Crush washers for front brakes (and master cylinder)

[yosso]

After getting my "new to me" front brake system installed (2005 S2R800 dual discs) I've been unable to bleed the system completely.  I've tried the conventional approach, the Mity-vac approach, and the keep the brake lever squeezed overnight (man, was I tired the next day  ).  Still no luck.  So I got to thinking, can the copper crush washers not be sealing and should I be using aluminum crush washers?

Bike specs: 2000 M750 with a 2005  S2R calipers and master cylinder (big black coffin style).

Thanks for reading.

Mike
My Monster Blog

[booger]

You could anneal the copper washers, then lap them a bit with some 600 grit and reuse them and be fine. That's what I have basically always done with oil drain plug washers on my cars if the filter kit didn't come with a new copper crush washer. By all means use new ones though if you can locate them easily.
It might be that one of the washers is not quite sealing properly, who knows. if you've done everything there is to do to get your hydraulics bled and you still have air in the lines then I'd look at the banjo fittings for nicks or imperfections that could negate a proper seal. Then I'd get some new washers all around, or take some time to rehab the old ones. Then I'd fully inspect the masters and calipers for any leakage. If everything passes the test I'd button it back up and try try again. Using aluminum washers should work fine as well, but I'd think the copper ones would just be better. Just get some new washers and try again.

[ducpainter]

Copper is the correct material.

If there was a lack of sealing you would see a fluid leak.

Why do you say it's not completely bled?

Spongy lever?

[yosso]

I was using new copper washers (sourced from auto-parts store) all the way around.  I read on a website (www.bevelheaven.com) that aluminum crush washers should be used with the aluminum banjo bolts and the copper was for steel banjo bolts.

The lever goes all the way to the grip unless pumped several times.

I'm trying to source a single line banjo bolt w/a bleeder so I can bleed the master cylinder.  I did pump up the lever and tried to bleed via cracking the banjo bolt, but I'm not sure how successfully that worked.

Thanks again for the help.

Mike

[DarkStaR]

If there is an air bubble up near the master,
pushing the pistons back into the calipers
may force the air up. 
If you try this, keep an eye on the fluid
as it may overflow.

[yosso]

If there is an air bubble up near the master,
pushing the pistons back into the calipers
may force the air up. 
If you try this, keep an eye on the fluid
as it may overflow.

I'll give this a try today.  I had ordered some new aluminum crush washers, and a bleeder banjo bolt for the master cylinder, but they didn't arrive today. 

Anyway, I noticed last night that the crush washers on the original master cylinder and brake cylinder are about half the thickness of the copper crush washers...would the extra thickness not allow the hole in the bolt to align properly with the matching hole in cylinder?

Just curious.

Thanks in advance.

Mike

[DarkStaR]

I really don't think it's the crush washers.  As previously mentioned, if you don't see any fluid, it's most likely sealed.

The last time I bled my masters, the levers felt like crap until I got the air out of the masters...but I have bleeders at the masters.

It's not impossible to get the air out near the masters without bleeders, but you do have to be crafty. 

[dlearl476]

I'd say just keep pumping.  I replaced all my lines with new Galfers last winter and I used a pressurized pro system on the fronts, but I don't have a cap that fits the rear or the clutch and I swear I had to pump the clutch 700-800 times before I got any "pedal" at all.  And I still haven't gotten the rear to work for shit.
FWIW, here's  an interesting tip I saw on another forum:

Someone suggested using a 50CC irrigation syringe and a length of tubing and injecting fluid through the bleed nipple.  Said it works like a charm.

[yosso]

I really don't think it's the crush washers.  As previously mentioned, if you don't see any fluid, it's most likely sealed.

The last time I bled my masters, the levers felt like crap until I got the air out of the masters...but I have bleeders at the masters.

It's not impossible to get the air out near the masters without bleeders, but you do have to be crafty. 

I've now replaced the banjo bolt in the MC with a bolt that has a bleeder...and I just ran a quart of brake fluid thru (with a Mity vac) and the lever still goes all the way to the grip and will not pump up.

Just what is the correct method the bleed the MC with the bleeder? Can I use the Mity-vac to simply pull fluid thru?  That would seem to also pull fluid from the calipers...

Could the MC be bad?  It appeared be "new" when received. Guess I need to get a rebuild kit for the MC.

I'm beginning to think that parting out the bike would be the best solution. 

[Howie]

I've now replaced the banjo bolt in the MC with a bolt that has a bleeder...and I just ran a quart of brake fluid thru (with a Mity vac) and the lever still goes all the way to the grip and will not pump up.

Just what is the correct method the bleed the MC with the bleeder? Can I use the Mity-vac to simply pull fluid thru?  That would seem to also pull fluid from the calipers...

Could the MC be bad?  It appeared be "new" when received. Guess I need to get a rebuild kit for the MC.

I'm beginning to think that parting out the bike would be the best solution. 

Proper method is to bleed from the furthest point from the master and work your way up to your new bleeder at the master.  Attach a clear hose to the bleeder and put the other end in a clear container.  Pump slowly, hold the brake lever in the applied position, close bleeder, wash, rinse, repeat.  When you get bubble free fluid you are pretty much done, though you may have some trapped air still in the master.  Zip tie the lever to the bar and if there is trapped air it should return through the reservoir.  The closer to level the master is, the less likelihood of trapped air.

Yes, you could have a bad master.  A sure fire way to find out is to find a short bolt and screw it into the master with a crush washer.  Bleed it by loosening that bolt.  The volume is small, so it shouldn't take much.  No pressure, bad master.

[yosso]

Still unable to get a firm lever...I've dumped two quarts, and another pint of fluid yesterday.  So, today I pulled the calipers off the forks and placed some wooden shims between the pads, presto, firm lever, remove the shims from the left caliper, reinstall the caliper, presto no more firm lever.

I realized that in my original post, while I have the bike and brake specifics, I forgot to add, that I'm running 749S forks...and therefore had some "spacers" between the caliper bracket and fork mounting pad.  While my research said a 5mm shim was required, unless I used a smaller shim (3mm) on the lower bolt the caliper would not clear the interior surface of the disc.

So to summarize, I've got two questions, why is there a firm lever w/the calipers removed and why do I need two different size spacer bushings at the caliper mounting.

Again, bike and brake specs and posted above and the forks are off a 2004 749S.

Thanks for reading.

Mike

[Raux]

were the thickness of the wood and rotors the same? are your rotors 4mm thick?

and you have no leaks? two quarts and a pint?

[DarkStaR]

I don't get the deal with the spacers?

I've mixed a bunch of brake stuff from an S2R800, M620, M800, S2R1000, SC1000S, Multistrada, & 749/999...and the calipers were a bolt on deal.

[Raux]

oh just realized the spacer issue

749s brakes are 15mm offset

so you need both 5mm spacers

show a pic

[Raux]

sounds like your brakes are trying to grab the rotors at an angle.