Kawasaki VN750 Forum banner

1 - 12 of 12 Posts

·
CWO3 Navy (Retired)
Joined
·
722 Posts
Discussion Starter #1 (Edited)
Need advice: My front brakes seize after about 50 miles or so or riding, and using the front brake sparingly. So, after posting my first plea for help and doing what was suggested; I'm back with the same problem. Here is all that I have done so far:

1. Rebuilt both calipers, new pistons and seals.
2. Installed speed bleeders
3. New brake hoses (all 3 of them)
4. New rotors
5. New pads (OEM)
6. Rebuilt master cylinder with new pistion, spring, seals.
7. New DOT 4 brake fluid (several times over)

I have ordered new union bolts for all the hoses; short of buying new housings for the calipers and master cylinder, I've replaced everything else.

The brake is firm with little play, pads don't rub. Still pressure builds and the calipers grab the disc and I slow to a crawl. Let off the pressure and I'm riding again.

Any suggestions?
 

·
CWO3 Navy (Retired)
Joined
·
722 Posts
Discussion Starter #3
Thanks, looks like another fun evening of taking it down. I have ordered a new cap, why not I replaced everything else? I'll update after I put in the new union bolts and cap.
 

·
Old Truck Junkie
Joined
·
4,133 Posts
The pressure is between the master cylinder and the calipers or the lack of vent in the whole system causes the pressure.
 

·
CWO3 Navy (Retired)
Joined
·
722 Posts
Discussion Starter #5
Thank you, I'm hoping that the new union bolts will help. The original ones are still on the bike. It pretty much sat for about 10 years with only being started from time-to-time. When I got it I had the carbs serviced, I cleaned the tank, and now I'm on the brakes and I'm oh so close. If the new unions don't work I'll break down and buy a new MC but I'm hoping this will do it. I have a solid brake right now, a little too solid but I have nothing to compare it to so it may just be normal. Rode tonight and no lock up, I may just be there and don't know it. Again thanks for responding, I love this forum, I'm learning an awful lot.
 

·
CWO3 Navy (Retired)
Joined
·
722 Posts
Discussion Starter #6
One last thought, any chance it could be the brake joint where the hoses all come together? That's the only part I haven't replaced. I'll clean it good when I replace the union joints, just a thought.

Tks
 

·
CWO3 Navy (Retired)
Joined
·
722 Posts
Discussion Starter #7
Solved the Brake Seizing problem.

PROBLEM SOLVED. Lesson to be learned, count your washers! It takes 11 to do the entire system from master cylinder to the calipers. The problem was the union bolt for the right caliper. I had 2 washers ahead of the brake hose, which put the hose opening over the threads and not the opening in the bolt and that caused pressure to build and not get released. :beerchug:
 

·
CWO3 Navy (Retired)
Joined
·
722 Posts
Discussion Starter #8
Hopefully last update, the washer issue was definitely a problem but not the last word so I found out. While I didn't seize anymore, I did have too much pressure at the lever. After reading the forum again I learned about the pinhole in the master cylinder that can get clogged, and sure enough it was. I used the smallest sewing needle I could find to carefully work the opening until it was clean. The brakes are finally normal. Long ride today and they were great. Thanks to everyone who posts on the forum, you helped me out!
 

·
Premium Member
Joined
·
2,850 Posts
Interesting....and some real good info for anybody picking up a bike that's been sitting. (not just a Vulcan either)

Glad you got past that problem, these are pretty nice bikes once you get all the kinks worked out.
 

·
Registered
Joined
·
135 Posts
It's good to know the washers are that critical.I had replaced all mine with new when I replaced the cylinder.I didn't mess with the pinhole as my instructions stated that you should not try to clear it with a wire or any thing that might enlarge it's diameter.
 

·
CWO3 Navy (Retired)
Joined
·
722 Posts
Discussion Starter #11
I read the same book, but desparate times call for desparate measures so I took a chance at it. You really only need to work the point of a needle into the very opening and twist it a little, then try the brakes, do it again until you see it start to clear. Since doing mine the brakes have been GREAT! You wouldn't think one washer would make that much difference, but it certainl did.
 

·
Linkmeister Supreme
Joined
·
7,960 Posts
I read the same book, but desparate times call for desparate measures so I took a chance at it. You really only need to work the point of a needle into the very opening and twist it a little, then try the brakes, do it again until you see it start to clear. Since doing mine the brakes have been GREAT! You wouldn't think one washer would make that much difference, but it certainl did.
Your story reminds me of a lesson I learned while building my house 30 years ago. Namely, measure twice (sometimes 3 times) and cut once. From your experience I guess we learn to check and recheck when reassembling anything on the bike. Thanks for sharing and glad you found the problem and were able to fix it before it caused an accident.:smiley_th
 
1 - 12 of 12 Posts
Top