Home » Public Forums » GMCnet » Low Front Ride Height (Help detemining the problem.)
| Low Front Ride Height [message #254050] |
Tue, 01 July 2014 22:49  |
Adrien G.
Messages: 474
Registered: May 2008
Location: Burns Flat, OK 73624
Karma: 1
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Hello netters,
I'm helping a person with a new to them 75 GMC Santana Roll-A-Long. According to the PO, this coach has always been low in front, by about 2 inches.
The lower control arm has been reinforced, the std way not the new stronger way. Using the tool, I turned in the adjusting screws 1 inch with little result, and only about 3/4 inch remains on the screw to go. I felt around the TB socket on control arm for any deformity, and didn't feel any sign of bad socket.
Can the A arm TB socket be bad without showing external evidence? If not, could the TB be weak? How can weak TB be determined?
Would new adjustable pork chops be the solution?
I don't want to cause unnecessary cost to them by guessing.
Thanks all.
Adrien & Jenny Genesoto
75 Glenbrook (26-3) Mods LS3.70 FD / Reaction Sys / 80mm Front&Intermidiate / Hydroboost / 16" Tires / Frame Rebuild / Interior Rebuild
Yuba City,Ca. Text 530-nine-3-three-3-nine-nine-6
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| Re: [GMCnet] Low Front Ride Height [message #254052 is a reply to message #254050] |
Tue, 01 July 2014 23:08  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Adrian,
It's definitely possible for the TB socket in an A-arm to be "blown out" in
an area that cannot be seen, and probably not felt, except with the TB
removed. That was the situation with the one I got with my first 1-Ton
installation. It was so concealed that neither Manny nor his welder who
additionally reinforces the sockets noticed it.
That's not to say that I'd guess that is the cause of the problem you
report. Especially if it's low on both sides with similarly adjusted
bolts. I think it unlikely that both sockets would fail simultaneously.
First think I'd do is get longer adjusting bolts (Gr8, 9-16 NF x 4",
IIRC). You'll have to round the ends of the new bolts to match the
original ones. It that doesn't allow you to achieve normal ride height,
THEN consider the A-arms.
As far as fatigued torsion bars, I'm strictly guessing that an
over-stressed one would show residual strain which would cause the flats on
the hex ends to no longer be parallel (as I THINK they originally were).
That is, if you lay one on a dead flat surface, a good bar should show no
end-to-end twist.
HTH,
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, etc., etc.
www.gmcwipersetc.com
On Tue, Jul 1, 2014 at 11:49 PM, Adrien Genesoto wrote:
> Hello netters,
>
> I'm helping a person with a new to them 75 GMC Santana Roll-A-Long.
> According to the PO, this coach has always been low in front, by about 2
> inches.
> The lower control arm has been reinforced, the std way not the new
> stronger way. Using the tool, I turned in the adjusting screws 1 inch
> with little
> result, and only about 3/4 inch remains on the screw to go. I felt around
> the TB socket on control arm for any deformity, and didn't feel any sign
> of
> bad socket.
>
> Can the A arm TB socket be bad without showing external evidence? If not,
> could the TB be weak? How can weak TB be determined?
> Would new adjustable pork chops be the solution?
>
> I don't want to cause unnecessary cost to them by guessing.
>
> Thanks all.
>
>
> --
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Low Front Ride Height [message #254053 is a reply to message #254050] |
Tue, 01 July 2014 23:13 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
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Senior Member |
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The socket in the control arm can be worn allowing the TB to turn several degrees of rotation before actually engaging the control arm. Mine are. You can't tell from the outside. Also, you must unload the control arm (jack the coach on the frame and let the wheels drop) when you adjust the pork chop bolt. If you don't you will damage the threads on the bolt or the nut that it screws into. Be sure to jack BOTH sides of the coach evenly at the same time or the twist can unseat or break the windows.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: Low Front Ride Height [message #254055 is a reply to message #254050] |
Tue, 01 July 2014 23:28 |
lotsofspareparts
Messages: 726
Registered: May 2014
Location: Arlington, WA
Karma: -9
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Senior Member |
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Dave (otterwan) informed me of the twist that can occur resulting in window loss.
A 3 ton floor jack (as I have used) will lift the coach easily from the middle of the front crossmember. It lifts evenly so no chance of the windows blowing out.
Jared
Jared & Tina Lazaron + 14yr old Daughter.....
77 Eleganza II "Recherché".....
73 Canyon Lands 230 "Elephant"
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| Re: [GMCnet] Low Front Ride Height [message #254057 is a reply to message #254052] |
Tue, 01 July 2014 23:48 |
jim kanomata
Messages: 257
Registered: March 2007
Location: fremont,ca
Karma: 12
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Senior Member |
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We notice that some models like the coachman and that 77-78 seem to ride lower after 100,000 miles.
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Low Front Ride Height [message #254060 is a reply to message #254057] |
Tue, 01 July 2014 23:58 |
Guy Lopes
Messages: 499
Registered: April 2004
Location: Sacramento, CA
Karma: 3
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Senior Member |
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Jim,
I'm curious. 23' and 26' Coachman? Both?
Why would Coachman GMCs be different from any other? What causes this?
Thanks,
Guy Lopes
76 Birchaven "Orion"
Sacramento, CA
W6TOL
www.GMC-Guy.com
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of jim kanomata
Sent: Tuesday, July 01, 2014 9:48 PM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Low Front Ride Height
We notice that some models like the coachman and that 77-78 seem to ride
lower after 100,000 miles.
--
Applied/GMC, Fremont, CA
1-800-752-7502
jimk@appliedgmc.com
www.appliedgmc.com
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Guy Lopes
76 Birchaven "Orion"
Sacramento, CA
W6TOL
www.GMC-Guy.com
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| Re: [GMCnet] Low Front Ride Height [message #254066 is a reply to message #254060] |
Wed, 02 July 2014 00:30 |
Adrien G.
Messages: 474
Registered: May 2008
Location: Burns Flat, OK 73624
Karma: 1
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Senior Member |
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Thanks All,
Since the coach has always been low both sides (by PO 1st owner) and several different angle pork cops where made, originally could the wrong ones have been used causing it to be low when all the interior was added?
I'll pull the TB and check each item ( sockets, TB, and ? ). It's low enough that it's a problem getting under to it jack up.
Thanks all.
Adrien & Jenny Genesoto
75 Glenbrook (26-3) Mods LS3.70 FD / Reaction Sys / 80mm Front&Intermidiate / Hydroboost / 16" Tires / Frame Rebuild / Interior Rebuild
Yuba City,Ca. Text 530-nine-3-three-3-nine-nine-6
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| Re: [GMCnet] Low Front Ride Height [message #254087 is a reply to message #254053] |
Wed, 02 July 2014 07:38 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Terry,
I'm sure you didn't mean to do so, but your wording may make some newbies
think that unloading the control arms by jacking the front wheels off the
ground will be sufficient to unload the adjusting bolts. That IS NOT
sufficient -- it is essential to use a torsion bar adjusting tool to unload
those bolts so that they are not the forcing tool in moving the pork chop.
Just so no one misunderstands.
Oh yeah, Adrian, just in case you don't have it, here's a sketch showing
how to measure the porkchop angle.
Ken H.
On Wed, Jul 2, 2014 at 12:13 AM, Terry wrote:
> The socket in the control arm can be worn allowing the TB to turn several
> degrees of rotation before actually engaging the control arm. Mine are.
> You
> can't tell from the outside. Also, you must unload the control arm (jack
> the coach on the frame and let the wheels drop) when you adjust the pork
> chop
> bolt. If you don't you will damage the threads on the bolt or the nut
> that it screws into. Be sure to jack BOTH sides of the coach evenly at the
> same
> time or the twist can unseat or break the windows.
> --
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Low Front Ride Height [message #254095 is a reply to message #254087] |
Wed, 02 July 2014 09:36 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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Senior Member |
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Didn’t see a drawing Ken!
JR Wright
GMC Great Laker MHC
GMC Eastern States
GMCMHI
78 GMC Buskirk 30’ Stretch
1975 GMC Avion (Under Reconstruction)
Michigan
On Jul 2, 2014, at 8:38 AM, Ken Henderson wrote:
> Terry,
>
> I'm sure you didn't mean to do so, but your wording may make some newbies
> think that unloading the control arms by jacking the front wheels off the
> ground will be sufficient to unload the adjusting bolts. That IS NOT
> sufficient -- it is essential to use a torsion bar adjusting tool to unload
> those bolts so that they are not the forcing tool in moving the pork chop.
>
> Just so no one misunderstands.
>
> Oh yeah, Adrian, just in case you don't have it, here's a sketch showing
> how to measure the porkchop angle.
>
> Ken H.
>
>
> On Wed, Jul 2, 2014 at 12:13 AM, Terry wrote:
>
>> The socket in the control arm can be worn allowing the TB to turn several
>> degrees of rotation before actually engaging the control arm. Mine are.
>> You
>> can't tell from the outside. Also, you must unload the control arm (jack
>> the coach on the frame and let the wheels drop) when you adjust the pork
>> chop
>> bolt. If you don't you will damage the threads on the bolt or the nut
>> that it screws into. Be sure to jack BOTH sides of the coach evenly at the
>> same
>> time or the twist can unseat or break the windows.
>> --
>>
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> GMCnet mailing list
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_______________________________________________
GMCnet mailing list
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: [GMCnet] Low Front Ride Height [message #254147 is a reply to message #254134] |
Wed, 02 July 2014 16:23 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Terry,
I suggest you use your method to your heart's content.
I'll continue to do it as I've done it the past 15 or 20 times over the
past 15 years.
Others may choose freely between our techniques, without criticism from me.
JWID,
Ken H.
On Wed, Jul 2, 2014 at 2:54 PM, Terry wrote:
> I STAND BY WHAT I SAID! Read that manual and see that it says " NEVER
> ATTEMPT TO INCREASE THE RIDE HEIGHT OF THE MOTOR HOME USING THE ADJUSTING
> BOLT
> WHILE THE VEHICLE IS ON THE GROUND." This is page 3a-20 and 21 in my
> manual from GM. Mentions NOTHING about using the tool to change the
> adjustement.
> It DOES say to raise the vehicle, just like I said! READ HERE:
> http://www.gmcmhphotos.com/photos/maintenance/p55078-page3a-20.html
> http://www.gmcmhphotos.com/photos/maintenance/p55079-page3a-21.html
>
> --
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Low Front Ride Height [message #254157 is a reply to message #254147] |
Wed, 02 July 2014 17:43 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
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Senior Member |
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It's not my method, it's just what's in the GMC service manual that came with the coach. When replacing the torsion bar, I had to do it a totally different way when the unloading tool refused to work the way Robs manual indicated. When I tried to do it with the tool I almost lost a helper due to flying parts of the tool. The way I ultimately had to do mine was incredibly dangerous and I will not recommend it to anybody no matter how qualified they are. And I kept both of my helpers standing 12 feet away to avoid the danger. After it was installed, I had no problem turning the lubricated screw up with a standard size ratchet when the wheels were hanging, just like the manual I have says to do. My manual was published in October 1973, and there are some procedures in there that I cannot condone (Like putting the GMC on a 2 post lift!) even though I know they are possible.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: [GMCnet] Low Front Ride Height [message #254183 is a reply to message #254157] |
Wed, 02 July 2014 19:54 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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Bullitthead wrote on Wed, 02 July 2014 16:43It's not my method, it's just what's in the GMC service manual that came with the coach. When replacing the torsion bar, I had to do it a totally different way when the unloading tool refused to work the way Robs manual indicated. When I tried to do it with the tool I almost lost a helper due to flying parts of the tool. The way I ultimately had to do mine was incredibly dangerous and I will not recommend it to anybody no matter how qualified they are. And I kept both of my helpers standing 12 feet away to avoid the danger. After it was installed, I had no problem turning the lubricated screw up with a standard size ratchet when the wheels were hanging, just like the manual I have says to do. My manual was published in October 1973, and there are some procedures in there that I cannot condone (Like putting the GMC on a 2 post lift!) even though I know they are possible.
I've used the tool on a couple of GMC's and even then I'm surprised how much load is on that pork chop. I have to raise mine about 1 1/2 inch and I think I will lower the wheels and use the tool !
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Low Front Ride Height [message #254203 is a reply to message #254183] |
Wed, 02 July 2014 22:09 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
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Senior Member |
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I hope you have a better tool than the one that I borrowed, Bob. I used it to remove the tension to remove the adjuster and all was well. And then I too was amazed at the tension on that setup when putting it back together. However, I was not so amazed that I didn't stop cranking on it to get the chop up far enough to get the adjuster back in and it broke before I got it up far enough. So I had to pay the friend to replace his tool (which of course was not available for over a week) and figure out another way to get that chop adjuster in place. I will not do it that way (the dangerous way I had to do it) again if I ever have to do that job again. If there is a next time to replace the bars I will separate the lower ball joint, hopefully without using a pickle fork that would damage the grease boot. Just adjusting the height up is a much easier thing, as all I need to do is take the coach weight off of the wheels, let them drop, and since I already greased the bolt threads and the cups they go into on the chops, the bolt turns very easily.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: [GMCnet] Low Front Ride Height [message #254240 is a reply to message #254203] |
Thu, 03 July 2014 08:36 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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Senior Member |
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There are a number of people using homemade tools to work with the torsion bar unloading and ride height setting. Some may be robust and some may be less than. I am NOT saying that you should not use what you have, but if one comes apart on you it can be a disaster. The tool that I use is from Tony Lammi and ran about $80 when I bought it few years back and is the strongest I have seen of the newer tools. It is a very good copy of the KM J-22517-02 torsion tool. I have used it on a number of coaches both for disassembly and ride height setting. I always raise the coach up to unload coach weight when adjusting the ride height. Just how I do it. It looks like this:
http://1.bp.blogspot.com/_O22rRx8tVMo/Rs7IOEFMuPI/AAAAAAAAAEE/crmo3RtpUc0/s1600-h/torson.jpg
Tony can be reached at tslamm@acewb.com if he is still making them.
Jim K also sells two version of torsion bar tools too.
JR Wright
GMC Great Laker MHC
GMC Eastern States
GMCMHI
78 GMC Buskirk 30’ Stretch
1975 GMC Avion (Under Reconstruction)
Michigan
On Jul 2, 2014, at 11:09 PM, Terry wrote:
> I hope you have a better tool than the one that I borrowed, Bob. I used it to remove the tension to remove the adjuster and all was well. And then I
> too was amazed at the tension on that setup when putting it back together. However, I was not so amazed that I didn't stop cranking on it to get the
> chop up far enough to get the adjuster back in and it broke before I got it up far enough. So I had to pay the friend to replace his tool (which of
> course was not available for over a week) and figure out another way to get that chop adjuster in place. I will not do it that way (the dangerous way
> I had to do it) again if I ever have to do that job again. If there is a next time to replace the bars I will separate the lower ball joint, hopefully
> without using a pickle fork that would damage the grease boot. Just adjusting the height up is a much easier thing, as all I need to do is take the
> coach weight off of the wheels, let them drop, and since I already greased the bolt threads and the cups they go into on the chops, the bolt turns
> very easily.
> --
> Terry Kelpien
> 73 Glacier 260
> Smithfield, Va.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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