trouble bleeding

[jomama]

If you are like me, every once and a while you run into a problem that defies conventional methods. If you have ever had a set of front or rear brakes you just couldn't get the air out of then try this. IT WORKS. Assuming you dont have a vacuum bleeder kit then just get the trusty old shop vac out and put the crevice tool on the end and then place several sizes of ruber hose into each other gradually decreasing in size till your last piece fits snug on the bleeder. Try and use a clear piece for the last so you can monitor the air bubbles. Seal all the connections good w/duck tape. Fill the master cyl and apply either the hand or foot lever all the way open. crack the bleeder,turn on the vac and watch it draw the air through the lines until you have pure fluid. close the bleeder and youre good to go.

 

[OliverB]

Neat trick but you would want to be real careful it doesn't suck the reservoir dry real fast and introduce a lot more air into the system. It does seem like a few air bubbles do sometimes gets stuck in there and a regular vacuum bleeder just won't pull them out. Been there, had that happen!

 

[lhaolpa]

You can just open the bleeder a little,and in a while,you'll have fluid coming out of the bleeder.It may take a while,but it works for sure. lha

 

[new kid on the brat]

another sweet trick i have used is to simply push the calipers back in by hand and with the natural rise of the bubbles will push them back into the reservoir then just pump back up with the lever.

 

[HoughMade]

Having bled many cars and trucks by myself, and having a 6 1/2' arm span, I find bleeding motorcycle brakes the old fashioned way downright simple.

 

[jomama]

I have been wrenching for well over 50yrs and although it is relatively simple , Murphy's Law applies to everything.

 

[drewpy]

also zip tie the lever pulled over night, any bubbles will be allowed to rise into the resevoir

 

[jlearning1]

Any more suggestions. I am having a hella time bleeding my front brakes on a 1980 Yamaha xs400SG. I have pumped and pumped and pumped and handle is still spongy.

Thanks

 

[jomama]

Just about all the methods I am familiar with have been mentioned here. BUT there could be a problem with a mushy 31 yr old brake hose. I mean if you arent getting any air bubbles and its all straight fluid it could be something to look at.

 

[jlearning1]

I am getting brake fluid down to the caliper. When I open the bleeder screw, brake fluid does come out of the bleeder screw. I dont know if I mention, but I just rebuilt the caliper with a new caliper kit. I cleaned that brake cable and I am getting fluid through the brake line. I took an air blower and blew right through it. From one end to the other.

Thanks

 

[jomama]

When you describe the brake handle as "spongy" what do you mean ? It can be pumped up and definately had resistance but spongy or there is never any buildup at all?

 

[jlearning1]

There is never ant build up at all. Brake level is very spongy(loose) will not stop front wheel

Thanks

 

[HoughMade]

Have you taken the caliper apart to see if the piston is seized or free?

 

[jomama]

After reading all posts, i dont see where anybody thpught to ask the standard question. Are you using the right DOT fluid?. I know i know its a basic question but crazier things have happened .I have done them . I once used drum brake fluid only ( i doubt its even made anymore ) in a system that had both disc and drums which is still common in many cars and it swelled up the front seals they would not release and solidly locked up the front end. So just checking the DOT # on the cap matches the can.

 

[drewpy]

i use Milk!

 

[reed]

i second jomama sounds like inside of hose is broke down

 

[jlearning1]

Yes I am using DOt 3 brake fluid in the resevoir. Does anyone have an illustration on how to replace the master cylinder kit? I think it may be time for a master cylinder rebuildit. I have look inside where the black plunge is located and have no idea how to remove it. A step by step guide would be nice if ant onr has one.

Thanks

 

[jomama]

I would have responded sooner but went away camping . Howeve in the repair manual it shows the whole shooting match being held in by a snap ring. onced removed at all should come apart. Best advice is invest in some type of manual, Clymer, Haynes etc. I have one for every piece of equiptment i own .

 

[drewpy]

I would have responded sooner but went away camping . Howeve in the repair manual it shows the whole shooting match being held in by a snap ring. onced removed at all should come apart. Best advice is invest in some type of manual, Clymer, Haynes etc. I have one for every piece of equiptment i own .

I went camping and got arrested...

I was charged with Loitering within tent

 

[Kimball_Walker]

I am new to this forum (and new to the XS400)

My bike is also having problems with the front brake.
My line started leaking, so I purchased a used one from Ebay. It was clogged and when I attempted to squeeze a little harder to try and clear it…(stupid I know) my MC started leaking.
I ordered a new (not used) line and took apart the MC. The only thing that I could find wrong with it was the cylinder cup was out of place.
After cleaning and reassembly, I am unable to build pressure. When bleeding, the MC does not draw from the res. (I checked and both holes are clear, no clogs.
Even a vacuum will not draw from the res. (handle squeezed and free).
I do see movement of the fluid in the line, it goes back and forth as I squeeze the handle, but does not advance beyond the same point even after 20 pumps.
Any assistance would be greatly appreciated.


Jlearning1 – I have just figured out how to do that using the manual (and a lot of trial and error), here is what I came up with but take care, I may very well have made a mistake somewhere which could be why my MC isn’t working correctly.
1. Clamp the assembly in place.
2. Remove dust boot.
3. Using a bent nail, push down the piston, then clamp the nail in place.
4. Remove the snap ring.
5. Release the nail (be careful or the piston may launch) and remove the piston assembly.
6. Push the spring and stopper valve out from the other side.
7. Clean everything with brake fluid.
Now comes the fun part… Putting it all back together. The manual mentions a “Cylinder cup installer” I really wish I had one. What I used was the end from a solid food injector (plastic pointed tube with a split end), it worked like a charm.
8. Re-clamp the assembly.
9. Replace spring and stopper valve.
10. Ensure the Cylinder cup is positioned properly on the piston, then re-insert the piston.
11. Replace the washer, snap ring and dust boot.

If I have just given bad directions, please let me know, because this is what I did to mine!