Rear brake pedal got tight suddenly

[Scarfall]

Hello all,

I have a 2015 1200GS. I was away for a few days, and when I got back I took the bike out for a spin and wash. I noticed the wheels were resisting rolling forward. I thought it was just some rust in the brake disc so I rode for a bit, washed it and applied ACF150.

The rust of the brake disk is gone but the brake pedal is tight and doesn't spring back up. Please see the video to see what I mean.

Whats wrong with it, and how do I fix it? Many thanks!

https://youtu.be/lAycdkT37jw

 

[BigKev67]

Should return under spring action. Check spring condition. Check for a foreign object obstructing the pedal.

 

[bosnjo]

Probably rusty pins on the calipers don't allow pads to return. Seen that before. As for the pedal, it needs to be removed, cleaned and lubricated.

 

[Deleted account 221212001]

A small foreign object, perhaps a stone trapped in the mechanism at the pivot point?

 

[theoneandonly]

take the pivot apart and grease it ...

 

[Lord Snooty]

Start with checking the pedal pivot, a strip, clean and lube won't do it any harm. If it persists then remove the caliper and give that a good overhaul.

 

[pcarnut]

Start at the brake pedal and work your way back to the caliper.

First check for any binding movement in the pedal or pivot, then check the actuating rod that pushes into the brake cylinder, there should be a little bit of free play between the rod, the brake arm and the cylinder. If not then don't ride the bike until this is addressed, it could lead to overheating of the brake and then locking up of the rear wheel.

Once the pedal mechanism is determined to be working properly, move to the rear caliper and check for binding between the rotor and the caliper. If things are tight, you may be able to release pressure with a quick bleed of the fluid and release of the nipple. At this point you if you still have binding then the caliper will need, at the least a good cleaning. Not necessarily a rebuild but at least clean the piston. Youtube would be your friend at this point.

 

[Pablo1]

had a similar issue, brakes were binding

 

[SBD]

If you need to open the bleed nipple to get the brakes to release, your problem is the master cylinder is not returning fully.
The moving seal is still covering the reservoir port.

 

[pcarnut]

If you need to open the bleed nipple to get the brakes to release, your problem is the master cylinder is not returning fully.
The moving seal is still covering the reservoir port.

Correct. Something is either binding, or the cylinder actuating rod has insufficient play in it.

 

[knutk]

Start at the brake pedal and work your way back to the caliper.

First check for any binding movement in the pedal or pivot, then check the actuating rod that pushes into the brake cylinder, there should be a little bit of free play between the rod, the brake arm and the cylinder. If not then don't ride the bike until this is addressed, it could lead to overheating of the brake and then locking up of the rear wheel.

Once the pedal mechanism is determined to be working properly, move to the rear caliper and check for binding between the rotor and the caliper. If things are tight, you may be able to release pressure with a quick bleed of the fluid and release of the nipple. At this point you if you still have binding then the caliper will need, at the least a good cleaning. Not necessarily a rebuild but at least clean the piston. Youtube would be your friend at this point.

And don't forget what @bosnjo suggested.
A 6 year old bike with rust issues on the brakes will be prone to develop stuck sliders, meaning that the force applied to the pistion in the calipper, allowing the callipper to slide on the slider-pins may not return and relieve the mechanical pressure due to corroded pins. If this is the issue, the typical seniario will be that one of the pads is still rubbing towards the disk while the pad being pushed on by the pistion in the calipper will relive it's pressure, thus allowing the wheel to turn, but with friction.

On cars, driven on salted roads, the issue will be identified by the fact that the rotor has one rusty side and one shiny side...

 

[pcarnut]

^ Very good point.

 

[JerseyNeil]

What is this ACF150 you speak of? Is it better than ACF50?

 

[Bem]

What is this ACF150 you speak of? Is it better than ACF50?

3 times better!

 

[Engineer]

Hello all,

I have a 2015 1200GS. I was away for a few days, and when I got back I took the bike out for a spin and wash. I noticed the wheels were resisting rolling forward. I thought it was just some rust in the brake disc so I rode for a bit, washed it and applied ACF150.

The rust of the brake disk is gone but the brake pedal is tight and doesn't spring back up. Please see the video to see what I mean.

Whats wrong with it, and how do I fix it? Many thanks!

https://youtu.be/lAycdkT37jw

It's not uncommon for the rear brake lever to stick in the down position due to corrosion and dryness of the brake lever pivot - waggle it about to free it up and apply plenty of lube to make sure it is no longer sticking.

Warning don't put a bike away wet after washing and keep moving bits well lubed.

 

[Stantman]

Same thing came up as an issue on my MOT, 2015 1200lc. I took the pedal off greased the bracket and it's back to perfect. It was surprisingly how dry the grease had become. Hadn't noticed before the MOT but on trip to Snowdonia my mate also on a 1200 had got about 10% better fuel economy, so wondering if the rear was rubbing slightly.