| Rear suspension clarification [message #159685] |
Wed, 08 February 2012 23:17  |
Luvn737s
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Registered: June 2007
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The only time the bogies move about the pins is when you go over a bump or raise or lower the vehicle, right? When greasing the bogie is there any benefit to raising or lowering it to help move the grease around the pin?
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
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| Re: [GMCnet] Rear suspension clarification [message #159692 is a reply to message #159685] |
Thu, 09 February 2012 03:34  |
rssbob
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Registered: January 2004
Location: La Mesa, Ca. (San Diego a...
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Some time ago I heard that the best time to grease the bogie pins is right after stopping from a trip. The theory is that with everything warm from the trip the grease will melt and be pulled into the joints through capillary action.
On Feb 8, 2012, at 9:17 PM, Randy wrote:
>
>
> The only time the bogies move about the pins is when you go over a bump or raise or lower the vehicle, right? When greasing the bogie is there any benefit to raising or lowering it to help move the grease around the pin?
> --
> Randy
> 1973 26' Painted Desert
> Ahwatukee (Phoenix) AZ
>
>
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Bob Sobrito
78 Palm Beach
La Mesa, Ca
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| Re: Rear suspension clarification [message #159697 is a reply to message #159685] |
Thu, 09 February 2012 07:41 |
Dennis S
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Registered: November 2005
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Randy,
It is generally considered good to remove the weight from the bogie when greasing and JimB mentions using a shovel to raise and lower the wheel/tire to allow the grease to move about the pin. With the weight off the assembly is easily moved up and down with a little leverage.
Dennis
| Luvn737s wrote on Wed, 08 February 2012 23:17 |
The only time the bogies move about the pins is when you go over a bump or raise or lower the vehicle, right? When greasing the bogie is there any benefit to raising or lowering it to help move the grease around the pin?
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Rear suspension clarification [message #159698 is a reply to message #159697] |
Thu, 09 February 2012 07:57 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
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From when I first bought my GMC in '98, I've heard "move the wheels while
greasing". What I've never understood is how that can improve lubrication.
It seems to me that when the coach is at rest, most of the pin/bushing
clearance will be on the bottom, with the coach weight on the top.
Assuming all of the clearance is filled with grease, when the coach moves,
load variations will cause the clearance to increase in some areas and
decrease in others. That "jiggling" would cause the grease to flow as the
clearance varies. I think there will be much more "jiggling" during the
first 100' of vehicle travel, with horizontal, vertical, and rotational
movement, than can be achieved during a day of moving the wheel up and
down. Neither method will affect how the majority of the travel load is
applied, which is what determines the wear pattern.
JMHO, with no empirical justification. I squirt grease 'til it comes out
of each bushing, period.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
On Thu, Feb 9, 2012 at 8:41 AM, Dennis Sexton <dennisfsexton@aol.com> wrote:
>
> Randy,
>
> It is generally considered good to remove the weight from the bogie when
> greasing and JimB mentions using a shovel to raise and lower the wheel/tire
> to allow the grease to move about the pin. With the weight off the assembly
> is easily moved up and down with a little leverage.
>
>
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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] Rear suspension clarification [message #159707 is a reply to message #159698] |
Thu, 09 February 2012 10:41 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
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""JMHO, with no empirical justification. I squirt grease 'til it comes out
of each bushing, period.
""
I agree Ken. It's another one of those "feel good" things that doesn't do any harm but seems to have no basis in fact to me.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Rear suspension clarification [message #159710 is a reply to message #159698] |
Thu, 09 February 2012 10:46 |
emerystora
Messages: 4442
Registered: January 2004
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Ken
When they said to move the wheels while greasing they meant to move
the wheels up and down. When I got my GMC back in 1981 the common
wisdom at the time was to jack up the bogie and then use a shovel
under the tire to move it up and down while putting in grease.
I think you can see how this makes more sense than rotating the wheel.
Emery Stora
On Feb 9, 2012, at 6:57 AM, Ken Henderson <hend4800@bellsouth.net>
wrote:
> From when I first bought my GMC in '98, I've heard "move the wheels
> while
> greasing". What I've never understood is how that can improve
> lubrication.
> It seems to me that when the coach is at rest, most of the pin/bushing
> clearance will be on the bottom, with the coach weight on the top.
> Assuming all of the clearance is filled with grease, when the coach
> moves,
> load variations will cause the clearance to increase in some areas and
> decrease in others. That "jiggling" would cause the grease to flow
> as the
> clearance varies. I think there will be much more "jiggling" during
> the
> first 100' of vehicle travel, with horizontal, vertical, and
> rotational
> movement, than can be achieved during a day of moving the wheel up and
> down. Neither method will affect how the majority of the travel
> load is
> applied, which is what determines the wear pattern.
>
> JMHO, with no empirical justification. I squirt grease 'til it
> comes out
> of each bushing, period.
>
> Ken H.
>
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| Re: [GMCnet] Rear suspension clarification [message #159711 is a reply to message #159707] |
Thu, 09 February 2012 10:56 |
Dennis S
Messages: 3046
Registered: November 2005
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Ken and Bob,
May have to have you on a session of myth busters... along with ZDDP and such...
Anyway -- Randy has a 73 coach -- if original the pins are smaller and only have one grease outlet -- so, kinda like the benefit of bogie greasers on later coaches, I still think moving the swing arm while greasing the pins would be of some benefit.
And, as has been said, couldn't hurt.
Dennis
| Bob de Kruyff wrote on Thu, 09 February 2012 10:41 |
""JMHO, with no empirical justification. I squirt grease 'til it comes out
of each bushing, period.
""
I agree Ken. It's another one of those "feel good" things that doesn't do any harm but seems to have no basis in fact to me.
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Rear suspension clarification [message #159717 is a reply to message #159710] |
Thu, 09 February 2012 11:51 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
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Emery,
That could have been worded better. The rotation I meant is the rotation
of the suspension arm about the pin by lifting & lowering the wheel.
I should say what I mean! :-)
Ken H.
On Thu, Feb 9, 2012 at 11:46 AM, Emery Stora wrote:
> Ken
>
> When they said to move the wheels while greasing they meant to move
> the wheels up and down. When I got my GMC back in 1981 the common
> wisdom at the time was to jack up the bogie and then use a shovel
> under the tire to move it up and down while putting in grease.
>
> I think you can see how this makes more sense than rotating the wheel.
>
>
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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] Rear suspension clarification [message #159719 is a reply to message #159711] |
Thu, 09 February 2012 12:05 |
sgltrac
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Registered: April 2011
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This conversation prompted me to go and inspect the old pins I replaced when rebuilding my bogies. The wear and pitting was severe at or near the grease ports in the pins as often as areas of the pins away from the grease exit ports(4 per pin late style) which leads me to think that the grease will not flow out the lube holes evenly but continue to flow out the hole with the least resistance. I would rotate the arm as far as possible(maybe even remove the shock and airbag to allow more range of movement)maybe as an annual greasing or prior to storage and return to service routine and then pump some in as it sits before every trip. I did not enjoy the bogie pin and bushing rebuild very much and don't plan on doing it again. Ever. I think it is worth the small amount of extra time and effort at least once a year to know that I have done all I can to prevent having to rebuild them again. J.W.I.T.
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] Rear suspension clarification [message #159721 is a reply to message #159719] |
Thu, 09 February 2012 12:22 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
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Sully,
That's interesting. I wish I'd examined the pins I replaced 12 years ago.
This may be a suitable time to poke an old sleeping dog: There's (or was)
an individual in Quebec who replaced the suspension arm bushings with
needle bearing packs. He claimed 15 years or so of trouble-free service,
AND that if necessary, the bearings could be replaced very quickly without
removing the bracket (bogie).
I was one of several who spent a lot of time corresponding with him. He
was trying to make an arrangement with someone to commercialize his
"invention". Trouble was, he was totally paranoid about the possibility of
someone stealing his "marvelous idea". My involvement with him ended when
he began to divulge the details to me: "Buy XYZ bolt and get back with
me."..."Now turn the XYZ bolt to xyz and get back with me."..."Now
buy..."... That attitude, along with my skepticism about using needle
bearings under heavy, reciprocating, load caused me to abandon the project.
My research into replacing the bushings seemed to indicate that some of the
modern composite bearing materials may be better than bronze. I never
reached a definitive conclusion about the use of needle bearing packs.
Now that we've got a whole new crop of ingenious GMCers, perhaps someone
wants to tackle this challenge?
Ken H.
On Thu, Feb 9, 2012 at 1:05 PM, sgltrac wrote:
>
>
> This conversation prompted me to go and inspect the old pins I replaced
> when rebuilding my bogies. The wear and pitting was severe at or near the
> grease ports in the pins as often as areas of the pins away from the grease
> exit ports(4 per pin late style) which leads me to think that the grease
> will not flow out the lube holes evenly but continue to flow out the hole
> with the least resistance...
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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] Rear suspension clarification [message #159727 is a reply to message #159721] |
Thu, 09 February 2012 13:01 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
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""This may be a suitable time to poke an old sleeping dog: There's (or was)
an individual in Quebec who replaced the suspension arm bushings with
needle bearing packs. He claimed 15 years or so of trouble-free service,
AND that if necessary, the bearings could be replaced very quickly without
removing the bracket (bogie).
OMG--now there's a solution looking for a problem 
I just squirt some grease in there when I remember to and so far in 20 years they feel snug and not frozen up. I haven't bothered with the bogie greasers since I can't stand the looks of them.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Rear suspension clarification [message #159751 is a reply to message #159727] |
Thu, 09 February 2012 16:04 |
sgltrac
Messages: 2797
Registered: April 2011
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I don't suppose they would freeze up. Mine looked nice and greasy but when I had the bag/shocks/wheel off there was a considerable amount of play in the forward facing arms which will cause a constantly changing toe and camber situation(especially toe). You cannot tell if they are worn without completely unloading them and checking for side play.
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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