best (easiest and most efficient) way to bleed brakes...

on an 81 550 maxim...

took the brake cylinder/lever off to rebuild the master cylinder...

havent decided yet on swapping out the old line for my new (5 years ago?) Chacal stainless lines but in the mean time i need help getting some brake fluid inside the dumb brake lines and the air out...

 

when i was trying to see if my lines were good i would take a hose that was attached to the bleeder with a syringe on it and create a vacuum in the syringe while pumping a few times and being careful to not run the master cylinder dry. it seemed to pull the fluid right through the line

 

You can also fill the syringe with brake fluid, attach it to the bleeder with a small length of hose, and then push the fluid into the caliper. The fluid will flow through the caliper and upward along the brake lines, and into the master cylinder. This has one advantage in that the fluid is flowing in the same direction that air bubbles wish to go ( i.e., the air bubbles want to migrate up toward the highest point in the system.). Be sure to have the top off of the master cylinder, and place rags or paper towels to prevent brake fluid overflow from getting on the bike.

 

I've seen people who leave the banjo bolts slightly open and let gravity do its thing over time(over night or so). Helps get a bit of the air out, making bleeding much easier.

 

Would the mityvac be the answer here? Wouldn't that just forcefully suck fluid from the MC down through the system and out of the bleed valve? (hose from mityvac connected to bleed valve)

I may be way off here...

 

Dave you can use my MityVac. Did you do the caliper yet?

The MityVac only helps; there is NO quick or easy way to bleed an empty Yamaha system. There's frustrating, really frustrating or becoming suicidal.

You can use the MityVac or similar to help fill the system with fluid; bleeding takes seemingly forever and requires patience and a lot of brake fluid+two days or so. I've been through this multiple times since I did the brakes on the '81 in "stages." (Mistake.)

 

Agree most whole-heartedly with Bigfitz52. I did a complete rebuild on the front end brakes on my 82 Maxim 750. Bleeding the brakes was an incredibly frustrating exercise. I used every method conceivable. Pre-filled the lines and calipers. Then, using the brake handle, pumped fluid from the master cylinder down to the caliper bleeder. Repeatedly. Brake handle still very soft. Checked to make sure that the tiny fluid return hole in the master cylinder was clear and functioning - it was. Put a MityVac on the caliper bleeder and pulled vacuum from the bottom end. Repeatedly. Brake handle still soft. Cracked the fittings on the cross-over pipe and pumped fluid with the brake handle to get rid of any air trapped in the cross-over. Brake handle still soft. Went to the farm supply store and got a huge plastic horse syringe. Filled the syringe with brake fluid and force-fed it into the calipers from the bleeder fitting. Repeatedly. Brake handle started to harden up, but would then fade if held continuously. Remember - we are talking about all new everything in the system - brake lines, caliper piston seals, banjo fitting gaskets, complete master cylinder rebuild kit, etc, etc. Finally said, "Screw It", walked off and left it standing for a week. Came back, pumped the handle a few more times, and it FINALLY hardened up. Only thing I can think of is that small air bubbles gradually worked their way to the top of the lines as it sat for the week. Then, the last of them were expelled into the master cylinder reservoir through the tiny fluid return port. ??? I honestly think the best way to do this is take it to a shop that uses pressurized bleeder tool. They will clamp a plate (with rubber gasket) to the top of your master cylinder reservoir, open the bleeder fitting on the caliper, and then pressure pump new fluid into the system until hell won't have it.

 

yep ...... MityVac. set you back some dough but worth the purchase. Did my brakes lines in spring and saved time. Now if it would only fix my carb.

 

A plastic bottle with a hole on the side, a tube connected to the bleeder, the bottle is held above the Mc. Fill the bottle with brake fluid, then squeeze the bottle with your thumb covering the hole to force fluid in to the brakes, it takes a couple of goes, but when there is nothing but liquid coming up in the MC yr good.

 

Easiest way:

Evacuate and clean the MC Reservoir.
Remove Bleed Screw from Caliper.
Wrap Bleeder with several tight layers of Teflon Tape.
Trim Teflon to assure Bleeder is open to flow.

Reinstall Bleeder.
Attach 8-feet of tight-fitting Clear Vinyl Hose to Bleeder.
Fill Reservoir.
Have assistant keep Reservoir filled with fresh Brake Fluid.

With Bleeder OPENED; place the Hose to your lips and draw a vacuum.
Draw-out Air and Fluid until that which fills hose nears lips.
CLOSE Bleeder.
Remove and evacuate Hose.
Replace emptied Hose on Bleeder.
Open Bleeder.
Repeat process until you get nothing but Fluid exiting Caliper.

Once you have evacuated the lines and caliper of Air ...
Close Bleeder.
Test for Hydraulic Pressure by pumping Brake Lever.
If Hydraulic Pressure is good ...
Pump-up pressure.
Hold.
Open Bleeder: Observe flow. Close Bleeder. Pump.
If Lever is frim, ... you're done.

 

Rick that is beautiful man! I think I may go that route and cancel my order for the mityvac! Question is, where to get a piece of 8 foot long nylon hose?

 

I use a Mityvac. I'm perfectly happy not knowing what brake fluid tastes like.

 

Well with an 8 foot run of hose I dont see how the fluid would even get close to your lips. I would think you'd have plenty of time to take lips off and drain the fluid into some sort of bucket..?

 

I have a nice little medical vacuum pump with a reservoir on it, works wonders. A buddy of mine who works for a home oxygen company got a broken one for me. The on/off switch is stuck on so I just added a switch to the power cord.

 

A pickle jar and an idling car

Connect a hose from the caliper to the jar - the car or truck provides a steady vacuum.
I got a 25' Oxygen hose from a COPD patient.

 

You can get Clear Vinyl Hose at TruValue or Home Depot.

I put a 2-Inch length of Rubber Hose and a Union at the Bleeder-end to assure a tight fit and alleviate the hassle of forcing the Vinyl Hose on the Bleed Screw.

The Vinyl Hose was 10-cents a foot.
The clerk gave me 2-inches of Rubber Hose for free.

 

Ltdave, the whole process is harder with a suspect MC. When was yours last overhauled?