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Motor mount lower plate

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Old 03-13-2019, 04:09 PM
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merchauser
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Default Motor mount lower plate

nearly certain that my MMs are the originals from 1990 with OEM part number 928 375 039 00 on mount. the orientation of the lower plate looks like its 180' out?
aren't the hooks suppose to engage each other? lower plate also looks distorted; shouldn't it be relatively flat?

Old 03-13-2019, 04:50 PM
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soontobered84
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I doubt that those are the original motor mounts unless you have documentation that they are original. More probable is that a "mechanic" not familiar with 928s was using a PO's wallet to learn.
Since the lower plate got so screwed up, I would say that the "mechanic" that installed those motor mounts did not learn much from the experience.
Old 03-13-2019, 07:26 PM
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C531XHO
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Just redoing mine with Volvo mounts but not completed yet. I need to confirm this but I think the "hook" features sort of interlock as if you were placing your hooked fingers together. I think your plate is upside down and 180 degrees out on rotation..

also are the mounts upside down???
Old 03-13-2019, 09:20 PM
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merchauser
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Originally Posted by C531XHO
Just redoing mine with Volvo mounts but not completed yet. I need to confirm this but I think the "hook" features sort of interlock as if you were placing your hooked fingers together. I think your plate is upside down and 180 degrees out on rotation..

also are the mounts upside down???
yes, the hooks are suppose to interlock, and yes these are 180' out, and upside down. very fortunate to have tons of receipts from day one; mounts have never been replaced, but oil pan gasket was done 05/03, and when the crossmember was dropped, the mechanic must have improperly oriented the lower plates. it is impossible for the mount to be put in upside down. good luck with your project
Old 03-13-2019, 10:48 PM
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dr bob
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The "hooks" are there to offer some restraint on the motor in an accident. The hooks should be close to each other but not touching when the new mounts are installed. As the mount sags over time, that gap between hooks gets larger. A telltale of the need for new mounts is a gap big enough to pass a fat finger through. With the taller Volvo mounts, you will likely want to do a little bending/reforming of the hook on the plate, so the hooks don't touch. If they do touch, you'll get a bit of banging/rattling with the engine running.

----

I replaced the original factory mounts with new factory mounts the first time around. Since then, after installing many sets of Volvo mounts on clinic cars, I finally allowed that they might be an acceptable substitute especially considering the cost difference. A few winters ago I went in to replace the oil pan gasket due to a couple drops on the floor after the prior winter hibernation. The replaced factory mounts were still fine, less than 1/4" of sag in a dozen years, so they went into the serviceable original spares bin and were replaced with the Volvo mounts. Mine came from 928 International, and still had the locating pins intact. (IIRC, Roger cuts them off for you.) I drilled a hole in the engine-side bracket to receive the pin, (pictures on RL in a thread somewhere) and added a thick spacer washer under the top nut to help hold it all together. Drilling for the pin means there will be no twist/distortion on the mount when the lower nut is tightened, as it's also located by a pin that engages an existing hole in the crossmember. I bent the little hook on the bottom plate to have about an eighth of an inch (0.125") gap between the hooks, and it worked out fine.
Old 03-13-2019, 10:59 PM
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soontobered84
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Originally Posted by merchauser
yes, the hooks are suppose to interlock, and yes these are 180' out, and upside down. very fortunate to have tons of receipts from day one; mounts have never been replaced, but oil pan gasket was done 05/03, and when the crossmember was dropped, the mechanic must have improperly oriented the lower plates. it is impossible for the mount to be put in upside down. good luck with your project
If I was a "professional mechanic" and I had done work like this, I wouldn't have billed it in the chance that someone might see what had been done.

Honestly, it does appear that the motor mount is upside down. It would not be impossible for the persistent.
Old 03-14-2019, 12:22 AM
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GregBBRD
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At this point in time, almost nothing prior "mechanics" have done to 928 surprises me:
However, I would have not thought this was possible.

With the lower "washer" turned 180 degrees, it has to be bound up into the upper housing, which totally eliminates any movement of the mounts.

Even Volvo mounts will be an improvement over this situation!

​​​
Old 03-14-2019, 05:10 AM
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FredR
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Paul,

That is disgusting! Presumably you now have to check that the mounting carrier frame is fully viable.

On the positive side you can now hopefully tick that one off to experience.
Old 03-14-2019, 05:29 AM
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C531XHO
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....maybe you need (we all need) to check that nothing else is upside down across the rest of the car

...mind you it would make changing the sump gasket easier...
Old 03-14-2019, 07:37 AM
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merchauser
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Originally Posted by soontobered84
Honestly, it does appear that the motor mount is upside down. It would not be impossible for the persistent.
the factory mounts cannot be installed upside down since the upper location "tab" is rectangular surrounding the stud, and the lower pin is a large round dowel away from the stud

Old 03-14-2019, 07:38 AM
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merchauser
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Originally Posted by dr bob
The "hooks" are there to offer some restraint on the motor in an accident. The hooks should be close to each other but not touching when the new mounts are installed. As the mount sags over time, that gap between hooks gets larger. A telltale of the need for new mounts is a gap big enough to pass a fat finger through. With the taller Volvo mounts, you will likely want to do a little bending/reforming of the hook on the plate, so the hooks don't touch. If they do touch, you'll get a bit of banging/rattling with the engine running.
thanks for the clarification. will make sure they don't touch.

Old 03-14-2019, 07:39 AM
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merchauser
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Originally Posted by C531XHO
....maybe you need (we all need) to check that nothing else is upside down across the rest of the car

...mind you it would make changing the sump gasket easier...
ha ha...good form
Old 03-19-2019, 05:16 PM
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merchauser
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FWIW: here is a good look at the original 1990 collapsed mounts; nice


Old 03-19-2019, 10:04 PM
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Maybe you could reinflate those through those ports on the bottom.

Old 03-20-2019, 07:48 AM
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merchauser
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^^^^I could install a Schrader valve and dump a can of tire inflate in there


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