It sounds like your L brackets are too far back on the tongue. I know I can't get to 90 without the trailer contacting the tow vehicle. But when I do have it back that far the bars are still about 3 inches from falling off the L bracket.
Maybe take a tape measure and make sure the L brackets are between 27 - 32 inches from the tip of the tongue. If they are at 32 try moving them closer to the ball by an inch or so.
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2001 Suburban 4x4. 6.0L, 4.10 3/4 ton **** 2005 Jayco Jay Flight 27BH **** 1986 Coleman Columbia Popup