SMC Leveling Jack Replacment

[Karl Welhart]

My original SMC leveling jacks (to the axle) have been leaking for some time.  Others have experienced the same problem and because replacement jacks are not available, most have elected to go with HWH air leveling systems at a cost of just under $5,000.00.  I tried to get the jacks rebuild, but to no avail decided to find a way to replace them with new hydraulic jacks.

Searching the internet and talking to all the current manufacturers of hydraulic leveling systems in the county. I decided to try Bigfoot (Quadra MFG) jacks.  The capacity of each jack is slightly less (12,275#s vs. 17,600#s) and the bracket needs some modification w/3/4" spacers, but in the end they work fine.  The cost for materials (jacks, switches, foot/pads and misc. hardware) is about $1,800.00 and labor was $600.00.

Now, just keeping my fingers crossed that my control panel, level sensor and brain keep working....

[Keith Moffett]

Karl
Beaver Coach Sales manufactures a replacement control system should yours crap out.  We also have the SMC leveling and are keeping a close eye on it for the same reasons.

Good luck
Keith

[Edward Buker]

Karl,

I assume that pricing was for one jack?

Later Ed

[Karl Welhart]

Ed,

No, that is for all 4 jacks..  New jacks, hardware, pads, and fittings.

[Edward Buker]

Karl,

That sounds reasonable for all the change that was made. Congratulations for going where no Beaver owner has gone before...

With the weight capacity being less one might rationalize that the ram diameter would be less. With the same volume of fluid coming through the pump and valves that would translate into a faster moving ram during lift as well as a faster "fall". My sense is that the rate of fall is already too fast. What is the experience with the new cylinders, is the size really different, what might have changed performance wise?  Did you have the old "feet" cut off and welded on the new cylinders?

Later Ed

[Karl Welhart]

Ed,

The old cylinders were a 2.0" ram, 3.0" bore, 3.5" OD and 9.5" stroke.  The new ones are 1.5" ram, 2.5" bore, 2.875" OD and 10" stroke.  I have only cycled a few times and I do not think the air is completely out of the system.  The upstroke does not seem any faster than the old ones, not sure about the retract.  Auto retract seems about the same, but manual retract seems faster.  I have only done one (1) auto retract and two (2) manual retracts.

Yes, I purchased new pads from Bigfoot and cut them down to 4" round, then welded a 3/4"x 4" tubing to the new cut pad.  The result was a pad that looks just like the old one.  Originally, I was going to cut off the old pads and use them on the new ones, but decided to just modify the new ones.  BTW, the new ones bolt one with a special locknut.  The old ones are welded on.  Will check these overtime, just to make sure they are not being damaged by the landing pads.

The biggest issue is the distance between the frame to center line of cylinder/ram from the old to the new.  The difference is almost an 1" and ended up using 3/4" spacers on the new cylinders between the frame and mounting brackets.  The mounting hole locations are also a little different.  Width is fine, but the precut holes on the new ones are OK for the top two, but different enough on the other four (4) to require some modification on the brackets.  There are six (6) bolts on each jack bracket with loose bolts and nuts on the front, but permanent bolts w/loose nuts on the rear.  The final alignment seem right on at this point.

Not sure that every application of the SMC leveling system can use this method to replacing the old cylinders.  Nor will everyone that has the SMC leveling system want to keep the hydraulic jacks vs. the HWH air leveling system.  Additionally, I am comfortable that these old jacks can be rebuilt (someone reported on this forum they did successfully rebuild theirs), but for not a lot more money it appears to be new replacements that will work.  BTW, these replacement jacks by Bigfoot are re-buildable.

Another option that I considered was Bigfoot jacks that would be re-located on the frame behind the axles than go to the ground for leveling using the SMC control/pump system. Just keeping my fingers crossed that this will hold up for a few more years.

[Edward Buker]

Interesting, love to see a photo if you feel like posting one some time. You certainly went in deep on this project.....glad it is working out.

Later Ed

[Karl Welhart]

Ed,

Yes, this has been a very interesting venture.  Not 100% there yet, but after 3 months, I am hopeful at a good end result.  Will try to get some pictures.

[Karl Welhart]

Ed,

Just as a follow-up: I have filled the reservoir (took a gallon) and everything is working fine.  The speed seems the same as before except the manual retract does seem faster.  Not sure why that would make any difference.  The auto retract was always faster than the manual retract, now they are about the same speed.

[Edward Buker]

Karl,

Glad it is all working.

I have never liked the retract process as it is on automatic, seems very fast and abrupt especially when the suspension does not call for air. I do not leave the leveling system one once leveled and I do not know if that would make a difference in the auto retract speed. I leave it off thinking that fewer power on hours may have it last longer given they are not readily available.

Since owning this coach the best process I have found is to air up which will sometimes only fill some of the air bags due to leveling having one end of the coach high enough for the ride height valves are not calling for air. I bump the manual retract on and off in short cycles until the air starts to fill the bags (you can watch the gauge) and when that system has fully aired all the bags I can then do a more aggressive retract until fully retracted. This is the gentlest version of retract that I have come up with. Not sure what you do or if you want to try that with the new cylinders if in fact they are more abrupt in the "fall".

Later Ed

[Karl Welhart]

Ed,

I normally, shut my system off during any stay of more than a couple of nights.  Thus, you can only use the manual retract as the auto retract will not function due to turning the system off.  However, my experience is a little different than yours.  My manual retract was slower and therefore smoother than the auto retract method.  It will be interesting to see how these new jacks perform under the two retract methods.  At this point, I am on relatively level ground and the new jacks have not (or cannot) fully extend, therefore the retract mode is very hard to judge compared to real campground situations.

[Marty and Suzie Schenck]

Ed,
      When I had my leveling system repaired at BCS in 2008, that is the way they told me to bring the levelers up. Air up the system bags and then bring the levelers up. If I am just spending the night at a facility I will use my onboard air compressor (it's quiet) to air up the system then bring up the levelers. That way I can light off the engine, drop it in gear and idle out without disturbing sleeping neighbors.
Marty

[Edward Buker]

Marty,

Do you have air leveling when you are parked or just the standard air bag suspension? With the standard air bag suspension the coach frame has to be low enough to open the ride height valves, so many times while you are using the frame to axle jack leveling system you have to drop some without any air in the bags in the front or rear or both, just to get the air valves to open. Maybe you have both systems and can force air in the bags, not sure.

Later Ed

[Marty and Suzie Schenck]

Ed,
      I just have the standard SMC hydraulic leveling no air. To level, turn on system, after it thinks press auto or semi. I press auto and it dumps the air then the rams do their work on the axles. When BCS repaired my system (two wires and two hoses reversed) they said always start it up and air the system and then raise the leveling jacks. Since then (2008) I have had no problems with that system (fingers crossed LOL).
Marty

[George H. Wall]

Marty, When I bought mine new, I also had 2 hoses reversed. Must have been a FRIDAY or MONDAY job on ours!!  Henry