Rear Brake Sticking for 20 seconds

[madpanfan]

Hi all,

I need help with my 2003 cbr1100xx 28,000 miles. Linked brakes

My rear brake is giving a problem. Out for a spin and the rear brake disk was very hot even though I had 'rolled to a stop' after a few miles of motorway driving. I didn't even use any brakes to stop. Jumped off and the disk was way too hot to touch. Ouch!!!! :xm

Got home and did the following...

Stripped rear caliper, used red rubber grease and pistons now very easy to operate and can push them back in with my little finger. Caliper slides on the pins freely

Front LEFT caliper rotating smootly to operate 2nd master cylinder.
Applied red rubber grease to both front calipers after cleaning up pistons. Slides freely & pistons operating freely.

Put bike on centre stand and I pressed the rear brake pedal by hand. With my free hand I checked and this locked the rear wheel as normal.
Released the brake pedal but the rear wheel remained 'locked up solid' for at least 20 seconds. I could not rotate the rear wheel by hand.

Wheel spinning by fingertip pressure 20 seconds later!!!
So again, and again I pressed the brake pedal and the same result each time. I could not rotate the wheel until I counted to 20 or so.

Any ideas????

 

[Jaws]

If you are only pressing the rear brake lever and not touching the front brake lever at all it does kinda elimate almost everything

All that is really left is the footbrake lever sticking ( unlikely as I think you would have noticed that ! @tu* ) or more likely the master cylinder has been and gone awol on you..
If it IS the master cylinder I do believe I have several on the shelf for about ?15.00 a go

 

[Duck n Dive]

Squirt some penetrating oil into the brake pedal pivot bushing ... if it's that sticking it should free it up.

Then remove it and grease the pivot.

 

[madpanfan]

The rear pedal does not seem to be sticking itself & I did check to see did the pedal return up fully so it must be the rear master cylinder itself.

Thanks for the offer Jaws. I have a master cylinder here from a st1100 or a gsxr1100w. I can use one of them to check does it rectify the problem (if it fits). Or could it be one of those valves in the linked system? Do they give any trouble?

Cheers...

 

[CBRDEAN0]

Not sure if the BB brake calipers are the same but I had an issue like this on a car once.

I had put the piston seals in the wrong way and they were not withdrawing the piston a fraction like they should.

Turned the seals around and all was sorted.

 

[ov24604]

I have the same problem with my rear brake. It gets really hot even when i'm not breaking. When the bike's on the centre stand it takes a strong grip to even spin the wheel (no finger pressure would ever move it). Did you get the problem sorted in the end?

Or does anyone else have any suggestions? Thanks.

 

[Jaws]

Check the pivot on the front left hand leg.. Chances are the 2ndry master cylinder is not coming all the way off.... It is quite common I am afraid

 

[4_4_2]

I would strip and clean the rear brake caliper if its not been off the bike for a long time. replace the piston seals and make sure the seals are in the correct way round as suggested above. the rubbers do swell with age and could be disintegrating causing the piston to stick and not return smoothly...

 

[g1948]

My 2p worth. As my Bird has been standing (see the sticky ignition switch in another post, thanks all btw for the advice, have some graphite powder on order) I check levers and things. Noticed my rear brake light was staying on for too long, so I squirted some lubricant into the foot lever mechanism and worked it by hand a few times, everything back to normal. I was prepaed to strip the lot out, but the lube worked @tu*

 

[silverfox.xx]

I have the same problem with my rear brake. It gets really hot even when i'm not breaking. When the bike's on the centre stand it takes a strong grip to even spin the wheel (no finger pressure would ever move it). Did you get the problem sorted in the end?

Or does anyone else have any suggestions? Thanks.

Yours sounds like the calipers seized on the 'float' pins.

 

[radicalrabit]

FOUND THIS WHICH MAY HELP


Re: blackbird brake problem?

Originally Posted by Roland
Can anyone help the rear brake disk on my Blkbrd runs very hot , if I don`t use the rear brake at all the rear brake disk still runs hotter than the front disks , if I use the rear brake the rear disk gets very hot to the point where the disk will turn a shade blue, I have replaced the rear disk , pads and caliper and put a kit thru the rear slave cylinder and adjusted right off ?





99% of the time this will be due to an issue with the secondary master cylinder on the left fork leg. This cylinder is opetated due to the caliper rotating and moving the caliper upwards and towards the fork leg ......... this pushes the cylinder pushrod up which pushes fuid to the rear calliper.
So for there to be no pressurised fluid on this part to the system the caliper has to drop back when the brakes are not being operated (doesn't matter which brake)
Problems that cause this not to happen i.e the caliper not dropping back
1. The pivot pin that mounts the front LH caliper being dry / corroded - remove, clean and grease.
2. The pivot bolt (above) has been overtightened - torque to the rec value.
3. The hoses have been moved and are actually lifting the caliper.

I have seen all three of the above causing severe rear brake problems.

Easy check - assuming you have checked the rear caliper pistons as bullit has suggested.
Lift rear wheel and try and spin - should be free but there may pad pressure - which suggests a problem. If the wheel free spins then it is another problem.
Unbolt the seconday master cylinder from the fork leg and allow the caliper to drop / push it down.
Spin rear wheel again and compare the 'freeness' with the first test.
If the wheel spins more freely then you have one or more of the 3 issues above (assuming that the cylinder piston moves freely).
Lift the cylinder back up to its mounting position and you will see the caliper being lifted ........... which is what is applying the rear brake pressure.​