Bleeding brakes

[alan0043]

Hi Everyone,

I have the need to bleed the brakes on my trailer. I was doing same maintenance on the trailer. I changed the brakes pads. When I was pushing the piston back into the caliper I noticed brake fluid coming out at the bottom of the bleeder. The bleeder had a crack in it. I was able to put a new bleeder in the caliper. That project is a story to it's self. Now back to bleeding the brakes. The trailer has a Titan Brake Rite EHB electric - hydraulic actuator. I am using a Mityvac vacuum pump to pull the brake fluid out. But it does not seem like it is pulling any fluid out. I did not lose much fluid when the brake bleeder broke. The reservoir did not go low. Is the Mityvac the right tool for this job ? Right now I do not have anyone helping me. That is one reason to use the Mityvac. What am I missing ? How would you do this job ?

Thank you for any help,
Al

[Fulltimer51]

I have pulled the emergency brake switch in the past then just bled the brakes.

[remoandiris]

Is this brake the furthest from the reservoir?  If not, you might have to do the furthest first, then work your way back to this one.  At least that is how it is done on most cars.  If air got in, no telling where a bubble might be.

I have used a Mity Vac on a minivan and several motorcycles.  Always worked for me.

[gjhunter01]

Try to bleed out the brakes the old fashion way. Now that you have a good working bleed valve, just crack it open and have someone step on the brake pedal and then close the valve before they release the pedal.

Greg

[ALLOY]

The vac won't pull fluid through the pump in the actuator.

 

 

 

 

 

 

[GlennWest]

If by yourself, go to auto parts and buy a brake bleeder kit. I used mine to bleed my new disk brake install. 

 

 

 

[alan0043]

2 hours ago, remoandiris said:

Is this brake the furthest from the reservoir?  If not, you might have to do the furthest first, then work your way back to this one.  At least that is how it is done on most cars.  If air got in, no telling where a bubble might be.

I have used a Mity Vac on a minivan and several motorcycles.  Always worked for me.

Hi remoandiris,

What is interesting is that the Mityvac manual wants you to start with the shortest line. Here is a statement from the manual. " Wheel cylinders and calipers in succession beginning with the wheel closest to the master cylinder and working to the farthest one."

Please keep the help coming.
Al

[gjhunter01]

Let us know how you solved this, I think J-T is on to something here.

Greg

[Ronbo]

When morryde installed mine, they just pulled the emergency switch. 

[alan0043]

16 hours ago, Ronbo said:

When morryde installed mine, they just pulled the emergency switch. 

Hi Ronbo,

When you say emergency switch I am not sure what you are telling me. I have a Hayes air activated brake controller. I thought maybe if I turn the key to the on position in the truck and pull the black brake lever on the controller to the right I would activate the trailer brakes. I am not sure that is happening.

Al

[Chad Heiser]

11 minutes ago, alan0043 said:

Hi Ronbo,

When you say emergency switch I am sure what you are telling me. I have a Hayes air activated brake controller. I thought maybe if I turn the key to the on position in the truck and pull the black brake lever on the controller to the right I would activate the trailer brakes. I am not sure that is happening.

Al

When he says emergency switch, he is referring to the emergency brake break away cable at the pin box.  When you pull this cable out of the actuator it will apply full pressure to the trailer brakes until the plunger is replaced in the actuator.  Of course it will also be pulling power from your battery bank to do this, so don't leave it this way for extended periods of time and drain your batteries.

[alan0043]

15 hours ago, Chad Heiser said:

When he says emergency switch, he is referring to the emergency brake break away cable at the pin box.  When you pull this cable out of the actuator it will apply full pressure to the trailer brakes until the plunger is replaced in the actuator.  Of course it will also be pulling power from your battery bank to do this, so don't leave it this way for extended periods of time and drain your batteries.

Hi Chad,

Thank you for the help. Do I need to have the key in the truck in the on position ? I assume that I need the have the trailer plugged into the truck. Right now I don't thing I have any voltage going back to the trailer. I will give pulling the emergency brake away cable a try. I will report back later. I am going to go over the rear trailer plug with my meter an see if I have voltage go to the line for the brakes. I need to find a picture of the plug so I can do some testing. I can not find my info on my plug. Doesn't that figure.

Al

PS; Going to the resource guide now

[Chad Heiser]

 

10 minutes ago, alan0043 said:

Hi Chad,

Thank you for the help. Do I need to have the key in the truck in the on position ? I assume that I need the have the trailer plugged into the truck. Right now I don't thing I have any voltage going back the trailer. I will give pulling the emergency brake away cable a try. I will report make later. I am going to go over the rear trailer plug with my meter an see if I have voltage go to the line for the brakes. I need to find a picture of the plug so I can do some testing. I can not find my info on my plug. Doesn't that figure.

Al

PS; Going to the resource guide now

Al,

Your trailer does not have to be connected to anything for the emergency brake breakaway cable to work.  It is completely standalone and is designed to be that way.  It is intended to activate the trailer brakes when the trailer becomes disconnected from the tow vehicle while in transit and the two vehicles (tow vehicle and trailer) separate from one another.  This way the trailer will stop on its own.  It will draw power from the trailer battery bank to activate the trailer brakes whether or not it is hooked up to anything else.

[ALLOY]

 

Just for fun....turn the battery  (if you have one) disconnect off and/or all the power off to the trailer and pull the plug out of the breakaway switch.....the brake actuator should still run.......if it doesn't that something needs to be looked at.

Things I've found:

- brakes connected to the wrong side of a disconnect

- the loose brake wire in the bottom of the battery box.

- a wire for the breakaway that had fallen/pull out the butt connector and was wrapped in electric tape. 

- on our own trailer the plastic broke.....keep a spare screwed to the wall in the front storage now.

The breakaway this is something that if you are driving regularly should be tested a minimum of once a month.  We test it every time before we tow.

 

[alan0043]

2 hours ago, Chad Heiser said:

 

Al,

Your trailer does not have to be connected to anything for the emergency brake breakaway cable to work.  It is completely standalone and is designed to be that way.  It is intended to activate the trailer brakes when the trailer becomes disconnected from the tow vehicle while in transit and the two vehicles (tow vehicle and trailer) separate from one another.  This way the trailer will stop on its own.  It will draw power from the trailer battery bank to activate the trailer brakes whether or not it is hooked up to anything else.

Hi Chad,

Thank you for the help. I tried the idea about using the emergency brake away cable. It worked out just fine. One thing that I did find out was the batteries in the trailer needed to be connected to make the trailer  brakes to work when using the brake controller. I would have thought that the brakes on the trailer would have worked from power from the truck. But that is not the case. With my trailer you need to have the batteries connected in the trailer and the truck brake controller will work just fine. I think that I am on the right path now.

Live and learn,
Al

[alan0043]

Hi Everyone,

One more question. How much time do I have if I pull out the emergency cable to get the brake controller to run ? I don't want to damage the Brake Rite controller because I left it run to long. Can I get away with 2 to 3 minutes of run time. I am doing this job by my self. By the time I crawl under the trailer and back out, it could take me about 3 minutes.

Any thoughts ?
Al

[Chad Heiser]

I think you will be fine with that amount of time. Think how long you sit on the brake at a long stop light.  There isn't much difference between that and what you are doing.

[alan0043]

Hi Everyone,

Here is an update on the brake bleeding. The job is all done. The idea amount using the emergency cable and switch worked out great.

Thank you to everyone for your help. I learned how the brake system works on the trailer.
Al

[Ronbo]

4 hours ago, alan0043 said:

 

[Ray,IN]

RE; the breakaway switch. It must be powered by the trailer batteries in order to stop the trailer after it becomes detached from the tow vehicle. This applies full battery amperage to the switch, which will melt the switch if engaged too long. One time a granddaughter pulled my breakaway cable while visiting us at a CG. When I finally(perhaps 4 hrs)discovered the pulled cable, the breakaway switch had melted/shorted out. I had to replace the trailer batteries shortly after that.

[SCClockDr]

Glad you got it sorted.

One thing to note when contemplating bleeding brakes on an electric over hydraulic trailer is the bleeder itself. There are the standard ones that just seat in the caliper and are otherwise hollow. Then there are the check valve type designed to be "more convenient". I've found the latter type to resist the vacuum type of bleeder.

When using a vacuum bleeder the hose seal is absolutely critical. I use chassis grease to prevent air intrusion.

Once a flow is established I lower the drain container to the ground and gravity will pull out all the air and old fluid if the standard, hollow bleeder is used.

I've also found some pumps cavitate introducing micro bubbles.

For a completely/mostly dry system a full pump reservoir will usually self drain with an open brake line.

As a last resort, I use a fairly long large hose sized to fit over the fill & a bit of lung pressure. (Keep the ends discrete & discard when done).

[RBH]

Another way to activate the hydraulic brake pump is to use a "remote starter" switch. Essentially a momentary on push button switch that mechanics use to activate the starter from under the hood. With long enough patch cords the switch can be used to activate the pump from under the trailer at the caliper. You are than able to activate the switch, open the bleeder, run the fluid thru until it comes out clear, close the bleeder and deactivate the switch. Of course you have to make sure that the reservoir never goes empty. I up-end a quart size bottle of brake fluid into the neck of the reservoir, it will automatically feed fluid as the level drops and if you are using a quart size bottle and vacuum tube pushed onto the bleeder nipple to catch the outgoing fluid you know exactly when to change out the feed bottle. Once you have the set up the actual bleeding goes very quickly. All this works only if the bleeders aren't  seized of course which is a topic for another discussion.