 Air Bag Repair [message #285820] |
Tue, 25 August 2015 14:11  |
mechanic007
Messages: 31
Registered: August 2015
Location: Santa Monica, CA
Karma: 0
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The rear end of my '73 23' GMC is very low, about 4" off the ground. It rises up a bit when the engine starts. What are the likely causes of this? How do I repair it?
Is there a way to temporarily make the air bags to raise the rear?
Is there a way of towing it in this condition without having to use a low boy tow truck?
1973 Canyonlands 230 (23')
Odometer reads 37K but probably 137K or 237K
Side wet bath/Rear bed/couch
Kitchen to the rear of the door
inSanity Monica,California
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| Re: Air Bag Repair [message #285825 is a reply to message #285820] |
Tue, 25 August 2015 14:41  |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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mechanic007 wrote on Tue, 25 August 2015 14:11The rear end of my '73 23' GMC is very low, about 4" off the ground. It rises up a bit when the engine starts. What are the likely causes of this? How do I repair it?
Is there a way to temporarily make the air bags to raise the rear?
Is there a way of towing it in this condition without having to use a low boy tow truck? Get a portable 12VDC compressor and two Schrader valves (one for each bag) and some pipe joint compound (NOT TEFLON TAPE). Take the fitting out of the end of the airbag and install the Schrader valve. Air it up high just enough to tow it. Be careful to not overinflate or the bag will explode, and could cause serious injury or death. If you need to run it like that, remove the fuse for the OEM air compressor to keep from burning it up.
[Updated on: Tue, 25 August 2015 14:45] Report message to a moderator |
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| Re: Air Bag Repair [message #285826 is a reply to message #285825] |
Tue, 25 August 2015 14:53 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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You will need to get the frame distance from the road surface to about 8 5/8". This distance is measured from the lower frame edge, under the slot in the frame, located about 4 feet behind the boggies, toward the rear of the frame. Should take about 90 pounds of air pressure. This is close enough to get you home safely. Schrader valves and cut-offs are an important inexpensive addition to the OEM system.
Just what I have done.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: [GMCnet] Air Bag Repair [message #285837 is a reply to message #285832] |
Tue, 25 August 2015 18:00 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Mark,
If you note in the Towing Instructions there are only two acceptable ways pictured, front wheels off the ground and on a flat bed
(lowboy). Despite there being a copy of the MM in the procedure I did not include a picture of a GMC being towed all wheels down
because "I" did not want someone to come back at me noting that my procedure said was OK to do so and the tow truck driver towed a
GMC at highway speeds and ruined the transmission!
Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
-----Original Message-----
From: A.
To expand on what Rob wrote, the Manual says you can tow it all wheels down for up to 50 miles if you don't exceed 35 mph. After
that, you risk damaging the transmission (the tail shaft doesn't get lubed when the vehicle is not under its own power).
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Air Bag Repair [message #285852 is a reply to message #285844] |
Tue, 25 August 2015 21:05 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Mark,
You have a point in this case but I'll bet dollars to donuts what people will remember is that "it's OK to tow a GMC all wheels
down" they'll forget about the distance and speed.
I direct your attention to your sig file stating; "There will always be a demand for scapegoats. The job sucks, but the work is
steady."
When they do and their transmission gets fried guess who is going to be the scapegoat! ;-)
Regards,
Rob M.
The Pedantic Mechanic
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of A.
Sent: Wednesday, August 26, 2015 10:27 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Air Bag Repair
USAussie wrote on Tue, 25 August 2015 18:00
> Mark,
> If you note in the Towing Instructions there are only two acceptable ways pictured, front wheels off the ground and on a flat bed
> (lowboy). Despite there being a copy of the MM in the procedure I did not include a picture of a GMC being towed all wheels down
> because "I" did not want someone to come back at me noting that my procedure said was OK to do so and the tow truck driver
> towed a GMC at highway speeds and ruined the transmission!
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia
I mentioned the flat towing limitations in case he only needs to go 50 miles and he could ride in the cab of the tow truck and raise
holy #3!! if the driver gets to 35.0001 mph.
--
'73 23' Sequoia For Sale
'73 23' CanyonLands For Sale
Upper Alabama
There will always be a demand for scapegoats. The job sucks, but the work is steady.
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Air Bag Repair [message #285861 is a reply to message #285857] |
Tue, 25 August 2015 23:19 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Pay the $ to tow with a large sling truck front wheels off the ground. You
don't need a landoll and you don't need a flatbed ( most flat beds are too
small in capacity anyway).
Why risk the possible damage?
Done it twice too recently
Sully
77 royale
Seattle
On Tuesday, August 25, 2015, A. wrote:
> USAussie wrote on Tue, 25 August 2015 21:05
>> ...guess who is going to be the scapegoat!...
> Pedantic and paranoid. A winning combination.
> --
> '73 23' Sequoia For Sale
> '73 23' CanyonLands For Sale
> Upper Alabama
> There will always be a demand for scapegoats. The job sucks, but the work
> is steady.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: Air Bag Repair [message #285870 is a reply to message #285820] |
Wed, 26 August 2015 07:32 |
77Royale
Messages: 461
Registered: June 2014
Location: Mid Michigan
Karma: 6
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Senior Member |
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One thing worth noting is making sure the air bag actually holds air. The cut offs as mentioned will remove the air lines and compressor from the equation, but if the airbag is torn or has any type of puncture it needs to be replaced. That side can be set up with a dog bone, or other rod as an emergency fix. and there are write ups on a few different ways to do this.
It sounds as if the coach will rise a bit, which is good. so perhaps its a leak in one of the air lines, to which the cut off valves and Shraeders will be a good solution, and I would put those on anyway. Air up the bags to under 90PSI and see if the coach will hold for a few hours, or even better overnight. Spray the aired up bag with some soapy water and look for bubbles. If the airbags will hold like this with the cut offs, you should be good to go. It also depends on how far you need to go. A few miles versus a few thousand miles will make a bit of a difference.
If you do have a bad air bag, depending on location someone may be able to loan or get you a spare good bag until you get the coach to where it needs to go to complete the repairs properly.
To that end, I have no affiliation, but there are 3 bags for sale on the swap meet if you find you need them.
Good luck.
77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson carb and dizzy.
Mid Michigan
[Updated on: Wed, 26 August 2015 07:34] Report message to a moderator |
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