OldFart Posted September 13, 2018 Share Posted September 13, 2018 I just picked up a 1998 VFR800 two weeks ago and today the brakes virtually locked up on me as I was pulling into my drive after a long hot ride. I say virtually as I was able to use the motor to muscle the bike up the drive but the brakes were so tight I could not push the bike in any direction without engine power. (At this point I am realizing that I should have tried to get it on the center stand so I could tell if it was one wheel or both, duh!) As they cooled they gradually released a bit. I had noticed on earlier rides a little dragging after a ride but assumed that was normal as I have had the same feeling with other bikes, and today it was way worse. I have the mechanical sense of a 9 year old girl so any help or advice would be much appreciated! Link to comment Share on other sites More sharing options...
Member Contributer JZH Posted September 13, 2018 Member Contributer Share Posted September 13, 2018 Probably something to do with the linked brakes and the secondary master cylinder or proportioning valve. Time for a fork swap! Ciao, JZH Link to comment Share on other sites More sharing options...
OldFart Posted September 14, 2018 Author Share Posted September 14, 2018 57 minutes ago, JZH said: Probably something to do with the linked brakes and the secondary master cylinder or proportioning valve. Time for a fork swap! Ciao, JZH Ahhh...any other suggestions? Link to comment Share on other sites More sharing options...
Lee 2002 Posted September 14, 2018 Share Posted September 14, 2018 You really don't provide any information that is useful for diagnosis other than brakes not releasing. If it was me, and things were locked up I would: Determine if the symptoms are universal, rear only, front only or (if you have the ability) front left, or front right Depending on which, systems were affected, I would start at the master cylinder(s) for that system and crack open the lines to see if the calipers release If they do release, rebuild that master cylinder As mentioned above, the linked system bikes have multiple master cylinders and a proportioning valve that isolates the systems. Work your way down the system to the caliper to see if the affected calipers release I once had a girlfriend who had a car with a bad hose at the wheel that functioned like a check valve and would not release the caliper If cracking the system doesn't release the affected calipers, investigate the pins that allow the calipers to float If the pins are floating, investigate the pistons in the calipers for cleanliness. (This is actually the most likely cause, but not where I would start) Your best bet would probably be to just do a system rebuild since you don't know the history. (The bike is 20 years old and needs it anyway) In the great scheme of things, brakes are very forgiving to abuse and it takes quite a bit of neglect for them to fail. Be honest with yourself, if you don't have the mechanical skill to do this take your motorcycle to a competent mechanic. Link to comment Share on other sites More sharing options...
Sweeper Posted September 14, 2018 Share Posted September 14, 2018 Moisture causing the pistons to expand from the heat? Time to change fluids and inspect calipers and master cylinders. Maybe.Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
GreginDenver Posted September 14, 2018 Share Posted September 14, 2018 Stop, Wait, Hold on for a moment... there might be a really easy, simple explanation for this situation. And it's an easy thing to check (just by looking at the front brake lever on the right handlebar) When people mess with the front brake lever on the VFR800 (like when they take it off to service/rebuild the front brake master cylinder) they sometimes put the plunger in backwards. I'm talking about the golden-colored piece of metal that transmits your hand-force between the "cup" on the inside of the front brake lever and the front brake master cylinder piston. When this piece is installed backwards it sets up a situation where the pressure from braking the bike cannot properly bleed off when you release the brake lever, so the pressure builds up (bit by bit) and locks the brake just as you described. I'm referring to part number 13 in this picture. If it's properly assembled it will look like this: You will be able to see the tapered portion of the part. If it is installed backwards you won't see any taper on the part. Link to comment Share on other sites More sharing options...
OldFart Posted September 14, 2018 Author Share Posted September 14, 2018 Outstanding. I will check it first! Thanks, Bill Link to comment Share on other sites More sharing options...
GreginDenver Posted March 23, 2019 Share Posted March 23, 2019 3 hours ago, Mac Morgan said: PS I don’t think the the pin on the front brake lever is the problem! . Well now, that's an interesting opinion you have there. Funny that the Original Poster on this thread replied, "Outstanding. I will check it first! Thanks, Bill" to my suggestion that it just might possibly be something as simple and easy to correct as a mis-assembled brake lever. And this reply was made on September 13, 2018 which is now 6 months ago and he never returned to say that he hadn't been able to solve the problem. Whether the cause of the problem was actually a mis-assembled brake lever or something else, doesn't really matter, it seems that the Original Poster was able to sort the bike. Link to comment Share on other sites More sharing options...
Member Contributer Egg on Leggs Posted March 23, 2019 Member Contributer Share Posted March 23, 2019 It the discs are getting that hot they will exhibit a blue hue. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.