Front Brake Problem

[Pezman4200]

I've been in the process of getting a 91 FJ1200 back on the road. It sat for 11+ years and I've done a bunch of stuff already to get it road worthy.
Today, while riding (not too far just a few miles) front brake started to lock up. So much where the lever was Rock solid and barely could move bike. Pulled off into parking lot and accessed. Ended up loosening bleed screw on right side caliper and spewed fluid. Did same to left no fluid came out. (I was just trying to release pressure of brake)  Once I relieved pressure wheel spun freely and I was able to drive home.  I did use brake as I got closer to home and it seemed to work ok and never locked up again.

Has anyone ever had this happen?   I have purchased but not installed new front brake lines yet.

[aviationfred]

I would say that a rebuild of your calipers is in order. Or replace them all together with a set of blue dots.

Randy had rebuild kits available at RPM and blue dots are easily available on eBay.

Fred

[Pezman4200]

I've never done a rebuild of a caliper. Is it easily done? 

On eBay, are blue dots sold for FJ1200?  Or am I looking for them off another bike?

Also? I've been reading that with older / dirty lines that the pin hole that allows fluid back into master could have been blocked. Any thoughts on that? 

[simi_ed]

Blue dots or gold dots from a YZF600 or YZF1000.  Don't buy the later Radial mounted type and/or 6 piston model.  They WON"T FIT!  Far better deal than a rebuild.

[FeralRdr]

In regards to the 'pin hole' getting blocked: yes, that is quite often what causes the brakes to lock in this manner.  The 'pressure relief port' (not sure the proper term for it) in the master cylinder reservoir can get clogged by debris in your brake lines.  That debris can come from either your brake lines delaminating (deteriorating from the inside), or grit being pushed up into your lines from a dirty caliper piston being squeezed back into the caliper.  If you take the cap off your brake master cylinder and look at the bottom of the reservoir, you will see two holes.  The smaller hole is the 'port' (pinhole) we are talking about.  The best way to check if this is the culprit, is to have the brakes lock up again, but if this can't be done you can look for other indicators, such as the condition of the brake fluid: Is it opaque or dark colored, does it look like there is something suspended in it?  is there any black colored debris in the bottom of the reservoir? If any of these conditions exist, you very well may have encountered a clogged port.  Unfortunately, you may not be able to confirm it unless the brakes lock up again.  If you can get them to lock up again, you can verify that this is the culprit by trying to clear the port with a bristle, from a metal bristle brush.  Using a pair of needle nose pliers and a pair of wire cutters, snip off one of the bristles.  I use the needle nose pliers to hold on to the bristle while doing this.  Next push the bristle down into the smaller hole (port) and move it in and out a few times.  If the brakes are locked, you may feel a 'pop' as the pressure is released.  In any event, if you remove the clog, the brakes should unlock.  The fact that the brakes unlocked when you loosened the bleeder valve reinforces the suspicion that the port was clogged.

Now what to do about it.

I would recommend a full brake system rebuild: master cylinder, brake lines (hopefully your new ones are steel braided), and calipers.  If the debris is coming from your old lines delaminating, then replacement of the lines is absolutely necessary, and should solve the problem.  If there is debris in your system, you will want to make sure that you clean it out of the whole system as well, thus rebuilding the master cylinder and the calipers is highly recommended.  Since your going to have to take them apart to properly clean them, you might as well get rebuild kits and be done with it.  Rebuild kits will provide you with a complete set of fresh seals that will leave you with a brake system you should not have to worry about for the foreseeable future. 

[Pezman4200]

I have not taken anything apart yet.  Need some time to do this.
The bike has been sitting for many years and if the back brake fluid is any indicator of what the front will look like when I drain it, well, it wont be pretty.  I just finished up doing a GSXR wheel swap and new brake line in the back.  Drained and flushed out rear master cylinder and installed a new braided line.  YES, I did get braided lines for the front too. 
I have ridden the bike a handful of times and this is the first (and only) time this has happened.  I am going to clean out the front brake system, replace the brake lines and see what happens.  Im sure more than likely I will end up rebuilding the master, and both calipers.  Im just looking to get me by for a little while as ive been spending a fair amount of $$ relatively quickly on this bike so far.

I see prices all over the place for Blue Dots ($10 each to 100 for set) .  What should be an average price I should expect to pay and is there anything I need to do to them before installing on my bike?  Also, is there a group of years i should be looking for?

Thanks for all the help.

[ribbert]

I have not taken anything apart yet.  Need some time to do this.
The bike has been sitting for many years and if the back brake fluid is any indicator of what the front will look like when I drain it, well, it wont be pretty.  I just finished up doing a GSXR wheel swap and new brake line in the back.  Drained and flushed out rear master cylinder and installed a new braided line.  YES, I did get braided lines for the front too. 
I have ridden the bike a handful of times and this is the first (and only) time this has happened.  I am going to clean out the front brake system, replace the brake lines and see what happens.  I'm sure more than likely I will end up rebuilding the master, and both calipers.  Im just looking to get me by for a little while as ive been spending a fair amount of $$ relatively quickly on this bike so far.

I see prices all over the place for Blue Dots ($10 each to 100 for set) .  What should be an average price I should expect to pay and is there anything I need to do to them before installing on my bike?  Also, is there a group of years i should be looking for?

Thanks for all the help.

If you're looking for some "FJ fiscal respite" there is no need to do a stem to stern reco on the brakes. The advice you're getting is good but involves a lot of spending. You had a one-off event that at this point seems to have resolved itself, one that is most likely related to long term storage. It is unusual to have a multiple component failure (although occasionally one can have a knock on effect). Simply replacing everything is the ultimate fix but at this stage it's an unwarranted expense.

A failure in the braking system can usually be traced to one problem. Many bikes, unlike cars, spend long periods of time unused and this can cause many issues when returned to service. I would not be surprised if this didn't happen again. If it does, the problem will most likely be as suggested, the master cylinder.
I would leave the calipers alone unless there is some specific need to play with them. When the brakes are applied and released nothing actually slides. The piston 'rolls' on the seal so there is virtually no wear taking place. I have seen plenty of calipers do up to a million kilometres (on a cars) untouched. Flush the old the fluid out if you want, bleed them and they should be good to go. They are one of the most trouble free components on the bike.

The front and rear brakes on my bike are both second and and of unknown age or mileage. I just bolted them up, bled them enough for a complete fluid change and have never given them another thought.
That was probably 50,000 kms ago, although I have changed the fluid once of twice.

Forget about the Blue Dots, Gold Dots, Polka Dots, you have late model 4 piston calipers already. Some claim they give improved braking, some say it's a load of codswallop, either way it's unlikely to address your problem.

The reason you only got a squirt from one bleeder was that it released the pressure and both sides are fed by the same line.

All good advice you've given but if you just want to get it on the road, wait and see if it happens again, if so, just fix the offending part and worry about all the upgrades and fancy new bits later when the coffers refill.

Noel

[Pezman4200]

Took bike back out today.  Have not had the time to replace lines yet just wanted to see if it was going to do the same thing again. 
Rode for about 5 miles......... no issues.  Did some hard braking to test, working fine. 

I do plan to R&R Brake lines, clean master and replace all fluid before any major riding.  (just need time)

[Capn Ron]

I like this guy's approach to servicing the front brake calipers:

http://www.youtube.com/watch?v=tUyGTvLDrt4&list=PLAQ0_LN9NlXrMjhjmHcvAmrYV5tyYi1su[/img]]

[red]

Took bike back out today.  Have not had the time to replace lines yet just wanted to see if it was going to do the same thing again.  Rode for about 5 miles......... no issues.  Did some hard braking to test, working fine.  I do plan to R&R Brake lines, clean master and replace all fluid before any major riding.  (just need time)

Pezman,

Brake fluid absorbs water from the air; that's normal enough.  When the brake fluid gets old, or if the container is left open a while, the brake fluid then carries water.  Hot brakes can boil out that water.  The boiling water makes steam pressure, and this pressure applies the brakes. The brake lever gets "rigid" and the brakes can not be released (without using a wrench on the bleeder).  More heat happens as you drive, which makes more pressure, and the brake will lock up the wheel, at some point.  You vented the steam pressure when you opened the bleeder.  There will be more than enough water carried in the old brake fluid for a repeat performance.  I would not ride the bike anywhere (not even a short ride) until all of the brake fluid is replaced with new, clean brake fluid (check the manual, for the right DOT spec brake fluid).  Use paper towels to remove as much of the old brake fluid from the master cylinder as you can, before you begin the brake bleeding process. Before you begin the bleeding, that would be a great time to install the new brake hoses as well, but all new brake fluid is the big priority.

Cheers,
Red

[Capn Ron]

Sorry...try this link:

Motorbike brake calliper servicing

[Pezman4200]

Well, that didn't go so smoothly!!!

Decided to do the brake lines and fluid change today.  Removed all old lines and routed new lines.  (went from 3 line system to 2 lines, both from master to calipers)  Took off Master and drained fluid and cleaned the inside of the master with brake cleaner.  There is two holes in the bottom of the master.  Are they both supposed to flow?  I assume one is pressure out, other release pressure back to master?  no?  Let me know if I'm not thinking this correctly. 
Anyway,  after reinstalling i couldn't get brakes to bleed.  Took master apart again re-cleaned inside and blew some air through.  I have not rebuilt master because I didn't have parts and i really don't know how  to.   (my gut says its not that hard but I'm not really sure where to begin.)

Well, after too much time, and taking it apart too many times I think I may have done something to the master.  Would Brake cleaner ruin any seals or would shooting air through it cause damage? 
Where I'm at now is I finally got brake fluid to to though line but and too the bleeder but i cannot get any sort of pressure on the lever.  Im going to see if i can get a rebuild kit locally but can somebody tell me  "how do i rebuild the master".  Is there a video or detailed photo explanation anywhere?   Ive searched but came up empty. 

Thanks

[Fj.itis]

I doubt there is anything wrong with your master, to check just run one of your hoses back on itself directly to the master ( not connected to brake calipers at all) . To bleed just crack the banjo bolt the same as you would the  nipple. If you get pressure , ( and you will pretty quick ) then your master is fine you just need to get all the air out of your system.

Warning.... When opening the banjo fluid is going to spurt out so cover everything you dont want to get ruined.

Are you bleeding with the cap resting on the master or the cap screwed down tight? I usually bleed with the cap just resting.

[andyb]

You likely had a bit of debris in the master plugging the return.  It's still there, possibly floating about someplace.  If nothing else, give it a good flushing and get fresh fluid in there.  A rebuild on everything wouldn't hurt, certainly, but isn't entirely necessary--for this issue.  Odds are the whole system could use some attention from age alone, though.

[ribbert]

Well, that didn't go so smoothly!!!

When you dismantled the m/c, did you remove and refit the piston?

Noel