Correct installation of J20 body mounts.

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nutwood
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Joined: Sat May 12, 2018 3:45 pm

Correct installation of J20 body mounts.

Postby nutwood » Sun May 13, 2018 1:55 am

I posted this query elsewhere with no response and have been advised to try this forum. The problem is that I've recently purchased new body mounts for my J20 and am unsure as to the best way to install. The parts I have comprise a traditional hockey puck and a "Michelin man midriff" that fit together with a bush. The Michelin man has a hex recess that is a good fit for a 5/8" nut.
My current installation has a 7/16" bolt and a couple of ancient rubber mounts. I'm thinking that the best way to use the new mounts is with a section of all thread. Set a nut into the top mount and lock the top mount and hockey puck to the chassis. Then sit the body down onto the top mount and lightly lock down, possibly with a second nut.

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tgreese
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Re: Correct installation of J20 body mounts.

Postby tgreese » Sun May 13, 2018 5:29 am

Why use all-thread instead of the original bolts? If you can remove the bolts, they do not wear out. Just install them the way the factory did and you're done.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 FCA Jeep Cherokee KL Trailhawk, ECO Green

nutwood
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Re: Correct installation of J20 body mounts.

Postby nutwood » Sun May 13, 2018 8:20 pm

Thanks for the reply. Thing is, I'm not sure the current bolts are original. The new poly mounts have a 5/8" hole through them and a hex recess that's an nice fit for a 5/8" nut. I'm trying to figure how they are intended to go in. If I install as per the current arrangement, the mount with the hex recess in it simply gets sandwiched between the body and the chassis, so why did they go the trouble of putting a hex recess in it?

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Stuka
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Re: Correct installation of J20 body mounts.

Postby Stuka » Wed May 16, 2018 6:00 am

There may be another application for them. But I cannot think of what it would be for on an FSJ. Use the original bolts.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
2017 JKU Rubicon Stock, but not for long!
Pevious Jeeps: 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

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tgreese
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Re: Correct installation of J20 body mounts.

Postby tgreese » Wed May 16, 2018 6:31 am

Here's what the parts book shows -

Image

There's no better reference than this, other than the original truck.

If this is an aftermarket package of mounts, different suppliers have more or less strict interpretation of applicability. If the parts are different from the original application, you will have to figure out how to use them, or reject them as not fitting. As I recall, there are no insulators between the truck bed and the frame.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 FCA Jeep Cherokee KL Trailhawk, ECO Green

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Stuka
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Re: Correct installation of J20 body mounts.

Postby Stuka » Wed May 16, 2018 7:50 am

tgreese wrote:Here's what the parts book shows -

Image

There's no better reference than this, other than the original truck.

If this is an aftermarket package of mounts, different suppliers have more or less strict interpretation of applicability. If the parts are different from the original application, you will have to figure out how to use them, or reject them as not fitting. As I recall, there are no insulators between the truck bed and the frame.


Mine has rubber isolators that are flat and square. They are about 1/4" thick.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
2017 JKU Rubicon Stock, but not for long!
Pevious Jeeps: 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

nutwood
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Joined: Sat May 12, 2018 3:45 pm

Re: Correct installation of J20 body mounts.

Postby nutwood » Fri May 18, 2018 1:28 am

Many thanks for the manual extract. I can't refer to the part numbers as the whole mount has the same number, but that's much as I see it all going together, however, where is the cab in the diagram? The drawing simply shows the arrangement of the mounts and the chassis.
Looking at the centre mount in the diagram, is the top "mushroom", what the lower bolt screws into? If so, does the cab bolt down to this same mushroom from above? The alternative is that the bolt simply passes through the mount and the cab, before being secured by a nut and washer within the cab.

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tgreese
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Re: Correct installation of J20 body mounts.

Postby tgreese » Tue May 22, 2018 8:15 pm

Drawing shows the cab end of the frame.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 FCA Jeep Cherokee KL Trailhawk, ECO Green

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Stuka
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Joined: Thu May 12, 2011 5:53 pm
Location: Sonora, CA
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Re: Correct installation of J20 body mounts.

Postby Stuka » Tue May 22, 2018 9:56 pm

In the photo, left most and center are the cab mounts. The right most is the radiator support.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
2017 JKU Rubicon Stock, but not for long!
Pevious Jeeps: 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ


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