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| Adjusting the bogie pin top hat clearance [message #146649] |
Sat, 15 October 2011 21:14  |
Dennis S
Messages: 3046
Registered: November 2005
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Per the Maintenance Manual,
"tighten control arm lock nuts until hat section spacers are firmly seated, then
back off until control arm moves freely and retorque nuts to 15-20 ft lbs."
I have soaked the top hats several times with penetrating oil. Today I attempted
to get the hat sections to move. If they are moving it is not perceptible by my
eyes. But, the control arm end-play (in/out at the outer end) goes away when I
tighten them -- only to return if I loosen them. (I did not have my torque
wrench with me to quantify -- I was just working today on getting things
loosened up)
How much torque can I safely apply to the lock nuts? They require a 1 1/2 inch
socket on my coach.
http://www.gmcmhphotos.com/photos/showphoto.php?photo=35727&title=bogie-gmc-009&cat=5590
If the top hats are not moving -- what is changing to eliminate the control arm
end-play?
I am aware that the hat sections can be frozen from corrosion -- and that some
have had to use up to a 20 ton press to remove them. Pulling the bogie
assemblies is not a project I can consider at the moment.
Thanks,
Dennis
Dennis S
73 Painted Desert 230
Memphis TN Metro
[Updated on: Tue, 18 October 2011 09:08] Report message to a moderator |
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| Re: Adjusting the bogie pin top hat clearance [message #146983 is a reply to message #146649] |
Tue, 18 October 2011 20:54  |
Dennis S
Messages: 3046
Registered: November 2005
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Second attempt at adjusting the top hats...
after considering the size of the nut and pin -- I torqued the nut to over 85 ft-lbs and had no movement in the top hat. Next plan is more diligent use of penetrating oil and application of heat using a small propane torch. The control arm swing or play measured at the edge of the brake drum was under 1/8 inch.
Does anyone have access to the GM Service Bulletin #75-TM-4 which is quoted as saying 1/8 inch measured at the spindle is maximum?
At maximum allowable of 1/8 inch (the control arm is approx 18 inches long and the bogie pin portion is approx 6 inches) play at the pin would be .0417 thousandths. But, that would require at least .014 th of end play. So, it seems to me that reducing end play by .005 would result in .045 less swing at the spindle.
A couple of thoughts...
Regularly adjusting the end play to spec should reduce the rapidity of wear on the bogie pins.
Less end play will reduce odd wear on the rear tires.
Those who have a four bag system that uses the bogie pin extensions for mounting the center support are going to have more trouble doing any regular maintenance on the top hats and end play.
Any feedback appreciated.
Dennis
| Dennis S wrote on Sat, 15 October 2011 21:14 |
Per the Maintenance Manual,
"tighten control arm lock nuts until hat section spacers are firmly seated, then
back off until control arm moves freely and retorque nuts to 15-20 ft lbs."
I have soaked the top hats several times with penetrating oil. Today I attempted
to get the hat sections to move. If they are moving it is not perceptible by my
eyes. But, the control arm end-play (in/out at the outer end) goes away when I
tighten them -- only to return if I loosen them. (I did not have my torque
wrench with me to quantify -- I was just working today on getting things
loosened up)
How much torque can I safely apply to the lock nuts? They require a 1 1/2 inch
socket on my coach.
http://www.gmcmhphotos.com/photos/showphoto.php?photo=35727&title=bogie-gmc-009&cat=5590
If the top hats are not moving -- what is changing to eliminate the control arm
end-play?
I am aware that the hat sections can be frozen from corrosion -- and that some
have had to use up to a 20 ton press to remove them. Pulling the bogie
assemblies is not a project I can consider at the moment.
Thanks,
Dennis
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Adjusting the bogie pin top hat clearance [message #146989 is a reply to message #146983] |
Tue, 18 October 2011 21:10 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Dennis,
Good luck moving the top hats. I hope you figure out a way. One thing to
remember when you start applying heat: There's supposed to be a seal (I
don't recall the OEM configuration, but probably O-ring replacement) between
the swing arm hub and the mounting bracket -- don't burn it up.
You're right about the difficulty of adjusting the top hats with the
Harrison 4-bag system -- it's virtually impossible -- I haven't done it in
12 years. It's probably no easier with the Quad Bag.
Bottom line is, I suspect there have been VERY few GMCs on which the top hat
adjustement has been maintained well -- if at all. That said, I think a
reasonable alternative is to install True-Tracks, at least on the middle
arms. That's probably a more effective way of restraining lateral movement
and reducing pin/bushing wear than trying to manage the top hats.
JMHO,
Ken H.
On Tue, Oct 18, 2011 at 9:54 PM, Dennis Sexton <dennisfsexton@aol.com>wrote:
>
>
> Second attempt at adjusting the top hats...
> after considering the size of the nut and pin -- I torqued the nut to over
> 85 ft-lbs and had no movement in the top hat. Next plan is more diligent use
> of penetrating oil and application of heat using a small propane torch. The
> control arm swing or play measured at the edge of the brake drum was under
> 1/8 inch.
>
> Does anyone have access to the GM Service Bulletin #75-TM-4 which is quoted
> as saying 1/8 inch measured at the spindle is maximum?
>
> At maximum allowable of 1/8 inch (the control arm is approx 18 inches long
> and the bogie pin portion is approx 6 inches) play at the pin would be .0417
> thousandths. But, that would require at least .014 th of end play. So, it
> seems to me that reducing end play by .005 would result in .045 less swing
> at the spindle.
>
> A couple of thoughts...
>
> Regularly adjusting the end play to spec should reduce the rapidity of wear
> on the bogie pins.
>
> Less end play will reduce odd wear on the rear tires.
>
> Those who have a four bag system that uses the bogie pin extensions for
> mounting the center support are going to have more trouble doing any regular
> maintenance on the top hats and end play.
>
> Any feedback appreciated.
>
> Dennis
>
> Dennis S wrote on Sat, 15 October 2011 21:14
> > Per the Maintenance Manual,
> > "tighten control arm lock nuts until hat section spacers are firmly
> seated, then
> > back off until control arm moves freely and retorque nuts to 15-20 ft
> lbs."
> >
> > I have soaked the top hats several times with penetrating oil. Today I
> attempted
> > to get the hat sections to move. If they are moving it is not perceptible
> by my
> > eyes. But, the control arm end-play (in/out at the outer end) goes away
> when I
> > tighten them -- only to return if I loosen them. (I did not have my
> torque
> > wrench with me to quantify -- I was just working today on getting things
> > loosened up)
> >
> > How much torque can I safely apply to the lock nuts? They require a 1 1/2
> inch
> > socket on my coach.
> >
> >
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=35727&title=bogie-gmc-009&cat=5590
> >
> > If the top hats are not moving -- what is changing to eliminate the
> control arm
> > end-play?
> >
> > I am aware that the hat sections can be frozen from corrosion -- and that
> some
> > have had to use up to a 20 ton press to remove them. Pulling the bogie
> > assemblies is not a project I can consider at the moment.
> >
> > Thanks,
> > Dennis
>
>
>
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Adjusting the bogie pin top hat clearance [message #146992 is a reply to message #146989] |
Tue, 18 October 2011 21:23 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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Ken,
Getting them free may be impossible without removing the assembly -- but at least I will have cleaned the area well and be more familiar with the current state. Then In future I can quantify any deterioration/wear; and I can plan pin/bushing replacement if it becomes necessary.
The early coaches (this is on my 73) did not have the o-ring you mention.. I suspect an o-ring may help reduce the corrosion but don't know.
I also expect tru-tracks might be the solution --
Thank you for the feedback.
Dennis
Dennis Sexton
7 GMC
Germantown, TN
USA
-----Original Message-----
From: Ken Henderson <hend4800@bellsouth.net>
To: gmclist <gmclist@temp.gmcnet.org>
Sent: Tue, Oct 18, 2011 9:10 pm
Subject: Re: [GMCnet] Adjusting the bogie pin top hat clearance
Dennis,
Good luck moving the top hats. I hope you figure out a way. One thing to
emember when you start applying heat: There's supposed to be a seal (I
on't recall the OEM configuration, but probably O-ring replacement) between
he swing arm hub and the mounting bracket -- don't burn it up.
You're right about the difficulty of adjusting the top hats with the
arrison 4-bag system -- it's virtually impossible -- I haven't done it in
2 years. It's probably no easier with the Quad Bag.
Bottom line is, I suspect there have been VERY few GMCs on which the top hat
djustement has been maintained well -- if at all. That said, I think a
easonable alternative is to install True-Tracks, at least on the middle
rms. That's probably a more effective way of restraining lateral movement
nd reducing pin/bushing wear than trying to manage the top hats.
JMHO,
Ken H.
n Tue, Oct 18, 2011 at 9:54 PM, Dennis Sexton <dennisfsexton@aol.com>wrote:
>
Second attempt at adjusting the top hats...
after considering the size of the nut and pin -- I torqued the nut to over
85 ft-lbs and had no movement in the top hat. Next plan is more diligent use
of penetrating oil and application of heat using a small propane torch. The
control arm swing or play measured at the edge of the brake drum was under
1/8 inch.
Does anyone have access to the GM Service Bulletin #75-TM-4 which is quoted
as saying 1/8 inch measured at the spindle is maximum?
At maximum allowable of 1/8 inch (the control arm is approx 18 inches long
and the bogie pin portion is approx 6 inches) play at the pin would be .0417
thousandths. But, that would require at least .014 th of end play. So, it
seems to me that reducing end play by .005 would result in .045 less swing
at the spindle.
A couple of thoughts...
Regularly adjusting the end play to spec should reduce the rapidity of wear
on the bogie pins.
Less end play will reduce odd wear on the rear tires.
Those who have a four bag system that uses the bogie pin extensions for
mounting the center support are going to have more trouble doing any regular
maintenance on the top hats and end play.
Any feedback appreciated.
Dennis
Dennis S wrote on Sat, 15 October 2011 21:14
> Per the Maintenance Manual,
> "tighten control arm lock nuts until hat section spacers are firmly
seated, then
> back off until control arm moves freely and retorque nuts to 15-20 ft
lbs."
>
> I have soaked the top hats several times with penetrating oil. Today I
attempted
> to get the hat sections to move. If they are moving it is not perceptible
by my
> eyes. But, the control arm end-play (in/out at the outer end) goes away
when I
> tighten them -- only to return if I loosen them. (I did not have my
torque
> wrench with me to quantify -- I was just working today on getting things
> loosened up)
>
> How much torque can I safely apply to the lock nuts? They require a 1 1/2
inch
> socket on my coach.
>
>
http://www.gmcmhphotos.com/photos/showphoto.php?photo=35727&title=bogie-gmc-009&cat=5590
>
> If the top hats are not moving -- what is changing to eliminate the
control arm
> end-play?
>
> I am aware that the hat sections can be frozen from corrosion -- and that
some
> have had to use up to a 20 ton press to remove them. Pulling the bogie
> assemblies is not a project I can consider at the moment.
>
> Thanks,
> Dennis
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Adjusting the bogie pin top hat clearance [message #147001 is a reply to message #146989] |
Tue, 18 October 2011 21:57 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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Ken,
I looked over the parts book again -- regarding the o-ring -- the early coaches DID have them, it shows a change in later coaches, perhaps at the time of the larger pins.
Thanks! I will watch where I apply the heat.
Dennis
| Ken Henderson wrote on Tue, 18 October 2011 21:10 |
Dennis,
Good luck moving the top hats. I hope you figure out a way. One thing to
remember when you start applying heat: There's supposed to be a seal (I
don't recall the OEM configuration, but probably O-ring replacement) between
the swing arm hub and the mounting bracket -- don't burn it up.
You're right about the difficulty of adjusting the top hats with the
Harrison 4-bag system -- it's virtually impossible -- I haven't done it in
12 years. It's probably no easier with the Quad Bag.
Bottom line is, I suspect there have been VERY few GMCs on which the top hat
adjustement has been maintained well -- if at all. That said, I think a
reasonable alternative is to install True-Tracks, at least on the middle
arms. That's probably a more effective way of restraining lateral movement
and reducing pin/bushing wear than trying to manage the top hats.
JMHO,
Ken H.
|
Dennis S
73 Painted Desert 230
Memphis TN Metro
|
|
|
|
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| Re: [GMCnet] Adjusting the bogie pin top hat clearance [message #147046 is a reply to message #147041] |
Wed, 19 October 2011 10:59 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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Rob,
Thank you for the link --
reading the bulletin, they only mentioned measured at the spindle, extrapolating to the outer edge of the tire 32/18 X .125 = 0.2222 allowable play to be in spec.
Also, interesting to read that the early bushings were teflon.
Regards,
Dennis
| Robert Mueller wrote on Wed, 19 October 2011 09:36 |
Dennis,
Here's Bdub's link to the Service Bulletins, the file is 37Mb.
http://www.bdub.net/manuals/X0021/index.html
Service Bulletin #75-TM-4 starts on page 132.
Regards,
Rob M.
-----Original Message-----
From: Dennis Sexton
Does anyone have access to the GM Service Bulletin #75-TM-4 which is quoted as saying 1/8 inch measured at the spindle is maximum?
Dennis
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Adjusting the bogie pin top hat clearance [message #147114 is a reply to message #147046] |
Wed, 19 October 2011 19:47 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Dennis,
You're welcome.
I'm guessing but they probably changed from Teflon to bronze because Teflon cold flows.
Poly(tetrafluoroethylene), more commonly known by the trade name, Teflon, is incorporated with other materials to induce the
self-lubricating effect. Teflon also exhibits the property known as cold flow. At room temperature, Teflon with change shape when
pressure is applied.
http://web.mst.edu/~wlf/chem381/chap26.html
Regards,
Rob M.
-----Original Message-----
From: Dennis Sexton
Rob,
Thank you for the link --
reading the bulletin, they only mentioned measured at the spindle, extrapolating to the outer edge of the tire 32/18 X .125 = 0.2222
allowable play to be in spec.
Also, interesting to read that the early bushings were teflon.
Regards,
Dennis
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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: Adjusting the bogie pin top hat clearance [message #147117 is a reply to message #146649] |
Wed, 19 October 2011 20:13 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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Dennis,
I took my left bogie out last weekend. The pins are well worn.
I removed the pins by tapping them out with a hammer,
(not hammering on the threads though). I also had a lot
of side clearance between the top hat and the arm.
The side bushings were not worn much (after 120,000 miles).
Now I am trying to remove the tophats.
I soaked them with gasoline mixed with transmission fluid.
One of them will move if I put a pipe on the tophat and
then use a big hammer on the other end of the pipe.
The other tophat is stuck.
My next plan is to use a hydraulic press and try
using more force. It must take 1000's of pounds
of force to remove them. I wonder if they were
press fit at the factory?
Regards,
Bill
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: [GMCnet] Adjusting the bogie pin top hat clearance [message #147136 is a reply to message #147114] |
Wed, 19 October 2011 21:15 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Rob,
Perhaps it was also a time (early 70's) for testing a few new materials in special applications. I would like to see an early original bushing that was removed.
Thank you for the link to the teflon site.
Regards,
Dennis
| Robert Mueller wrote on Wed, 19 October 2011 19:47 |
Dennis,
You're welcome.
I'm guessing but they probably changed from Teflon to bronze because Teflon cold flows.
Poly(tetrafluoroethylene), more commonly known by the trade name, Teflon, is incorporated with other materials to induce the
self-lubricating effect. Teflon also exhibits the property known as cold flow. At room temperature, Teflon with change shape when
pressure is applied.
http://web.mst.edu/~wlf/chem381/chap26.html
Regards,
Rob M.
-----Original Message-----
From: Dennis Sexton
Rob,
Thank you for the link --
reading the bulletin, they only mentioned measured at the spindle, extrapolating to the outer edge of the tire 32/18 X .125 = 0.2222
allowable play to be in spec.
Also, interesting to read that the early bushings were teflon.
Regards,
Dennis
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73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Adjusting the bogie pin top hat clearance [message #147142 is a reply to message #147136] |
Wed, 19 October 2011 21:29 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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I think your guess is right, Dennis. In '78 I bought a '76 Titan motorhome
on a Dodge 440 chassis. It had teflon (or maybe nylon) king pin bushings.
They were worn out before 20K miles.
Ken H.
On Wed, Oct 19, 2011 at 10:15 PM, Dennis Sexton <dennisfsexton@aol.com>wrote:
>
>
> Rob,
>
> Perhaps it was also a time (early 70's) for testing a few new materials in
> special applications. I would like to see an early original bushing that was
> removed.
>
> Thank you for the link to the teflon site.
>
>
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Adjusting the bogie pin top hat clearance [message #147149 is a reply to message #147142] |
Wed, 19 October 2011 22:02 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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| Ken Henderson wrote on Wed, 19 October 2011 19:29 |
I think your guess is right, Dennis. In '78 I bought a '76 Titan motorhome
on a Dodge 440 chassis. It had Teflon (or maybe nylon) king pin bushings.
They were worn out before 20K miles.
Ken H.
> I had a 71 Winnebago on a Dodge chassis . I was told that it needed new king pins so I bought the new king pin kit from Dodge and installed it. The front end shop didn't like it and said it was still worn out. Apparently the Teflon bushings just don't fit as tight as the brass ones
Roy
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Roy Keen
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76 X Glenbrook
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| Re: [GMCnet] Adjusting the bogie pin top hat clearance [message #147154 is a reply to message #147149] |
Wed, 19 October 2011 22:55 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Did yours shimmy like crazy too?
Ken H.
On Wed, Oct 19, 2011 at 11:02 PM, <roy@gmcnet.org> wrote:
>
>
> Ken Henderson wrote on Wed, 19 October 2011 19:29
> > I think your guess is right, Dennis. In '78 I bought a '76 Titan
> motorhome
> > on a Dodge 440 chassis. It had Teflon (or maybe nylon) king pin
> bushings.
> > They were worn out before 20K miles.
> >
> > Ken H.
> >
> >
> > > I had a 71 Winnebago on a Dodge chassis . I was told that it needed new
> king pins so I bought the new king pin kit from Dodge and installed it. The
> front end shop didn't like it and said it was still worn out. Apparently the
> Teflon bushings just don't fit as tight as the brass ones
> > Roy
>
>
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Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Adjusting the bogie pin top hat clearance [message #147630 is a reply to message #147159] |
Sun, 23 October 2011 23:22 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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I spent the weekend installing new bushings and pins.
I got the hats on my bogie pins removed. After removing the hats and cleaning the rust off of them, they had some clearance and slid easily in the housing. This might not be desirable if the hat turns inside the housing (instead of holding stationary and turning against the bronze bushing against the arm).
JimK loaned me the reamer to size the bushing to the pins.
The pins fit very snug, but turn easily.
I'm done with one side.
Here are some photos:
hxxp://www.gmcmhphotos.com/photos/showgallery.php?cat=5932
Maybe the hats won't turn after putting a load on them.
Regards,
Bill
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: [GMCnet] Adjusting the bogie pin top hat clearance [message #147643 is a reply to message #147630] |
Mon, 24 October 2011 08:20 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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Bill,
Many thanks for the photos and comments. They look great!
Dennis (still soaking his top hats)
| bwevers wrote on Sun, 23 October 2011 23:22 |
I spent the weekend installing new bushings and pins.
I got the hats on my bogie pins removed. After removing the hats and cleaning the rust off of them, they had some clearance and slid easily in the housing. This might not be desirable if the hat turns inside the housing (instead of holding stationary and turning against the bronze bushing against the arm).
JimK loaned me the reamer to size the bushing to the pins.
The pins fit very snug, but turn easily.
I'm done with one side.
Here are some photos:
hxxp://www.gmcmhphotos.com/photos/showgallery.php?cat=5932
Maybe the hats won't turn after putting a load on them.
Regards,
Bill
|
Dennis S
73 Painted Desert 230
Memphis TN Metro
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