Partial safety block usage

Topic: Partial safety block usage (Read 1177 times) previous topic - next topic

Partial safety block usage

December 28, 2020, 01:29:13 pm

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?

Re: Partial safety block usage

Reply #1 – December 28, 2020, 01:36:56 pm

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.

Re: Partial safety block usage

Reply #2 – December 28, 2020, 01:44:20 pm

Quote from: Elliott – December 28, 2020, 01:29:13 pm

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?

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.

Re: Partial safety block usage

Reply #3 – December 28, 2020, 01:49:51 pm

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.

Re: Partial safety block usage

Reply #4 – December 28, 2020, 01:57:03 pm

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.

Re: Partial safety block usage

Reply #5 – December 28, 2020, 02:57:42 pm

Sage advice regarding blocking both sides in the rear, it makes sense. Thanks guys.

Re: Partial safety block usage

Reply #6 – December 28, 2020, 02:59:01 pm

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.

Re: Partial safety block usage

Reply #7 – December 28, 2020, 03:18:25 pm

Make sure that you are on level ground before blocking . ..

Re: Partial safety block usage

Reply #8 – December 28, 2020, 04:54:43 pm

Better be safe then sorry. Block all 8 spots.

Re: Partial safety block usage

Reply #9 – December 28, 2020, 11:58:07 pm

I block using eight for the air suspension. Also do not forget to block the tires.

Re: Partial safety block usage

Reply #10 – February 16, 2021, 10:55:31 pm

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.

Re: Partial safety block usage

Reply #11 – February 16, 2021, 11:04:28 pm

Of course use it. They hopefully are strong enough to handle the weight.
Johnh

Re: Partial safety block usage

Reply #12 – February 16, 2021, 11:05:38 pm

Hello Elliott.

Can I ask what you are using for safety blocks? I am going under mine soon.

Thanks.

-FT

Re: Partial safety block usage

Reply #13 – February 16, 2021, 11:14:03 pm

See Working Safely around your Foretravel

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.

Re: Partial safety block usage

Reply #14 – February 16, 2021, 11:27:19 pm

Quote from: FtRoadTrip – February 16, 2021, 11:05:38 pm

Can I ask what you are using for safety blocks? I am going under mine soon.

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.

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Re: Partial safety block usage

Reply #15 – February 16, 2021, 11:52:49 pm

Quote from: Elliott – February 16, 2021, 11:27:19 pm

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.
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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.

Re: Partial safety block usage

Reply #16 – February 16, 2021, 11:56:34 pm

Quote from: Chuck & Jeannie – February 16, 2021, 11:52:49 pm

the pressures you mention are too low.

Thanks Chuck, that doesn't surprise me in the least given the questions I'm working through in my air system.

Re: Partial safety block usage

Reply #17 – February 17, 2021, 11:22:53 am

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

Re: Partial safety block usage

Reply #18 – February 17, 2021, 11:27:24 am

Quote from: dicksop – February 17, 2021, 11:22:53 am

Are they too high? Am I going to run into issues fitting them in?

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

Re: Partial safety block usage

Reply #19 – February 17, 2021, 11:28:56 am

yup...I guesS so... Hopefully I wont have to have them cut like elliot has had to!
PETER

Re: Partial safety block usage

Reply #20 – February 17, 2021, 11:32:35 am

Quote from: dicksop – February 17, 2021, 11:22:53 am

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

I think you're going to have to go out and test fitment at all 8 blocking points

Re: Partial safety block usage

Reply #21 – February 17, 2021, 11:36:19 am

Quote from: dicksop – February 17, 2021, 11:28:56 am

Hopefully I wont have to have them cut like elliot has had to!

I will appreciate the company here in the corner. I'm sure we can find another dunce cap for you.

Re: Partial safety block usage

Reply #22 – February 17, 2021, 11:53:42 am

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.

Re: Partial safety block usage

Reply #23 – February 17, 2021, 11:59:13 am

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

Re: Partial safety block usage

Reply #24 – February 17, 2021, 12:02:22 pm

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

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