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Too much caster??? Help please!

73bronco

Sr. Member
Joined
May 10, 2007
Messages
936
So I just finished cutting and re-welding my C's for caster. I HAD to do it due to the wandering. It was all over the road after finishing the 5.5" lift and trying to run stock C bushings(to save the driveshaft). SO before I took it apart I measured 9 degrees of NEGATIVE castor with my angle finder. Way to far negative! To help my driveshaft issue I figured I would install 4 degree C bushings backward to tilt my pinion up figuring I was going to rotate the C's anyway to get whatever caster I wanted. Anyway, I ended up getting it to about 8 degrees of POSITIVE caster. Before I rotated the C's it drove fine except for the wandering. NOW it starts the DEATH WOBBLE at 25 to 45 m.p.h. It is so severe that I have to lock up the brakes to stop it. I have not been able to get over 45 to see what happens. It is by far the worst I have ever felt in a vehicle and I work on j**ps for a living. Is my 8 degrees of caster causing this??? I never had a death wobble before going to positive caster. I am pretty sure it is I just want some opinions before I tear it all apart again.
 

rednck21

Newbie
Joined
Feb 27, 2002
Messages
3,914
if you have 8 degres of caster you should have a terrible pinion angle, correct?

have you checked the toe?
is the axle centered under the bronco?

it could be 100 different things...
 
OP
OP
73bronco

73bronco

Sr. Member
Joined
May 10, 2007
Messages
936
My pinion angle is great. I cut the C's that the ball joints mount to off the axle housing and re-welded them to give my positive caster without dropping my pinion angle. The toe is right at 3/16's of an inch...right where it was before lifting it higher and right where it was before cutting and welding the C's. I built a trac-bar riser off the axle so the axle is centered for sure.
 

rednck21

Newbie
Joined
Feb 27, 2002
Messages
3,914
what about camber? was the axle in a jig when you re welded the C's?


i ran 5.5?" coils on an old rig with 7 deg C's and it rode like a dream...
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,821
8° should not be too much. I dn't have my book in front of me but I thought that later Broncos (78/9) were in the 7-9° range as acceptable.

Have you looked at the tratitional death wobble problems? good track bar bushings and frame not broken?
 

fordtrucks4ever

Bronco Guru
Joined
Oct 8, 2006
Messages
1,280
Loc.
DFW
IF its 3/16 toed in, adjust to a + zero or up to 1/4 inch out. If something is not worn, should fix it right up. At least try it before getting second thoughts.
 

eb66to77

Bronc'Ownly
Joined
Mar 26, 2005
Messages
2,558
Loc.
NOVA
3.5 positive is what the alignment machine said was the correct setting for 78-79 but not sure of the max. Just to be sure you are calling it POSITIVE caster when the bottom balljoint is forward of the upper right?

I am not sure what would cause this other than the reassembly did soemthing to it.
 

Hazegray

Sr. Member
Joined
Aug 10, 2004
Messages
795
If you had the "death wobble" before and still continue to have it after modifications, then the problem lies elsewhere. Try rotating your tires from rear to front and see if you get the same wobble.
 

gearida

Bronco Guru
Joined
Jun 8, 2007
Messages
1,428
Loc.
Newburgh, IN
I had a '74 Ford van that did the wobble, front end was like new. Found the steering box had broken the frame. Had to take the box off to find it.
 

toddz69

Sponsor/Vendor
Bronco Guru
Joined
Nov 28, 2001
Messages
10,062
8° should not be too much. I dn't have my book in front of me but I thought that later Broncos (78/9) were in the 7-9° range as acceptable.

That's exactly right. Factory spec on '78-'79 Broncos is 6-9 deg. positive. Ford added 5 deg. of positive caster in '78. That's what I used as my target when I had my C's rotated a few months ago.

Todd Z.
 

bmc69

Contributor
Bronco Guru
Joined
Jun 11, 2004
Messages
11,849
I hav to agree on yourcaster not being the problem..since all mine are between 6 and 10 degrees. And all have had, at various times, death wobble too. Since the 'death wobble' is a fundamental characeristic of this suspension system adn always lurking near by, it is so dang hard to find the root cause on any particular rig. In my case, nearly EVERY single case was cured by 'playing' around with finding a tire that didn't cause it (all the other suspects being nice and tight)..something that is frustrating and costly. My '69 went through 16-38.5 TSLs (extreme eye-blurring death wobble at 35) to 12.50-38 TSLs (could drive on through it around 35-40 yr nads were big enough) to the 13.50-39.5 IROK radials I run now..which have never given the slightest hint of death wobble..ever.

Let me repeat again...nothing in the suspension or steering was so much as touched by hand or tool as I went through that progression from death-defying ride to solid performer..nothing but tires.
 

csjr

Sr. Member
Joined
Apr 18, 2007
Messages
675
Loc.
Lighthouse Point, FL
How are you measuring your caster? When I put a straight edge on the front of my axle C I measure almost 10 degrees of positive caster with an angle finder. On the back of the C it's 5 degrees. I think the C is thicker on the bottom, hence the difference. I would have to agree with the others that first you must check trac bar and steering linkage, bearings, etc. I'm surprised to hear in the last post that the tires could make all the difference, especially in absence of any other issue. THAT is an expensive and frustrating fix. I know some guys have problems running the wide 38" TSL's, but the 38x12.5's ride just fine. Good luck and let us know if you find anything wrong or what your solution you find...
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,821
How are you measuring your caster? When I put a straight edge on the front of my axle C I measure almost 10 degrees of positive caster with an angle finder. On the back of the C it's 5 degrees. I think the C is thicker on the bottom, hence the difference. I would have to agree with the others that first you must check trac bar and steering linkage, bearings, etc. I'm surprised to hear in the last post that the tires could make all the difference, especially in absence of any other issue. THAT is an expensive and frustrating fix. I know some guys have problems running the wide 38" TSL's, but the 38x12.5's ride just fine. Good luck and let us know if you find anything wrong or what your solution you find...

I have always heard of measureing on the flat of the ball joint to get a simple caster measurement. Ball joints are generally in line with each other on a straight axle. (warning for those wanting to measure caster on something with IFS, ball joints are not a good place for those, there is no good place for those using an angle finder).
 

rednck21

Newbie
Joined
Feb 27, 2002
Messages
3,914
i checked on our Hunter machine today at work and the specs on every year except 71 was 3.5 deg of caster. 71 called for 2.5 deg. both of those specs are with .75 deg of tolerance up or down. the camber spec was 1.5 deg positive. in a nutshell, the specs are the same for all years exept for the 71 requiring 1 deg less caster. the toe was similar with 66-72 calling .25 deg of total toe, 73-76 calling for .31 total toe and 77 calling for .32 deg of total toe;)

IMHO, 8+ deg of caster sounds like too much to me. as bad as i hate to say it.. if i were you id spend the money and put it on a machine....


hope this helps.
 
OP
OP
73bronco

73bronco

Sr. Member
Joined
May 10, 2007
Messages
936
Fixed!!

It is fixed!!!!! I was just really fried last night and wasn't thinking straight. I inflated the tires finally after mounting them. Drives great now! No wobble at all. Amazing what 5 p.s.i. to 25 p.s.i. will do. Thanks for all the input!! This site is great!
 

bmc69

Contributor
Bronco Guru
Joined
Jun 11, 2004
Messages
11,849
woo hoo!..last I checked, air was a lot cheaper than what holds it in.;D
 
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