get it fixed.
I can't argue with what everyone else has said so far, but i'll add an alternative. Check the rear wheel and disks carefully. Run your hand or a spirit- damped rag over the surfaces.
You are looking for a thin layer of grease, which may be caused by the incorrect grease being used in the wheel bearings, or by a workman with dirty hands. Wrong grease or over- greased bearings will spin-dry their contents over the wheels and disc surfaces. The discs may clean themselves, but the pads will be well lubricated.
To cure, take the pads out, take the wheel out. Gently prise off the oil seals and clean out as much of the grease as you can. The bearings are sealed anyway, and most of the lubrication they need is trapped inside. The seals and the spacers need just a smear. Degrease the disc. Take a good look at the pads. They may need to be replaced, but sometimes it is adequate to clean them by rubbing the surfaces back and forth lengthways on fine wet and dry laid on a smooth flat surface.
Hope you get it fixed.