EV Brake Bleed

[screamday]

Decided to flush the brakes on the EV. Bought a Mityvac.....did a search on this site to read through all the other posts. So, I figured I start with the left front first. I bought new pads from Harper's so I put in the new pads first. Pulled the bleed nipple and wrapped teflon tape around the threads. Sucked out the old fluid from the rear MC and replaced with new. Hooked up the MV and started sucking. I was getting a lot of air bubbles, even with the teflon tape. I decided to put a zip tie around the tubing at the nipple. Started again....no bubbles this time, the vacuum builds, but when I open the bleed screw the fluid moves to the top of the bend in the tube and stops. The vacuum does not drop. I can't seem to get the fluid flowing. It seems that there might be a bigger problem....maybe a frozen caliper? I was able to compress the pistons before I replaced the pads so the pistons moved.

Any ideas?

T

[Perazzimx14]

My advise is throw the Mity-vac away and reverse bleed the brakes. Youtube has tons of videos showing the simple process.


Parts needed: 2 syringes (60cc at Tractor Supply are $3.29 per) and a small section of 1/4"ish tubing.

1. Open MC and suck out as much of the old fluid as possible.
2. Tie brake lever to the handle bar or weight the foot pedal to simulate braking.
3. Fill syringe full of brake fluid
4. Put the proper size box end wrench over the bleed nipple and then connect the brake bleed nipple to the syringe with a small section of tubing.
5. Hold the syringe upright to let the tubing fill with fluid and the air bubble to go up towards the plunger
6. Syringe in 1 hand and while gently depressing the plunger w/ your thumb crack the bleed nipple with your other and inject air free brake fluid into the caliper.
7. When MC gets full close the bleeder and suck out the old fluid in the reservoir then repeat until clear fluid fills the MC.

The advantage of reverse bleeding is you are pushing any air up to the MC and not trying to suck in downward through the caliper. I bled the linked brakes on my V50 with a Mity Vac and it took hours and pints of fluid to get them properly bled. After rebuilding the calipers and adding SS lines on my T3 I was not looking forward to bleeding the brakes. Then I found out about reverse bleeding and thought what the heck I'll give it a try. In 20 minutes I was cleaning up the tools and admiring a job well done.

[screamday]

Thanks, but I'm already going down the MV road. Worked great on the right side front caliper. Worked just like it was suppose to. Just can't get the fluid to move on the left front.

[guzzisteve]

Did you bleed out the splitter?  I do front then splitter then rear, then repeat, pump up pedal once & awhile. I never remove bleeder or add tape. It helps to have 125psi all the time.

[fotoguzzi]

remove caliper and raise it above the rest of the system?

[screamday]

Did you bleed out the splitter?  I do front then splitter then rear, then repeat, pump up pedal once & awhile. I never remove bleeder or add tape. It helps to have 125psi all the time.

Splitter??

[screamday]

remove caliper and raise it above the rest of the system?

I'll try that.

[twhitaker]

After I installed Speedbleeders on my bikes I've never had another bubble.

[screamday]

remove caliper and raise it above the rest of the system?

That didn't make a difference.

After I installed Speedbleeders on my bikes I've never had another bubble.

Bubbles aren't the problem. Nothing's moving.....the vacuum gauge does not even go down when I open the bleeder. It's as though something is plugged up. I hadn't noticed any major braking problems before I started the process so....

[Perazzimx14]

Take the caliper off and split in two. Get a can of brake cleaner and hose out the small 1/8"ish hole until it flow freely out the bleeder opening.

[Rich A]

Or you might just remove the bleeder completely and make sure it isn't plugged (or get a new one).

Rich A

[screamday]

Or you might just remove the bleeder completely and make sure it isn't plugged (or get a new one).

Rich A

That's a good idea, I'll check it out.

[screamday]

Or you might just remove the bleeder completely and make sure it isn't plugged (or get a new one).

Rich A

Blew some compressed air through the bleeder.....seems to be clean and open.

[screamday]

Thought I'd bring this back from page 4....I know everyone was on the edge of their seats wondering how I made out.   Well, I could not get the left front brake caliper to bleed using the Mitivac. So I enlisted some help and did it the old fashion way.......pump and purge. Worked with very little effort. Now I just have to reassemble with new brake pads and go for a test ride. I'll you all know how it works out.....either way. 

[tris]

Thought I'd bring this back from page 4....I know everyone was on the edge of their seats wondering how I made out.   Well, I could not get the left front brake caliper to bleed using the Mitivac. So I enlisted some help and did it the old fashion way.......pump and purge. Worked with very little effort. Now I just have to reassemble with new brake pads and go for a test ride. I'll you all know how it works out.....either way. 

Exactly the same problem on my 95 Cali and the same solution (left the vac pump hooked up for luck). Domestic management wasn't to impressed with the Press - Hold instructions 

[pehayes]

1. Open MC and suck out as much of the old fluid as possible.
2. Tie brake lever to the handle bar or weight the foot pedal to simulate braking.

While I do prefer to reverse bleed, I don't understand your instruction #2.  If you compress either master cylinder, you will never get fluid to pass its piston and flow up into the reservoir.  You need to leave the brakes relaxed, not compressed.

BTW, my take on the current symptoms.  When he tries to vacuum bleed, it begins and fluid rises in the tool but then ceases.  It sounds like the brake peddle and linkage are not properly adjusted.  If the seals inside the master cylinder are too close to the reservoir port, they your vacuum suction could pull the piston forward and thus block the port, preventing further bleeding.  I might suggest disconnecting all the linkage from the master cylinder.  I might suggest gently gripping the piston to ensure that it is fully retracted and thus exposing the port between the reservoir and the bore.

Patrick Hayes
Fremont CA

[Kiwi_Roy]

Don't use Teflon tape on the bleeder, the thread is not part of the valve, the tip of the bleeder closes a hole in the caliper.

[twhitaker]

Don't use Teflon tape on the bleeder, the thread is not part of the valve, the tip of the bleeder closes a hole in the caliper.

When using the Mity Vac to bleed the system the vacuum will draw air around the threads of the bleeder leading the operator to believe there is an infinite quantity of air in the fluid. A smear of heavy grease around the bleeder will serve the same purpose.

Speedbleeders have thread sealant bonded onto the fitting.