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Radius Arm Bushing Bump

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Old Aug 26, 2004 | 05:48 AM
  #1  
BOYD FLY429's Avatar
BOYD FLY429
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Radius Arm Bushing Bump

I Have Been Experiencing A Problem That Reoccures. I Have Replaced My Radius Arm Bushings 3 Or 4 Times In The Past Two Years And The Bump Allways Comes Back Allmost Immediatly. I Have Been Told To Replace Radius Arm, Replace Radius Arm Bracket. I'm Not Sure What To Do, Anyone Have A Similar Experience?
 
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Old Aug 26, 2004 | 06:49 AM
  #2  
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fcarruth
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From: Medina, Tn.
Have you checked your axle pivot bushings ? I am told that mine are so so but I have never replaced them.

Good luck,
 
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Old Aug 26, 2004 | 09:05 AM
  #3  
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bronco5.8
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When the bushings were replaced did you see how the condition is on the radius arm bracket? Is the nut side of the bracket rusted out and if the shape of the hole round anymore? How is the condition of the bushing, is the hole in the bushing oval?
These are some of the things I've seen working on Bronco's.
1- Bracket needs replacing if hole is no longer round and all rusted up. This condition will just chew up the bushings.
2- Is there a heat shield covering the bushing on the nut side? If not the heat from the catalytic convertor will soften the bushing (especially polys) causing the hole to oval. This will cause the arm to move up and down. If you don't have this shield you can get one from Ford (small metal cup that slips over the bushing on the nut side).
3- And the torque specs for the radius arm nut is 120ft.lbs.

Warr
 
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Old Aug 26, 2004 | 02:55 PM
  #4  
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ERIC79XLT
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This is a stupid question, but what are you considering radius arm bump? Do you actually feel the radius arms bumping against the brackets?

I have some kind of a wierd problem going on right now that may be what you're talking about. I have a '79 Bronco and after I've stopped at a light or something I feel a "thump" like slack is coming out of the truck somewhere when I start to accellerate. I know that many of my bushings are pretty bad and was wondring if that might be the source. It doesn't seem like a drive shaft or tranny thing. If I'm totally on the wrong track let me know and I'll bail out of this thread. Thanks for any help.
 
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Old Aug 26, 2004 | 08:24 PM
  #5  
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richartdana44
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From: Ponca City, OK
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You might want to check the slip joint on your rear driveshaft. I had a thump just as you described everytime I took off after a complete stop. Turns out the slip joint becomes dry and "pops" when it moves. Try removing the rubber cover and lubing the joint.
 
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Old Aug 26, 2004 | 09:28 PM
  #6  
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The Bump

Originally Posted by ERIC79XLT
This is a stupid question, but what are you considering radius arm bump? Do you actually feel the radius arms bumping against the brackets?

I have some kind of a wierd problem going on right now that may be what you're talking about. I have a '79 Bronco and after I've stopped at a light or something I feel a "thump" like slack is coming out of the truck somewhere when I start to accellerate. I know that many of my bushings are pretty bad and was wondring if that might be the source. It doesn't seem like a drive shaft or tranny thing. If I'm totally on the wrong track let me know and I'll bail out of this thread. Thanks for any help.
I AGREE WITH RICHARTDANA44,
YOUR PROBLEM I THINK IS A DRY SLIP JOINT WHAT I A REFERRRING TO IS A BUMP DISTICTIVE IN THE FRONT FLOOR BOARD OF WHICH EVER SIDE THE BUHING IS BAD ON. IT WILL ACTUALLY BUMP LIKE A SHARP STRIKE ON THE FLOOR BOARD.
 
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Old Aug 26, 2004 | 09:32 PM
  #7  
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The Bump

Originally Posted by ERIC79XLT
This is a stupid question, but what are you considering radius arm bump? Do you actually feel the radius arms bumping against the brackets?

I have some kind of a wierd problem going on right now that may be what you're talking about. I have a '79 Bronco and after I've stopped at a light or something I feel a "thump" like slack is coming out of the truck somewhere when I start to accellerate. I know that many of my bushings are pretty bad and was wondring if that might be the source. It doesn't seem like a drive shaft or tranny thing. If I'm totally on the wrong track let me know and I'll bail out of this thread. Thanks for any help.
WHEN I REPLIED THERE IS ONE IMPORTANT THING I FORGOT TO MENTION THE BUMP ONLY OCCURRES AT INTIAL POINT WHEN YOU PUT YOUR FOOT ON THE BRAKE
 
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Old Aug 26, 2004 | 09:36 PM
  #8  
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Bushings

Originally Posted by bronco5.8
When the bushings were replaced did you see how the condition is on the radius arm bracket? Is the nut side of the bracket rusted out and if the shape of the hole round anymore? How is the condition of the bushing, is the hole in the bushing oval?
These are some of the things I've seen working on Bronco's.
1- Bracket needs replacing if hole is no longer round and all rusted up. This condition will just chew up the bushings.
2- Is there a heat shield covering the bushing on the nut side? If not the heat from the catalytic convertor will soften the bushing (especially polys) causing the hole to oval. This will cause the arm to move up and down. If you don't have this shield you can get one from Ford (small metal cup that slips over the bushing on the nut side).
3- And the torque specs for the radius arm nut is 120ft.lbs.

Warr
WHEN I REPLACED THE BUSHINGS I DID NOT NOTICE THE BRACKET BEING DEFORMED BUT, THE BUSHINS DO COME OVAL. HEY ARE DEFORMED BUT I DO HAVE THE HEAT SHEILDS ON THEM. IS THERE SOME WAY TO MIC. THE HOLE IN THE BRACKET OR THE OUTSIDE DIAMETER OF THE RADIUS ARM AT THE POINT OF CONTACT WERE THE BUSHING MATTS UP?
 
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Old Aug 27, 2004 | 01:21 PM
  #9  
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bronco5.8
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From: New York
You may have to put an additional shield on just to deflect the heat. Had one truck with an occurring problem, put an aluminum plate on the frame between the cat and radius arm bushing. That solved the bushing oval problem. The aluminum is 1/8th inch thick with a 90 degree 1 inch lip so it can be riveted onto the frame.

Warr
 
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Old Aug 30, 2004 | 06:57 PM
  #10  
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ERIC79XLT
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Sorry to keep intruding on your post, but I just wanted to say thanks to Richartdana44 and Boyd Fly429 for their advice on the dry slip joint. I greased that thing up over the weekend and the "thump" I was talking about seems to be almost completely gone. It took a good 20-30 shots of grease before any started coming out the little vent hole in the end of the slip yoke. The thing was dry as a bone! The Ford-Trucks Forums saves me again! Thanks guys.
 
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Old Sep 2, 2004 | 04:29 PM
  #11  
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ckirwan514
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From: georgia
had same prob. did the drive shaft fix still had same prob. went into goodyear for oil change and tire rotation while my bronco was up on rack walked under and saw that my radius ard ushings weere not only finished but had torn out of their mount on drivers side. replaced and no more thunk.
 
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