Need on-site help bleeding disc brakes

[wdk450]

Gang:
I have a "little" job I need another person for, and maybe that could happen at the Jackson Rally. I need to bleed my disk brakes system. I have the procedure from the manual for the Carlisle Hydrostar actuator, and need a 2nd person to pump the brakes in the truck and maybe a 3rd to watch that the brake fluid level does not run out in the actuator. I also noted that the disk brake calipers have 2 bleeder screws on each piston (4 per wheel). Do I crack them both together, or seperately?

I have a big bottle of extra fluid, but will buy a bleeder kit from an auto parts store prior to the rally. This bleeding procedure might solve the 3 seconds braking lag I have been experiencing.

A note to any other disk brake equipped trailer owners out there: The Carlisle Hydrostar manual says that the system should be re-bled after it has been in service 7-10 days. I didn't remember hearing that from MorRyde when it was installed. I had my system disassembled last Fall with my major frame repair, and we bled the brakes as the last step of repairs. I am not sure, though, if my mechanic bled the actuator when he did the calipers. I also do not know if he opened both bleed screws.

I think that during that 2014 Fall repair, I inadvertently removed one of the jumper cables in my 4 battery trailer 12 volt system, causing 2 of the batteries not to receive a charge. Of course, the braking actuator was connected to the positive terminal of 1 of the 2 non-charging batteries, causing my trailer braking system to stop functioning without my knowing it. I don't know if the low voltage damaged the actuator, but I am hoping not. Of course, I replaced the missing battery system jumper.

Anyways, if anyone can help me out, I would REALLY appreciate it.

On edit: I think I will make this request a "Maybe". I am going to call Les Schwab locations either in Marysville, or on my way to Jackson, and see if they can do the job. I just measured the brake controller voltage at the truck connector and at the wire going into the actuator, and only measured a 0.2 volt drop on about a 3 volt braking voltage. I think that is O.K.

 

[jbeletti]

Re: EVENT: Heartland Chapter Rally: CA, Jackson - 9/17/2015 to 9/21/2015

Bill - I won't be there or I'd help you do this. As a suggestion - with or without help, consider making up an electric rig that allows you to actuate the brake controller from the wheel area. See my electric rig in the photos in this post. Note that later, I wired the female end of an AC cord to a female 7-wire socket. This rig works great to bleed the system on your own using only any handy 3-wire extension cord with the electric rig.

 

[wdk450]

Re: EVENT: Heartland Chapter Rally: CA, Jackson - 9/17/2015 to 9/21/2015

Bill - I won't be there or I'd help you do this. As a suggestion - with or without help, consider making up an electric rig that allows you to actuate the brake controller from the wheel area. See my electric rig in the photos in this post. Note that later, I wired the female end of an AC cord to a female 7-wire socket. This rig works great to bleed the system on your own using only any handy 3-wire extension cord with the electric rig.

Thanks, Jim,!!!

 

[Jesstruckn/Jesstalkn]

Re: EVENT: Heartland Chapter Rally: CA, Jackson - 9/17/2015 to 9/21/2015

Bill I posted that I would be there to help you out if you need it yesterday but I must have been on a different thread.
We'll have to make sure we don't spill a drop of brake fluid on the concrete because that campground is spotless.

Sent from my XT1254 using Tapatalk

 

[wdk450]

Re: EVENT: Heartland Chapter Rally: CA, Jackson - 9/17/2015 to 9/21/2015

Bill I posted that I would be there to help you out if you need it yesterday but I must have been on a different thread.
We'll have to make sure we don't spill a drop of brake fluid on the concrete because that campground is spotless.

Sent from my XT1254 using Tapatalk

Not that I plan to spill, but brake fluid is clear. I also have 10 days to maybe implement Jim B's neat idea. I carry a 100 foot orange extension cord with me.
Question: Do you have to pull off the tires/rims to do the brake bleed?

 

[wdk450]

Re: EVENT: Heartland Chapter Rally: CA, Jackson - 9/17/2015 to 9/21/2015

Bill - I won't be there or I'd help you do this. As a suggestion - with or without help, consider making up an electric rig that allows you to actuate the brake controller from the wheel area. See my electric rig in the photos in this post. Note that later, I wired the female end of an AC cord to a female 7-wire socket. This rig works great to bleed the system on your own using only any handy 3-wire extension cord with the electric rig.

Jim:
I didn't see the wiring diagram for your one man brake bleeder cable on your post in the other thread, but am assuming you are connecting the braking wire (terminal #2 blue wire) to the charging wire that has 12 volts DC on it from the trailer battery (terminal #4 red wire ) on the trailer 7 pin connector to turn on the electrohydraulic brake actuator as needed.



Jim., BTW if I have to pull off the wheels to do this, I will most likely take it to the tire shop (Les Schwab).

 

[jbeletti]

Re: EVENT: Heartland Chapter Rally: CA, Jackson - 9/17/2015 to 9/21/2015

Bill - I didn't write down my wiring diagram but from your drawing - yes, short pin 2 to pin 4 and instant full braking!

Found a picture of my completed rig:


On my Dexter brakes, I had to remove the wheels. Unsure on the Kodiak brakes. A LOT easier to get to everything with the wheels off.

Now that you've found someone to help you with this, I'm moving these brake posts out of the Jackson rally thread and into their own new thread in the Brakes forum.

 

[Titanguy]

I am assuming the 3 second delay is new and did not have the delay when Mor/ryde installed. Is that correct?
There is no reason you should need to bleed a second time.
Voltage at the truck plug & the actuator should be 10+v minimum checking the blue wire(controller) while brake pedal is depressed. 3 volts will not work.
Test: with truck unhooked, pull the breakaway switch, the pump should come on and bog down as it builds pressure. Mentally record how long it takes for the pump to bog down. If this occurs then the pump is fine.
Test 2: With the truck hooked up depress the controller manual override, the pump should come on and bog down as it builds pressure. Time should be similar to bog down.
If there is air in the lines the pump will not bog down/build pressure at all or will take an extended amount of time. Anything over 4 seconds is excessive.

Bench tests on the Carlisle actuator show 3.0-3.5 sec to full pressure.

 

[wdk450]

I am assuming the 3 second delay is new and did not have the delay when Mor/ryde installed. Is that correct?
There is no reason you should need to bleed a second time.
Voltage at the truck plug & the actuator should be 10+v minimum checking the blue wire(controller) while brake pedal is depressed. 3 volts will not work.
Test: with truck unhooked, pull the breakaway switch, the pump should come on and bog down as it builds pressure. Mentally record how long it takes for the pump to bog down. If this occurs then the pump is fine.
Test 2: With the truck hooked up depress the controller manual override, the pump should come on and bog down as it builds pressure. Time should be similar to bog down.
If there is air in the lines the pump will not bog down/build pressure at all or will take an extended amount of time. Anything over 4 seconds is excessive.



Bench tests on the Carlisle actuator show 3.0-3.5 sec to full pressure.

I will try the bog down test today before I move to another park.

3 seconds lag to feeling the trailer brake is about what I experience when travelling about 15 mph and actuate the manual brake controller lever. I was told on this forum that braking with the electric over hydraulic disks should be instantaneous with no lag. When I phoned Hydrostar they repeated the no braking lag normally opinion, and suggested I bleed the brake system. I personally thought that it would take a few seconds to build up hydraulic pressure in the actuator, but usually defer to professionals (the Hydrostar reps.).

One alternative I can envision to the current electrohydraulic system is a pressurized hydraulic pressure reservoir (similar to the air reservoir used in truck air brakes), and a proportional hydraulic valve applying the hydraulic pressure to the trailer brakes. BTW, the truck air brakes system DOES give a low pressure air alarm in the truck cab when a trailer brake line is broken, unlike the present electrohydraulic disk brake systems used in our trailers, which give NO indication of trailer braking system failure.

I did have the axles removed last Fall during a major rear trailer frame repair by a welder/mechanic. Bleeding the trailer brake system is the last thing we did together.

I found a quote in the Carlysle/Hydrostar actuator manual in the section on brake bleeding that said bleeding should be repeated about 7 days after initial installation. I would think that the same instruction would apply after any opening of the brake lines during trailer repairs.

 

[Titanguy]

Bench tests on the Carlisle & Dexter actuators show an optimum .9-1.1 second lag. The "lag" is the amount of time it takes the actuator to build pressure to 250 psi which is where you will feel the brakes kick in. There are no mfg. using accumulators on Electric/Hydraulic Systems. At .9-1.1 sec a disc brake system is still so far superior to electric brakes it is not close.
Titan uses a 5 piston pump that generates 70 cu. in. per minute vs. Carlisle & Dexter's 3 piston that generates 38-44 cu.in. per minute. This results in a response time of .3 sec vs. the .9-1.1 for the competition.

 

[danemayer]

At .9-1.1 sec a disc brake system is still so far superior to electric brakes it is not close.

60 mph = 90 ft/sec.

How long does it take electric brakes to actuate? Less than 1 revolution of the tire for the shoe to move against the drum. Circumference = Pi * D = 3.14 * 2.5 feet = 7.8 feet. Working backwards, that's about .1 seconds to actuate.

On the other hand, if it takes 1.0 seconds to actuate the disc brakes, you'll have traveled 90 feet before they actuate. If 3.0 seconds, that would be 270 feet.

If disc brakes have a significant delay in actuation, it makes me wonder how they would actually compare in stopping distance when there's a hard stop.

Or do I have this all wrong?

 

[whp4262]

60 mph = 90 ft/sec.

How long does it take electric brakes to actuate? Less than 1 revolution of the tire for the shoe to move against the drum. Circumference = Pi * D = 3.14 * 2.5 feet = 7.8 feet. Working backwards, that's about .1 seconds to actuate.

On the other hand, if it takes 1.0 seconds to actuate the disc brakes, you'll have traveled 90 feet before they actuate. If 3.0 seconds, that would be 270 feet.

If disc brakes have a significant delay in actuation, it makes me wonder how they would actually compare in stopping distance when there's a hard stop.

Or do I have this all wrong?

Yup! Always someone out there that has to throw some math in there to mess up the claims in the glossy brochures.


Sent from my iPhone using Tapatalk

 

[Titanguy]

You are actually right that the activation time is faster with electric brakes. But, what happens after activation is completely different on the 2 systems. The electric magnet system can only apply 300-500 lbs of pressure vs. the 1,500+ psi applied with disc systems. These are benchmarks so, ideal conditions.
Most of us know the issues with electric brakes, brake fade from heat, constant modifying the gain and regular brake adjustments to keep the system operating properly. Most only do what is necessary to get by so electric brakes are very inconsistent.
With disc brakes there are no brake adjustments, the is no need to modify the gain and disc brakes run much cooler that electric drum so there is no brake fade.

Even with a 1 second lag you should still stop 30%-40% faster. It is not close. With the Titan actuator at .3 sec to activate, we will stop a trailer up to 50% faster.
3 seconds is a problem that can be fixed, regardless of the actuator.

BTW, the last 3 disc brake installs that I have done on new trailers have had at least 1 wheel position where the brakes were covered with grease.

 

[jnbhobe]

Cookie and I both run 1/4 inch line from the controller to the split, I can't say I have any noticeable delay.

 

[Titanguy]

The 1/4" line improves volume. All 3 axle trailers must use 1/4" to get the volume. Response time is more a function of the pump spinning from 0 psi to 250 psi. There is an inherent lag time that can be compound by other issues. Most common is bad ground or improper wire gauge.

 

[cookie]

I know what the bench test says about 1/4 vs 3/16, but us laymen have no bench and rely on what is happening on the road to tell us what works.
I ran the 1/4 in line and have no noticeable lag in braking.
I will share the following.
A guy contacted me a while back wanting to know if I knew anything about the brake lag that he had. I asked, and was told that he bought a kit with all the lines included. All were 3/16. I suggested that he run 1/4 in.
He contacted me once again and reported that after replacing the 3/16 with 1/4 in. line his braking lag time was no longer an issue.
So, take from that what you may, but I maintain that 1/4 in. is the way to go.

Peace
Dave

 

[Titanguy]

Evidently I mis spoke, 1/4" line vs 3/16 line can improve lag time.
Bench testing the actuator is done by attaching electronic measuring devices to the hydraulic output line, attaching the actuator to a 12v battery and measuring the time it takes to get to 250 psi.
Isolating the actuator from the system and measuring the time it takes to go from 0 psi to 250 psi at 12v will vary by manufacturer from .3 seconds to 1.1 seconds. This has nothing to do with any other part of the system that indeed could adversely effect lag time.

 

[jmgratz]

All I know is what I have personally experienced and that is the disc brakes stop the coach faster than the electric brakes as I have had both on all 3 of our 5ers.

 

[wdk450]

Dave:
Thanks for the story from your friend. The job of replacing all of the steel tubing sounds daunting to me. I wonder if MorRyde knows about the 3/16 inch versus 1/4 inch tubing and actuation time? You said that this improves things, but I have difficulty seeing how it would make an improvement when the hydraulic outlet on the actuator is 3/16 inch. Maybe that isn't a real factor. I need to talk with my son, the aerospace engineer.

 

[cookie]

Bill, I cannot verify the difference in the two sizes with respect to braking. All I know is what I have and how it works and the story from the other person.

And you're right about the 3/16 fitting which is why I changed mine to a 1/4 in. fitting when I installed the system.
Good catch.

I spoke to Gary Wheeler from MorRyde about the line sizes and he does not agree with the size difference.

Peace
Dave