Pitman / Idler Arm help needed

number9l · August 30, 2016

Guys, I got (wife's) an '03 4x4 1500 Yukon with about 170K on it (bought it with 36K on it)

Steering system needed a go-thru of course.

I had all 4 ball joints replaced and then I replaced, myself, both wheel hub/bearings, tie-rods and pitman / idler arm, and idler arm bracket and new tires as well. Threaded the new tie-rods to same length as the old ones I pulled out and of course had it lined up after the work was done.

Long story short, it's had bump steer ever since. When you go over a rise / dip and the suspension cycles, as the front rises (suspension extends) it pulls to one side (can't remember which) and then pulls to the other side when the front compresses (suspension compresses).

I've found that with the front skid plate removed and looking through the air dam under the bumper at the centerlink, when comparing it's "levelness" to the swawbar, the crosslink is not level. It's higher on the pass side. Measuring from the concrete floor up to the bottom of the inner tie-rod, the pass side is about 1" higher than the driver side. Also, looking at the tie-rod angles, the pass side looks close to same angle as the A-arm, but the driver side looks almost flat (level).

I had the GM dealership screw up once and put a 1/2-ton idler on my 2500HD and it had same symptoms - so I know even the dealership can have a parts screwup.

The parts I put on it were ACDelco from RockAuto.

Idler Arm # 46C1120A
Idler Arm Bracket # 46C1123A
Pitman Arm # 46C0069A

I stopped at the dealership today and bought the GM Idler Arm/Bracket combo and Pitman Arm to compare to what I've got and see if one is obviously different. They were $340 and the guy said I can return them so I am trying my best to compare them and not get the new ones dirty / greasy in the process.

I'll take some pics and update in a bit, pics are worth 1000 words.

At any rate - if anyone has ran across this before, would happen to have pics of their idler / pitman or could even confirm that the crosslink DOES run level on their truck, it would be a HUGE help.

number9l · August 30, 2016

Here's the pics.

Showing difference in tie-rod angles (compare tie rod to axle shaft & lower A-arm)

Centerlink at angle, not horizontally level like the swaybar is.

Pitman Arm - ACDelco # 46C0069A

Idler Arm - ACDelco 46C1120A

If anyone with same gen 4x4, 1/2-ton,SUV / truck could confirm their Pitman / Idler looks the same as these and/or their Centerlink is horizontally level or at an angle when compared to the swaybar like in the pics above, it would be a fantastic HUGE help!!

...

number9l · September 1, 2016

I'm going to keep updating for anyone that may be following or have this issue and find this thread.

Returned the ($350) GM parts to the dealer yesterday and talked to "their best front end guy". When I asked him if the centerlink is supposed to be level or at an angle, he said he'd never really paid any attention and the discussion really didn't help any.

There was an '05 Tahoe in their lot that I looked at and took pics of. Tie rods on it looked to be at closer angles than mine. Below pic is showing my truck on top.

Something is different between the two, maybe it's due to the ACDelco Advantage Pitman Arm I got not seating far enough up on the gearbox? I don't know.....

I placed an order from GMPartsGiant for the GM Pitman / Idler for $231 shipped. I'm going to try the pitman arm first and see how much better it will seat on the gearbox and what difference it may make.

Something I did notice looking at the pic above, is that my pass side wheel looks to have negative camber, but I'm not sure if that would cause the bumpsteer this truck has. I'm going to get an appointment to have the alignment checked out again before putting the new arms on.

....

Matt1982 · September 24, 2016

Have you figured this out yet? I have a 04 avalanche . Having bump steer issues after pitman arm idler bracket and arm and inner/outter tierod install. Centerlink is not level with frame of truck.

Edited September 24, 2016 by Matt1982

rdnkcpa · September 26, 2016

The top left picture of your truck's suspension looks like the sway bar link is missing. Don't know if that is an illusion or what, but is your sway bar link good?

Ron_Sneyd · November 4, 2016

did anyone ever figure this out? just replaced idler arm & bracket pitman arm,inner and outer tie rods, upper arms and new tires on my 04 avalanche and 4 alignments later i still have bump steer . and i found my center link is about 1" higher at the idler arm. i bought another idler arm and installed it and its still the same but it turned my steering wheel to the right. my new pitman arm also wouldn't go all the way on the steering box. if i could get it up all the way it would make the center link close to straight. i guess il buy another pitman arm tomorrow and try. this has to be the issue. thanks

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NSFW · November 4, 2016

Bump-steer.

Adjust the steering box tensioner to accommodate for waer/play/slop is the only thing I can think of right off the top of my head.

That set to spec and I would check to see if there is excess play in the steering setup from the steering box to the steering wheel. However I don't believe play above the

steering box that would chiefly relate to bump steer problems, but it might (the pitman arm being allowed to slap from side to side would make the truck bump steer).

Bump steer problems, or sensitivity to bump steer issues are mainly caster adjustments. Caster is important, as it governs the behavior of the vehicles desire of self-centring steering
and to drive in a straight line.

the roads up here in Canada have a 3 degree crown engineered into them (even the big 2 lanes) and setting on 0-0 caster results in hand pressure applied to the left to make the vehicle go down the road or it starts to go right. Canada doesn't just exclusively set this 3 degrees and its standard everywhere. Dirt roads have less crown to prevent the dirt from being washed into the ditch. Dirt roads are usually 1 degree or flat. City drainage is about 3 to 6 degrees. In areas that don't get precipitation (like tunnels) there is no need for a surface crown. Take

these circumstances, then rope it together with road surface quality that greatly varies from coast to coast, and its a very hard thing to do to get a vehicle to be aligned and

work in all scenarios without causing frustration with the driver.

SOME day, they will make adaptive alignment. A vehicle that looks at the road, and sets up the alignment to spec with what its scanner 'sees'. C'mon Musk.. get with it.

Thinking about this post I went and took my truck for a drive. When I am in the right lane at speed the truck tracks straight, with a slight (I mean over 200ft travel) arc drift to the right.

Meaning, my left hand is resting on the wheel and no left applied force by my arm is 'holding' the truck straight on the road. The weight of my hand resting on the left side

of the wheel is all it takes to result in a straight driving track. I can switch hands, and the result is the same. When I take my eyes off the road, the truck doesn't wander. It just tracks straight.

My caster adjustments are 5.2 degrees on the drivers side wheel, and 2.1 degrees on the passenger wheel. My split camber is .5 degree (.25 of a degree negative on each wheel)

My ride height is lower then stock. But I should add its not the same for both sides of the truck. I measure out 1-1/2 inch from the top of the adjusting bolt head, to the threaded boss on the passenger torque rod, and 1-3/16 on the drivers side. I have .75-.9 degree toe in which pulls straight with the force of the rear tires pushing the works down the road.

In the right lane the truck tracks straight, but in the passing lane, the truck pulls to the left, and I need to hold the wheel to the right to keep the truck driving straight.

Allot of companies (including dealers) tech's don't follow basic analysis routines when aligning vehicles due to the prevalence of online or documented specs, pecking order at the shop, work flow and other things. But the level of the fuel tank, a toolbox that's always full of tools, a ladder rack. Weather the vehicle is full of people often play a factor.
Usually an alignment is set up to do all things well, not any one thing well. True these stipulations don't usually effect alignment a whole hell of allot, but when a driver of a

vehicle is 300lbs... and the vehicle tends to pull to the drivers side, alignment can correct 'MOST' of this. A bent receiver hitch, or a distorted hidden hitch mount, bad tongue, crappy alignment on the trailer be it goose neck or otherwise can lead to wierd driving traits, and wierd wear on the tires It's allot to take into consideration.

my minds list on steering gear changeover (overhaul)

wheelberings
ball-joints
outer tie's

inner tie's
drag link (whole component)
pitman arm taper joint
*steering box slack adjusted to spec
*bushings in steering box play to spec
*bushings in steering column including tilt to spec

Followed by an alignment to spec, test drive, then final adjustments after test drive.

The biggest problem that I experienced while performing my 1/2 tonne to 3/4 tonne changeover was finding an actual alignment shop that 'would' actually align the truck and not just take
my money.

Being that I don't work in the shop where I learned aligning thus not able to have access to thier LASER machine there, finding a shop that wasn't merely throwing the truck on the rack and adjusting it to computer spec was if not impossible to find. I ended up going thru a 4x4 shop, that does custom 4x4 work, and getting their alignment guy to help me set the truck up. After that it was good.

Steering box tensioner. It's measured by using a drag indicator up at the steering wheel, not sure what the specs are, but there are specs for it.

peace

Ron_Sneyd · November 4, 2016

my avalanche was fine and was aligned one before from this place before i installed all front end parts. when they first did alignment it was real bad. it pulled hard to the right. second alignment wasn't much better. third alignment it now tracks fairly straight. but this bumpsteer is bad. when doing 40 or 50 mph and right tire goes over a bump the truck goes left ,so i steer right then left. so every bump has me steering, left-right-left. so it feels like im constantly trying to correct the steering . the only thing that looks out is the center link is like 1" higher at the idler arm then it is at pitman arm. and the new pitman arm wont go up on steering gear all the way.

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NSFW · November 5, 2016

Puzzling... I'm gonna think on this. Somethings screwy here.

Crazyjmk · June 3, 2017

I know this is an old thread but this is my issue exactly. Did anyone find a solution?

J

dwm · November 30, 2018

Been dealing with this exact problem.

I found my solution when I purchased a SuperSteer idler arm bracket with the reinforcement gusset.

It was the damn bracket mount was bent towards the front by about 3/16". This caused the idler arm to be forced upward at the center link.

We forced it back into position and secured with the gusset and now my center link is level.

When it started I was at 180k on my '03 z71 Tahoe and decided to make it a toy. I paid to have the entire front end rebuilt. Had issues and then tore it down and replace EVERYTHING myself after 10k to verify the install.

I went to Cognito uca's and PISK, Kryptonite tie rods and hubs, Energy Suspensions 1+ swaybar end links, AC Delco original equipment lca's, SuperSteer idler bracket, RareParts extreme duty pitman and idler arms, full body bushing kit, you name it, it was replaced.... but I held off on the idler bracket gusset. Still had the passenger side tie rod rubbing my swaybar on right turns. Went to install the gusset and there it was plain as day. Bent mount.

Don't know how it happened. I've driven every mile on my rig and never hit anything more than a pothole at substantial speed.

It came downt to remembering that I was stuck once and was in 4wd getting out. The front was spinning and then I hit traction with the passenger side front wheel and I was jolted pretty hard out and bounced pretty good coming out of the hole I had dug with the tire while stuck.

Out of curiosity I took a part rig I had bought and bent the idler arm bracket mounts a lil to the front and reassembled the front suspension. EUREKA! I was able to recreate the issue with very little force to the mounts. The further forward the bend, the more pronounced the lift to the center link.

Hope this helps.

Fyi- this may be the issue with many GM trucks/suv's because sometimes the only time it will show is at a full lock turn. I discovered mine by noticing grease on my swaybar after lubing the front end and then checking it a few days later. As time went on, it became more pronounced. So much so that I first went with a longer end link. Within 6 months it was hitting again.

It's been about 12k since my proper build and addition of the gusset and the problem has not reintroduced itself after some hard trys.

Good luck!

Edited November 30, 2018 by dwm
misspellings

Supreme Pizza · December 1, 2018

I have the same issue after replacing all of the front end parts. Had it aligned at a shop. It is somewhat mild, and I only notice at one particular spot on a certain road than has sudden abrupt elevation changes. As the suspension compresses, it pulls the steering wheel to the left, and when the suspension returns to the normal position, the wheels pulls to the right, and then centers out. I have not attempted to diagnose the issue, but I can say that the pitman arm did not "go on" as far as the OEM one did. The new pitman arm sits about 1/2 to 3/4 inch lower on the splines.

Lucas2001 · March 31, 2024

Has anyone had the problem where the idler arm bracket bottom bolt was hitting the tensioner pulley bracket? Also, how did you fix the problem where the center link was higher? Did you pull down on the center link?

jcg · March 26

On 11/4/2016 at 12:57 PM, Ron_Sneyd said:

my avalanche was fine and was aligned one before from this place before i installed all front end parts. when they first did alignment it was real bad. it pulled hard to the right. second alignment wasn't much better. third alignment it now tracks fairly straight. but this bumpsteer is bad. when doing 40 or 50 mph and right tire goes over a bump the truck goes left ,so i steer right then left. so every bump has me steering, left-right-left. so it feels like im constantly trying to correct the steering . the only thing that looks out is the center link is like 1" higher at the idler arm then it is at pitman arm. and the new pitman arm wont go up on steering gear all the way.

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It's the control arm bushings. Every vehicle I've delt with have a bump steer or bump shake control arm bushings fixed is.