Pulls under acceleration - Hmmmm

Lutzgaterr

Well-known member
Apr 23, 2004
578
0
LUTZ, Florida
My truck wants to pull to the left under acceleration. Know where I can begin to diagnose?
It began after the shop did an alignment job since it was required after tire-rod ends installed.
Facts:
97 Auto 2inch lift
All new tie-rods
All new bushings
New 235/55 BFG MT, 4K miles
Just had it aligned, then had the shop check it a 2nd time after 1 week, still in spec, but still pulls.
I rotate tires + spare in anticlockwise direction, so spare goes on rear-right, rr to fr, and so on.

Got any clues?
Thanks in advance
 

Lutzgaterr

Well-known member
Apr 23, 2004
578
0
LUTZ, Florida
Come on you bunch of techies! I know someone out there has gone through this before. Anything would be appreciated, well probably maybe almost anything...
Oh and yes, Gordo, no, it was happening before the liquid courage forced me up that dirt-hill into the trees...
 
D

D Chapman

Guest
Could be a busted belt in the tire. Swap tires from left side to right, if it starts to pull right you know it the belt. It's not common on BFG's, but it is in other makes.
 

nosivad_bor

Well-known member
Mar 27, 2004
6,059
63
Pittsburgh, PA
Can you go into some specifics on which bushings you changed? who changed them are they torqued evenly?

what brand of bushings?

I am leaning toward the bushings :)

rd
 

bri

Well-known member
Apr 20, 2004
6,178
152
US
I would check the alignment myself. When you say within spec, exactly what do you and the shop mean? Ask them and also ask what they did for alignment. All there is for alignment on Disco is toe-out, should be 0-2mm according to the manual.

even if it is within spec, it may not be perfect for your setup. I.e. maybe your truck needs to be at 0mm vs 2mm. Just a tought, but I had to play with mine to minimize wandering.

And yes, torque on bushings should be to spec too, too tight and you might get binding. If you are doing the bushing bolts you need a decent torque wrench, because they are damn tight.

Brian
 

p m

Administrator
Staff member
Apr 19, 2004
15,617
838
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La Jolla, CA
www.3rj.org
I've the same issue.

Which bushings were replaced? I'd suggest you lift the truck on the jackstands under the frame, and move the axle(s) around to see if there's anything loose.
If you have 2" lift, most likely, your trailing arms' bushings (at the frame ends) are at best soft.

Oh, also, alignment should have _nothing_ to do with the pull. All the alignment you have on the Disco is toe-in/toe-out; I'd set it at either zero, or 1-2mm _in_ - for better stability. But it won't fix the left pull.
 

Lutzgaterr

Well-known member
Apr 23, 2004
578
0
LUTZ, Florida
Yup, when I am not under acceleration, truck is dead-on straight, no wondering at all. So I am fairly convinced that alignment is correct, they used a Hunter machine to set alignment with mirrors hanging on all four tires etc? I know nothing about the machinery, but it was re-checked and all was good. Yes, discussions with alignment shop concerned toe-out specs and they seemed aware that was all that was required.

Bushings, Panhard, trailing arms, real links, new tie-rod ends, all accomplished by me. The bushings are all rubber, not Poly.
Aha! A Very Good Point indeed, re-check the torque on these bolts.

Motor Mount, no issues since this was recently checked, engine sits tight under revs.

Tire Belts, possibly, who knows. I do tire rotations, counter clockwise and use spare tire in that rotation. But I have to believe if tire issue was the origin, it would manifest itself under both acceleration as well as coasting. My answer may be found if I swap the left-side tires, back to front. We shall see.

Thanks all for the input. Now I have two diagnostic avenues to pursue.
I will post a follow-up once I address these next weekend.
 

bri

Well-known member
Apr 20, 2004
6,178
152
US
If it happened right after the alignment, would this not be suspect? Maybe you just did not notice it before. Did it happen after the lift, i.e. loss of camber?
 

Lutzgaterr

Well-known member
Apr 23, 2004
578
0
LUTZ, Florida
First, lift is 3 years or so ago.
Now, after alignment and I noticed, certainly. Was it there before alignment, if so, yes it may be the fact that the alignment revealed a hidden issue.
Alignment as stated was double checked, so the hidden or repressed issue that makes the truck pull is now the question.
Regardless, thanks for your input, always appreciated.
 

marc olivares

Well-known member
Apr 20, 2004
3,535
0
i had this very issue with my disco this past week.
turns out, all the driving with aired down tires softened the sidewall on my passenger side front tire. pulled to the right like mad. and the detroit in the rear has a tendency to make the pull worse.
check your tires.
 

Lutzgaterr

Well-known member
Apr 23, 2004
578
0
LUTZ, Florida
Tire pressures were immediatley checked once the problem was noticed. I run TTs front and rear and I developed a habit of checking tire pressure on a regular basis.
Thanks anyway.
 

marc olivares

Well-known member
Apr 20, 2004
3,535
0
Rikstaboogie said:
Have you swaped your tires across...??? (left to right)


yeah that's what i was getting at....

lutz-
i'm talking about a soft side wall...(i.e. bad tire),
not low air pressure
 
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Lutzgaterr

Well-known member
Apr 23, 2004
578
0
LUTZ, Florida
Marc,
I think maybe you hit it on the head.
YES, it has been resolved by swapping tires.
WOW, what a $#@%$#@ difference. The outside appearance of these tires does not look different at all.

Regardless, IT IS FIXED, Yea! :)

Thanks again to all who offered suggestions.
What a great board.