[MDairheads] Brakes / Hydraulic hoses. An inquiery

[Aloha Charlie]

I agree. It doesn't seem to be a function of the brake hose to regulate how much fluid is returned to the MC. And you rebuilt the MC so there shouldn't have been any obstruction to the return hole. 

After all the previous work it seems that new hoses were just the thing needed. Maybe your bike was just trying to tell you something?

Were these OEM type hoses? I have heard the rubber in them collapses internally and shows little outward effects. That could be the explanation you are looking for. The more popular metal clad hoses today fail somewhat differently as I recall but I don't remember now exactly how that was. 

Charlie Wixson
1975 R90/6
ABC & MOA





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On Tue, 3/26/19, Bill Lambert via MDAirheads <mdairheads at casano.com> wrote:

 Subject: [MDairheads] Brakes / Hydraulic hoses.  An inquiery
 To: "Maryland Airheads" <mdairheads at mail.casano.com>
 Date: Tuesday, March 26, 2019, 8:40 PM
 
   Gentleman, Ladies,
 
   In recent efforts to sort out
 nagging brake issues, I have a question.  What causes
 old rubber brake fluid hoses to stop allowing fluid to
 return to the master cylinder reservoir upon releasing the
 brake lever ?  With the caliper and the master cylinder
 fully reconditioned, and new fluid pumped in, the brake pads
 only partially retract .  A small parentage of drag or
 squeeze remains. The wheel refuses to spin freely. 
 When the old hoses are tossed in the trash and new hoses are
 installed, compliance is restored.   I don’t get it.
 
 
   With 120psi blasted through the
 old hose, no obstruction is witnessed.  When the rubber
 hose is razor knifed into short sections, no crimp, kink or
 obstruction is obvious.  The ID appears
 consistent.  The old hose acts like a one-way
 check-valve.  Pressure is squeezed in, but fails to
 escape. 
 
   Any ideas.
 
    Bill.  
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