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FFCobra Fanatic
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2,600 Posts
Discussion Starter · #1 ·
At the last autocross I dialed in a little more rear brake and experienced axle hop under hard braking. I have heim jointed control arms all around. I have the rear upper arm on the lower hole and the lowers level (second to bottom hole in the bracket). 250# rear and 650# front with sway bars front and rear. 3-link. Any cure??
 

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739 Posts
I would agree, the heim joints on a 4 link is likely the root of the problem. In the factory mustang design, the upper links actually have to slightly change in length as the suspension bounds and compresses. It works ok with soft and compliant rubber bushing like the mustang arms had from the factory. It works not so well with hard polyurethane bushings. I would have to imagine... it just doesn't work at all with heim joints everywhere. They don't allow any deflection, and the suspension just binds up.
 

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Unconventional Builder
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5,498 Posts
3 link will solve the problem. 4 link binds and even worse with heim joints
He has a 3 Link suspension. Maybe you need stiffer springs out back. I run 700 front 500 rear. No hop just sliding:001_smile:
 

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Not a waxer
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12,092 Posts
Although it might cost a bit of forward bite try raising the upper arm.

650/250 does seem a bit soft at the rear. I run 750/500 currently; had 750/350 for a while but the car was a bit tight for my style with that combo.

Jeff
 

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138 Posts
yep, I missed the 3 link. How about broken weld on the 3 link mount, or oblongated or worn holes on frame where control arms mount.

wheel hop usually has to do with axel windup there is just not enough weight transfer to cause wheel hop.
 

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FFCobra Fanatic
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2,600 Posts
Discussion Starter · #8 ·
The ABS was kicking in and its the first time that I've activated it under hard braking in ther rear. Maybe its due to sitting practically on the rear axle?
 

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FFCobra Craftsman
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25,961 Posts
Can't help w/ what the abs might have been doing, but one of those fast guys at Cumberland,who also runs in the DC area, recommended running the 3 link arm in the upper hole at the frame mount. Worked for me. I have an adjustable dual MC setup and had the same issue for a while until i moved that frame mount pivot.
 

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FFCobra Fanatic
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Discussion Starter · #10 ·
Thanks. Will try moving the arm.
 
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