Bogie pin grease Question

Agoogol

Member
Mar 3, 2020
102
21
18
Centennial CO
So I have a 77, and I just cleaned out the grease from my rear bogie pins using the straw method, and have a few of questions. Some of this may be in the manual, which is at the storage facility where the GMC is...

A. How do you know you got enough out? I mean, it seems like there may be some caked on the sides, or stuck, and piling new grease on old grease that doesn;t move doesn;t hep that much? Is there a way to get more out, or really flush out the old grease to be sure, or is it really just not necessary?

B. Do these really provide any benefit on top of the standard 4 zirk fittings? https://www.gmcrvparts.com/product-p/gm14-14.001.16a.htm

C. Stupid question - Does every bit of grease needed on the GMC is it the same? Dave Lenzi reommended Mobil 1 for the front knuckle bearings, and as I go around greasing everything else, do I use all the same?

D. Are they all same size fitting everywhere?

Thanks!
 

tmsnyder

Active member
Oct 7, 2019
422
85
28
Buffalo NY
What's the straw method? Oh are you talking about getting the old grease out of the passages behind the zerk fitting?

You could shoot it out with brake cleaner and compressed air, or push fresh grease through to displace it and wipe the old stuff away before reassembling.

B. I wouldn't think so.

C. No it doesn't need to be all the same, just pick one good grease and use it everywhere.

D. Yes zerk fittings on the GMC are all the same I believe.


Those bogies get grease at every 1000 mile interval right? Wow that's frequent. You're supposed to unload them too by jacking them up and getting the weight off them, so the grease can get around the whole pin.
 

Matt Colie

Active member
Oct 25, 2019
322
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28
South East Michigan near DTW
There many opinions here. Looking at the statics of the rear suspension, there is just about no simple way to relieve the load on the working side of the pin. Jacking the coach up won't do it. Even if you rock the arm by putting a shovel under the tire, it still won't actually unload the pin. Chaumière is a 73 with the small pins and gets greased about every thousand miles. We seem to be doing just fine on pine wear with Valvoline Synpro. Yes, that is expensive grease, but it is still cheaper than parts.
Matt
 
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JPB

New member
Jan 15, 2020
11
3
3
It would be nice to see a static load diagram showing how the weight of the coach is supported by the pins.

There are two bogie pin diameters. Earlier coaches had the 1-1/4" diameter pins with a single grease port at the center of the pin.

Later coaches came with 1-1/2" pins that had two grease ports facing upward and centered in the load bearing surfaces.
On JimK's website he sells both diameter pins with dual grease ports.

The easiest way to determine the number and location of grease ports in a bogie pin is to remove the zerk fitting and probe with a piece of stiff wire with a small 90 degree bend at one end.

My 76 Royale has 1-1/2" pins with two grease ports so I made bogie greasers with two zerks.
I attempted to grease the pins with the rear wheels on the ground. They were so tight against the bushings that grease was forced back out the threads on the zerks as seen in the fitting on the right. I then deflated the air bags and jacked up the bogie to relieve the load on the pins. The tires were still on the ground but not supporting the weight of the coach. Grease then flowed easily through the pins.

JP
 

Agoogol

Member
Mar 3, 2020
102
21
18
Centennial CO
It would be nice to see a static load diagram showing how the weight of the coach is supported by the pins.

There are two bogie pin diameters. Earlier coaches had the 1-1/4" diameter pins with a single grease port at the center of the pin.

Later coaches came with 1-1/2" pins that had two grease ports facing upward and centered in the load bearing surfaces.
On JimK's website he sells both diameter pins with dual grease ports.

The easiest way to determine the number and location of grease ports in a bogie pin is to remove the zerk fitting and probe with a piece of stiff wire with a small 90 degree bend at one end.

My 76 Royale has 1-1/2" pins with two grease ports so I made bogie greasers with two zerks.
I attempted to grease the pins with the rear wheels on the ground. They were so tight against the bushings that grease was forced back out the threads on the zerks as seen in the fitting on the right. I then deflated the air bags and jacked up the bogie to relieve the load on the pins. The tires were still on the ground but not supporting the weight of the coach. Grease then flowed easily through the pins.

JP
Well JPB - Those do look cleaner. But I don't have the time or resources to put that together myself, so will most likely just order from one of the vendors. But you know, you could make some money selling those!
 

JPB

New member
Jan 15, 2020
11
3
3
Kevin,

Thanks for the thumbs up. I'm happy with the results. Those greasers require a lot more fabrication than other models. Just for starters, on the large nut the only ones available with the correct threads are a specialty part for antique Volkswagen brake lines and quite expensive for a set of four. To avoid that expense I bought plugs for cheap then drilled and tapped for the outer zerk. Then there's all the other pieces/parts.... So anyway not too practical to produce and sell. If I did it over I would use a straight zerk rather than the 90' elbow on the side.

JimK sells a nice looking bogie greaser that uses the Brass L block as the main body.

JP
 

Eric S.

New member
Aug 4, 2020
6
2
3
Santa Barbara, CA
I've got the Jim K greasers in my '78. Nice design as it has concentric tubes that supply the inner and outer crosschannels in the pin independently. This way both the inner and outer bushings get fully lubricated, even if one has more resistance than the other. Just keep pumping until grease comes out of the appropriate bushing gap. Clever, Jim!

-Eric
 
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Eric S.

New member
Aug 4, 2020
6
2
3
Santa Barbara, CA
Forgot to mention, this only works on the newer larger pins, since the older pins only have one cross-channel in the center. -E.
 
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Agoogol

Member
Mar 3, 2020
102
21
18
Centennial CO
So reading the birdfeeder forum old site, which, as much knowledge is there is so difficukt to navigate I really am thankful for this new site, just have to say!

Anyway, saw this comment from 2011, and wanted to know if any of you have tried this?


Side note: I also have the piece of leaf spring but do not bother to use it any more. I just rotated the tires prior to going to the GMCMI rally without ever getting the coach high enough to get the rear tires off of the ground. It turns out with the coach supported in the middle between the bogies and the bag completely deflated there is next to no weight on the the wheels and they can be removed and installed with the tires still touching the ground. You can lift up on the wheel hub if necessary by hand.

One time went out to help a Black Lister with a flat tire on the Indiana Toll Road. I asked before I left if he had a jack and hook. He said yes. I brought a long bar and the correct socket which he did not have. It turned out I should have asked if the jack worked. It didn't.

Not wanting to drive about 40 miles round trip to my coach to get a good jack, I took some short 2x4 cutoffs I happened to have out of the bed of my truck. I had him air up that bag as far as possible then placed the 2x4's under the jacking point of the bogie. We dropped the coach on the 2x4's and completely deflated the bag. We removed and installed the spare at that height.

Try lifting the wheel hub by hand next time you have a wheel off and no air in the bag. It works.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 

6cuda6

Active member
Oct 3, 2019
442
107
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Ontario, Canada
Im a firm beleiver that you can over complicate things if you like....most important thing is to grease them....so put the grease gun on the zerk and pump until your hear the grease move...once it does, its greased. As the coach moves up and down, side to side, the grease will be forced to move as well spreading grease through the bore.

So get a good grease gun, good quality synthetic grease and grease it as the manual suggests.
 

Agoogol

Member
Mar 3, 2020
102
21
18
Centennial CO
Im a firm beleiver that you can over complicate things if you like....most important thing is to grease them....so put the grease gun on the zerk and pump until your hear the grease move...once it does, its greased. As the coach moves up and down, side to side, the grease will be forced to move as well spreading grease through the bore.

So get a good grease gun, good quality synthetic grease and grease it as the manual suggests.
Thats fair. I got the HF grease gun, cuz, well, how bad can it be. It squirts grease. I greased the bogies, but extra was only coming out the front. Ordered the JimK greasers, thought it was worth a try to force the grease in the back.

But I don't have a chunk of leaf spring, and was more asking about this suggestion to see if it would work for changing out tires. I need to get my new rubber mounted this weekend, start rear bearings and brakes maybe and next weekend putting on the new JIMK greasers.
 

Matt Colie

Active member
Oct 25, 2019
322
74
28
South East Michigan near DTW
Kevin,
When the Hazard Fright grease screws up, take it back and then go buy a good one. When I went to load the second cartridge, the feed rod would not stay back. That alone almost cost me the 8$us tube of grease.
Look up Lock-n-Lube. That is a 30$ coupler that is worth it. I used to do a full grease job in about an hour and then come up for air. That was the day. Now I don't struggle to get the coupler on and keep it on and I use one hand. I just have to pump about twice as many times. My Lincoln grease gun was not cheap either.
Matt
 

Agoogol

Member
Mar 3, 2020
102
21
18
Centennial CO
Kevin,
When the Hazard Fright grease screws up, take it back and then go buy a good one. When I went to load the second cartridge, the feed rod would not stay back. That alone almost cost me the 8$us tube of grease.
Look up Lock-n-Lube. That is a 30$ coupler that is worth it. I used to do a full grease job in about an hour and then come up for air. That was the day. Now I don't struggle to get the coupler on and keep it on and I use one hand. I just have to pump about twice as many times. My Lincoln grease gun was not cheap either.
Matt

We shall see Matt! Never know. I have bought some surprisingly good quality stuff there, and you just never know.
 

JPB

New member
Jan 15, 2020
11
3
3
So reading the birdfeeder forum old site, which, as much knowledge is there is so difficukt to navigate I really am thankful for this new site, just have to say!

Anyway, saw this comment from 2011, and wanted to know if any of you have tried this?


Side note: I also have the piece of leaf spring but do not bother to use it any more. I just rotated the tires prior to going to the GMCMI rally without ever getting the coach high enough to get the rear tires off of the ground. It turns out with the coach supported in the middle between the bogies and the bag completely deflated there is next to no weight on the the wheels and they can be removed and installed with the tires still touching the ground. You can lift up on the wheel hub if necessary by hand.

One time went out to help a Black Lister with a flat tire on the Indiana Toll Road. I asked before I left if he had a jack and hook. He said yes. I brought a long bar and the correct socket which he did not have. It turned out I should have asked if the jack worked. It didn't.

Not wanting to drive about 40 miles round trip to my coach to get a good jack, I took some short 2x4 cutoffs I happened to have out of the bed of my truck. I had him air up that bag as far as possible then placed the 2x4's under the jacking point of the bogie. We dropped the coach on the 2x4's and completely deflated the bag. We removed and installed the spare at that height.

Try lifting the wheel hub by hand next time you have a wheel off and no air in the bag. It works.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
The air bags and some cribbage are quite useful for raising the rear of the coach for repairs etc. I'm not sure what air bag and brake set up KenB has. On my coach with dual air bags and drum brakes I can lift the bogie arm but it's a bit heavy and awkward and drops back down too quickly to mount a wheel. Most dual air bags have shutoff valves to Isolate the bags so one can be inflated to support the coach while the other is deflated for tire change. I use a HF 12 ton compact bottle jack to support the bogie arm for tire change. This could also be done with cribbage and no jack would be needed. I would also cribb under the center of the bogie arm (as Ken did) in case the inflated air bag decided to vent suddenly.

JP
 

Agoogol

Member
Mar 3, 2020
102
21
18
Centennial CO
So raised one side. No issues. New tires mounted and back on the rig.

Coil over shocks on the back? Anyone seen this? PO must have loved them, they were on the front too. What? Suppose I should change.

Funny, while I was waiting for tires to be mounted, I finally took the time to do a small thing...changed the fuel filter by the carb. Discovered The one in there was installed incorrectly, spring on the wrong side, filter was twisted. Changed it out, and immediate better throttle response and power. It can be the little things.
 

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JSanford

Active member
Oct 4, 2019
157
40
28
44
Sacramento, CA
So raised one side. No issues. New tires mounted and back on the rig.

Coil over shocks on the back? Anyone seen this? PO must have loved them, they were on the front too. What? Suppose I should change.

Funny, while I was waiting for tires to be mounted, I finally took the time to do a small thing...changed the fuel filter by the carb. Discovered The one in there was installed incorrectly, spring on the wrong side, filter was twisted. Changed it out, and immediate better throttle response and power. It can be the little things.
That is odd since the GMC needs shocks that dampen when being extended, which is the reverse from normal shocks. My understanding is that only Bilstien and KYB make the reverse damping shocks we need.
 

Agoogol

Member
Mar 3, 2020
102
21
18
Centennial CO
Kevin,

I do believe that your PO has carefully displayed a most complete mis-understanding of the GMC suspension I have ever known.

Matt
Matt,

I ordered the KYB KG5436 shocks that are recommended. It seems interesting to me that they dont actually advertise that these operate opposite normal shocks, but I trust by ordering the correct number they are the correct shock.
 

Matt Colie

Active member
Oct 25, 2019
322
74
28
South East Michigan near DTW
I believe that if you are ordering by number, you may have some remote idea what it is you are doing. When I was the aftermarket for McCord gasket, I had more than a few zz (aka "bomb") parts that I put in the catalog. The were only in the sales catalog and not the printed version so the knowing clients could order them. They were "bomb" parts because if installed wrong they could do damage to a stock engine.
Matt