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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Solly on October 17, 2015, 10:40:17 AM

Title: Soft Stinking Pedal
Post by: Solly on October 17, 2015, 10:40:17 AM

Hey all! would like to throw out a question that I think I know the answer to already. Bled my brakes because of a soft low rear pedal and then I found a bubble that would present itself on the rear line to the ABS I unit under pressure. So I thought NO BRAINER replace the hose, bleed and go. But then the rear master started leaking. GRrreat. So I ordered a kit and have not installed it yet. What I wanted to know is do the ABSI units have the ability to bypass inside like I have seen on some automotive applications{ giving the feeling of a sinking pedal} ? I would hope not because it is somewhat rare autos and trucks.

Title: Re: Soft sinking pedal
Post by: johnny on October 17, 2015, 11:07:28 AM

greetings solly...

i have two eleven hundert motobricks... one has a very firm pedal from the get go... one has a soft pedal from the get go...

both gotts braided metal hoses... getts new fluid annually... bled a couple times a year... have good pads... and ridden often... donts know why they are different butts they are...

my old eleven hundert was neither 100% hard or 100% limp... it was more like 5/8 erect... on the brake side that is... it would power stroke day and night effortlessly...

to me... the main thing is will the abs engage immediately during full on braking... both of mine brake hard and engage the abs... just different pedal strokes...

j o

Title: Re: Soft sinking pedal
Post by: The Mighty Gryphon on October 17, 2015, 01:06:24 PM

Pull off the rubber boot on the end of the master cylinder.  When I did that on my bike I found a teaspoon of brake fluid that leaked past the seals.  Means you need at least a rebuild or worse, a new or relined master cylinder. 

Thanks for reminding me.  I have a freshly relined cylinder that I need to install this winter.  Have to put it on the work list.

Title: Re: Soft sinking pedal
Post by: Solly on October 20, 2015, 09:04:14 PM

Thanks wasnt sure if it would be that simple. They rarely are in my world.

Title: Re: Soft sinking pedal
Post by: The Mighty Gryphon on October 21, 2015, 10:20:50 AM

With the master cylinder being the lowest point in the rear brake system, it makes sense that any water is going to collect there and corrode the junk alloy master cylinder body.   This is what makes annual fluid flushes mandatory for at least the rear.   


 I had a reline done with a brass sleeve that should easily outlive even my offspring.  There are places that will do stainless sleeves, but IMO that is overkill.

Title: Re: Soft sinking pedal
Post by: Tuco on October 22, 2015, 01:30:18 AM

Gryph, what is the inner diameter of the rear brake master cyl. This sounds worth doing!

Title: Re: Soft sinking pedal
Post by: The Mighty Gryphon on October 22, 2015, 01:02:36 PM

It's 12mm on my '94 RT.  These are the guys that did mine.  Two week turnaround.

http://applehydraulicsonline.com/pages/motorcycles-1

If you do have them do it, make sure you remove the plastic cap that has the hose to the reservoir barb on it.  It prys out with a couple of knife blades.  I didn't and they chewed it up a bit pulling it off.  It still works, it just looks like shit.