Bleed your trailer brakes

[WHazelwood]

I just recently changed out the Lippert 8000 lb. axels on my DRV suites. My own laziness cost me.
I checked the pads before making a trip to Montana last summer and they were about 1/2 worn. (I only looked at the rear axel because the steps and sewage lines make it harder to look at the front axle) While in Montana I had to make a couple of emergency stops but didn't think any thing of it. By the time we got back to Huntsville AL my trailer brakes weren't holding. I'd scored the front disks with metal to metal so bad the disks couldn't be turned. The rear axle pads still showed over 50% thickness. they were air locked. Not sure they had ever been bled. New axles, new brakes, all cylinders bled and now had to turn down the brake controller gain because of increased braking capacity on the trailer.
Don't be lazy it'll cost you and maybe someone else too.
Keep grinnin,
Walt

 

[Cummins12V98]

What year DRV? You replace the calipers also?

 

[NIsaacs]

Why did you replace the axles, and who did you go with? Who supplied the brakes?

 

[GCroyle]

Walt,

Any pics of the brakes?
What brand of brakes and actuator?

Any explanation of air-locked folks. I own a trailer with Dexter four piston brakes pretty familiar with them but trying to understand how un bled brakes dragged and created the problem for Walt. These systems do not hold hydraulic pressure but mechanical binding is another story.

This is also a good reason for internal TPMS sensors that pick up temp in the wheel, I bet it would have detected this in advance. It did on my rig when I had a dragging pad.

Gary

 

[JR]

If I'm understanding correctly he's saying he only checked the rears for pad thickness and because they weren't properly bled from initial set up they were not pulling their share of the load therefore wearing the fronts much more quickly.

 

[Wiredawg]

I performed full service on my axles and brakes on my 2015 DRV and everything was great. I lubed caliper slides, replaced pads, ~40% material left, and lubed axles and IS arms. I perform full inspection every year.

Cheers, Ron

 

[WHazelwood]

It's a 2009 DRV. I replaced the axels because they had sealed bearings and the disk/hub is no longer made. The brakes are Kodiak. Lippert gave me a 2 for 1 price because of that.
The axels came complete with brakes & springs. I bought new grease bolts and shocks in addition.

 

[WHazelwood]

It's a 2009 DRV. The axels had sealed bearings that were in good shape, no play. I replaced because the disk/hub is no longer available. Lippert gave me a 2 for 1 price. I also bought new grease bolts and shocks. The brakes were Kodiak. Seems like all the braking was only one side so the caliper slide bolts were also stuck.
Nothing beats pulling the wheel and inspecting. I got lazy and it bit.

 

[Wiredawg]

I recently helped a friend repack the bearings, service the brakes, and used my torque wrench to properly torque lug nuts. I told him he REALLY needs a torque wrench to add to his toolbox. He didn't follow my instructions, got a slow leak in one of his tires, changed it, and guessed at the torque. A few weeks ago, he left from Cibolo TX to Tallahassee FL and on the way, all 5 lug bolts sheared off and lost the entire wheel and tire. He apparently over torqued them.

Anyhoo, just a side story recurring maintenance and proper procedures critical to health and safety of RV.

Cheers, Ron

 

[WHazelwood]

When I installed the new axels I bled the brake lines before I hooked them up to the calipers. The rears were blocked and it took a few seconds before any fluid came out, that's why I'm not sure they had ever been bled. After I hooked the lines up to the calipers I bled them again and fluid came out immediately.
The axels were replaced because the disk/hub is no longer available. They were the sealed bearings so I didn't need to inspect and repack other than check for play. Lippert gave a 2 for 1 price and I also bought new shocks and grease bolts.

 

[WHazelwood]

Sorry for the double post. I need more coffee

 

[GCroyle]

If I'm understanding correctly he's saying he only checked the rears for pad thickness and because they weren't properly bled from initial set up they were not pulling their share of the load therefore wearing the fronts much more quickly.

JR,

It's one circuit from the actuator split four ways to each caliper. Hyd pressure (by design) is available equally throughout the system. But mechanical binding issues is a new story.

Gary

 

[GCroyle]

When I installed the new axels I bled the brake lines before I hooked them up to the calipers. The rears were blocked and it took a few seconds before any fluid came out, that's why I'm not sure they had ever been bled. After I hooked the lines up to the calipers I bled them again and fluid came out immediately.
The axels were replaced because the disk/hub is no longer available. They were the sealed bearings so I didn't need to inspect and repack other than check for play. Lippert gave a 2 for 1 price and I also bought new shocks and grease bolts.View attachment 119413 View attachment 119414

WHazelwood,

An air bubble anywhere in your trailer brake circuit first will affect how long it takes for your trailer brakes to kick in and start applying brakes. The actuator is a hyd pump and as long as it doesn't run out of fluid will just keep pumping, compress the air completely and then start to make hyd pressure. Air = delayed braking. The TV has a master cyl and you use one stroke to do the same when it's fully bled, no delay.

This is a write up I did on my rig in 2012 where I actually measured Pressure vs Time using video editing software to get the values, it's shown in the YT video link. Some of this also addressed a design oops Airstream did on the short hose they used, different issue.

https://www.airforums.com/forums/f439/disc-brake-lag-pressure-vs-time-96724.html

Do you have single piston calipers? Those are a lot easier to bleed assuming the bleed screw is on the TOP of the caliper. If you don't have an IR temp gun this is a great reason to get one as you watch the behavior of these brakes and get things normalized.

Your pic showing one side of the rotor worn off sure looks like caliper/pad drag on one side. You have disc brakes they are tops in braking and should behave that way. I think until an RV trailer owner experiences what disc brakes feel like, it's like a packaged donut vs a hot Krispy Kreme.

Gary

 

[GCroyle]

I recently helped a friend repack the bearings, service the brakes, and used my torque wrench to properly torque lug nuts. I told him he REALLY needs a torque wrench to add to his toolbox. He didn't follow my instructions, got a slow leak in one of his tires, changed it, and guessed at the torque. A few weeks ago, he left from Cibolo TX to Tallahassee FL and on the way, all 5 lug bolts sheared off and lost the entire wheel and tire. He apparently over torqued them.

Anyhoo, just a side story recurring maintenance and proper procedures critical to health and safety of RV.

Cheers, Ron

You picked a fine time to leave me loose wheel!

 

[Cummins12V98]

I had a similar LOOKING issue with my 07.5 MS with the same rotors calipers and sealed bearings. The pads were simply POS and literally one side had fallen off the the caliper was digging into the rotor.

Kodiak sent me new parts for free. I really doubt it had a darn thing to do with bleeding. Bleeding is very important for sure and when doing so with the HydraStar actuator I highly advise having someone adding fluid while someone is bleeding as it's easy to get air in the system and if that happens the brakes just don't work like they should.

My Current DRV pictured below had the caliper bushings simply wear out from poor quality materials. Two failed and two were fine.

 

[Cummins12V98]

Those with 2016 era DRV's I highly suggest checking the caliper rubber bushings. I know a few people with this issue! It causes the caliper to get crooked and bind causing the above damage!

I replaced EVERYTHING and went to true oil bath last fall with EBC pads.

 

[GCroyle]

Cummins12V98,

Looks real good. You're lucky those calipers take automotive pads, I don't know of an optional pad for the Dexter 4 piston calipers.

Hydrastar reservoir while bleeding as you state it's a wee bit smaller than I'd like too.

Gary

 

[GAmes]

He apparently over torqued them.

I'm inclined to think he under torqued them. It is a common occurrence with outboard boat engine props. The nuts loosen and the wheel wobble shears the studs.

 

[rikbakke]

Just finished an electric drum to hydraulic disc upgrade on my Northwood Fox Mountain fifth wheel. Great, outstanding change. Yes, the hydrastar actuator has a small reservoir. If you’re not careful and consistent during bleeding, you’ll run the reservoir dry and pump air into the lines. There’s an add on extended reservoir but it’s another $150. I carefully bled the system 3 times. I was still getting a little air out during the second bleed. I figure a lot of installs out there are not bled sufficiently. I used kodiak e-coat discs, hydrastar actuator and steel lines cut and bent to fit. I won’t miss electric drums one bit.

 

[GCroyle]

Rik,

Dexter offers an actuator also. https://www.dexteraxle.com/docs/def...h-actuator-(lit-609-00).pdf?sfvrsn=5978e448_2 They describe "large brake fluid reservoir" but don't say how many oz that is. I've never worked with the Kodiak but being single piston it should be easier to bleed than the Dexter 4 piston calipers. As you get to know this system if you feel delay in trailer braking then consider bleeding again. i have used three folks if available on mine. Wrench man, slider person and a fluid topper upper while bleeding to get a longer cycle.

Enjoy the real brakes.

Gary