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Redneck
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9 Posts
Discussion Starter #1
Hi I recently bought an '86 VN750 for $600 with 23000 miles on it, after working on some electrical issues and getting the carbs cleaned and tuned the bike seems to run good.

The only issue I'm having is the front brakes seem to stick or drag some after being used. Normal pull on the lever and M/C full of fluid no spongy feeling, you can tap on the calipers with a rubber mallet and the free ride up until you use them again.

I've been told this can be cause by "dirty pucks" and that a simple rebuilding or cleaning of the calipers is all that's needed.

I have not yet done this.

While I'm very familiar with braking systems on a car I've never worked on bike brakes much. Just looking for a little insight tips or suggestions or even if I'm heading in the right direction.

Any help is greatly appreciated
Thanks much
 

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..have a vulcan good day!
Joined
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4,508 Posts
Hi I recently bought an '86 VN750 for $600 with 23000 miles on it, after working on some electrical issues and getting the carbs cleaned and tuned the bike seems to run good.

The only issue I'm having is the front brakes seem to stick or drag some after being used. Normal pull on the lever and M/C full of fluid no spongy feeling, you can tap on the calipers with a rubber mallet and the free ride up until you use them again.

I've been told this can be cause by "dirty pucks" and that a simple rebuilding or cleaning of the calipers is all that's needed.


I have not yet done this.

While I'm very familiar with braking systems on a car I've never worked on bike brakes much. Just looking for a little insight tips or suggestions or even if I'm heading in the right direction.

Any help is greatly appreciated
Thanks much
Drain, Clean, & Flush (new fluid worked for me).

After, ..... I had a problem w/bleeding the system (a day & a half), had to perform the drip over nite bleed, then was persisted w/ front brake lever not fully returning...which kept the brake light on....
discovered tiny hole (inside MC) return(air) hole was the problem, (difficult to see, it is located very close to MC fluid outlet hole). Cleared air hole, .....problem resolved.

PM me with questions...
hope this helps

:smiley_th

:smiley_th
 

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Super Moderator
Joined
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11,958 Posts
Doesn't sound like a bleeding problem to me, but as mentioned "dirty pucks".

The brake pads are pushed out by a piston inside of a cup. Dirt, brake dust and even rust can collect there preventing the piston from retracting smoothly.

Disassembly and cleaning is the cure. Many time you can do this without taking the calipher apart, which avoids having to re bleed the brakes.

You can try spraying some brake cleaner under the pads, but most times you at the least need to remove them to clean out the piston cups.
 

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ass hole extaordinaire
Joined
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3,780 Posts
Doesn't sound like a bleeding problem to me, but as mentioned "dirty pucks".

The brake pads are pushed out by a piston inside of a cup. Dirt, brake dust and even rust can collect there preventing the piston from retracting smoothly.

Disassembly and cleaning is the cure. Many time you can do this without taking the calipher apart, which avoids having to re bleed the brakes.

You can try spraying some brake cleaner under the pads, but most times you at the least need to remove them to clean out the piston cups.
x2 remove and clean and dont ride until you do i had it happen to me and the front brake locked up before i had stopped completely could have sucked bad if i was on the highway and they locked up
 

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Redneck
Joined
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9 Posts
Discussion Starter #6
I only rode it once using back brakes only and that was just to get it home from the local bike shop (I had some carb work done) I plan on working on it later today when the sun comes out better and I will let y'all know what the out come is
Thanks again
 

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FREEBIRDS MC CENTRAL NY
Joined
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16,222 Posts
Doesn't sound like a bleeding problem to me, but as mentioned "dirty pucks".

The brake pads are pushed out by a piston inside of a cup. Dirt, brake dust and even rust can collect there preventing the piston from retracting smoothly.

Disassembly and cleaning is the cure. Many time you can do this without taking the calipher apart, which avoids having to re bleed the brakes.

You can try spraying some brake cleaner under the pads, but most times you at the least need to remove them to clean out the piston cups.
my goldwing has to have the pucks cleaned if she sits for a while.(will have to it after i fix waterpump,as she has sat for a while)
 

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Redneck
Joined
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9 Posts
Discussion Starter #9
Alright guys, I ended up re-building M/C and both front calipers (boy were they dirty!)
Still having trouble getting all the air out of the lines but after re build (without kits) the brakes work great minus spongy brake lever due to air in the lines. Went on a cautious easy ride today (68 miles) and everything went great except my project is still on going because I learned that my bike is not charging properly (sat on side of the road for 30 mins with dead battery LOL) Thanks for all the help I'll go to appropriate forum for help with the charging system if needed. Thanks again Y'all
 

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Registered
Joined
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1,253 Posts
I have a question for y'all about dragging brakes. What does that feel like exactly? My bike felt kind of funny when I pull the front brake lever like maybe the pads were catching on a spot on the rotor. When I spin the front wheel with the bike on the center stand it sounds like it is rubbing, but it doesn't seem to slow the wheel a whole lot. In the Clymer manual it says that the pads should be touching the rotor so I'm not sure how it would not make a rubbing sound in that case.

At any rate, today I pulled both of the calipers and checked the pad thickness, I'm still good there. Also checked the rotor thickness and it is fine. I tried to check the run out on the rotor but I need to find some way to properly anchor my dial indicator to get an accurate measure, but I think it is fine. I also pulled the wheel and greased the axle and made sure it was torqued correctly. Anything else I should check? The lever doesn't feel spongy and has good pressure and it stops good. When I went riding after all of that it didn't feel like it was doing it anymore so maybe the lubing was all I needed.
 
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