KarlS Posted March 15, 2009 #1 Posted March 15, 2009 A month ago I posted how after bleeding brakes on the 83 Venture the brakes locked up on the test drive and had no play in pedal. The bike is at a friends and he just got back from 3 weeks in Florida so I got to work on it for the first time today. First I adjusted the brakes so I had free play in the pedal. Took for test drive and after using the brakes twice the rear and left front locked up again. Took bleeder wrench so cracked rear caliper bleeder, released pressure and didn't touch brakes until I got back. Two or three hits on the brakes and locked up again. Now this time took a small hammer and tapped on master and brakes released somewhat. Now the master was already taken apart and cleaned. So I believe the problem is with master cylinder. So the questions are. Should the master be talking apart and cleaned again or should I look for another master cylinder? And is it agreed the Master cylinder is the most likely reason for the lock ups? Thank You.
Squeeze Posted March 15, 2009 #2 Posted March 15, 2009 Sounds like the Expansion Hole in the Master Cylinder is clogged. This can happen either mechanically by the Pedal adjusted wrong to no Free Play or the Pivot Point of the Pedal is sticking somewhat and ist releasing the Piston completly. If those Points are fine, you have to undo the M/C and clean the Expansion Hole.
Squidley Posted March 15, 2009 #3 Posted March 15, 2009 Sounds like the Expansion Hole in the Master Cylinder is clogged. This can happen either mechanically by the Pedal adjusted wrong to no Free Play or the Pivot Point of the Pedal is sticking somewhat and ist releasing the Piston completly. If those Points are fine, you have to undo the M/C and clean the Expansion Hole. I agree with Lutz 100% I had the same thing happen and the inside of the master cylinder was clogged. I have also seen the freeplay in the petal too cause this, those are the most likely culprits.
bongobobny Posted March 15, 2009 #4 Posted March 15, 2009 I will be the third to agree with this! Another possibility could be that there is a nasty ridge on the cylinder wall and should be honed out. Also, I would assume that when you took it apart, you installed a new rebuild kit. The fact that tapping freed up the brakes suggests that some kind of stickage is preventing the piston from returning to the "Home" position. As mentioned, make sure those 2 little holes, especially the one that has the countersunk area, are clear and free. If you reused your old sealls, hopefully you did not soak them in solvent as that makes the seals swell and increase in size. If that is the case, bake them for about 10 minutes at around 200 deg F...
5bikes Posted March 15, 2009 #5 Posted March 15, 2009 There is a vast amount of sludge inside both top and bottom (master and slaves). They are a closed system but dirt and water eventually get inside. I have cleaned many master and slave/wheel cylinders and all over 5 years are dirty and corroded. Water oxidizes the aluminum and makes the pistons seize or move slowly. I have flushed my 84 clutch 4 times in 8 months and finally rebulit the slave cylinder. Brake and clutch systems work on the same principle. Personally I believe the slave and brake cylinders are more at fault. But make sure the 2 small holes in the masters are not plugged.
KarlS Posted March 15, 2009 Author #6 Posted March 15, 2009 I have free play in brake pedal. I did not use a rebuild kit when master was cleaned before. I'll see if I can find a rebuild kit and take this thing apart again. Brakes and headlight are the last things left to do and then it's road ready. Headlight just quit working, I've been reading the posts about 1st gen headlight problems and will try the tests and fixes. Thanks for the in put.
KarlS Posted March 18, 2009 Author #7 Posted March 18, 2009 (edited) Getting back to brakes on Thursday, like I said bike not at my house so have to go whenever friend home during the day. Wish me luck. Edited March 18, 2009 by KarlS spelling
skydoc_17 Posted March 18, 2009 #8 Posted March 18, 2009 Hey Karl, Try Flatout Motorsports Here's the link: http://www.flatoutmotorcycles.com/ Better yet, call Chris at 765-342-6335. He works at Flatout and be sure to tell him that you are a VR.ORG Member and he will fix you right up. Best prices I have found for OEM parts. Earl
CrazyHorse Posted March 18, 2009 #9 Posted March 18, 2009 A month ago I posted how after bleeding brakes on the 83 Venture the brakes locked up on the test drive and had no play in pedal. The bike is at a friends and he just got back from 3 weeks in Florida so I got to work on it for the first time today. First I adjusted the brakes so I had free play in the pedal. Took for test drive and after using the brakes twice the rear and left front locked up again. Took bleeder wrench so cracked rear caliper bleeder, released pressure and didn't touch brakes until I got back. Two or three hits on the brakes and locked up again. Now this time took a small hammer and tapped on master and brakes released somewhat. Now the master was already taken apart and cleaned. So I believe the problem is with master cylinder. So the questions are. Should the master be talking apart and cleaned again or should I look for another master cylinder? And is it agreed the Master cylinder is the most likely reason for the lock ups? Thank You. Did you bleed the left front air can get trapped in that line.
Yammer Dan Posted March 18, 2009 #10 Posted March 18, 2009 Flushing that system may clear it and get air out.
mraf Posted March 19, 2009 #11 Posted March 19, 2009 Do not overfill the master cly. Brake fluid will expand when bike warms up and apply themselves slowly. Don't ask how I know. No amount of cleaning will fix the brakes if master cyl is pitted. Good advice above on the other posts. For piece of mind I would buy another master. Bleeding the brakes on a 83 can be hard especially since there is not a place to bleed fluid at the highest point by the steering head. The 86 and newer ventures placed a bleed screw there. If I still had my 83 I would have done this upgrade just to make the process easier.
KarlS Posted March 19, 2009 Author #12 Posted March 19, 2009 (edited) Yes bleed L- front, flushed fluid, and leaving fluid about 1/2" low for expansion. Hope its that cleaned master before flushing and got something in it again. No problem bleeding with vacuum bleeder. Taking master apart tomorrow to check and clean again. Will post tomorrow with results. Edited March 19, 2009 by KarlS added contant
KarlS Posted March 19, 2009 Author #13 Posted March 19, 2009 (edited) That did it, re-cleaning master cylinder took care of the brakes locking up. I think now that they are working I'm changing all the pads because I really smoked them a few times getting them working. Tomorrow pulling CMU to see if I can get the headlight working. Close to riding time. THANKS for all the help. Edited March 19, 2009 by KarlS spelling
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now