Home » Public Forums » GMCnet » Jacking up the coach (Is there a right and wrong way to change a wheel?)
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| Re: Jacking up the coach [message #361218 is a reply to message #360917] |
Mon, 28 December 2020 13:33   |
boybach
Messages: 566
Registered: December 2020
Location: Vancouver Island
Karma: 4
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I don't know (and it's impossible for me to find out till I get there in April) but there's a pretty good chance there was no blocking installed when she was stored in August, so there's a real possibility that the bags might be totally flat. Hopefully that isn't the case.
The coach was driven 2500 miles to the storage area by someone who could drive it but with no experience with GMC systems.
Driver didn't camp in it, stayed in motels on the way. It just got parked up in the storage yard, tarped over and there she sits.
Larry
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
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| Re: Jacking up the coach [message #361821 is a reply to message #360917] |
Sun, 17 January 2021 14:45 |
boybach
Messages: 566
Registered: December 2020
Location: Vancouver Island
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It looks like I will be doing the tire and wheel removal myself in the storage yard. I'll be taking the tires off and taking them to the tire installer to have the new tires fitted and balanced. The tires are actually at least 10yrs old and I've heard they are going flat in storage.
I intend to get the spring steel bars made up to jack up the bogies.
Initially I was thinking of doing one rear side at a time, but would it be possible to remove all four rear tires working on one side at a time, blocking the bogie then moving to the other side? I'll have a jack and some cribbing with me when I show up at the yard but the tire place is about 20 miles away and I don't mind making 2 trips. Unless I can get all 4 rears off and loaded down to the installer in one shot I'll have to make 3 trips.
For the front, I'll get the spare mounted along with the four rears so that after replacing the rears and setting her back down I can mount the spare on one side and then take the remaining two old fronts along to get them done.
How does that sound?
any advice appreciated guys
thanks
Larry
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
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| Re: Jacking up the coach [message #361825 is a reply to message #360917] |
Mon, 18 January 2021 08:07 |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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If you have enough cribbing and the right jacks, you can "fly" it and take all six wheels at once. My order of operations is as follows, do as you wish:
3 ton jack under rear frame near bogies with a 4x4 between jack head and frame, long ways, along the frame to distribute the pressure point. Start jack, when it is holding some weight, release air bag. Continue to jack until tires are clear and place wood block or jack stand under the bogies. Lower jack so weight is on bogies. Repeat on the other side.
Go to front. Put jack under center cross member and raise the front until wheels are clear. Place jack stands on the outer edges of the cross member and release jack enough that all three are holding weight.
Return to rear and put safety cribbing under the frame where doubled up "C" and cross members intersect.
When I left it this way for extended time, I added another safety cribbing under the front frame.
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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| Re: Jacking up the coach [message #361826 is a reply to message #361821] |
Mon, 18 January 2021 08:10 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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You can remove all four rear tires at the same time. With enough cribbing! Do not jack one side all the way up and then do the other side. Instead, raise one side part way, move to the other side, match the height, then back to the original side and finish the job.
Break the lug nuts loose before even starting, them babies are tight. Breaker bar is your friend. Plus, get an impact rated socket for the lug nuts. I broke a typical socket while playing tire mechanic.
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: Jacking up the coach [message #361828 is a reply to message #360917] |
Mon, 18 January 2021 11:42 |
boybach
Messages: 566
Registered: December 2020
Location: Vancouver Island
Karma: 4
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Thanks for the help guys - I can see I'm going to have pack a whole load of lumber up there when I drive up there to get it!
I have a 3-1/2 ton floor jack and a bottle jack. In other posts and from what I've seen on youtube, people have placed cribbing under the bogie castings to support the coach. I've also heard tips about jacking the wheels up on the bogie castings. What isn't all that clear is where to place the jack (jacking point?) if you intend to lower it down so the bogie casting rests on the cribbing?
I've seen the hook bottle jack attachment and using that in the rear, is there enough room get the cribbing in place under the bogie casting? If the hook is used on the front, where does it locate?
TIA
Larry
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
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| Re: Jacking up the coach [message #361829 is a reply to message #361828] |
Mon, 18 January 2021 12:21 |
mghamms
Messages: 466
Registered: March 2016
Location: Ware, Massachusetts
Karma: 2
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I use the hook and bottle jack for the rear. 4x6 under the bogie.
Front i jack the middle of the crossmember with the floor jack.
boybach wrote on Mon, 18 January 2021 11:42Thanks for the help guys - I can see I'm going to have pack a whole load of lumber up there when I drive up there to get it!
I have a 3-1/2 ton floor jack and a bottle jack. In other posts and from what I've seen on youtube, people have placed cribbing under the bogie castings to support the coach. I've also heard tips about jacking the wheels up on the bogie castings. What isn't all that clear is where to place the jack (jacking point?) if you intend to lower it down so the bogie casting rests on the cribbing?
I've seen the hook bottle jack attachment and using that in the rear, is there enough room get the cribbing in place under the bogie casting? If the hook is used on the front, where does it locate?
TIA
Larry
1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
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| Re: Jacking up the coach [message #361830 is a reply to message #360917] |
Mon, 18 January 2021 13:37 |
blur911
Messages: 166
Registered: December 2020
Location: Kingston, Ontario
Karma: 4
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I just measured the block of wood I used under one of the sides, it's 7-1/4" square. Might be of help when picking out pieces for cribbing.
BTW, about these J-hook jack adapters, is there a dimensional drawing or similar online so I can make one, I have the ability and tools.
Or, is it proprietary, as in, someone designed this and I should buy it from them?
Burl Vibert
Kingston, Ontario
1976 GMC 26 foot, Sheridan reno, don't know original model but we call her Roxie
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| Re: Jacking up the coach [message #361831 is a reply to message #361830] |
Mon, 18 January 2021 17:51 |
boybach
Messages: 566
Registered: December 2020
Location: Vancouver Island
Karma: 4
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Quote:BTW, about these J-hook jack adapters, is there a dimensional drawing or similar online so I can make one, I have the ability and tools.
Or, is it proprietary, as in, someone designed this and I should buy it from them?
There's a bunch of stuff on the hooks here:
http://gmcmotorhome.info/rear.html#RAISING
Larry
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
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| Re: Jacking up the coach [message #361832 is a reply to message #360917] |
Mon, 18 January 2021 17:53 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Larry, Mike and Burl,
I originally posted this mid-year and there was a simplified version I posted in this thread in December. I suggest you read both and if you have questions, I will be back tomorrow. Realize that this is an owner that had both fuel tanks down five times, his black tank down twice and pulled the front frame twice. Before you ask why I didn't do it right the first time, the only of those I could have avoided was one of the fuel tank drops if I had known then what I learned later. I have a lot of "under the coach" hours. In later times I learned how to lift the rear with my car lift, but not many have that option.
Posted:
I need to lift the rear of my GMC and I only have one jack. Can this be done safely? (For both me and the coach?)
The simple answer is yes, but the complete answer is far from simple.
Ready?
You need a collection of 4X6 timber blocks and one that is a full 6' long. Have the yard (unless you have a really big saw) cut some 4x6 in 12 and 18 inch long pieces. You will want at least two of each, but more is better. And, a 3-ton floor jack.
The nature of the beast is such that you do not want to lift the coach weight directly on the frame ever except at the approved hard points. (I have seen lots of coaches with the resulting damage.)
Take that long timber all the way aft. You can get a head start by putting it on two of the cut pieces. If you lift it there, you are not lifting the whole (or even the rear half) of the coach weight. There is a considerable hard point where the rear cross frame bolts to the stringers.
The proof in the math. A typical 26' coach is in the 12K# region. Of that, there is 4000+ in the front and about 8K for the rear. When you do the math, you will discover that even at 9400 on the rear, lifting the rear frame is still less than 6000. So, there should be some room there.
Before I got the Merrill hitch installed, I lifted my coach (admittedly only a light 23) there several times. When I did this with a 3 ton floor jack, I would put a 4x6 across the rear most frame and lift in the center. Then place cribbing (blocks) under the bogey castings. When she was set on the cribbing - usually two hunks of 4*6 - I would let the floor jack off and give the coach a solid body check. An acquaintance was watching this procedure and asked if I were afraid I might knock the coach off the blocks. To this I replied,"I'm sure not worried now."
This lift never caused Chaumière any additional frame damage. (She came with some.) The notable point here is that you are not lifting as much weight as you would have to when lifting any farther forward. You are distributing the weight you are lifting across that rear frame (and the bumper as well if you have a Merril hitch).
A warning about wood, it does not have a yield strength. When/If you hear a crack, that is it. You are done. My long 4x6 is still here. It was used for other things before the coach and has been used for many other things since.
Another caution here. When you are lifting the rear only do it when the front is on its own suspension. I have been told that having the front on solid stands can cause the body to flex enough to crack a windshield. If you need to lift the front too, do that later.
I am sure you can do this, but it still requires that you use due care.
Matt Colie
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Jacking up the coach [message #361842 is a reply to message #360917] |
Tue, 19 January 2021 09:44 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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I use 4x4s, it just takes more of them. (Some while back an employer gave me a pickup load of treated 8' 4x4s.) NEVER simply place one directly atop the other, ALWAYS criss cross. On atop the other cost me an aluminum radiator when the coach came down.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: Jacking up the coach [message #361844 is a reply to message #361833] |
Tue, 19 January 2021 10:23 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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boybach wrote on Mon, 18 January 2021 19:43Quote:one 4 x 6 that is a full 6' long
Well Matt up here in BC where all the logs come from  we don't commonly use 4 x 6's - would a 4 x 4 be ok to use for the 6' piece under the jack?
Larry
Larry,
Used 4*6 because that is what I have and it did work well to lift the rear of my coach.
If 4*4 is what you have, give it a try but stay clear. Wood had zero yield strength, when you hear it crack, it is done. if it doesn't crack, it could also flex enough to bend the rear most cross member. If that is a worry, just put a block at each end so the long part has more room to bend.
Your coach is heavier than mine, most are. In the case that a 4*4 does not make the lift. Come back here and I will tell you about what I was going to try before I found that I could get by with a single piece of wood there.
You will have to lift and then let the air off the rear so you don't blow out the shocks.
And yes, don't stack two 4*4 chunks. That won't be stable.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Jacking up the coach [message #361846 is a reply to message #361844] |
Tue, 19 January 2021 10:56 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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I personally NEVER use wood to block or "crib up" ANYTHING that I plan on
crawling about under. On coaches, my procedure kinda goes like this: Front
end first. 6 ton floor jack under the center of the front crossmember
directly under the engine front mounting holes. Raise high enough to place
large steel 6 ton jack stands on the side frame rails where the front clip
joins the side rails. Jack stands that I use are tall enough that the
extension is clear down. (Not harbor freight ones) I have a local tool only
store that I shop at. Not cheap, but daily use professional quality stuff.
Then on to the rear. Same heavy duty 6 ton floor jack. Under the bogie
box. Unload the suspension with the floor jackets, then let about 1/2 the
air out of the bags. Finish raising the coach high enough until the side
frame is nearly level. Then, I use 4ea 3 ton jack stands, located ahead and
behind the tires. Location determined by crossmembers. Lower the jack under
the bogie box.
So, there are 6 jack stands total. 4 in the rear, two in the front.
This is in an enclosed, heated, well lighted shop with a concrete floor.
I didn't get to be 80 years old by being stupid about jacking heavy
stuff off the ground. Safety first.
Jim Hupy
Salem, Oregon
On Tue, Jan 19, 2021, 8:24 AM Matt Colie via Gmclist <
gmclist@list.gmcnet.org> wrote:
> boybach wrote on Mon, 18 January 2021 19:43
>> Quote:
>>> one 4 x 6 that is a full 6' long
>>
>> Well Matt up here in BC where all the logs come from :) we don't
> commonly use 4 x 6's - would a 4 x 4 be ok to use for the 6' piece under the
>> jack?
>>
>> Larry
>
> Larry,
>
> Used 4*6 because that is what I have and it did work well to lift the rear
> of my coach.
>
> If 4*4 is what you have, give it a try but stay clear. Wood had zero
> yield strength, when you hear it crack, it is done. if it doesn't crack, it
> could also flex enough to bend the rear most cross member. If that is a
> worry, just put a block at each end so the long part has more room to bend.
>
>
> Your coach is heavier than mine, most are. In the case that a 4*4 does
> not make the lift. Come back here and I will tell you about what I was
> going
> to try before I found that I could get by with a single piece of wood
> there.
>
> You will have to lift and then let the air off the rear so you don't blow
> out the shocks.
>
> And yes, don't stack two 4*4 chunks. That won't be stable.
>
> Matt
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
>
> _______________________________________________
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> Unsubscribe or Change List Options:
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| Re: [GMCnet] Jacking up the coach [message #361851 is a reply to message #361846] |
Tue, 19 January 2021 13:21 |
boybach
Messages: 566
Registered: December 2020
Location: Vancouver Island
Karma: 4
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Quote:So, there are 6 jack stands total. 4 in the rear, two in the front.
This is in an enclosed, heated, well lighted shop with a concrete floor.
I didn't get to be 80 years old by being stupid about jacking heavy
stuff off the ground. Safety first.
Jim Hupy
Salem, Oregon
Sounds great James but I will not have the luxury of having the concrete floor and workshop. She's sitting outdoors, 300 miles away in a storage yard on grass with temps in my pick up window (late March) just above freezing. No power and the only tools and cribbing available will be what I drive out there with. Despite the less than optimal conditions, I have to change the 10+ year old tires one way or another.
I don't think I'll attempt to raise up the entire coach but I would like to do the rears in one go if possible.
Some of my apprehension and need for advice is due to TOTAL unfamiliarity with the GMC regarding everyday stuff like the frame, bogeys, front A-arms, stringers etc. I have not yet seen the underbody of any GMC coach, not just mine!
All I have to go on to prep for the work is the advice from the forum and what images I can find on the net.
The coach is located in a small community called "Scotch Creek" and I don't want to be up there "without a paddle"
Larry
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
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| Re: [GMCnet] Jacking up the coach [message #361852 is a reply to message #361851] |
Tue, 19 January 2021 13:46 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Bogie box is the descriptive term most often used for the part of the rear
suspension that is bolted solid to the frame of the coach. It is the GMC
approved jacking point on the rear of the coach. That is where you would
place a large hydraulic floor jack to lift the coach. It is also where the
jack hooks and smaller hydraulic bottle jacks can be used.
The bogie arms are the movable arms that anchor into the bogie box via
bushings and pivot pins. They have spindles on the outboard ends that the
hubs, wheels, tires, and shocks attach to. Usually NOT a good idea to use a
jack under them, or jack stands either.
So to summarize, there are 3 point jacking supports. Center of the
front crossmember, and the 2 bogie boxes.
Hope this helps you, rather than confuses you.
Jim Hupy
Salem, Oregon
On Tue, Jan 19, 2021, 11:22 AM twlldeen--- via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Quote:
>> So, there are 6 jack stands total. 4 in the rear, two in the front.
>> This is in an enclosed, heated, well lighted shop with a concrete floor.
>> I didn't get to be 80 years old by being stupid about jacking heavy
>> stuff off the ground. Safety first.
>> Jim Hupy
>> Salem, Oregon
>
> Sounds great James but I will not have the luxury of having the concrete
> floor and workshop. She's sitting outdoors, 300 miles away in a storage yard
> on grass with temps in my pick up window (late March) just above freezing.
> No power and the only tools and cribbing available will be what I drive out
> there with. Despite the less than optimal conditions, I have to change the
> 10+ year old tires one way or another.
>
> I don't think I'll attempt to raise up the entire coach but I would like
> to do the rears in one go if possible.
> Some of my apprehension and need for advice is due to TOTAL unfamiliarity
> with the GMC regarding everyday stuff like the frame, bogeys, front A-arms,
> stringers etc. I have not yet seen the underbody of any GMC coach, not
> just mine!
>
> All I have to go on to prep for the work is the advice from the forum and
> what images I can find on the net.
>
> The coach is located in a small community called "Scotch Creek" and I
> don't want to be up there "without a paddle"
>
> Larry
> --
> Larry - Victoria BC -
>
> 1977 Palm Beach VIN TZE167V101295 - 39,000 miles
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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| Re: Jacking up the coach [message #361854 is a reply to message #360917] |
Tue, 19 January 2021 14:25 |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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I like the "Up Scotch Creek without a paddle" word play...
The standard to get the coach up safely to change tires is logically a lower standard than to leave the coach for an extended period that includes you actually being under it. The temptation is to "just take a look at X..." Don't do it - especially on an unknown coach!
You asked for clarification on jacking the rear in such a way to then put something under the bogies...the frame around the rear wheels area looks plenty solid from the curb view of it - it is not strong enough to jack directly on the frame, or put a single jack stand under it. If you distribute some weight it does fine - that's why I said I use a 4x4 (at least two feet long) between my 3 ton jack and the frame. There are cross members every four feet or so that go side to side
Here are some pics of a frame by itself
http://www.gmcmotorhomemarketplace.com/stuckey/
Ideally, you want to catch one of these "T"s in the frame, with a distributing block on your jack. Lift only enough to take the weight, reduce air bag pressure to not overextend the shocks, then continue lifting enough to then place stout wood blocks under the bogie.
Alternately, you can jack under the bogie directly, and then crib up the frame for safety.
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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| Re: [GMCnet] Jacking up the coach [message #361855 is a reply to message #361851] |
Tue, 19 January 2021 15:09 |
stu@97381.com, Emery
Messages: 232
Registered: June 2020
Karma: 2
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Senior Member |
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You should put a piece of plywood over the grass or at least a pice of 2x10 a foot long. This should prevent your jack from sinking down into the dirt or grass.
Emery Stora
emerystora@mac.com
> On Jan 19, 2021, at 12:21 PM, twlldeen--- via Gmclist wrote:
>
> Quote:
>> So, there are 6 jack stands total. 4 in the rear, two in the front.
>> This is in an enclosed, heated, well lighted shop with a concrete floor.
>> I didn't get to be 80 years old by being stupid about jacking heavy
>> stuff off the ground. Safety first.
>> Jim Hupy
>> Salem, Oregon
>
> Sounds great James but I will not have the luxury of having the concrete floor and workshop. She's sitting outdoors, 300 miles away in a storage yard
> on grass with temps in my pick up window (late March) just above freezing. No power and the only tools and cribbing available will be what I drive out
> there with. Despite the less than optimal conditions, I have to change the 10+ year old tires one way or another.
>
> I don't think I'll attempt to raise up the entire coach but I would like to do the rears in one go if possible.
> Some of my apprehension and need for advice is due to TOTAL unfamiliarity with the GMC regarding everyday stuff like the frame, bogeys, front A-arms,
> stringers etc. I have not yet seen the underbody of any GMC coach, not just mine!
>
> All I have to go on to prep for the work is the advice from the forum and what images I can find on the net.
>
> The coach is located in a small community called "Scotch Creek" and I don't want to be up there "without a paddle"
>
> Larry
> --
> Larry - Victoria BC -
>
> 1977 Palm Beach VIN TZE167V101295 - 39,000 miles
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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