Problem getting Crown body mount to fit

TRevs

YJ Enthusiast
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I’m replacing the two body mounts in the crossmember in front of the fuel tank (I’ll get to the rest of them later), and the new rubber isolator doesn’t seem to fit through the opening in the crossmember.

I’m using Crown 5200 2660, which I confirmed is the part number from the Factory parts list. The metal post fits nicely into the rubber isolator, but even with silicone grease and the entire weight of the tub on it, it wont fully seat through the crossmember. It is holding the tub up off the two nearest mounts:




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Ideas? Should the rubber go in first then get the metal cap on last?
 
That’s weird….I just installed a crown kit a few days ago and it fit perfectly. I got this one from Amazon which was the cheapest non-bolt it I could find. Seemed very nice quality.

Crown Automotive Body Mount Kit... https://www.amazon.com/dp/B008VPVF82/?tag=yjforum-20

For your problem I’d first say make sure you’ve got the right mount your trying to install in that spot, if that’s for sure confirmed then maybe install bushing first, but you’re going to need to jack up the body considerably higher to fit the in there after the bushing is in place.
 
I will add that while what you’re experiencing is not normal for the rare mounts, the center ones under the doors will not touch the body when body bolts are loose. Tightening the bolts flexes the frame and body to each other to strengthen each other.

So while you need to fix the rear mount issue obviously, don’t be surprised if when you’re done the center main mounts still don’t touch the tub at rest. They will once bolts are torqued.
 
...the center ones under the doors will not touch the body when body bolts are loose. Tightening the bolts flexes the frame and body to each other to strengthen each other....
I don't know why but I find that funny and can hear Jeep when something doesn't fit saying "It's a design feature" lol
 
It’s possible I dented inward the lower part of the hole while trying to get the old rubber mounts out. They were really stuck in there and I was trying all kinds of methods. After they were out, I tried to round out the metal with a socket, but I may need to do more of that.
 
I looked into the issue more last night and am still baffled. The new upper isolators fit fine in the rearmost mount positions but are 1-2mm too wide to fit in either the holes in front of the gas tank. The old rubber isolators from the rearmost position don’t fit in there either. I confirmed the part number on several websites.

Everything I see indicates those 4 mounts should be identical.

I think I may have to enlarge the frame holes and/or reduce the diameter of the rubber a little bit.

Can you debulk rubber with sandpaper?
 
Maybe it’s one of those “variations “ in manufacturing that I hear about with older Jeeps.
 
Very odd. Maybe some PO screwery, though I don’t know how they make a hole smaller.

The factory intent was for the rear 4 to be identical. Mine were and my new ones were, everything went right in.
 
Possibly the crossmember had been replaced with an aftermarket one? Although it all looks original and it’s hard to imagine the crossmember was rotting away while everything is is barely rusted at all.
 
I'm a little confused..you say the 2 mounts in front of the fuel tank but the pics show the rear crossmember and the side?

If we are indeed talking about the crossmember in FRONT of the fuel tank..there is 2 pieces of metal that form the area where the rubber mount fits into. They are not always perfectly aligned. I would suspect there is a build up of crud between the pieces and that won't let the bushing slide down.

Can you get your hand in there with a wire brush or sand paper and clean the hole up?
 
I'm a little confused..you say the 2 mounts in front of the fuel tank but the pics show the rear crossmember and the side?

If we are indeed talking about the crossmember in FRONT of the fuel tank..there is 2 pieces of metal that form the area where the rubber mount fits into. They are not always perfectly aligned. I would suspect there is a build up of crud between the pieces and that won't let the bushing slide down.

Can you get your hand in there with a wire brush or sand paper and clean the hole up?
Sorry for the confusion; the photos were intended just to show the gap that remained after having lowered to tub all the way down. The problem is in the crossmember in front of the fuel tank.

I’ll try cleaning up those holes. There could be old rubber stuck in there too because the old mounts were absolutely socked in and I had to tear them out piece by piece.

Maybe a couple 2x4s between the tub and frame to support the tub instead of just a jack while my hands are up there…
 
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Sorry for the confusion; the photos were intended just to show the gap that remained after having lowered to tub all the way down. The problem is in the crossmember in front of the fuel tank.

I’ll try cleaning up those holes. There could be old rubber stuck in there too because the old mounts were absolutely socked in and I had to tear them out piece by piece.

Maybe a couple 2x4s between the tub and frame to support the tub instead of just a jack while my hands are up there…
I bet once you clean them up It will solve the problem. Please report back
 
I used sandpaper and a little grindstone to clean up the hole, and measured with calipers. The hole diameter is about 1.5-2mm less than the bushing.

Is the center ring supposed to be there? It seems lightly tacked to the rest of the crossmember. If that comes out the the outer hole would be about 38mm which I’m afraid would let the bushing move around.

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How does that opening compare with all the others? Is that a typical factory weld for the body mount bracket? Looks like some welder had a bad hangover that day.
 
I'm not sure what that ring is in there but it needs to come out.
It has a small flange on the top of the crossmember; I’ll see if I can get a photo.

If I do get it out, it won’t matter that the remaining hole is ~4mm wider than the rubber bushing? Will the clamping force be sufficient to keep it secure?
 
It has a small flange on the top of the crossmember; I’ll see if I can get a photo.

If I do get it out, it won’t matter that the remaining hole is ~4mm wider than the rubber bushing? Will the clamping force be sufficient to keep it secure?
I have a bare frame in the garage I can measure tomorrow. Can you message me your phone number?