Hi, me again...
The rear passenger side airbag has a slow, overnight leak it it. The aux pump kicks in 6 or so hours after we level the rig out and keeps us level. When raising the rig manually, that corner is noticeably slower to raise. So, I assume I have a small leak somewhere between the six pack and the bag(s?) that I need to hunt down.
I mention the symptoms because I know I'll get some bonus insight but my real question is: when I put my safety blocks between the two frames to start troubleshooting this, can I block just the one corner I'm working on? Or do I need to put all 8 blocks in?
We have a GV so for me if I lift the coach I use at least four on the back, if iam going to have it up for awhile I use all eight. ^.^d
Agree with Andy - you should at minimum put 4 stands in place at the rear end - two on each side.
If you were to only use 2 stands on one corner, and the other 3 corners were lowered (either intentionally or by chance) then the frame could be badly twisted. It is vitally important to the long term health of your coach to NEVER subject the frame to a severe twisting condition.
Failure to observe this rule will lead to costly damage, including broken windshield glass.
I always use all 8 and lower the coach onto the blocks.
Using all 8 prevents twisting the coach.
Lowering the coach onto the block prevents getting a finger or limb in a tight spot then having the coach un-expectedly lowering down.
I am sure others with more experience will comment about the potential for a leak internal to the six pack. I just ordered the re-build kits so I do not have hands on experience yet.
It is simple enough to use soap bubble solution to check the air bags and associated air lines/connectors. If no leaks found there, then that only leaves an internal leak in one of the 6-pack solenoid valves OR the internal check valve on the affected side of the 6-pack.
Sage advice regarding blocking both sides in the rear, it makes sense. Thanks guys.
Use kiddie bubbles, starting at the 6 pack. Should be able to identify the leak pretty easily.
Said another way, do NOT rule out the 6 pack.
Note: sometimes it takes a whole 12 pack to motivate one to overhaul the 6 pack. Just basic Foretravel math.
Make sure that you are on level ground before blocking . ..
Better be safe then sorry. Block all 8 spots.
I block using eight for the air suspension. Also do not forget to block the tires.
Quick question guys:
I have two leaky airbags in the back, behind the rear drive wheels (one on each side). There's maybe 10" of clearance to get safety blocks in because when I really try to pump up the bags, the path of least resistance becomes the leak. My blocks are 11". Is it safe to put a bottle jack in there and raise the frame that extra inch to get the block in there?
I think the answer is yes, because a 1" offset side to side must be almost routine at any given time while driving but I just want to make sure before I go hog wild.
TIA.
Of course use it. They hopefully are strong enough to handle the weight.
Johnh
Hello Elliott.
Can I ask what you are using for safety blocks? I am going under mine soon.
Thanks.
-FT
See Working Safely around your Foretravel (https://www.foreforums.com/index.php?topic=10632.msg50986#msg50986)
Use 11" - 12" square receiver tubes placed ust inboard of the air bags, 4 for each end. Best to do all eight. If just one end do all 4, one at each bag.
I am using the receiver tubes that are used my many of the folks around here. I'm sheepishly not able to recall which member pointed me to the Harbor Freight ones but here's the link: https://www.harborfreight.com/class-iii-12-in-x-2-in-standard-receiver-tube-69879.html
There seems to be two types of members on the forum: those that can fit 12" blocks and those that can only fit 11" blocks. It turns out I'm in the latter and therefor find myself having these tubes trimmed down by the the Sun City West metal club. I recommend you first max the extension on your bags and measure then buy your blocks because only and idiot would do it the other way around.
To get full extension you:
- Start the engine and wait for your air pressure to get up to the max "travel" psi (probably 90ish psi)
- Put your HWH control pane into the "raise" mode. Watch the pressure dropping in your gauges. It'll probably bottom out around 75ish PSI and then start going back up
- Once it quits going up, you're maxed out and can go measure.
[/list]
Your procedure is correct, but the pressures you mention are too low.
Your "MAX" (compressor cut-out) pressure (where the air dryer purges) should be around 120 psi.
Your minimum (compressor cut-in) pressure should be around 90 psi.
You can adjust the D2 governor to raise cut-in and cut-out pressures. The differential between the two is fixed at approximately 20 psi.
Thanks Chuck, that doesn't surprise me in the least given the questions I'm working through in my air system.
HMMMM...With all these views of "not" being able to get the safety blocks in, I just purchased 8- 12" safety blocks ( 12 " hitch extension)
Are they too high? Am I going to run into issues fitting them in?
Peter
Not to state the obvious, but the answer to your question will be revealed when you try them.
FWIW, 12" hitch extensions fit in all 8 positions on our coach with
at least 1/2" extra clearance to spare.
Safety Stand Placement (https://www.foreforums.com/index.php?topic=38814)
yup...I guesS so... Hopefully I wont have to have them cut like elliot has had to!
PETER
I think you're going to have to go out and test fitment at all 8 blocking points
I will appreciate the company here in the corner. I'm sure we can find another dunce cap for you.
It looks like 12" receiver tubes at Harbor Freight are about $13 each. It is a good price and they are painted.
If you need them the be shorter then consider shopping for a 48" receiver tube. I got mine from Northern Tool for about $40 each. Probably more now. Any 2x2x1/4 steel tube will do. Shop around. Easy to cut with a Sawzall. More work with a hacksaw.
I cut mine at 11 3/4" and they fit in any position when the coach is raised all the way up.
If you are blocking the coach up you might want to add a tag on the steering wheel that reminds you to remove them before moving the coach.
The attached photo should give you an idea of how long the stands can be. The bag from the bottom mount to the top is 8 3/8" with the total from the bottom mount to the top of the air inlet stud being a total of exactly 10 inches. The stud itself is 1 5/8" long so looking at the photo, it appears there is around 2" clearance from the top of the stud to the bottom of the mounting plate above. With that in mind, a 12" safety stand may just fit...or not.
I did this with our air/hydraulic jack without lifting the tire off the ground so there may be some additional clearance to be gained.
I used a couple of my adjustable stands for each airbag I changed so I never measured the total length of the safety stand needed.
Pierce
My 12" HF specials fit easily, as long as I am patient. Those last ones on the rear take a long time to build up to high. When they do, the lowest space is 1/2" with some up to 1 1/2".
Hint: yelling at them or DW doe NOT help, especially the latter!
Trent
Our 12" spacers fit fine both front and back. When the front stops rising, I put the 4 stands in place, by then the back is usually high enough to insert the stands. When all 8 stands are in place then I'll lower coach onto the stands.
But what do you do if you have a large enough bag failure on the road that a plug won't fix it? You can't get full height and or may not be able to have the tire clear the fender well with only one bag to do the heavy lifting.
Pierce
Where/how did you do this? Was the jack on the ground with some sort of extension running to the frame? I think I'm going to buy this hydraulic jack and it would be nice to not have to lift all 30lbs of it into place between the two frames: https://www.harborfreight.com/12-ton-air-hydraulic-bottle-jack-94487.html
The 20 ton was on sale plus I had a discount coupon so about $60 each so I bought two. 12 ton would be fine. Use coach air to raise.
Yes, the jack is too heavy so just keep it on the ground. You should have an adapter like I made to avoid an accident. I only used the ViceGrip to hold the adapter in place while I brought the jack up. I did unscrew the jack's center part several turns so I got max lift from the jack. I made a couple of adjustable safeties to fit between the 2"x3" tubing. My 18V 1/4" drill/impact spins them to the desired extension.
I did have to cut a slot in the adapter small circular ring to get clearance. I also made a relief in the bottom adapter piece so It can't go sideways for any reason.
Pierce
That's my experience too with three coaches. If the coach is aired up it's at about 130psi. I raise until it drops to 75 or so and then do it again. Sometimes twice until that rear end is up high enough. I'm pretty experienced at this as I have to do the same thing to get out of my driveway.
If you're home it's faster to fire up a compressor, plug in an air hose and raise it that way.
Elliott. Seriously, two ells and two tees?
Lets talk in round numbers here. Your U320 weighs about 32,000 pounds. One half of that is 16,000 pounds and we know that in reality one end is heavier than the other. A 12 ton jack lifts 24,000 pounds. That's 0.75 times the jacks rated capacity. Me personally I like to see at least 2X capacity as a safety factor, so for your 16,000 pound half of your RV, 32,000 pounds or 2(16,000). The 20 ton jack is 40,000 pounds for a safety factor of 2.5. Much safer for all involved when you go to lift the heavy half of the coach. I know you're going to load the jack up. We all do it.
Purchase the 20 ton jacks. When you change the airbags, you'll forget the cost of the jack.
Take it from someone who has more than once said "If this thing starts to move on its own step back and wait." Only to see someone with the best of intentions try to stop a (insert large number here) pound machine by pushing with his hands and arms.
Reminds me of the time I wanted to replace the aft U-joint on a '72 Cheevy Van with raised suspension. Van, as usual, was parked in our driveway, which sloped from the garage down to the street. I knew the auto trans was in (P)ark, and assumed the parking brake was set. Chocks? I don't need no stinkin' chocks. Slid under the van from the passenger side ahead of the rear wheel. Removed the retaining bolts on the U-joint and tried to drop the end of the drive shaft. Darn thing was stuck tight and wouldn't move. HMMmmmm... Grabbed my MECHANICS hammer and gave the U-joint a mighty whack. End of drive shaft popped loose with a SPROING noise, and van started to roll slowly down the slope. I grabbed the axle tube and tried to stop it. NOPE! Rear tire was getting close to my body so I skittered sideways out from under the van, which was picking up speed. Ran around the back of the van to the other side and tried to open the driver door. LOCKED! Stood there and watched as the van rolled down the driveway, across the street, jumped the opposite curb, and then stopped in my neighbor's front yard after smashing his mailbox. Learned a few valuable lessons that day.
Never lift the coach unless it's flat and don't put the jack on dirt to lift it. Buy two large HF rubber chocks and run a 3 foot line between the two. Never try to use one, use both, one in front of the wheel and one behind the wheel. You can never drive away from the chock that way. Store the two chocks in the step actuator compartment where they are hidden but instantly available.
Utility companies, fire dept, etc always chock the wheels when the vehicle is parked on the street. Get in the habit.
Pierce
Driving across Pennsylvania in the Rockwood I tried to apply the brakes and felt, and heard a brake pad crumble. A brand new riveted brake pad. We parked at a Loves and I replaced the bad pad with the best of the ones I removed. I did not strap the wheel chocks to the wheel. When I went to put the wheels back on, the Rockwood shifted and fell onto the safety blocks. I went inside and had a cup of coffee. When I began working to raise the rig again a Loves guy came out to talk to me. He left. I finished the job. At the next campground, with the permission of management and some borrowed tools I spent the week changing out the calipers and installing higher quality brake pads. This time I wrapped a ratchet strap around the wheel chocks.
And Eliot? Cut some 1/2" weather proof plywood into 1' squares to place under your jacks. The pavement will thank you and the dirt certainly will do so.
I've already got them cut!
Two els and two tees btw, it's more symmetrical.