CANNOT BLEED BRAKES!!!

I am working on bleeding the brakes on my 1982 maxim 650. I have totally cleaned the calipers, MC, and installed new brakes. I have bought a vacuum bleeder and cannot get the brakes to "tighten" up. I can get plenty of fluid to come out and I have to keep filling the MC but cannot get all the air out. Would not having thread tape on the bleeder valve affect it that bad?? I wouldn't think so....but...I dont know. What am I doing wrong!!!!???? Thanks!!

 

Start at the furthest bleeder and work tward the closest.
I have bled mine 3 or 4 times with the original fluid change this season and then all the upgrades and MC and lines, etc. just pump up the vac. pump, pull a vacuum and don't worry about the little stream of air bubbles they are seeping in between the vac. tubing, bleeder and the bleeder threads. Grab a handful of brake open the bleeder, close the bleeder and grab another handful of brake, repeat. As long as you don’t release the brake lever while the bleeder valve is open you’re fine.

 

I've had trouble on mine too. (1980 650 Maxim). I've decided that it's a couple of problems. Firstly, the lines are old, and therefore soft. New brake lines are definitely going to give better feedback. Secondly, on my master cylinder/reservoir I'm getting a little bit of seep around the banjo bolt that goes into the M/C and a little seep around the break in the line a little below the headlight.

Being a sport-bike rider primarily, my first thought is to get steel braided lines for the system. Does anyone know of any off hand? or would they have to be custom made? Also, are there universal front brake kits; and/or ones from other bikes that will fit for a more modern brake setup?

 

Chacle has steel braided lines ready to go, in colors too, and his shipping is so fast you’d swear he shipped them before you ordered them. You can also get lines made at linespro on eBay.

 

When I pull the brake handle, it just bottoms out and then doesnt want to return. It is like there is NOTHING in there but like I said, I have filled the MC several times....

 

It may need a caliper rebuild, my piston in my caliper was doing the same thing.

 

keep pulling your lever back and forth 6 or 7 times to build pressure, like pumping the brakes in your car/truck. it sounds like you have a lot of air in there and you are going to have to compress it and then push it out, I read a posting on here a month or so ago about.... here it is, this worked for another XJ'er

 

Test the Master.
Take-off the Brake Line at the Master.
Replace the Banjo Bolt with a MATCHING Thread Bolt wrapped in Teflon Tape.

Test the ability of the Master Cylinder SEALS to build-up and --> HOLD Hydraulic Pressure.

If the Brake Lever does NOT become Firm and Tight during this TEST ...
You will have to Rebuild the Master Cylinder.

If the Master is "Fountaining" ... right now. Brake Fluid doing a little tiny "Old Faithful" while you are Bleeding the Brakesc ... Skip the TEST and go straight to the Rebuild.

 

ok, so I was getting just a little fluid to "fountain" up. Not much at all. The funny thing is that the brakes built up a lot of pressure before. What could have happened????

 

I forgot to mention that when I had it totally apart I cleaned everything! I took all hoses off and cleaned them all out (sprayed cleaner down them all). I have been reading some bench bleeding threads and wonder if I need to do that??? I pulled the banjo bolt off the MC and plugged up with my finger. It builds pressure and when I release my finger, fluid just dribbles out. Just thought I would add this...thanks for the help! This sucks!!

 

I had the same problem. I got a rebuild kit for the master cylinder. You need a pair of Master Cylinder pliers, the long ones that can reach 50mm deep. Don't try using needle nose pliers to get the snap ring out of the MC that holds the piston in the bore. You'll just eff things up. The MC pliers cost me 12 bucks. With those pliers the whole procedure takes about 3 minutes. The MC rebuild made a massive difference. I also rebuilt the calipers with new seals. That too made a major difference. Then I wrapped teflon tape around the bleeder screws. After all that, it bled out just fine and now the front brakes nice and strong, good progressive feel and the caliper pistons aren't sticking.
thx,
baz

 

sounds like you have a little work ahead of you kcoop, good luck and keep us updated on the progress.

 

I took an Old pair of Needle Nosed Pliers and spent a few moments at the Grinder.

Wound-up with my Super-Dooper Yamaha BrakeMaster Cylinder Circlip Tool.

 

nice work Rick, I love fabricating parts and tools, lucky for me that's what I get to do at the university for part of my day

 

I tried that too one time!! Didnt work so well! But hey, great minds think alike, right??

 

I just use e-clip pliers - available cheap at my favorite harbor freight

 

Ok, I put everything back together and had a friend help bleed brakes. I was finally getting a "fountain" to come out of tiny hole in MC. I put cap back on MC and had good pressure on brake handle. But....when I hold the brake lever, it gradually loses pressure and if I pump the handle, I get pressure again. What is going on here? I have NO fluid leaks...what gives???

 

The "Fountain" indicates that the Hydraulic SEAL which is supposes to be a ONE-WAY Seal is Leaking-by. And the PRESSURE which should be applied to the LINES to move the CALIPER PISTON isn't being held by the Front Seal.

The Master Cylinder is becoming Pressurized ... and forcing Brake Fluid OUT back through the Cylinder FILLING Port under pressure.

The Front Seal isn't Building-up Pressure. The Pressure Fluid isn't be pushed OUT of the MC.
The Fluid is "Bleeding-by" the Front Seal into the area between Seals which is supposed to replenish the Fluid Supply in the System as the Pads Wear Down.

The Fluid isn't being PUMPED Out of the MC.
The Leaking SEAL is causing a PRESSURE on the Contents of the MC Bore that is looking for a way out.

Brake Fluid is getting pushed-back into the Reservoir through the FILL Hole.
A 100% Indication that the SEAL isn't pushing the Fluid OUT without leaking.

 

So you are saying I need to rebuild my MC?? Correct??

 

Yes. And, ... after you get the Guts out and the Bore Cleaned ... shine a loght into the Bore and L@@K at the Bore for stratches and pitting.

If the Bore is Pitted ... you have to Hone the Pits out.