Brake Fluid - change

dtw1 · 07-30-2018, 10:12 PM

I have a 2012 DRV Elite Suites 38' long. It has Kodiak disc brakes and a Hydrastar hydraulic brake actuator. The brake fluid has never been changed. Both Kodiak and Hydrastar recommend changing the brake fluid every 5 years. This trailer gets a fair amount of use traveling from St. Louis to Palm Springs and back every winter plus assorted other trips in the Midwest. The usual mileage per year on the trailer is 5,000 miles. Is it worth changing the brake fluid? Should I use synthetic brake fluid?

juicesqueezer · 07-30-2018, 10:25 PM

I'm sure someone will chime in on here that has that system. I don't, so sorry!

Porthole · 07-31-2018, 12:39 AM

Do you ever change the brake fluid in your car or truck?

That said, I change my synthetic brake fluid on my motorcycle about every three years.

I don't ‘change’ the brake fluid in the RV, but I do a good brake system bleed every few years, with synthetic.

If you try bleeding the brakes,, use a piece of clear hose over the bleeder and capture the fluid in a clear jar.

If it is dark, non transparent - change it.

The Gritz Carlton · 07-31-2018, 11:25 AM

It never hurts to change ANY fluid in anything. Brake fluid in particular absorbs moisture faster than any other fluid. Change it, but using the bleeder method as Porthole mentioned...not draining it out.

Pete'sMH · 07-31-2018, 12:58 PM

Quote:

Originally Posted by The Gritz Carlton

It never hurts to change ANY fluid in anything. Brake fluid in particular absorbs moisture faster than any other fluid. Change it, but using the bleeder method as Porthole mentioned...not draining it out.

Is it “trickier” than that on a vehicle with ABS? I’m a big fan of changing fluids and I’d like to do it myself as I do on my old motorcycle. It’s interesting to me that many service folks don’t want to do it unless I insist. Same with transmission fluid. At least with cars.

mtntrek · 07-31-2018, 07:24 PM

I'm generally a "if it ain't broke, don't fix it".
Wondering if you've at least inspected your pads etc.?

With the age and mileage of your unit, I'd be prone to inspect inner, outer pads, check caliper bolts, lines for abrasions, etc.
It's not all that difficult to bleed the system, which "might" improve performance. The Hydrastar reservoir doesn't hold as much as you'd think. I've had to top it off after a couple caliper's, or you risk sucking air & having to start over.

The first time I bled, the fluid for whatever reason, was rather dark.
I've used a premium Dot4 as per Hydrastar recommend. It was indeed labeled synthetic.
Best of luck.

Fulltimer50 · 08-01-2018, 11:30 AM

Why do I have to change my brake fluid?
Google says:

Water in the brake lines lowers the boiling point of the fluid, so stopping ability can diminish in hard stops as heat in the system increases. In addition, over time the moisture can cause internal corrosion in the brake lines, calipers, the master cylinder and other components.

Cummins12V98 · 08-01-2018, 02:01 PM

I guarantee anyone that has not bled their brakes since new will have air in the lines.

f350ms38rssa · 08-01-2018, 02:23 PM

My 18 38rssa seems to hesitate a second when I apply the brakes. This is the first braking system like this I have had. Is this normal?

K0LCB · 08-02-2018, 12:50 AM

I pull the breakaway switch to bleed my brakes, I imagine that would work to pump old fluid out

K0LCB · 08-02-2018, 12:52 AM

Quote:

Originally Posted by f350ms38rssa

My 18 38rssa seems to hesitate a second when I apply the brakes. This is the first braking system like this I have had. Is this normal?

There is a slight delay between applying brake and operator charging brakes. The operator pump has to build pressure.

Cummins12V98 · 08-02-2018, 03:31 PM

Quote:

Originally Posted by K0LCB

I pull the breakaway switch to bleed my brakes, I imagine that would work to pump old fluid out

I just have someone hit the "OH SH!T" slide bar to actuate the pump as needed while under the RV. Truck needs to be connected to RV for this to work.

I would not leave actuator on the whole time you are under there bleeding the brakes!!!

Porthole · 08-02-2018, 03:36 PM

Quote:

Originally Posted by Cummins12V98

I just have someone hit the "OH SH!T" slide bar to actuate the pump as needed while under the RV. Truck needs to be connected to RV for this to work.

I would not leave actuator on the whole time you are under there bleeding the brakes!!!

I use a 20' long "jumper"

Speaker wire I had laying around, two spade terminals and a momentary on push button switch.

Some day I'll add a resister to reduce the output some.

Porthole · 08-02-2018, 03:49 PM

Quote:

Originally Posted by f350ms38rssa

My 18 38rssa seems to hesitate a second when I apply the brakes. This is the first braking system like this I have had. Is this normal?

Yes.

Multiple things happening that will give you a perceived or real delay.

The pump is at zero pressure, you hit the brakes and the pump has to "spin up" to start building pressure. Carlisle pumps have 3 pistons (DRV's), Titan pumps have 5 pistons and claim a faster spin up time.

Disc brakes, working correctly will have the pistons slightly retraced when no pressure is applied. If you rotors are not perfectly flat the distance between rotor and pad will increase even more. You have 4 or 6 pistons all acting at once. It is not much fluid, but you are pushing the combined surface area of 4 pistons plus whatever depth the pistons have to move to make contact.

You have a Ford which has some unique features.
Ford's use a pressure transducer in the truck's hydraulic lines for trailer brake input. So actual pedal input is used opposed to an inertia or variable resister input.

If you bring up the dash display showing the connected trailer you can watch the output while stepping on the brake pedal. You will probably see a delay here.

Ford's also reduce the brake current output at lower speeds to reduce the felt tugging in stop and go traffic. IIRC it is about a 20% reduction 11-12 mph or less.

So all of the above can give you a delay. Working correctly the delay is minimal and eventually you don't notice it.

Sure beats electric drum brakes.

Cummins12V98 · 08-02-2018, 03:56 PM

Quote:

Originally Posted by Porthole

I use a 20' long "jumper"

Speaker wire I had laying around, two spade terminals and a momentary on push button switch.

Some day I'll a resister to reduce the output some.

Great idea!

f350ms38rssa · 08-02-2018, 05:09 PM

So u r saying that the slight hesitation is normal?

Cummins12V98 · 08-03-2018, 01:13 AM

Depends on the brake controller. My MaxBrake has zero delay.

Porthole · 08-03-2018, 05:14 PM

Quote:

Originally Posted by f350ms38rssa

My 18 38rssa seems to hesitate a second when I apply the brakes. This is the first braking system like this I have had.

Is this normal?

Quote:

Originally Posted by f350ms38rssa

So u r saying that the slight hesitation is normal?

Quote:

Originally Posted by K0LCB

There is a slight delay between applying brake and operator charging brakes. The operator pump has to build pressure.

Quote:

Originally Posted by Porthole

Yes.

........

Porthole · 08-03-2018, 05:15 PM

Quote:

Originally Posted by Cummins12V98

Depends on the brake controller. My MaxBrake has zero delay.

Pump still has to go from 'zero' to suitable line pressure

Cummins12V98 · 08-03-2018, 05:42 PM

Quote:

Originally Posted by Porthole

Pump still has to go from 'zero' to suitable line pressure

Understood but the MaxBrake has a Honeywell pressure sensor that is tied into a line right on the MasterCylinder and applies voltage instantly as soon as the brake pedal is applied. It is a truly seamless braking experience.

You would have to tow with it to believe it! Honestly it feels like you are using the trucks brakes only.

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