weak brakes

[Lucky]

i took the wifes brakes apart Wed & cleaned & reassembled & bled everything.

except for a slight fold on one lip of the outer seal on the caliper, & removed some garbage, everything looked passable.

pressure sucks & went thru a half a bottle of fluid bleeding them.

has anyone ever tried to 'narrow the culpret' by isolating parts of the system? for example i think if i pull the hose off the caliper & install plain bolts with the copper washers, that would eliminate the caliper & if i then have pressure it tells me the caliper is fubared...

gotta run the boss just walked in, lol

--Lucky

[Rikugun]

Lucky, I'll be following this post with interest as I have brake work ahead of me. Your suggestion sounds like a practical test but I can offer one comment. I have used a bolt and copper washers before. Not for testing, but rather to keep the fluid from leaking as I was working on a caliper. I found a puddle when I came back as the fluid had spiraled along the threads and dripped over time. The washer had sealed against the bolt head but not at the threaded end. Maybe some sealer or Teflon tape on the threads? Just a thought. It may be that any weeping by the threads is insignificant if your goal is just to determine if the master cylinder is developing suitable pressure?

Was the symptom preceding this work a spongy lever? Was there any evidence of leakage around the caliper piston? Did you remove the piston and how easily did it come out?

[Walt_M.]

Where did Tiffanator get the brake line? It could be a cheapo and flexing.

[Lucky]

the brakes were dry & empty when we got the bike.  i thought she did a rebuild kit, but there was gunk in the master so i guess not, the line is stock.

good point about the threads..

[supervision]

 I had the same problem, I did a search and found this idea, works easy. You start with a empty master clynder, and fill slowly from the bottom up.



 

[RedRocket]

I had the same problem, I did a search and found this idea, works easy. You start with a empty master clynder, and fill slowly from the bottom up.

 

I've serviced many moto brakes that way, but I've strangely had trouble doing that with some Yamahas.
I had an F1200 that I could never bleed well enough, and I was unable to do it on a Venture.  I had to buy Speedbleeders to do bleed that one. 

[YellowJacket!]

I know this sounds like a dumb question to ask the expert (Lucky), but are you running the stock rubber brake lines?  Bulge?  Weak spot? 26 year old brake lines?

David

[Lucky]

the brakes were empty, but not completely dry.  it's been a week & they feel no better, so if they were going to 'swell' they would have by now.  i haven't gotten a chance to get back to them, hopefully tonight...

dave has some calipers for me to pick thru too.

--Lucky

[Rikugun]

I forgot to ask in my last post: Any recomendations to source caliper seals? I see on Bikebandit they only seem to list the seals with the piston. I've seen master cylinder rebuild kits in Dennis Kirk put no caliper rebuild kits.

[RedRocket]

I forgot to ask in my last post: Any recomendations to source caliper seals? I see on Bikebandit they only seem to list the seals with the piston. I've seen master cylinder rebuild kits in Dennis Kirk put no caliper rebuild kits.

Check my New Old Vision thread.  a member in there posted a link to a place.  The caliper is the same as a rear caliper on an RZ350 which you can get without the piston.