Home » Public Forums » GMCnet » Front engine mount (how to change engine mount)
| Front engine mount [message #274798] |
Thu, 02 April 2015 11:52  |
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Alan Story
Messages: 23
Registered: January 2015
Location: Maple Bay, BC
Karma: 0
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Is there a special procedure to follow to change the front engine mount or do you simply jack up the front of the engine and replace? Mine is toast.
Alan Story
1977 26' Eleganza, 455, 3.70 final drive, Eagles, Michelins, wireless air, Maple Bay, BC
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| Re: Front engine mount [message #274799 is a reply to message #274798] |
Thu, 02 April 2015 12:02  |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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I pulled the bolts out of the mounts, laid a 4x4 across the hatch and used ratchet straps to raise the front of the engine enough to get the old ones out and the new ones in. No big thing.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] Front engine mount [message #274800 is a reply to message #274798] |
Thu, 02 April 2015 12:03 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Alan, there are two distinct motor mounts that fit the front of the GMC.
They can be identified by the fact that one has bolts that go into the
mount from below the crossmember, and the other type has 7/16" N.C. studs
and nuts. They are interchangeable, but the stud type requires that the
engine be lifted a bit higher to replace, than the one with bolts. I
suspect that the bolt type was intended to be used as a replacement mount
in service, but do not have any factual data to back up those suspicions.
Jim K has them in stock, as do a couple of other vendors. To address your
question for proceedure, use a substantial hoisting device and lift from
above. If you jack up the oil pan to gain clearance as some others might
suggest, you run the risk of denting in the pan to the point where the
counterweights of the crankshaft makes contact with the pan. Makes a heck
of a racket. Also, watch for interference between the fan shroud and the
fan blades.
Jim Hupy
Salem, OR
78 GMC Royale 403
On Thu, Apr 2, 2015 at 9:52 AM, Alan Story wrote:
> Is there a special procedure to follow to change the front engine mount or
> do you simply jack up the front of the engine and replace? Mine is toast.
> --
> Alan Story
> 1977 26' Eleganza, 455, 3.41 final drive, Maple Bay, BC
> _______________________________________________
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| Re: Front engine mount [message #274801 is a reply to message #274798] |
Thu, 02 April 2015 12:13 |
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Alan Story
Messages: 23
Registered: January 2015
Location: Maple Bay, BC
Karma: 0
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Junior Member |
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Thanks Jim, I appreciate your input. I don't have any means of hoisting from inside so I will save it until the next time we get together. See you next month.
Alan Story
1977 26' Eleganza, 455, 3.70 final drive, Eagles, Michelins, wireless air, Maple Bay, BC
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| Re: [GMCnet] Front engine mount [message #274804 is a reply to message #274803] |
Thu, 02 April 2015 13:32 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Hmmm? Let's see. It's made out of rubber, it's 40 years old, it's soaked
in oil and anti freeze and road crud. There are steel parts bonded to
rubber parts. It is very likely that it is separated. Take a substantial
pry bar and pry between the cross member and the front steel mounting
bracket that the mount is bolted to.
There should be only a small amount of movement when you pry. If the engine
lifts freely, your mount is bad and needs replacing.
Jim Hupy
Salem, Oregon
78 GMC ROYALE 403
On Apr 2, 2015 11:20 AM, "Steve Weinstock" wrote:
> So...
>
> What's the simple method to determine if a motor mount needs replacement ??
>
> Is it an simple as : Put it in gear, step on the brake, give it some gas,
> and look to see if the engine lifts unexpectedly ??
>
> I suspect mine is suspect.
>
> Steve W
> 1973 23'
> southern California
>
>
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| Re: [GMCnet] Front engine mount [message #274805 is a reply to message #274804] |
Thu, 02 April 2015 13:57 |
appie
Messages: 902
Registered: April 2013
Location: denmark
Karma: 2
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Senior Member |
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Replaced mine as amatter of course when I replaced the engine. Did not seem to be anything wrong with the old one
Appie
eleganza 76 "Olga" now sadly sold
6 wheel discbrake
Quadrabags
Springfield stage 2 462 olds
Manny tranny
( pictures at http://www.gmcmhphotos.com/photos/g6489-olga.html
Fulltiming in Europe july 2014 til july 2016
Denmark
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| Re: Front engine mount [message #274809 is a reply to message #274799] |
Thu, 02 April 2015 15:06 |
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Alan Story
Messages: 23
Registered: January 2015
Location: Maple Bay, BC
Karma: 0
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Junior Member |
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Thanks Kerry, I might be able to handle your method.
Alan Story
1977 26' Eleganza, 455, 3.70 final drive, Eagles, Michelins, wireless air, Maple Bay, BC
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| Re: Front engine mount [message #274841 is a reply to message #274803] |
Thu, 02 April 2015 18:04 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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SteveW wrote on Thu, 02 April 2015 12:19So...
What's the simple method to determine if a motor mount needs replacement ??
Is it an simple as : Put it in gear, step on the brake, give it some gas, and look to see if the engine lifts unexpectedly ??
I suspect mine is suspect.
Steve W
1973 23'
southern California
Talk about timing ! When I was under mine the other day trying to figure out if my fan was hitting the shroud, I noticed it is much lower in the shroud than it should be. Also, I've been noticing a more abrupt "bump" when shifting between drive and reverse. Then, when adding a quart of oil after my trip, I saw it immediately pour onto the ground--my metal tube for the remote oil fill had pulled out of the silicon right angle fitting on the engine. Any or all of those can be clues that your mount has sagged.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Front engine mount [message #274843 is a reply to message #274800] |
Thu, 02 April 2015 18:16 |
powwerjon
Messages: 849
Registered: March 2013
Karma: -2
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Senior Member |
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As Jim has said, DO NOT jack the motor up by using the oil pan as a jack point. As the clearance between the pan and crankshaft is tight and you can push the pan into the crank.
This is the tool that I have used in the past to lift and support the engine in the past, it uses the block frame rails as the contact point.
http://www.gmcmhphotos.com/photos/general-pictures/p44882-engine-jacking-jig-for-lifting-motor.html
http://www.gmcmhphotos.com/photos/general-pictures/p44883-engine-jacking-jig-for-lifting-motor.html
http://www.gmcmhphotos.com/photos/general-pictures/p44884-engine-jacking-jig-for-lifting-motor.html
http://www.gmcmhphotos.com/photos/general-pictures/p44885-engine-jacking-jig-for-lifting-motor.html
J.R. Wright
30' Buskirk Stretch
Michigan
On Location in Tucson
> On Apr 2, 2015, at 10:03 AM, James Hupy wrote:
>
> Alan, there are two distinct motor mounts that fit the front of the GMC.
> They can be identified by the fact that one has bolts that go into the
> mount from below the crossmember, and the other type has 7/16" N.C. studs
> and nuts. They are interchangeable, but the stud type requires that the
> engine be lifted a bit higher to replace, than the one with bolts. I
> suspect that the bolt type was intended to be used as a replacement mount
> in service, but do not have any factual data to back up those suspicions.
> Jim K has them in stock, as do a couple of other vendors. To address your
> question for procedure, use a substantial hoisting device and lift from
> above. If you jack up the oil pan to gain clearance as some others might
> suggest, you run the risk of denting in the pan to the point where the
> counterweights of the crankshaft makes contact with the pan. Makes a heck
> of a racket. Also, watch for interference between the fan shroud and the
> fan blades.
> Jim Hupy
> Salem, OR
> 78 GMC Royale 403
>
> On Thu, Apr 2, 2015 at 9:52 AM, Alan Story wrote:
>
>> Is there a special procedure to follow to change the front engine mount or
>> do you simply jack up the front of the engine and replace? Mine is toast.
>> --
>> Alan Story
>> 1977 26' Eleganza, 455, 3.41 final drive, Maple Bay, BC
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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| Re: [GMCnet] Front engine mount [message #274854 is a reply to message #274841] |
Fri, 03 April 2015 00:12 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Senior Member |
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Speaking of the oil fill pipe elbow both elbows on recherché were rotten
and torn especially the engine side one. Since I had to get her on the road
quick and she was burping oil out the engine elbow I took the elbow with me
to oschucks and was able to buy 2 oe replacement molded hoses for about $13
and double up the skinny end with one and accomplish the bend and step up
to the engine pipe with the other. I saved the receipt with the part
numbers and cost if anyone interested. The same combo will work on the fill
side. might even be enough left of the $4.00 hose to bush up the skinny
pipe on the fill side leaving the second elbow a cost of about $9
Sully
77 Royale
77 eleganza 2
Seattle
On Thursday, April 2, 2015, Bob de Kruyff wrote:
> SteveW wrote on Thu, 02 April 2015 12:19
>> So...
>>
>> What's the simple method to determine if a motor mount needs replacement
> ??
>>
>> Is it an simple as : Put it in gear, step on the brake, give it some
> gas, and look to see if the engine lifts unexpectedly ??
>>
>> I suspect mine is suspect.
>>
>> Steve W
>> 1973 23'
>> southern California
>
> Talk about timing ! When I was under mine the other day trying to figure
> out if my fan was hitting the shroud, I noticed it is much lower in the
> shroud than it should be. Also, I've been noticing a more abrupt "bump"
> when shifting between drive and reverse. Then, when adding a quart of oil
> after my trip, I saw it immediately pour onto the ground--my metal tube
> for the remote oil fill had pulled out of the silicon right angle fitting on
> the engine. Any or all of those can be clues that your mount has sagged.
> --
> Bob de Kruyff
> 78 Eleganza
> Chandler, AZ
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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