Issue with front brake 1995 R1100GS with ABS and sidecar attached

[miacuelli]

Hi,

I am having an issue with my front brake. 90% of the time when I apply the front brakes I get a good solid response from the brake lever / brake actuation. 10% of the time the Brake lever travels 2/3rd of the way towards the grip prior to actuating the brakes. I still get brakes towards the end of the throw but it is not great and it hits the grip.

Some background: I just bought the bike with approx 9000 miles on it. When I first noticed this problem I found out that my front brake master cylinder was leaking. I bought a replacement piston for it, honed the master cylinder bore out and put it back together. I spent some quality time bleeding it and it worked…. Until the same problem came back to haunt me. Since that point I have spent some serious quality time bleeding both front brakes and the ABS unit. I had some air come out initially and now I am just pushing clean brake fluid through the system. I have also checked the master cylinder and it is not leaking.

What is weird to me is that once I notice a lack of resistance when pulling the brake lever I let it go and when I pull it again I have full brakes.

Normally I would attribute this to air in the system but it is weird that it only happens once in a while.

I did check that both rotors are still “floating” freely for whatever that is worth

Any thoughts would be welcome

Cheers!!

 

[m_stock10506]

If you haven’t already replaced the original rubber brake hoses with braided stainless hoses, that’s what you need to do before you really can get much further with this. The original hoses would be nearly thirty years old, if they are still there.

 

[miacuelli]

If you haven’t already replaced the original rubber brake hoses with braided stainless hoses, that’s what you need to do before you really can get much further with this. The original hoses would be nearly thirty years old, if they are still there.

With the exception of the line coming from the master cylinder, the brake lines were swapped out with braided lines by the previous owner

 

[m_stock10506]

Pump the lever so that it is nice and firm, then wrap some rubber bands around the lever and grip so it is held in that tight and firm condition. Leave it that way overnight. This procedure has been shown to force trapped air out of the lines.

 

[miacuelli]

Pump the lever so that it is nice and firm, then wrap some rubber bands around the lever and grip so it is held in that tight and firm condition. Leave it that way overnight. This procedure has been shown to force trapped air out of the lines.

I’ll give that a go - thanks for your input!