A couple of common problems with an RV hydraulic system that controls leveling jacks and some slides can be resolved with this simple fix. You will find both of these symptoms asked about fairly often online.
Note: This issue seems to be common on 5th wheels with hydraulic leveling systems. We're not sure about other types of RVs.
One symptom is very slow or sluggish system (jacks and slides). Sometimes it will start out fine then slow down to a crawl and possibly stop.
Another symptom is that the jacks or slides just don't operate at all. The system appears to be fine. All the lights are normal, but just don't DO anything.
While not always the case, the culprit is usually a 50 Amp thermal breaker.
These breakers tend to wear down over time and cause the strange symptoms mentioned above or fail altogether. The breaker usually resembles the one pictured to the right.
The simplest solution is to just replace the 50 Amp breaker with a replacement 50 Amp breaker.
We used to carry a spare for this purpose just in case our system stopped working, because that will always happen at the worst time!
However, if you all Grand Design with this issue, or ask online, the preferred solution is to replace it using an 80 Amp breaker. Since our jacks were feeling a bit sluggish anyway, we decided to be proactive and replace it now! GDRV is putting 80A breakers in new 2020 units standard. Thanks, Grand Design!
Consult your RV manufacturer before proceeding with this upgrade / replacement. If you are not comfortable with DC wiring and the inherent risks, please consult a trained professional.
Proceed at your own risk!
50A to 80A Concerns
If you're familiar with electrical wiring, you might be familiar with the general rule of sizing your breaker / fuse to the wiring. The breaker should be the weakest link in the chain because that's its sole purpose in life – to be the point of failure. With that in mind, one might be concerned about upgrading the breaker to 80 Amp without also upgrading all of the wiring involved as well.
The gauge of our wiring for the hydraulic system is all 6 AWG. The difference in gauge needed for 80 Amp versus 50 Amp (for these short distances) is 4 AWG vs 6 AWG, which is only one step difference. 6 AWG is rated at 70 Amps for these distances. Additionally, those ratings are for constant current, but the hydraulic pump only runs for maybe 30 seconds for the slides and around 2 minutes intermittently for the levelers. So, the wiring is sufficient to handle those loads for short durations and distances. If the hydraulic motor has a catastrophic failure causing a short, or the wiring itself shorts, the 80Amp breaker will definitely trip before the wiring gets hot.
Tools and Parts Required
The tools for this job will depend on your setup, but a basic socket set and a couple of screwdrivers should suffice.
Additionally, you will need:
- A replacement breaker – We chose the Bussmann CB185-80
- 6 AWG Cable – We used this battery cable set with 20″ cables (even though we only needed one of the cables in the set, the price is still right and we just kept the counterpart cable as a spare.)
CAUTION: Before proceeding, disconnect all sources of DC power. This will likely require more than just disconnecting the battery from the circuit, as there is also the converter / charger (or inverter / charger in our case) supplying DC power. In our case, we have disconnect switches for both. In most cases, disconnecting the battery (negative first then positive) and flipping the breaker for the converter will do the trick. If you're not certain, seek the assistance of a professional.
Proceed at your own risk! (yes, I said it TWICE) 😎
Note: For our rig, as well as most fifth wheels, all of this work will be done in the front bay.
The first step is to find the breaker you are bypassing. To do this, find the DC+ cable (hopefully it is red), suppling power to the hydraulic pump:
Follow that cable and it should lead you to the breaker. Ours is behind a cover:
Behind that cover should be the 50 Amp thermal breaker:
NOTE: To temporarily bypass the breaker if you're in a situation where the jacks aren't moving and you need to get them up (or down) now, simply move the connection on the left side of the breaker to the right. Be sure to not leave it like that. These breakers are there for a reason after all.
Mount the replacement breaker (anywhere you have room, but close enough for the stock cable to reach) and move the cable (the one going from the pump to the stock breaker) from the stock breaker to the new breaker. The side of the breaker does not matter, electrically speaking.
Then, connect the new cable (use the red one) from the other side of the breaker back to the DC+ bus side of the stock breaker.
Our setup has dedicated bus bars that I installed when installing our shunted battery monitor (blog post to come), so we connected to that DC+ source instead (for simplicity – but connecting back to the stock DC+ bus would have been fine too).
Of course, I put the cover back on it. This is all of our wiring, which includes the new breaker, battery monitor shunt, bus bars, full battery cut-off, and inverter wiring.
Once everything is connected and secured, reconnect the battery (positive then negative), and test the hydraulic system (slides or jacks). You might find (as we did) that the system is much more responsive!
Don't forget to turn your converter / charger back on as well.
Replacing / Upgrading the DC breaker for the hydraulic system is fairly straight forward and simple. Getting ahead of this point of failure now can surely save you time and headache on a travel day. And, you know it would have failed on a cold and rainy travel day! 🥶
If you have any questions or concerns, as always, feel free to reach out to us here. Take care and happy camping!
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