Cracked Duff radius arm

whitetrash96 · 08-21-2012, 10:01 PM

Recently while servicing my front diff I noticed another crack in my rod ended Duff radius arms. Last year I had a crack welded up on my ears and now it seems I have another crack in a new location. My question is what are people doing to beef up their Duff radius arms?

Unfortunatley photobucket isn't allowing me to upload any new pics

whitetrash96 · 08-22-2012, 09:46 PM

Here's where I had the ears welded up last year.

Here is the new crack I found. Not catastrophic but definatley worth looking after.

I've got to get my welder buddy to have a look at the new crack but was wondering if people have braced their arms.

pillen140 · 08-22-2012, 09:54 PM

i think there is something in the tech library about the duff arms cracking and a fix for it.... might be worth a look for you.

**88_Eddie** · 08-23-2012, 07:32 AM

i'd just add some 3/16" plate to them for extra bracing

**bobbywalter** · 08-23-2012, 09:33 PM

on the old style i was always twisting and craking/bending them along with wasting d35 beams.

but i was way off the expected path as well as far as power weight and tire size.

for what they are i cant complain. as you beat the fawk out of them you constantly monitor and maintain your whole suspension or build bigger etc....

i just consider it general maintenance.

whitetrash96 · 08-23-2012, 11:28 PM

Quote:

Originally Posted by pillen140

i think there is something in the tech library about the duff arms cracking and a fix for it.... might be worth a look for you.

I had a look but didn't find anything specific to repairing duff arms, thanks though.

I spoke with my welder this morning and picked up some 1/4" flat bar to brace the arms, hopefully have the cracks repaired and new plate installed this weekend. I'll post pics when they're done.

**4x4junkie** · 08-25-2012, 06:30 PM

I've seen reports (with pics) of that exact failure a couple times already (failures where the box section tapers down toward the tube section).

Agreed, I would grind out & weld up the crack, followed with a couple pieces of 3/16" plate bent to fit against the arm over where the crack is (a gusset along the top wouldn't hurt either).

How old is that Duff kit?

BRONCONUT · 08-25-2012, 07:06 PM

I would throw some plate on there instead of just welding it. Another thing that to stop a crack you need to drill a hole in the end of the crack to keep it from running after a weld/fix.

whitetrash96 · 08-26-2012, 01:09 PM

Quote:

Originally Posted by 4x4junkie

How old is that Duff kit?

I've been running it since January of 2006 its seen a lot of use wheeling and daily driving since that time.

whitetrash96 · 08-28-2012, 09:45 PM

Got the gussets welded on, while grinding out the ear cracks we found them to be much worse than anticipated and were like spider webs with cracks running everywhere. We cut out the rotten metal and built the area back up with weld, then ground everything smooth and formed radiused corners rather then the orginal 90 degree ones so as to not create any stress risers.

**4x4junkie** · 08-29-2012, 05:57 PM

Very nice work!

I'd probably even go a step further and double-plate the ears with another piece of 3/16" plate so they're 3/8" thick, just to make sure it doesn't crack again (at least on the driverside which supports the diff housing).

ThatGuy · 08-29-2012, 07:00 PM

Ahhh, if only I had my way......

08-21-2012, 10:01 PM	#1
whitetrash96 Junior Member Join Date: Aug 2007 Location: East Kootenays Posts: 61 Rep Power: 12 iTrader: (0)	Cracked Duff radius arm Recently while servicing my front diff I noticed another crack in my rod ended Duff radius arms. Last year I had a crack welded up on my ears and now it seems I have another crack in a new location. My question is what are people doing to beef up their Duff radius arms? Unfortunatley photobucket isn't allowing me to upload any new pics __________________ '92 Explorer Sport, 5-speed, swapped in manual t-case, 4.88s and Ecteds, on-board shower, Co2, Duff 5.5" lift with stock SOA in the rear, coming into its own.
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08-22-2012, 09:46 PM	#2
whitetrash96 Junior Member Join Date: Aug 2007 Location: East Kootenays Posts: 61 Rep Power: 12 iTrader: (0)	Here's where I had the ears welded up last year. Here is the new crack I found. Not catastrophic but definatley worth looking after. I've got to get my welder buddy to have a look at the new crack but was wondering if people have braced their arms. __________________ '92 Explorer Sport, 5-speed, swapped in manual t-case, 4.88s and Ecteds, on-board shower, Co2, Duff 5.5" lift with stock SOA in the rear, coming into its own.
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08-22-2012, 09:54 PM	#3
pillen140 Member Join Date: Jan 2008 Location: winston-salem, NC Year: 1995 Make: ford Model: ranger Engine: 3.0 Class: 4x4 off-road Used For: dd, weekend off roader. and annoying my girlfriend Posts: 3,254 Rep Power: 28 iTrader: (1)	i think there is something in the tech library about the duff arms cracking and a fix for it.... might be worth a look for you. __________________ MAJORITY, THE NEW MINORITY "Harry..... I TOOK CARE OF IT!!!" http://www.cardomain.com/ride/2983675 1995 RANGER EXT CAB 4X4, 6" SUSPENSION, 3" BODY, 35X12.50R15
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08-23-2012, 09:33 PM	#5
bobbywalter RBV Technical Advisor Join Date: Aug 2007 Location: higgins lake mi Year: 1988 Make: FORD Model: RANGERISH SORT OF THING Engine: BIGGER Class: 4X4 Used For: EVERTHING Posts: 15,080 Rep Power: 49 iTrader: (0)	on the old style i was always twisting and craking/bending them along with wasting d35 beams. but i was way off the expected path as well as far as power weight and tire size. for what they are i cant complain. as you beat the fawk out of them you constantly monitor and maintain your whole suspension or build bigger etc.... i just consider it general maintenance. __________________ 88 ranger ext cab low rider 4x4 propelled by 395 cubes of of non turbo SLOBBERIN DIESEL...BLAHHH...motating a 4l80 thats AUTHORITATIVELY turnin a ford 208 spinning 410 open dana 60s and whatever tire suits the mood that day. how ya like me now?
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08-25-2012, 06:30 PM	#7
4x4junkie Mall-Rated Join Date: Aug 2001 Location: So. Calif (SFV) Year: 1990,1994 Make: Ford Model: Bronco II, Ranger Engine: 2.9L, 4.0L Used For: Crawling over things Posts: 8,002 Rep Power: 10 iTrader: (0)	I've seen reports (with pics) of that exact failure a couple times already (failures where the box section tapers down toward the tube section). Agreed, I would grind out & weld up the crack, followed with a couple pieces of 3/16" plate bent to fit against the arm over where the crack is (a gusset along the top wouldn't hurt either). How old is that Duff kit? __________________ '90 Bronco II XLT 5" lift (Skyjacker Jeep coils), D35 & 8.8" w/5.13s (locked), 1354 dual T-case, 35x12.50s '94 Ranger XLT 6" Skyjacker, ARB D44 front, Detroit 8.8" rear, Atlas 4.3, 33s
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08-25-2012, 07:06 PM	#8
BRONCONUT Junior Member Join Date: Jul 2009 Location: Hartford, KY Year: '95~'00 Make: Ford Model: Bronco~Ranger Engine: 5.8~4.0 Class: 4x4 Extreme Posts: 68 Rep Power: 8 iTrader: (0)	I would throw some plate on there instead of just welding it. Another thing that to stop a crack you need to drill a hole in the end of the crack to keep it from running after a weld/fix.
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08-28-2012, 09:45 PM	#10
whitetrash96 Junior Member Join Date: Aug 2007 Location: East Kootenays Posts: 61 Rep Power: 12 iTrader: (0)	Got the gussets welded on, while grinding out the ear cracks we found them to be much worse than anticipated and were like spider webs with cracks running everywhere. We cut out the rotten metal and built the area back up with weld, then ground everything smooth and formed radiused corners rather then the orginal 90 degree ones so as to not create any stress risers. __________________ '92 Explorer Sport, 5-speed, swapped in manual t-case, 4.88s and Ecteds, on-board shower, Co2, Duff 5.5" lift with stock SOA in the rear, coming into its own.
	Tweet

08-29-2012, 05:57 PM	#11
4x4junkie Mall-Rated Join Date: Aug 2001 Location: So. Calif (SFV) Year: 1990,1994 Make: Ford Model: Bronco II, Ranger Engine: 2.9L, 4.0L Used For: Crawling over things Posts: 8,002 Rep Power: 10 iTrader: (0)	Very nice work! I'd probably even go a step further and double-plate the ears with another piece of 3/16" plate so they're 3/8" thick, just to make sure it doesn't crack again (at least on the driverside which supports the diff housing). __________________ '90 Bronco II XLT 5" lift (Skyjacker Jeep coils), D35 & 8.8" w/5.13s (locked), 1354 dual T-case, 35x12.50s '94 Ranger XLT 6" Skyjacker, ARB D44 front, Detroit 8.8" rear, Atlas 4.3, 33s Last edited by 4x4junkie; 08-29-2012 at 06:03 PM.
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08-29-2012, 07:00 PM	#12
ThatGuy Member Join Date: Aug 2009 Location: Oak Ridge, TN Year: 91 Make: Ford Model: Explorer Engine: 4.0L Class: Mall Rated Used For: bending shock mounts and picking up mountain whores Posts: 697 Rep Power: 10 iTrader: (1)	Ahhh, if only I had my way...... __________________ BAMF
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