stupid brakes!

[Striker]

Hey guys had somewhat of an issue occur. Yesterday rode to work and back with my front brakes and lever working just fine. This morning when I when I started up the fj and headed to work when I came to a stop the lever went all the way to the bars with very little effort. I checked the lines and no leak to hint at sudden pressure loss. Also fluid was a little low but not drastically. I bled the heck out of the lines and didn't see any bubbles but still no pressure at lever. I noticed the bleed nipples connected at anti-dive (yes I haven't gotten rid of yet ) I have lever tied to bar to leave overnight per suggestion I saw in another post. Any other ideas as to what may have happened and how to fix it? (I am saving for new braided steel lines and upgraded calipers but budget at moment is a little tight.) Thanks in advance for the help!!! (man i'm going to feel foolish if it's something idiotically simple after this long ass post!)    

[Dan Filetti]

Sure sounds like you have air in the lines.  Bleeding may/ likely will, not help (for long?) until you figure out how the air got in, in the first place.  If you see no evidence of a leak, then perhaps it's the master itself failing.  This would require a rebuild -pretty sure Rand has re-build kits.  Alternatively, it could be the calipers.  When was the last time you had them off for a clean and inspection?  This is worth doing anyway.

Good luck.

Dan

[Steve_in_Florida]

It's possible that your brake master cylinder is failing internally, allowing fluid to flow past the piston seals.

[Pat Conlon]

It's possible that your brake master cylinder is failing internally.....

...or another component of your ABS system.  Obviously, don't ride until you fix it.

[Arnie]

No question that some part of your system has failed.  If there's no leaks evident, my guess would be the piston seal in the master has ripped.

BTW Pat.... The bikes with AD didn't have ABS  just sayin :-)

Arnie

[Pat Conlon]

Ha! Thanks Arnie. I whiffed that one. Somehow I read anti dive and it registered abs....go figure. 

[racerman_27410]

I'm gonna go with failed seal in the master cylinder as well.... unless you can see fluid running out somewhere there isnt much else that could go wrong.


KOokaloo!

[Striker]

Thanks for the advice!! I going to guess then that my master cylinder has failed. I saw the clutch master rebuild kit on Randy's site. I assume the brake master is identical and rebuild is the same? Just to be extra sure I'm also going to have a friend who works at a bike shop take a look, as most of my mechanical experience has been working with cars. (Am learning more about working on the 85 and she's not to complicated but still nervous about relying on my own experience.)

[rktmanfj]

Probably isn't your main brake problem right now, but if you are riding with 26 year old OEM rubber brake lines, it's time to change them out, too.

Even if you don't want to modify/upgrade things, it's money well spent.

[mikeholzer]

I had something similar happen this last summer. I rebuilt my front master cylinder and all was well, but during my first full day of riding I had a similar problem occur; pull the lever and there was nothing. Turns out that I forgot to tighten the jam nut on the brake lever adjusting screw.

Dumbass on me, for sure. Check to see that the screw is engaging the plunger on the end of the M/C. Sometimes it's the simple things that cause the greatest problems.

[grannyknot]

Striker, I purchased a Brake M/C re-build kit from Yamaha for my stock M/C but since then I have upgraded to FZ1 M/C. You can have the re-build kit for the cost of postage. The members here have given me incredible
deals as well as free stuff so I gotta even the karma scales. Pm me if you want it.

[Striker]

Hey guys thank you again so much for the advice and help!! I hope to have this repaired and fixed asap! I would absolutely love to upgrade my brake system with braided steel lines and new calipers! (just taking a little while to get the money together.) Now I know this is not part of my original post but with regards to this about how much on average would the lines and calipers be? So I know how much I need to have. Also what better calipers bolt on to an 85 fj lowers, if any? This forum has been a huge help!

[flips]

Hi Striker.
( DISCLAIMER-I am no expert!.There are many others here with much greater experience and knowledge.I try and help if I can!)
I don't believe the clutch and brake master cylinder rebuild kits are the same(Someone will correct me if I'm wrong lol).I would warn against after market non yamaha kits as in my experience they are poor quality compared to the oem kits.If your going to upgrade the calipers on an 84 with anti dive this usually involves  upgrading to later model fj fork lowers to loose the much maligned anti dive units (these also can be disconnected) and provide the later model bolt pattern for the better later model four pot calipers (blue pots seem to be the preferred unit's) and 17" front wheel with the larger discs.The only four pot calipers that I'm aware of that will bolt on to the anti dive forks without adapter plates are off an 89 fzr400,but they are  hard to find and designed for 5mm solid disc's,so fitting them on the 7.5mm oem ventilated discs with new pads can be difficult!( I had to mill 1.5 mm off each pad to make them fit).The price of new braided lines can vary, from approx $150 to $300 depending on quality of materials (stainless/non stainless end fittings),how many hose's ( two- straight from the m/c to the calipers,three-the oem setup using one from the m/c to the oem splitter on the lower triple tree to the calipers or 4-5 retaining the anti dive units) and where you are.
Hope this helps!

Cheers

Jeff P

[fj11.5]

hi mate, i bought a set of calipers when i first changed my forks over , asked the seller for the measurments between the holes, gave me the right numbers for 84 forks but not fromthe right place, any way they are gsxr callipers nissin brand not sure what model they are off, can check for numbers if you want not sure if the disc would line up as i had changed forks but yes gsxr ones will bolt up to 16 inch forks

[fj11.5]

hi mate, i bought a set of calipers when i first changed my forks over , asked the seller for the measurments between the holes, gave me the right numbers for 84 forks but not fromthe right place, any way they are gsxr callipers nissin brand not sure what model they are off, can check for numbers if you want not sure if the disc would line up as i had changed forks but yes gsxr ones will bolt up to 16 inch forks

ps they are four spot