Bleeding linked brake system( a problem at the front caliper)

[ritratto]

Hi all.... trying to bleed the system, having rebuilt both calipers  and getting fluid at the proportioning valve, but can’t seem to get any at the front. Have tried the vacuum pump and the peddle. Nothing.
Ideas? Soultions?

[rodekyll]

Which bike?

[ritratto]

‘93 1000S

Far as I can tell, is the same as my ‘78 though.

[Frenchfrog]

Un-bolt the front caliper and lift it as high as you can and above the solid feed line under the tank.All the air in the line should then be under the bleed screw.Pump a few times and bleed,all should be fine.

[ritratto]

Will give it a try! Thanks.

[blackcat]

Try zip tying the pedal and leaving it overnight with the caliper elevated, and then see what happens.

[yogidozer]

Un-bolt the front caliper and lift it as high as you can and above the solid feed line under the tank.All the air in the line should then be under the bleed screw.Pump a few times and bleed,all should be fine.

this and tap the line. air bubbles will rise

[ritratto]

Like all of the last three suggestions! Cool!😎

[gearman]

Try zip tying the pedal and leaving it overnight with the caliper elevated, and then see what happens.

This works.

[Chuck in Indiana]

This works.

It works if you have *some* pedal.

[Chuck in Indiana]

This is the simplest, cheapest and most effective way to bleed brakes linked or not.

Like. 
It's what I use on airplanes with their sometimes convoluted brake systems with 2 master cylinders per brake.

[ritratto]

Reverse bleed them. You inject brake fluid into the caliper and it pushed the air up and out through master cylinder. Traditionally when you bleed brakes you try to suck the air downward and out through the caliper. Air in the system want to go to a high point and vent to atmosphere. So why try to for it in a direction it doesn't want to go while doing so under vacuum potentially sucking in more air. 

When I did my T3 I read and heard horror stories about trying to bleed the linked brakes. My system was totally rebuilt so there was no fluid in it. Reverse bleeding it took 15 minutes to bleed all 3 brake calipers and about 10 ounces of brake fluid.

Unless its an impossibility I will never bleed brakes the traditional top down method ever again.

All you need is a plastic syringe available at Tractor Supply or the like and a 6" piece of 1/4" Aquarium tubing.

1. Tie the brake lever back so that air and fluid can vent into the master cylinder reservoir.
2. Put a section of tubing on the syringe and drawl out a syringe full of new brake fluid.
3. Working from the caliper furthest away from the MC slip the other end of the tubing over the bleed nipple and hold it vertical so any rise to wards the plunger.
4. Crack open the brake bleed nipple and depress the plunger slowly (push hard and you'll have a fluid volcano the MC) and inject fluid into the system. When the syringe is almost empty close the bleed nipple refill and repeat until clear bubble free fluid is in the master cylinder reservoir.
5. Move to the next furthest away caliper and repeat.


One thing to mention is keep an eye on the MC reservoir that you don't over fill it. Use a syringe to suck out excess fluid as needed. 


This is the simplest, cheapest and most effective way to bleed brakes linked or not.

That sounds like an awesome way to do it! Will try next!

[Diploman]

  Reverse Bleed.  This procedure takes advantage of physics, with air bubbles wanting to migrate upwards.

I fitted this junction with bleeder under the tank of my V50 - at the highest point of the linked system - to simplify bleeding.   Works like a charm - hard pedal in under ten minutes.

[Tom H]

This worked for me.

Install Speed Bleeders. Remove rear caliper and put a block between the pads. Hang caliper so the bleed nipple is pointing up. Attach a hose to the bleeder and put the other end in a catch can. Bleed the rear brake first by pumping the pedal. Then bleed the front brake.

My EV has a valve/restrictor installed in the front brake line. If I bleed the front, the longest line first, when I bleed the rear the front looses the fluid. Don't fully understand it, but that's what it was doing.

I was going to try the reverse bleeding, but could not locate a syringe that would work.

Tom

[rodekyll]

Try your local pharmacy for a large irrigation syringe.  Mine is 60ml (2oz).  I have three.  One for Guzzi bleed sizes, one for other size hoses and one for dirty fluid.  They're a couple bucks r so each -- I paid $10 for my 3.  I give clear hose extra points.  I have a couple feet on the syringes to give me more range.

[Perazzimx14]

Or go to Amazon and type in 100ML (3.4 ounce) catheter tip syringe. You can get them buy the piece or in case quantities. 

[Tom H]

In a Tim Allen (I think) snotty sassy voice, "Just stop at your local pharmacy...." So I stopped at the local CVS, no we don't carry those, try a medical supply store. I guess I'm back to Amazon to search a good price. Then to top it off there. I figured I'd pick up a few things. Cool, all were on sale! Wrong, only if you have a CVS discount card   

Edit: Amazon had a few at decent pricing, shipping was high. Found the 150ML size on ebay at a good price.


Tom

[n3303j]

1. Tie the brake lever back so that air and fluid can vent into the master cylinder reservoir.
(SNIP)

With the lever tied down you have closed the path between the master cylinder and the reservoir and the system will not reverse bleed.
Lever must be left in the "at rest" position for the system to be open from the bleed nipple to the brake fluid reservoir.