Brake bleeding again

Ok guys I am not good with this site yet. Could some one guide me to the link regarding the easy bleeding of an XJ linked brake system?
I have an 81 XS1100 LH which also has the linked brakes. I an not for the life of me get the damn brakes to bleed properly.
I know every one is going to say "oh not another brake bleed question" but I am struggling with this badly and would welcome any help. Thank you.

 

Welcome. Can you update us with the condition(age) of the master cylinder internals and calipers if known? Then we'll go from there. Thanks.

 

Welcome indeed! not seen any other linked brake bleeding q's on here before tbh, I'd guess a linked system may respond more to a vacuum bleeder than most?

The only other thread on here I could find about linked brakes was this http://xjbikes.com/Forums/viewtopic/t=5 ... brake.html

Not sure if that contains the link you needed though?

 

no prob.

first take off the cap on the master cylinder. fill it with dot 3. then pump the brakes SLOWLY until you build up pressure. keep an eye on the cylinder and make sure to fill it when it is at least half empty.

then attach a piece of overflow hose or something about that size (i prefer a clear plastic tube so you can see whats going on) to the bleeder screw once you have pressure built up and there is fluid all the way threw the lines and in the caliper, then run that hose into some kind of container but don't reuse that brake fluid NO MATTER WHAT. Then pump the brake and hold the lever as far back as you can get it while taking a wrench and poping the bleeder screw loose letting air and fluid out. the lever will go all the way to the handle bars but keep holding it there. then tighten the screw and pump the lever again until pressure build up once again. repeat process.

every time you release the bleeder there will be air and fluid, once there is only fluid that caliper is good to go. then move on to the next caliper

 

Pull the Cover on the Master Cylinder.
Cover Painted surfaces against spills.
Syringe out the Brake Fluid leaving the Master Cylinder Reservoir 1/2 full.

Work the Brake Lever.
Observe the Reservoir.

IF you see a Fountain of Brake Fluid, ... (That looks like your own miniature Old Faithful or the display in the pool outside the Bellagio in Vegas ...)

Quit trying to Bleed the brakes.
You're wasting your time.
"Squirting-up" Brake Fluid means you have bad Seals inside the Master Cylinder.
Order a Kit. Replace the Guts.
Try again!

 

The calipers have all been rebuilt with new rubber seals and cleaned well. The pistons are in very nice shape.
The M/C's have both been rebuilt with new kits. The rear on this particular bike are very hard to come by, but I managed to find the correct one.
I am running the new stainless steel lines that Len has made available to the XS1100 riders as well.

 

When I did a google search it showed up as a thread that said "not another brake bleed question" so that is why I phrased it that way. Yes I am sure it will respond better to a vacuum bleed better. I have been having issues with the rear M/c being air locked it seems. I did circulate the whole brake system back caliper to front with a windshield washer pump to ensure all the air bubbles were out.

 

Thanks for the reply. Problem is that I was not able to build any pressure at all with the rear brake lever, so bleeding was out of the question. All of the air was circulated out with my windshield washer method except for the M/C to proportioning valve. That seems to be air locked. Maybe need to remove it and bench bleed it.

 

Brand new NOS rebuild kit in place. No Geyser action just some wee bubbles when I let off the brake. Not thinking it is a replace the guts type fix, but thanks for the input.

 

Once it was all said and done the air lock was in the rear M/C and once I got that out (took thirty pumps of the pedal to get fluid to the proportioning valve) the brakes bled fine. The fact that I had circulated the lines free of air was a major contributor to the ease of bleeding these brakes. Always bench bleed the M/C before doing this, it will save you time and much head scratching.

 

Glad you got her sorted, sounds like you had "fun"!

I'm not familiar with the system but perhaps a bleed-screw equipped banjo bolt somewhere close to the rear M/C would help if you ever have to do it again?

 

Nice job troubleshooting, and good choice on the SS lines. I added those this winter, and it took a long time (and two people) to get it right. Damn does she stop now tho, can't wait to relearn my stopping distances when the snow goes way.

 

So I was hoping to get a little more information about the geysering effect from bad master cylinder seals. I just bought a MC rebuild kit for my SECA because after bleeding several times and making sure the return port was nice and clean, I do have that wonderful fountain effect on pressure return to the MC.
It seems to be affecting the whole pressure return thing. Front tire spins freely untill you mash on the brakes a few times, then there is a little stick. Not enough to really affect the motion of the bike, but enough to make the wheel come short about 5 or 6 revolutions on just a hand spin compared to what I would considder a ground truth completely free spin. Don't need new rotors, but I'm not in the mood to drop a minimum of $300 on the front set right now.

 

Have you got new brake hoses fitted? old ones (see date code link in my signature along with other safety related links) can cause a "one-way valve" effect if they're breaking up internally.

Also could just be your pads sticking a little, worth removing & cleaning any muck off all surfaces down there & you can check if your caliper pistons are free at the same time. I don't know how much you mean it's dragging but hydraulic discs will always have a very tiny drag compared to drum brakes.

 

I'm alright with the little bit of drag. When you get the 550 pounds of bike and momentum you don't notice the slight drag on front calipers. Brake lines are braided stainless set of Speiglers, new three years ago with very little use.
I've cleaned and rebuilt both front calipers a couple of times and the pads are also brand new. New pads on old rotors was one of my thoughts.

 

Did you by chance rebuild the master cylinder while you were at it? That thing can get downright ugly over time and the seals can break down as well. Rick was refering to the seals wearing out when he mentioned his geyser test. My guess is that you are looking at a MC rebuild in the near future.

 

Have the MC rebuild parts in shop. Thankfully I had purchased a second XJ9 as parts bike and was able to secure a second MC that's getting cleaned/rebuilt and repainted probably this evening.

 

I doubt that'd cause excessive drag, although if they're a different brand to what you usually use perhaps they just drag a little more than normal? (EBC have a coating on them to help bite when new, for one example), or maybe the paint on the new pads is binding a little on the caliper bodies...

Hard to say really if everything's rebuilt & fresh, without seeing/feeling for myself it could just be normal. Sorry I can't think of anything else

 

When I tore apart my MC this ( http://xjbikes.com/Forums/viewtopic/t=41403.html ) was the ugliness that I found. I was having problems with mine not holding fluid so I rebuild everything. But the 30+ year old seals in the MC are probably the root cause of the geyser problem.

 

I just saw the posts from while I was typing my last reply, I thought the M/C was already rebuilt didn't twig that you'd just got the kit sorry! that's likely it then, blocked return hole can cause drag

 

osprey1000, The inside of your calipers kinda' looked like what I had found. Someone used slide grease to ease in the pistons and it left a ton of the stuff in the bore. The slide grease has a much larger coefficient of thermal expansion than the brake fluid and will also taint your fluid pink. I thought I had rust somewhere in the antidives or something the first time I bled the lines.

 

That could have been it as well. Either way when I put them back together the only lube on the seal was brake fluid and a clamp for force...

 

Drag is NOT good.
Drag is friction.
Friction caused HEAT.
Overheating will induce warping ... fade ... premature glazing.

 

..and it can cause the brake fluid to expand, causing the brake to be applied further, causing more friction, causing.......cycle repeats. Muy malo.

 

Agreed. They should not drag whatsoever. If they are, you missed something.

 

Some factors causing Drag:

Cheap aftermarket Pads.
Rotor Warp
Contaminated Caliper Seal Channel
Caliper Travel Mounts binding / contaminated.

 

So I rebuilt the donor MC last night. New guts, clean passages, a little bit of dot3 for lubrication. The cylinder walls looked nice and clean so I didn't hone the bore. Feels a lot different.
Unfortunately it had about three layers of bad black paint that I took of with a wheel. Polished the reserve cap, so it's all nice and shiny, painted the center strip only back and polished off the raised YAMAHA. I like the look, but am still deciding whether to repaint the reservoir or strip the whole thing and polish the visible parts before a clear-coat.

As far as the brakes grabbing a bit: Rotors are mildly gouged, but not warped and I've cleaned and rebuilt the calipers about three times making sure I didn't miss anything. Used the best slide grease I could find on the holding pins and spring clasps. Calipers put together with DOT3 only, everything is bled through up to the anti-dives (and those things like to hold little bubbles for some reason). I'm swapping the MCs out tomorrow. Guess I'm just crossing my fingers and hoping for the best...

 

So even after a MC rebuild I'm still having a bit of that "geysering" effect and the front wheel still has a bit of rolling resistance. Might be new rotor time?
Just not sure what's going on, and neither does anyone else in my shop. I don't know if I can do anything else. I have braided stainless lines (3 YO) from the MC down to the anti-dives, calipers are rebuilt, etc. Is the return pressure to high? Where would this be coming from, anti-dive internals maybe? I know I haven't rebuilt those yet.
The bike moves fine, the brake fluid return is good, nothing leaks, nothing binds, but if the front wheel is truely supposed to be completely free, I'm just not getting it there.

 

The anti-dive units shouldn't be causing brake drag, even if they aren't working. Did you, just by chance, happen to overfill the MC reservoir? If there isn't enough room for fluid expansion that can cause the brakes to drag...not that I've ever done that myself...<cough>

Another possibility is the wheel being slightly off-center. Loosen the axle pinch bolt and give the right fork leg a good rap with a rubber mallet. It is possible that the fork legs are just a bit too close together, not enough to see, or cause the wheel to bind, but enough to cause the brakes to drag slightly.

 

MC resevoir is not overfull, a little over halfway is all. I'll check the alignment of the front forks using the rubber mallet convincing method, but the '83 900RKs have a solid Al cross member about 35cm above the front axle used as the front fender mount. This should take care of spacing and alignment issues (theorhetically), but I'll take a swing at her anyhow.

 

Did you Clean the Caliper's Main Seal's Locating Channel right down to bare Aluminum?