AIR BAG LIFTERS
On Thu, 5 Mar 1998 16:40:10 -0600 "Chuck Blanford"
Has anyone installed the air bag lifters that are advertised in GMCMM? What was your experience, and what are the advantages/disadvantages?
Thanks
Chuck
77 Kingsley
Date: Fri, 06 Mar 1998 16:06:14 EST
From: davegreenberg1#juno.com (David L. Greenberg)
Subject: Re: GMC: Air Bag Lifters
Hi Chuck,
I had Alex Sirum install them when I was having new brakes done and frankly I can't say I feel any big difference. They are supposed to carry less air and theoretically they move the bags a tad farther away from a flailing tire in case of a blowout, but I do know they don't let you raise or lower the coach as far as you can with out them.
Probably someone out there has better experience to relate.
David Lee Greenberg
Date: Fri, 6 Mar 1998 16:22:50 -0500
From: "Bartz, Paul" <s9d3452#mail.drms.dla.mil>
Subject: RE: GMC: Air Bag Lifters
Scott:
The bag lifters are a kit of plates and hardware. You remove the bags, install the plates at the bag anchoring/mounting locations on each of the suspension arms (i.e. two plates per bag) and then re-install the bags, however the bags mount at the upper hole of the plates.
The principal is that the plates holding the repositioned bags, allow the bags to be positioned about two inches higher in elevation than original, provides a longer lever. Thus, less air pressure is required to elevate the coach to any given height. Additionally, it's claimed that a softer ride is achieved due to the lower bag air pressure.
I installed both the four-air bag and six-wheel disk brakes on our coach in March 1995 at the GMCMI Myrtle Beach Rally and am very happy with them. While installing them, there was no end of spectators watching the installation throughout the day and two GMC'er friends even helped with the wrenching.
The air bags definitely dampen the side-to-side and fore-to-aft movement of the coach while under motion. At the time, they eliminated about 60% of the wiggle one experiences when traversing rutted asphalt pavement. Bridgestone R-265 tires took care of the remainder of the wiggle.
My wife was the instigator behind upgrading the brakes once she learned that brake fade was not a factor in mountainous driving with them installed.
Paul Bartz
Date: Wed, 11 Mar 1998 22:47:50 EST
From: CHill113 <CHill113#aol.com>
Subject: Re: GMC: Air Bag Lifters
I haven't seen the ad you mention but I have installed air bag lifters which I bought from Ray Rhodes in Dallas. They are great. The ride is noticeably smoother (softer) because of the lower air pressure in the bags. I have not noticed any disadvantages. Handling is fine. I had one problem. Mine came with 'star' type lock washers. After about 2,000 miles the nuts loosened up. I replaced the lock washers with the split type and have not had any more trouble. I probably have 20K on the lifters.
You do not need to make any adjustments to the leveling mechanism. It works the same.
Justin Hill
Date: Wed, 11 Mar 1998 22:50:12 EST
From: CHill113 <CHill113#aol.com>
Subject: Re: GMC: Air Bag Lifters
They are extentions about 3 inches long that bolt where the air bag now bolts in. Then the air bag is bolted in new holes about 3 inches higher. This 'fulcrum' effect (if that is the correct term) doesn't require as much air pressure in the bags. The pressure is automatically adjusted by your present leveling device.
Justin
Date: Wed, 11 Mar 1998 23:54:08 -0500
From: 9675.0203#tcon.net
Subject: Re: GMC: Air Bag Lifters
Justin,
Do you have the address, tel # of Ray Rhodes? How about the cost? The ones I have seen an add for are from Paul Bennett in Columbia, SC, cost ..$119.95+SH for a complete set for both sides.
Ray Rhodes address is 9837 Chiswell Rd, Dallas, TX 75238. Phone 214-348-0616 You may encounter a new area code because there are now several area codes for Dallas. I don't recall how much I paid for my air bag lifters, but I don't think it was that much. Give Ray a call. He is a nice guy.
Justin
Date: Thu, 12 Mar 1998 10:02:10 -0500
From: "Bartz, Paul" <s9d3452#mail.drms.dla.mil>
Subject: RE: GMC: Air Bag Lifters
Justin:
The pin fixing the suspension arm to the center casting is the fulcrum. The bag is at the opposite end of the arm from the fulcrum, making the arm a lever. The air bag lifters extend the length of the arm. With the air bag lifter installed you have a longer lever.
Think of the effect as the mechanical advantage you get in going from a short handled lug nut wrench to a longer one. It is easier (less force is required) to turn the lug nut with a longer vs. a shorter length wrench.
Thus, with air bag lifters installed, less air pressure (force) is required to raise the coach to any given level compared to not having the lifters.
Paul Bartz
Date:98-03-12 12:17:43 EST
From:Chuck.Blanford#LPCorp.com (Chuck Blanford)
Justin,
Does your coach still have the full range of motion re raising/lowering/leveling that you had pre-lifters?
Date: Thu, 12 Mar 1998 17:56:54 EST
From: CHill113 <CHill113#aol.com>
Subject: Re: GMC: Air Bag Lifters
Chuck,
I have not been aware of any change in range of motion, but that is not to say there isn't any. I never was one to try to level significantly with the air bags, such as several inches. My wife says I'm too impatient to wait for it to pump up so I usually run it up on a block and then finish off with the air bags. I'm very pleased with the ride. We have a late model Buick Park Ave, and with good tires and balance I believe the GMC rides as good as the car. The coach is a late '77 and I have been fortunate that it tracks well on the highway and doesn't seem to have the wander I hear complaints about.
Justin
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Date: Thu, 12 Mar 1998 20:51:05 -0500
From: "The Hamiltons" <hamilton#king.igs.net>
Subject: GMC: Air Bag Lifters
I put air bag lifters on a couple of years ago based on the comments of some experienced users. My results have been no change in ride or control and I assume that is because the lower air bag pressure is off set by the increased mechanical advantage. I notice no difference when lowering the coach but have lost about an inch in maximum height for campground leveling. The benefit I like is the 20 to 30 or so lbs less of pressure in the bags which means less time the pump runs to level or to "travel". I adjusted the pump pressure regulator to cut off at 100 psi rather than 120 psi. The last 20 psi takes longer than previous 20 psi.
Al Hamilton
You don't say why you're replacing the bags, but, according to Cinnabar, if you can't see bare cord, they should still be fine. Like the new serpertine accessory belts on new cars, the rubber covering cracks from flexing, but the underlying structure is still strong. Once the rubber cover starts flaking off revealing the cord, it's time to replace. Of course, I understand that "hot dogs" can occur at any time for no apparent reason.
Your mileage may vary,
Patrick
Date: Fri, 25 Dec 1998 16:36:09, -0500
From: (MR EUGENE R FISHER)
Subject: GMC: air bags again
There is a new article in the Cinnabar GMC news (Dec98) that says:
Air bag extenders:
do not extend bag life
make the ride softer but increases the wallow side-to-side
move more toward problems than improvements
Good article we should all read it.
Four baggers:
stiffen the ride (reduce the wallow)
eliminate the prefered bogie action
reduce the leveling action
raise the pressure required
increase the bending load on the center arm
I will find the reference and post it on my web page.
Owners love all of these for different reasons. Be sure to read the
literature to make your own decision
gene
Date: Fri, 25 Dec 1998 20:16:05 -0500
From: "The Hamiltons" <>
Subject: GMC: Air Bags
I haven't read the Dec article in the Cinnibar Newsletter and I
suspect it is excellent based on the quality of other newsletters and
articles. I am going out on a limb and assume the author never used air bag risers/lifters and therefore is only making theoretical comments.
I asked a lot of questions before putting a set on in early 1996 or about 13,000 miles ago. Non-users were against them having not used them. Those that had substantial experience with them on either didn't notice any difference or some difference.
The air bag pressure is reduced from around 95 psi to about 72 - 75 psi. Somewhat less dangerous and damaging if and when a bag explodes. The air pressure regulator can be reset from a maximum of 120 psi to 100 psi - that took 30 to 40 seconds off total pump up time. The air pump doesn't have to labour that last difficult 20 psi.
I contend there is only one suspension change and it's an improvement with risers/lifters installed. The lower air pressure is off set by the increased control arm length and mechanical advantage - no change in ride. There is no change when lowering the coach. I think it may not go as high but has not been a noticeable problem in campground levelling. I believed I detected less sway since installing the risers and asked others for their opinion. Some noticed no change. Some felt there was less sway, and like I, could not explain it. Here is a possible reason there is less sway in my opinion. The air bag cones cause progressive dampening as the two ends of the bag are forced further and further to the wider parts of the cones. With risers on, the bag is on a narrower part of the cone at the same ride height as before - more force is required to move the air bag from a narrower part to the wider part, producing more dampening or less sway.
I would be interested in other opinions and experiences.
Al Hamilton
76 Eleganza II
Kingston, Ont
Date: Sun, 27 Dec 1998 17:40:43 EST
From:
Subject: Re: GMC: air bags again
The term "extenders" applies to the height of the bag and doesn't imply
longer bag life. Yes, it does make the ride softer and I have not experienced any wallow. I've had them on my coach for probably 30,000 miles with no problems so far. Just my experience with them'.
Justin 77PB
7PB
LIFTERS
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