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Main Area => General GS500 Discussion => Topic started by: f155mph on August 10, 2018, 01:21:57 PM

Title: Mushy rear brake
Post by: f155mph on August 10, 2018, 01:21:57 PM
Ok I am not sure what is wrong.  I bleed the rear brake multiple times already but it still feel mushy to me.  I have SS line running so I know that is not the issue.  I get plenty of rear stopping power since it can easily lock up the rear tire, but because it is mushy its hard for me to gauge the amount of pressure I should apply.  The bike is a 91 with 6K miles. 

Can it be something wrong with the rear master cylinder or is the rear brake just mushy?

Thank!
Title: Re: Mushy rear brake
Post by: Kookas on August 10, 2018, 01:42:00 PM
How many revolutions does your rear wheel make when you get the bike on the centre stand and give it a good spin?
Title: Re: Mushy rear brake
Post by: f155mph on August 10, 2018, 08:38:09 PM
I don't know.  Why you ask?  That said I was cleaning the chain the other day and I noticed when I was rotating the wheel there seem to be tight spot.
Title: Re: Mushy rear brake
Post by: Watcher on August 10, 2018, 09:51:30 PM
When I was having trouble with the rear on my Ducati recently I went ahead and bled every fitting.  Bled the banjo on the master, the banjo on the caliper, and finally the bleeder screw.
There may be a small pocket of air somewhere that just won't get out.
Title: Re: Mushy rear brake
Post by: sledge on August 11, 2018, 03:12:20 AM
Unlike the front the rear brake mechanism has several pivots, clevises and pins.

I would check the mechanism and and all linkages carefully for wear, any significant play in these parts could give rise to the condition you describe.

Lube everything with grease while it's apart.
Title: Re: Mushy rear brake
Post by: f155mph on August 13, 2018, 07:33:19 AM
How much free play should there be on the rear pedal before the brake is engaged?

Thanks
Title: Re: Mushy rear brake
Post by: sledge on August 13, 2018, 10:58:12 AM
EK to ER =47mms
ES to EY =55mms
K1 and on =55mms

Measured between the top of the foot rest and the top of the rubber sleeve on the brake pedal.


Courtesy of Haynes.