| Bumper shock aborbers [message #352973] |
Fri, 20 March 2020 23:53  |
Green machine
Messages: 184
Registered: July 2019
Location: North Vancouver BC
Karma: 5
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I've removed the bumper "shock absorbers" and was wondering if there is any sort of test I can perform to ensure the "bumper shocks" are operational. I have no fancy equipment - just a home shop. Im about to grind and remove rust to repaint but would like to ensure they are operational before I do as I a have parts coach that I could steal from if they are discovered to be non operational.
As always, any help is appreciated.
Thanks and stay safe!
Shawn Harris
North Vancouver,
Canada
1977 Palm Beach 403
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| Re: Bumper shock aborbers [message #352978 is a reply to message #352973] |
Sat, 21 March 2020 07:24  |
6cuda6
Messages: 975
Registered: June 2019
Karma: -6
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No test that i know of other than making sure they are about the same length. They are not really like suspension shocks, they are more of a single use type thing to dampen collision load.
Rich Mondor,
Brockville, ON
77 Hughes 2600
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| Re: Bumper shock aborbers [message #352979 is a reply to message #352973] |
Sat, 21 March 2020 09:09 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Oil filled and "I think" gas charged. No evidence of oil leaks is first criteria. Not a one time use device! They were supposed to absorb and rebound in impacts up to 5 MPH per government mandate. All GM cars starting 73 front (unless they could survive 5 MPH by other means) and then later added to rears.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Bumper shock aborbers [message #352980 is a reply to message #352973] |
Sat, 21 March 2020 09:11 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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You could compare weights in case oil has left so long ago there is no evidence of leaking any more.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Bumper shock aborbers [message #352988 is a reply to message #352973] |
Sat, 21 March 2020 11:41 |
Green machine
Messages: 184
Registered: July 2019
Location: North Vancouver BC
Karma: 5
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Thanks for the tips guys. I guess if they were only intended to absorb a 5 mph impact I won't concern myself with it too much. They look fine, no leaks, same weight and length. Ill just assume they are good to go.
Cheers!
Shawn Harris
North Vancouver,
Canada
1977 Palm Beach 403
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| Re: Bumper shock aborbers [message #353005 is a reply to message #352992] |
Sat, 21 March 2020 18:46 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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I suspect a 5 MPH collision would turn the front bumper into a pretzel regardless of the condition of the bumper shocks. In my opinion, they are next to useless. In fact I think the later coached did away with them.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: [GMCnet] Bumper shock aborbers [message #353007 is a reply to message #353005] |
Sat, 21 March 2020 18:48 |
Len Novak
Messages: 676
Registered: February 2004
Location: Las Vegas, NV
Karma: -3
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My 78 does not have bumper shocks
Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Fallbrook, CA new email: B52Rule@Roadrunner.Com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Carl
Stouffer via Gmclist
Sent: Saturday, March 21, 2020 4:47 PM
To: gmclist@list.gmcnet.org
Cc: Carl Stouffer
Subject: Re: [GMCnet] Bumper shock aborbers
I suspect a 5 MPH collision would turn the front bumper into a pretzel
regardless of the condition of the bumper shocks. In my opinion, they are
next
to useless. In fact I think the later coached did away with them.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive,
Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American
Eagles,
Solar battery charging. GMCSJ and GMCMI member
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Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Las Vegas, NV new email: B52sRule@Gmail.com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
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| Re: Bumper shock aborbers [message #353008 is a reply to message #352973] |
Sat, 21 March 2020 19:12 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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My 77 has them. The Feds had testing they had to pass. Was to stop nuisance insurance claims for parking lot taps below 5 MPH
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Bumper shock aborbers [message #353012 is a reply to message #352973] |
Sat, 21 March 2020 21:35 |
Rick Staples
Messages: 126
Registered: May 2014
Location: Johnstown, Colorado, USA
Karma: -1
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They are in the maintenance manual.
Yes, they are gas-filled. Do not heat or weld!
Manual says to test by compressing them by 3/8" and making sure they return to length.
One way was to use a jack between bumper and an immovable object. (Sounds sketchy.)
Other way was to remove and use a press.
IIRC, those "5mph" bumpers were required to absorb a 5mph impact with no damage to headlights or turn signals, quite
a job on a 12,000 lb vehicle. Just my opinion, but I like the idea and wouldn't remove them.
YMMV,
Rick Staples
Rick Staples, '75 Eleganza, Johnstown, CO
"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien
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| Re: Bumper shock aborbers [message #353015 is a reply to message #353012] |
Sat, 21 March 2020 23:31 |
Green machine
Messages: 184
Registered: July 2019
Location: North Vancouver BC
Karma: 5
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Rick Staples wrote on Sat, 21 March 2020 21:35They are in the maintenance manual.
Yes, they are gas-filled. Do not heat or weld!
Manual says to test by compressing them by 3/8" and making sure they return to length.
One way was to use a jack between bumper and an immovable object. (Sounds sketchy.)
Other way was to remove and use a press.
IIRC, those "5mph" bumpers were required to absorb a 5mph impact with no damage to headlights or turn signals, quite
a job on a 12,000 lb vehicle. Just my opinion, but I like the idea and wouldn't remove them.
YMMV,
Rick Staples
Perfect! Thanks Rick!
Shawn Harris
North Vancouver,
Canada
1977 Palm Beach 403
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| Re: Bumper shock aborbers [message #353018 is a reply to message #352973] |
Sun, 22 March 2020 00:02 |
GMC Cruse
Messages: 606
Registered: June 2009
Location: SE Michigan
Karma: 3
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When I installed my Blaine hitch, the one bumper half was not parallel to the plate it was to bolt
to. Found the one bumper shock was in about an inch. So they don't apparently rebound as they are suppose to, at least not after 45 years.
Mike K.
'75 PB
Southeast Michigan
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| Re: [GMCnet] Bumper shock aborbers [message #353022 is a reply to message #353018] |
Sun, 22 March 2020 02:23 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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On the other hand, several years ago I replaced the front brake pads but
didn't reseat them for 10 days. When I backed out of the garage, the brake
pedal went to the floor -- then the rear left bumper stopped me at the 8"
diameter sweetgum tree. There's still a gash in the left rear "fender"
from the bumper flange -- but the shock absorber quickly restored the
bumper to its original position. There's also a slight depression in the
face of the bumper, but not worth a replacement.
I won't do that stupid trick again. I cut down the sweetgum tree.
Ken H.
On Sun, Mar 22, 2020 at 1:03 AM Mike via Gmclist
wrote:
> When I installed my Blaine hitch, the one bumper half was not parallel to
> the plate it was to bolt
> to. Found the one bumper shock was in about an inch. So they don't
> apparently rebound as they are suppose to, at least not after 45 years.
> --
> Mike K.
> '75 PB
> Southeast Michigan
>
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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] Bumper shock aborbers [message #353026 is a reply to message #353024] |
Sun, 22 March 2020 09:05 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Since my '76 X-Birchaven (a Transmode) does have the shock absorbers, I
suspect all '76's had them. But that's only a WAG.
Ken H.
On Sun, Mar 22, 2020 at 9:06 AM Dave Stragand via Gmclist <
gmclist@list.gmcnet.org> wrote:
> My 1978 does not have them, but it’s a Transmode. It’s my understanding
> that Transmodes had the bumper brackets and the GM built coaches had the
> bumpers. Can anyone shed more light on that?
>
>>> On Mar 21, 2020, at 8:14 PM, John R. Lebetski via Gmclist gmclist@list.gmcnet.org> wrote:
>> My 77 has them. The Feds had testing they had to pass. Was to stop
> nuisance insurance claims for parking lot taps below 5 MPH
>> --
>> John Lebetski
>> Woodstock, IL
>> 77 Eleganza II
>>
>>
>> _______________________________________________
>> GMCnet mailing list
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>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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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: Bumper shock aborbers [message #353027 is a reply to message #352973] |
Sun, 22 March 2020 09:34 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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My pure guess. So far comments indicate 78 dd not have absorbers. Maybe true or not but they did up the GVW in 78 which may have exempted the Passenger Car classification and moved them into 5MPH exempted truck class. ????
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Bumper shock aborbers [message #353087 is a reply to message #352973] |
Tue, 24 March 2020 01:46 |
Green machine
Messages: 184
Registered: July 2019
Location: North Vancouver BC
Karma: 5
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Senior Member |
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My '78 parts coach does not have them... they have a mounts that looks like this )(
Who knew...
Thanks for the replies.
Shawn Harris
North Vancouver,
Canada
1977 Palm Beach 403
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| Re: Bumper shock aborbers [message #353097 is a reply to message #352973] |
Tue, 24 March 2020 11:05 |
Scott Nutter
Messages: 782
Registered: January 2015
Location: Houston/San Diego
Karma: 4
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Senior Member |
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I thought the GMC's with the 403's had the new X style instead of the shock absorber bumper mount.
Scott Nutter
1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, Dave Lenzi super duty mid axle disc brakes, tankless water heater, everything Lenzi. Alex Ferrera installed MSD Atomic EFI
Houston, Texas
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