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 Warped Rotor?
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currentresident
New Member

USA
5 Posts

Posted - 01/31/2006 :  10:49:54 PM  Show Profile  Visit currentresident's Homepage  Reply with Quote
1988 IH Thomas, DTA 360, MT640, 4 wheel disc brakes. When I get the brakes warmed up, ie long hill, I get a wobble when the brakes are applied. Then it goes away when they cool off. The only time it happens is at the bottom of a long hill. Gets pretty bad too.
Do I need to turn my rotors, or is this an issue at all?

wagonmaster
Top Member

USA
2298 Posts

Posted - 02/01/2006 :  03:33:16 AM  Show Profile  Reply with Quote
As a rule, warped brake rotors will be warped whether hot or cold. Sounds almost as if yours are warping worse when hot and "recovering" when cooler. A bit odd, but not unthinkable. Before you turn the rotors be sure and have them measured by a competent mechanic to determine if sufficient material remains to allow it. Your situation sounds almost as if the rotors are already very "thin" allowing the reaction you describe. If they have enough material clean them up on the brake lathe and replace the pads. Should be smooth then.
Joe

Joe
Land of the Free, because of the Brave!
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CornBinder
Active Member

USA
25 Posts

Posted - 02/01/2006 :  06:46:47 AM  Show Profile  Visit CornBinder's Homepage  Reply with Quote
Do you use a torque wrench on the lugnuts? If you are using chinese Advance Auto Parts rotors, hammering down the lugs with an air gun will tweak the snot out of the rotors.

Adding heat will only make it worse as the rotor cannot expand as it might need to.
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Joe Hartnett
Advanced Member

USA
359 Posts

Posted - 02/01/2006 :  08:59:55 AM  Show Profile  Reply with Quote
Use a dial indicator and check for rotor runout, rotor parallism, wheel bearing play and tire runout.
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ModMech
Top Member

USA
948 Posts

Posted - 02/03/2006 :  10:37:55 AM  Show Profile  Visit ModMech's Homepage  Reply with Quote
current,

Once a rotor is warped, it will ALWAYS be warped, you cannot fix it and it must be replaced.

Sure, you can have a rotor turned, but it is still warped. The surfaces are now just parallel, but it is warped just the same.

Lug nut Tq is a non-issue with the way the disc rotors are installed on every International from the early 80's to current.

If you want customer service, you NEED an International!
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currentresident
New Member

USA
5 Posts

Posted - 02/05/2006 :  8:11:41 PM  Show Profile  Visit currentresident's Homepage  Reply with Quote
Yeah, I knew the torque was no issue with the lug studs not mounted in the rotor. I just got back from a 320 mile round trip with a load of kids and the last 10 miles to the house is down a 7% grade, got the brakes a little warm and the wobble reappeared at the bottom. Doesn't seem to be an issue, just a little unsettling to the parents on board. I think I will disassemble the steer axle to the bearings this week and see what I can find.

Thanks and God Bless.

Work for the Lord, the pay isn't much, but the retirement is out of this world.
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currentresident
New Member

USA
5 Posts

Posted - 02/06/2006 :  10:18:34 PM  Show Profile  Visit currentresident's Homepage  Reply with Quote
I figured it out myself, I removed the tires and found hard spots on the rotors. It has been my experience that hard spots are non removable, turning or otherwise. so we will keep running it and when it comes time we will replace that rotor.

Thanks and God Bless.

Work for the Lord, the pay isn't much, but the retirement is out of this world.
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