ST Brakes

[ulti682]

Hi all, i have a question that i hope some can shed some light on...the rear brakes of my st 1100 won't release after they have been applied, the disc gets so hot i have to crack the bleed nipple to release pressure to keep going. the bike is a 98 model with abs and linked system..very confusing trying to chase where the problem could be? has anyone had a similar problem?

Brenton

[Brock]

It sounds like you may have an air bubble in the system some where. A brake fluid change may be in order, not sure of the procedure for the 1100 linked brakes.

[alans1100]

I haven't had the issue yet but it would help if one was to know which of the two bleeders you released.

The rear bleeder is fed from the rear master via the ABS modulator to the centre pot. This circuit also feeds the centre pots on the front callipers. Since you don't mention any issues with the front then I suspect this side of the system is ok.

The front bleeder on the rear calliper is supplied with fluid from the rear master via the secondary master above the LH front Calliper and then to a Pressure Control valve to the rear outer two pots.

That's the basics and the issue could be in anywhere from the secondary master, the PCV (sticking) and sticking pistons in the rear calliper.



 

[alans1100]

It sounds like you may have an air bubble in the system some where. A brake fluid change may be in order, not sure of the procedure for the 1100 linked brakes.

Bleeding the brakes on all ST1100 ABS-II (1996-2002).

1.Left front caliper upper bleed valve, using the front brake lever.
2.Right front caliper upper bleed valve, using the front brake lever
3.Left front caliper lower bleed valve, using the rear brake pedal.
4.Right front caliper lower bleed valve, using the rear brake pedal.
5.Rear caliper front bleed valve, using the rear brake pedal.
6.Rear caliper rear bleed valve, using the rear brake pedal.

[Bikebear]

Check that the pins that hold the clipers are free, mine were nearly seized and wouldn't let the caliper release properly. I pulled them apart and greased the pins with some high temperature disc brake grease.

[ulti682]

Thanks guys i will try this, it only started doing it after we pumped fresh brake fluid through the system, wonder if we did something wrong..

[ulti682]

If there is air in the system from not bleeding the lines in the correct way, could the air bubble be pressurized enought to force the pads against the disc creating drag?

[Brock]

As the air heats, it expands (or tries to)thus putting pressure via the oil onto the pads.

So yes..