Will my rear subframe bushings "uninstall"?

[540ig5]

So I used some silicone spray to ease the job of pressing in the rear subframe bushings on my '86 325es. But now that I think about it i'm kind of nervous that the subframe could slide on the bushings once on the car because there will not be enough friction to hold it tightly on the busing. Just want to hear your thoughts/experience with this. Thanks.

[flyboyx]

Yer gud. That 6" bolt and 2.5" washer will do its job of holding it all together for you

[E30arsen]

Yeah, you have nothing to worry about. Once it's in there, it ain't coming out.

[Mook613]

The bushing has the car's body on top and the bracket on the bottom and therefore can't move once it's all bolted in.

With poly bushings, it is even recommended to slather up the bushing in a grease or anti-seize when installing to prevent squeeking.

[540ig5]

Yer gud. That 6" bolt and 2.5" washer will do its job of holding it all together for you

So the washer does not actually come in contact with the subframe, there's probably a 1/3 inch gap between the two. The way I see it, there is nothing to keep the subframe from sliding on the bushing other than friction between the two.

Unless, once the bolt is tightened down, that makes the bushing "expand" within the subframe, wedging it in there so tight that there is no way it will move anywhere?

[540ig5]

The bushing has the car's body on top and the bracket on the bottom and therefore can't move once it's all bolted in.

With poly bushings, it is even recommended to slather up the bushing in a grease or anti-seize when installing to prevent squeeking.

True. The busing can't move, however the only thing to stop the subframe from moving up and down, is the friction between it and the bushing. The bolt, bottom bracket or top washer does not actually come in contact with the subframe. So the busing can't move, but the subframe technically can.

[YosemiteSam]

Yeah, when installing those bushings at a shop mechanics will usually slather them in grease or anti-seize to help them go in. They aren't going to come out.

[lukeADE335i]

true - mine were lathered in lithium grease when pressed in to lube them up and make sure they don't squeak.

Once the weight of the car is on the bush, as the bush is clamped by the bracket at the bottom and can't move, it will try to expand inside the sleeve on the subfame - there's no way the subframe is moving with around 500lbs of pressure transferred through the bush to the sleeve that the bush sits in (plus whatever pressure the bolt running through the bush puts on it too).

Sure - friction is the only thing holding the subframe, but that friction is pretty high!

[TobyB]

...and if it did, it wouldn't go far.

But it won't.

Yer gud.

t