Brembo brake conversion - help
Thread Starter
|
Cruiser
Joined: Jul 2008
Posts: 171
Likes: 5
From: Gifhorn, Germany
Brembo brake conversion - help
I changed on 2002 RKC to Brembo front brakes. Installation went ok, I bleeded the system and initially I had a real good pressure feeling in the lever. After moving the bike back and forth I am loosing the brake pressure. I get the pressure back after pulling the lever couple times. But when I move the bike again the issue is back.
What could be the problem? Perhaps the Piston of the master cylinder?
Looking forward to your ideas.
Frank
What could be the problem? Perhaps the Piston of the master cylinder?
Looking forward to your ideas.
Frank
Thread Starter
|
Cruiser
Joined: Jul 2008
Posts: 171
Likes: 5
From: Gifhorn, Germany
Can you explain me more why this could cause this problem. How much unbalanced can a rotor be? Is like 5 mm ( or less than 2/10 of an inch) to much?
Frank
Frank
Road Warrior
Joined: Nov 2008
Posts: 1,296
Likes: 3
From: Cheltenham, UK
Warped rotor sounds like a very good start point based on what you have described
When you have pumped the brakes a few times the pads are very close, if not in contact with the disk. Only a small movement of the lever is required to bring the brakes up to pressure
If the disk is warped, as you wheel the bike back and forth it forces the brake pistons back in to the caliper. You will then need a few pumps to get the pistons back out and in contact with the disk
When you have pumped the brakes a few times the pads are very close, if not in contact with the disk. Only a small movement of the lever is required to bring the brakes up to pressure
If the disk is warped, as you wheel the bike back and forth it forces the brake pistons back in to the caliper. You will then need a few pumps to get the pistons back out and in contact with the disk
Road Warrior
Joined: Mar 2009
Posts: 1,317
Likes: 14
From: Idaho
+1 on the rotor issue, but....
Stupid question, but are you sure no air in the line? Right amount of fluid? Did you cycle the caliper a few times before you installed them just to make sure there was movement ?
Stupid question, but are you sure no air in the line? Right amount of fluid? Did you cycle the caliper a few times before you installed them just to make sure there was movement ?
Road Warrior
Joined: Nov 2008
Posts: 1,296
Likes: 3
From: Cheltenham, UK
Bleeding is, agreed, the most obvious issue to be eliminated. The inference of the OP is that, without moving the bike, the brakes are fine. Worth double checking though
Trending Topics
Road Warrior
Joined: Nov 2008
Posts: 1,296
Likes: 3
From: Cheltenham, UK
Bit difficult to describe warping with text only using an iPhone, if you do a search on Google i am sure you will find dozens of graphic explanations
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
I use a Mity-Vac to bleed my brakes. It takes about 10-15 minutes to completely bleed both calipers on the front. You can pick one of the plastic bodied ones (sometimes branded as "OEM") at most auto parts stores for about 30-35 bucks. Much easier than trying to bleed manually.
Also, when you get brake pressure, hold the lever in and check all the fittings to make sure you're not leaking anywhere.
Before you start worrying about a warped rotor, check to make sure you don't have air still trapped in the lines. I think that's your culprit.
Also, when you get brake pressure, hold the lever in and check all the fittings to make sure you're not leaking anywhere.
Before you start worrying about a warped rotor, check to make sure you don't have air still trapped in the lines. I think that's your culprit.
Outstanding HDF Member
Joined: Jan 2010
Posts: 2,916
Likes: 31
From: earth
Is your rotor bent 5mm?