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Ok, whats the real trick to installing isolation pads. [message #128784]

Sun, 05 June 2011 17:29

RF_Burns

Messages: 2277
Registered: June 2008
Location: S. Ontario, Canada

Karma: 3

Senior Member

I followed the current thread and re-read John Shotwell's excellent write-up on changing out the isolation pads.

I've been hitting all the bolts for the last couple weeks every few days. Today I started early and first ran a die up the threads to clean them up. After about 6 hours I finally got them all off but one.

I could not get the large two hold down bolts at the back off so I loosed the 4 smaller ones holding the block in place.

I jacked up the back and put jack stands under the frame. I managed to get the 3 behind the back wheels changed although the frame came up off the jacks while doing it.

I have a Ragusa step so I tried to remove it. I got 3 of 4 bolts out. The last nut is hopelessly rounded now and its a grade 8 bolt so I can't budge it.

Also even though the hold-down bolts are all off but one, I can get the strap off.

In front of the wheels I have had no luck. I've plugged my ears so I can't hear the crackly of the body and lifted the front and back wheels off the ground and it barely moves! Something has to be holding still. I didn't remove the front donunt... yet. And I watched the clearance around the black water drain.

So now I've got three new thick ones on the back passenger side and old worn thin ones the rest of the way around. I'm beat for the day... do I go back and remove those three thick pads so it doesn't warp the coach?

Are you guys chaining the frame down on a lift when you are doing this?

I'm thinking I'll need to build some type of frame to work off the coach's frame and put the jack on that.

What am I doing wrong?

Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

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Re: Ok, whats the real trick to installing isolation pads. [message #128819 is a reply to message #128784]

Sun, 05 June 2011 21:07

thorndike

Messages: 406
Registered: January 2011
Location: Conifer, Colorado

Karma: 0

Senior Member

Bruce,

I am in the middle of doing this myself.

I had no luck until I was able to remove the two bolts in the rear corners. Luckily, these had hex-heads and was able to make use of my son to get them removed.

Once removed, I was able to jack the coach up a bit and begin to make progress with the pads. I DID have to have him and my wife sit on the bumper while I jacked up the body. This seemed to be enough weight (although it is so little compared to the rest of the coach) to help push the frame away from the body.

I have also found that using two jacks seems to help a bit. I place one jack at the pad I am removing, and one at the next pad forward (I am starting at the back.) Once I get separation on the pad I am removing, I lower that jack and use the next jack forward to keep the body off the frame so that I can use my scraper and remove the pad in question.

I am then 'leap frogging' the jacks to make removing the pads easier.

Bob

Robert Peesel 1976 Royale 26' Side Dry Bath Conifer, Colorado

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Re: Ok, whats the real trick to installing isolation pads. [message #128824 is a reply to message #128784]

Sun, 05 June 2011 21:30

gordh1

Messages: 332
Registered: February 2011

Karma: 0

Senior Member

Hi Bruce,

I just added a couple of photos of the floor framework and the hold down bracket that's just inside the door. Note in the other pic, one directly opposite on the other side, and a couple more two beams forward.

http://www.gmcmhphotos.com/photos/showphoto.php?photo=39506

http://www.gmcmhphotos.com/photos/showphoto.php?photo=39507

Mine is a 74 - later models have a full frame joining the front to the rear (parallel to the real frame between the bogies).

IMHO and that's seriously IMHO, the main mounts front and rear do little more than position the body to the chassis. If they're loose, well, fine, but I don't think that's your issue. As mine sits now I can lift any single cross member almost by hand - I would suggest perhaps a 2x4 and no more, across 2 of the cross members at a time to distribute the load, and it should move with little effort i.e. if the 2x4 snaps, that's enough (too much) pressure.

I'm always jacking on the outside of the real frame of course. I'd say one by one or try 'one' that's not near a window (maybe just behind the open door?) to see how it lifts. If the whole coach is lifting, something (IMHO) must be really stuck or still attached.

Suggestions only - of course this whole procedure to replace pads is relying on the coach body flexing so it's not going to be 'silent' so far as odd noises... just use care and try not to over stress the coach (especially glass) or yourself.

HTH,

Gord

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Re: Ok, whats the real trick to installing isolation pads. [message #128830 is a reply to message #128819]

Sun, 05 June 2011 22:19

Ken Burton

Messages: 10030
Registered: January 2004
Location: Hebron, Indiana

Karma: 10

Senior Member

thorndike wrote on Sun, 05 June 2011 21:07

One suggestion though I have only once had to do it on a couple of pads on the coach that had thin ones originally. Cut yourself a wedge out of a 2x4 or 2x2 and drive it in there immediately adjacent to the pad you are replacing. We only did this once and it was the pad immediately in front of the bogies on both sides.

As I stated before, If you originally had thick pad then you should be able to replace all of he pads WITHOUT removing the hold downs. If you feel you have to remove the holddowns, remove one HORIZONTAL bolt through the frame on each one, then loosen but do not remove the second bolt.

Read my previous posting in this thread for more details.

The slightly bent crow bar that Ken H. suggested really helped in removing my old ones.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

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Re: Ok, whats the real trick to installing isolation pads. [message #128840 is a reply to message #128784]

Mon, 06 June 2011 00:08

RF_Burns

Messages: 2277
Registered: June 2008
Location: S. Ontario, Canada

Karma: 3

Senior Member

Atthe rear I jacked up up the bogies and then set jack stands under the frame. Then I released the air from the rear suspension. This made the replacement of the rears fairly easy, although the frame would still come off the jack stand slightly

Mine being an early 77 (October 76 manufacture date), it has the thin pads, I'm installing the thick pads, all that is available but they would appear to work better.

I do have the nuts (except one) removed from the hold-downs along the side, but I can't seem to get the hold-down straps to drop down off the bolts.

I can understand why the frame will come up with body, I am lifting the weight off the frame. I need to figure how to hold it down or jack against the frame somehow.

I have a macerator and its bracketed to the frame. I can see this is a bad idea since the black tank is held to the body. I'll have to rework this to mount it to the body.

[Updated on: Mon, 06 June 2011 07:30]

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Re: Ok, whats the real trick to installing isolation pads. [message #128882 is a reply to message #128840]

Mon, 06 June 2011 09:15

jhb1

Messages: 303
Registered: February 2004

Karma: 0

Senior Member

Hi Bruce
I have an early 77 and also had the macerator mounted to the frame. Loosen the macerator or you will be changing some of the abs fittings you crack and then start to leak don't ask how I know. I changed my pads last year and it does make a large improvement in ride quality the trick is to support the frame with the wheels off the ground and slowly jack the body with a bottle jack next to the pad you are changing.
HTH

RF_Burns wrote on Mon, 06 June 2011 01:08

John H. Bell
77 Royale; QuadBag,Manny OneTon,Honda EV4010, FITech
Montreal Qc.

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Re: Ok, whats the real trick to installing isolation pads. [message #128905 is a reply to message #128784]

Mon, 06 June 2011 11:21

RF_Burns

Messages: 2277
Registered: June 2008
Location: S. Ontario, Canada

Karma: 3

Senior Member

Thanks for that info John. It makes more sense to raise the frame so the suspension is not pushing up on the body. That is what I did on the back end.

Did you go to the thicker pads as well?

I think I'll try to arrange to access the lift at the local fleet service garage I use, or at least the pit. That way I can access inside and outside of the frame.

Did you fasten the macerator to the body crossmembers? I am thinking that would be the best idea.

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Re: Ok, whats the real trick to installing isolation pads. [message #128918 is a reply to message #128905]

Mon, 06 June 2011 12:45

jhb1

Messages: 303
Registered: February 2004

Karma: 0

Senior Member

Bruce

I am in the middle of replumbing the macerator install from the PO it held together for 8 years so I will not complain to loudly I plan on use a muffler hanger and a 3" hose clamp. If you send me your e-mail address of line I will take some pictures. As for the body pads yes I used the thick ones I do not what was there before they where all missing

John H. Bell
77 Royale; QuadBag,Manny OneTon,Honda EV4010, FITech
Montreal Qc.

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Re: Ok, whats the real trick to installing isolation pads. [message #128919 is a reply to message #128784]

Mon, 06 June 2011 12:52

RF_Burns

Messages: 2277
Registered: June 2008
Location: S. Ontario, Canada

Karma: 3

Senior Member

John,
PM'd you with my email addy

thanks

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Re: [GMCnet] Ok, whats the real trick to installing isolation pads. [message #128994 is a reply to message #128882]

Mon, 06 June 2011 21:31

Ken Henderson

Messages: 8726
Registered: March 2004
Location: Americus, GA

Karma: 9

Senior Member

John, Bruce, et al,

I don't see anything wrong with mounting the macerator to the frame.
But it needs a flexible connection to the sewer lines. This is not a
very good photo, but does show a bit of the "picker hose" with which I
attached my 3" sewer outlet to the pump. "Picker Hose", from an
agricultural implement dealer is much thicker and more durable than
ordinary sewer hose, which it resembles.

http://www.gmcmhphotos.com/photos/showphoto.php?photo=371&cat=3048

Incidentally, my macerator is one of those without the small pipe
extension -- the 3" body
diameter is the inlet connection.

Also: On my Birchaven, the tanks are mounted to the frame, NOT the body.

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com

On Mon, Jun 6, 2011 at 10:15 AM, jhb1 <jhbmjk@gmail.com> wrote:
>
>
> �Hi Bruce
> I have an early 77 and also had the macerator mounted to the frame. Loosen the macerator or you will be changing some of the abs fittings you crack and then start to leak don't ask how I know. ...
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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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