[b.pete]

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The front brake lever does not return fully when released. It is so low that the brake light will not shut off unless I hold the lever open.

I'm changing the pads this weekend if they arrive in time and plan on chaning the brake fluid at the same time. Should this cure my problem or is it possibly time for a master cylinder rebuild?

 

[Frenchy]

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My money would be on the master cylinder!!

Worn shoes won't cause this type of problem......... You brake lever return is via a spring in the master cylinder. A good flushing with fresh fluid might do the trick, but she'll probably need a rebuild.:?

 

[SilverDave]

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  I had a front brake on my old SilverWing that did that ....It probably is time for a Master Cylinder  cleaning, at least../forums/images/emoticons/emoticonsxtra/grinner.gif. an amazing amount of gunge gets  into the  resevoir... Drain the resevoir, almost all the way, clean out the sediment with  a (disposable ) cloth... then bleed the brake line really well.. till it runs clear. Sometimes pushing fluid backwards up the  lines brings up some stuff too  (MityVac)  .. You might want to disassemble the hand lever, and clean around in there , too../forums/images/emoticons/emoticonsxtra/goofygrin.gif. These things will take almost no time... and if its still sticky...   then a new master rebuild .. SilverDave /forums/images/emoticons/emoticonsxtra/cooldj.gif

 

[exavid]

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b.pete wrote:

The front brake lever does not return fully when released. It is so low that the brake light will not shut off unless I hold the lever open.

I'm changing the pads this weekend if they arrive in time and plan on chaning the brake fluid at the same time. Should this cure my problem or is it possibly time for a master cylinder rebuild?

First I'd take the lever off and clean the old gease out and reassemble, it might not be the master cylinder spring, it could be a gummy pivot bolt.

 

[b.pete]

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Oh it's not the bolt. The lever moves freely. Looking at the rebuild kits I see the spring. If that's supposed to take up all the slack then it's stuck or broken or something. Can it be removed without having a kit? I don't want to destroy some gasket that I don't have.

 

[exavid]

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b.pete wrote:

Oh it's not the bolt. The lever moves freely. Looking at the rebuild kits I see the spring. If that's supposed to take up all the slack then it's stuck or broken or something. Can it be removed without having a kit? I don't want to destroy some gasket that I don't have.

The spring is there to push the piston back for another stroke after the lever is released. If you take it apart you should have the kit to replace the seals. Most likely the spring is okay, it's probably a swollen seal.

 

[GWEddie]

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I don't think a bad spring will do this. I always thought the brake fluid itself made the lever pop back and a blocked vent in the master cylinder would be the problem, apart fropm of course a seizing pivot.

 

[exavid]

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GWEddie wrote:

I don't think a bad spring will do this. I always thought the brake fluid itself made the lever pop back and a blocked vent in the master cylinder would be the problem, apart fropm of course a seizing pivot.

It's probably not the spring, most likely gump in the master cylinder or swollen seals making for too much friction for the piston to return after you let go of the lever. With disk brakes there are no springs in the brakes to push the fluid back to the master as there is with drum brakes, when you let go of the lever the pistons relax their pressure on the disk, but they do not retract back into the caliper like brake shoes do in drum brakes. I'd advise a master cylinder rebuild kit and a fluid flush along with the new pads and new caliper pistons seals.

 

[b.pete]

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Yeah that will definately fix it. The rebuild kits are pretty cheap and I got the pads yesterday. Looking at the bike this AM I find the lever all the way out and firm. I pull it and it doesn't return so I just lay my hand on the lever and can feel it coming back out slowly. The fluid is dark and I think it'll free up with a flush but I'm going to get a kit anyway.

Buying parts for this bike is a PITA. I can't seem toget everything I need for a project from one source. I can get pads for a good price from one place but they don't have the rebuild kit. Another place has the kit but the pads are twice as much. Looking for a carb sync and adjusting tool is the same deal. Tune up parts. Can't get plugs and oil filters reasonably from the same supplier.

It's not that I want one stop shopping but I'd like to find a couple of suppliers in CA where I can get most common stuff.

 

[exavid]

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Just be glad this is not in the days B.I. (BeforeInternet) imagine trying to find those parts then.

 

[b.pete]

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Put the new front pads on this evening. Once I got it pumped back up the problem with the lever is gone. I'm thinking I've got gunk in the bore and it was just sticking.I'm going to flush the system tomorrow and see how it is. I've got the rebuild kit coming but it'll be a week before it gets here.

 

[SilverDave]

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 Lets do the "Science "  of Zen and the Art of ...... If you put in new pads, the fluid has to go back into the resevoir , just a bit...  and it will stir around a bit with the other  fluid... and when you pump up the brakes ... the Sticky goes away ..... That tells me there is gunge in the top inch of the brake lines... I would  feel  you could do without the rebuild .. just clean,and flush the revevoir   Silver /forums/images/emoticons/emoticonsxtra/cooldj.gif

 

[GWNorman]

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I'd still do the rebuild asap. The swollen or gunged seal is probably just sitting in a cleaner spot now and will just be putting off the day of rebuilding anyway.

 

[b.pete]

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Well the kit is on it's way so there is no sense in not doing it. I agree though that it just had some crap in it and pushing fluid back throughthe system moved it around and unstuck the lever. I tend to be a little overly cautious with brakes and I'd rather haveit rebuilt unnecessarily then have brake problems while out riding.I haven't flushed it yet (been busy putting my Mustangs motor back together) but plan on doing that before I get the kit.

 

[exavid]

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Well if there's junk in the system and pushing it back with new pads cleared it, it's still there waiting to do it again. Needs a full flush and manual cleanout, good thing you've got a kit coming.

 

[b.pete]

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Well I flushed about 3/4 of a pint through it after I cleaned out the reservoir. Brake feels mutch better and it's not sticking. I need to be on the look out for other problems though. The fluid was black I hope there is no damage to the calipers or brake lines.