front brakes

I have an 81 650 maxim it has sat outside for about 3years I got it running and i went throught to do the brakes and I replace the brake shoes but when i went to bleed them there is no resistance to the brake lever. and the fluid level does not lower when i pump the brakes and fluid is not coming out the bleed hole. I have bled brake before and never have had this problem I know I have an airlock somewhere but I dont know the reason why or how to fix it any assistance would be greatly appreciated

 

First - if you didn't flush the entire system thoroughly it is probably full of all kinds of nasty gunk. Strongly recommend careful cleaning of the master cylinder (that little tiny hole in the bottom of the reservoir tends to get clogged), and flushing the system full of new fluid.

Second - Maxims are notorious for trapping air. The outlet on the master cylinder is the high point on the system and you can get an air pocket at the banjo bolt. Turning the bars all the way to the left tends to level the master cylinder and I've got better results that way. Also light tapping with a hammer handle at the banjo bolt seems to break bubbles loose.

I usually bleed mine on 3 successive days. It seems like the whole system traps tiny bubbles (foam). Over time they coalesce into bigger bubbles that will flush out.

 

Your brake system is acting like mine was after I rebuilt my 81's master cylinder and caliper. What I had to do was get a vacuum bleeder pump and attach it to the system. I had to physically pull the brake fluid down from the master to the caliper.

The reason it's not working properly is due to the lack of a vacuum in the brake lines to allow the fluid to pump out of the resevoir. But once you get brake fluid in the majority of the brake system, it will allow you to bleed the system with the handle.

 

you can pull the banjo bolt on the master cylinder look in the hole see if you see any fluid if it's empty fill the space till most almost runs out. install the banjo bolt and try pumping. if that don't work put a mc kit in it.

 

yeah that sound like a good start to me if I have any problems i ll let you know

 

i had a salavaged brake caliper i picked up a week ago that had the same problem as my other one a stuck piston. i thought the master cylinder was bad cause it did the same thing just pulled way to easy and wouldn't pump up. i pulled the banjo bolt checked that side it was empty i filled it up replaced the bolt started pumping and it started pumping up. bled it a couple times added more fluid bled it till it started running clear. it seems to be holding.
now i'll rebuild the original brake caliper and do the kit in the master cylinder and i ought to be good on brakes. and got to give all the guys that posted back credit for helping me out there a bunch of great guys.

 

yeah i tried what you guy said and a couple of bubbles came out of the master cylinder and then they quit i did the pumping and letting the air out of the bleed hole I repeated the process for an hour with no prevail it didnt take any of the fluid any other suggestions.

thanks
tired and confused

 

Make sure the stroke adjustment screw on the brake lever itself is adjusted such that you are getting a FULL stroke of the master cylinder when you pump. I had to adjust mine out before being able to generate sufficient pressure in the master cylinder to get a full bleed.

 

I spent a couple of weeks trying to get my brakes bled with the same issues you describe. WInk1018 is right, I picked up a mightyvac vacuum pump for about $25 and it worked instantly. Let me tell you, after weeks of frustration, that money was worth every penny to see that thing suck fluid through that entire system in a couple of seconds.

 

While you're at it, make sure that the tiny return hole inside the MC is not plugged.. If it is, the brakes might drag.

 

I got a mityvac pump and went to pump it and nothing comes out I am using the pump correctly and am loosening the bleed valve. My mc is probably plugged up but I dont know how to take it apart and clean it. When you pump the brake there arnt any bubbles coming out so it is probably clogged up how do I un clog it???

 

Remove the bleed screw and check that the holes are clear. This some times happens on cars bleed screws.

 

all holes are clear and still wont bleed

 

If you take off the banjo bolt off the MC itself, and put your finger on the hole, then squeeze the handle... do you feel any air pressure building up in there? It won't be much, but should still noticeable.

If not, You may have to remove the plunger from the MC and inspect it. Maybe it needs a rebuild kit, or just a thorough cleaning.

Behind the little rubber boot where the plunger sticks out is a circlip. You will have to remove the circlip to get the plunger out. It's a pain.

Once the plunger is out, inspect the rubber parts on it. If they look hardened or worn, you will need a rebuild kit. They are easy to come by.

The 2 holes in the MC chamber are easier to clean once the plunger is out.
You can use a very fine sewing needle to clear out the tiny relief hole. Take care not to make that hole any larger.

Did you make sure that the lines themselves are clear and free of gunked up brake fluid?

anyhow... when all of the above checks out... assemble, fill MC with fluid.
Put at least the rubber membrane on the MC, because when you squeeze the lever, that relief hole will shoot a stream of fluid several inches in the air.

Attach the vac to the bleed valve, open it just a little bit. Start putting vacuum on it, and at the same time squeeze the brake handle several times. You should see the fluid level drop in the MC. Take care not to let it drop too low, as you will pull in air bubbles. Keep putting vacuum on the system as you bleed it, at least until it's mostly filled. Once you got enough fluid in the system, the vacuum pump may no longer be necessary, and you can continue the bleed process the old-fashioned way.

Bleed it again after a couple of days, as MiCarl suggested.

 

I get what you are saying but I dont know how to remove the circlip
How do i get it out?

the Behind the little rubber boot where the plunger sticks out is a circlip. You will have to remove the circlip to get the plunger out. It's a pain.

Once the plunger is out, inspect the rubber parts on it. If they look hardened or worn, you will need a rebuild kit. They are easy to come by.

The 2 holes in the MC chamber are easier to clean once the plunger is out.
You can use a very fine sewing needle to clear out the tiny relief hole. Take care not to make that hole any larger.

 

the best way, of course, is to use the proper tool.

such as the one in the pic below.

In a pinch, you could take some fine-point needle-nose pliers and grind the tips down so they will fit in the holes of the circlip.

 

Thanks I will give it a shot
and let you know what happens

 

where do I buy a mc rebuid kit.

 

Piles of places carry them. Almost any parts shop can order it out of the PartsUnlimited catalog. My favorite online source is BikeBandit.com or you can purchase them from our site supplier Chacal (I'd check with him first, he is priced well and knows our machines).

 

I got a mc repair kit and now it works fine i appreciate all of the advice it was a huge help!

 

Another Satified Customer!!!
We are the threads that hold this community together.
Good Job Guys

 

I got a 750 Maxim Master Cylinder Repair Kit from OldBikeBarn.com and it came with the whole internal parts of the Master ... not just Seals.

Some kits are Rubber Seals ONLY.
The kit I got had everything; including the Dust Boot.

I think it was around 35~40 Dollars.