Hey Vortec Guys! / Sierra pickup / Suburban / Yukon etc - Finally has Index!

[02SonoraZ71]

Hey all,

I changed my idler arm (moog k6534) and idler arm bracket (moog k6723) a while back and noticed that after the repair my center link was sitting about 1" higher on my passenger side than the driver's side, I belive there was a slight angle before but is seems to have increased after the repair. This resulted in a higher tie rod angle on my passenger side and on full turns to the right , my inner tie rod boot rubs on the sway bar. I wanted to see if you guys have had this same issue. Ive read on other forums of this happening on some trucks due to the known bumpsteer issue on these models. Below is a pic and if you compare the sway bar link on the bottom to the center link on top you can see how it is sitting higher on the idler (left) side. If any of you guys have pics for me to compare that would be great help.

Thanks,
Fred

 

[rayra]

don't know anything about a 'known bumpsteer' on these vehicles. And it looks to me like your new idler mount is not a proper fit.
I changed everything in my steering linkages but my idler mount and didn't have such trouble, but there is an issue of sway bar clearance when trying to put in new inner tie rod ends, with the torsion bars cranked or keys replaced. The geometry of the parts interferes with the straight-in threading of the inner rods. I had to pull my sway bar end links and pivot the sway bar out of the way, during the swap.
details and pics buried in my 'hey vortec guys' mechanical / repair topic, link in my sig

 

[02SonoraZ71]

Ive double checked part fitment and it is for my model. One thing im suspecting is the frame mounts for the idler bracket may be bent causing the idler arm to be pushed up higher. Ive hit some rough roads and ruts in the past and its making me think that may be the cause. i do have my keys replaced and t-bars cranked. Bent the passenger side tie rod while offroading 2 months ago and i believe it was due to the larger angle on that side.

 

[02SonoraZ71]

rayra, i saw your repair pics and it looks like yours are straight. Must be me just abusing the truck and it finally bent something. I also saw that you tried getting the trans temp stepper installed. i went through the same issue on another '99 silverado i have and thought i could simply solder some contacts for the trans stepper pins. The reason they dont work is because under the PRND123 display there is a microprocessor that the 1500 dashes dont have. i just ended up getting a '02 2500 cluster instead of desoldering the microprocessor off the donor and then soldering it back onto my 1500 dash just to keep my original miles. My Sonora came factory with trans temp as in Mexico 1500's are considered 2500's.

 

[rayra]

iirc there's 3? bolts on the idler mount and it's in the corner of the frame rail and crossmember, tough spot to bend anything but the mount. Too, it's a common wear item on these vehicles because the GM geniuses put the grease fitting on its top, you have to either remove the skidplate or the air ducting to get to it and few people do apparently and 'Jiffy Lube' certainly isn't. So it wears badly.
Problem might be multi-year parts fit. Be worth looking at moog and other brands across many years and Chev / GMC / Cadillac and see if different parts are listed. All sorts of ways for error to creep in. And it sure won't be the first time I've seen such parts errors. GM keeps / holds a design for as many parts and years and models as they can, for as long as they can. It's possible that other geometries changed while the part fitment didn't. And maybe an aftermarket parts co. made their part fit 'most'.
My '85 C-10 had a lot of mid-series production changes, parts stores routinely have the wrong size air filter height, oil filter size, and even the trans filter is different even citing the correct trans model. And on my '02 Sub I discovered it uses the same size u-joints as my '85 C-10. Economies of scale.

Also makes me wonder if there's room enough on the mounting flange of the idler bracket to re-drill its holes higher up the plate and lower the part so that your center link returns to level. But you really shouldn't have to do that. Part ought to fit correctly.

Looks at the parts online it seems the only way to have that sort of elevation change in the idler is the have the original mount / bearings be shot / worn out. Only way I can see for things to shift that high. That or it's the wrong idler arm. It's not even possible to have flipped it. If you put the arm on upside down you'd raise that end of the center link at least 3-4". You idler is above the center link, isn't it? nevermind I can see that it is in your picture. But that ugly mess where the idler arm attaches to the bracket / shaft makes me think it might be badly work and that might give you enough slop there to result in that angle on the center link.

eta rockauto has the delco arm and bracket for $117 and Autozone Duralast replacement bracket for $82

On the trans temp I was able to use the Torque app and bluetooth CANBUS transmitter and found the PID code to pull the trans temp data into a virtual gauge, I have a 7" samsung android tablet I mount on my dash on road trips, using it for vehicle monitoring as well GPS speed and map navigation.

 

[02SonoraZ71]

The mess was due to me adding a bit too much grease when i re-greased the last time. After some use it oozed out and i never cleaned it. the new assembly has about 9 months. could be i got a bad one...i saw a cognito super steer idler bracket assembly that has a reinforcement weld-on gusset. i think this is a common issue on the 2500 guys doing 4wd launches or so because this kit is made for 8-lug applications but also for 6-lug so it makes me think this may be also be common for 1500 4wd silverados as well.

 

[Deleted member 374434BT]

Do we have a subthread for

"Weird ABS behavior on GMT800 trucks"

Figured i'd post up my findings for anyone with intermittent brake issues/power loss and no obvious cause. Never had an ABS or Brake warning lamp illuminated this whole time.

Been chasing a combination of brake issues over the last 6 years and 80k+ miles with my DD 2006 Silverado. No lights no codes.

Truck has had inconsistent pedal feel everytime i drive it. Sometimes it's hard pedal like a faulty booster, other times its soft factory GM overboosted brakes. Adjusted/checked rear shoes multiple times to get pedal firmness. Started with Front DS caliper originally sticking and overheating pad. Brakes never seemed to hold pedal feel long after after rear shoe adjustments. Bled air from system multiple times including cycling ABS module on dirt road and then immediately re-bleeding.

In 6 years I've replaced:

3 sets of front pads
2 pair of rotors
2 pair of Timken hubs
Pair of front calipers
Front soft lines
2 sets of Rear shoes
Drums
2 pair of wheel cylinders
Booster
Master cylinder.

Booster and master replaced 5 mos ago because brakes were dragging on highway like i was towing a 20' enclosed trailer. Flushed brake system with at least a gallon of DOT3 and problem reduced but soft pedal/hard pedal continued with intermittent lack of power. Calipers and shoes move freely when truck is off and on the lift. When brakes drag, I park truck and they are unstuck within 30 minutes like nothing ever happened. Booster maintains vaccum reserve the whole time truck is off. Take off driving and 10 mins into drive it starts to feel like I'm towing a 20ft enclosed trailer again.

Finally sourced a set of factory 2006 service manuals and find out the ABS EBCM controls front rear brake bias on the 2005-up trucks.

Pulled 60a ABS fuse underhood and pedal is like when i bought it in 2007 . Looking at $800+ for a new EBCM assembly now. Going to tolerate that annoying chime in the meantime.

EDIT:

Also, I randomly noticed the red brake warning light would be glowing very dimly in the mornings like it was being backfed. I know LEDs are sensitive to residual voltage. It was such a slight illumination i couldn't tell during the day.

The EBCM ground is on the backside of the DS front cab mount in case anyone experiences intermittent brake warning lights.

 

[Overlandtowater]

Im afraid i would have to go buy a bunch of line and bypass the abs system...I think its possible on this model.

 

[tacobronco]

Fun fact, they ditched the AC belt tensioner at some point prior to my 2011. You have to take the pump off the engine to change the belt, so mine still has the original belt on it.

No, there's a little twisty tool that lets you roll the belt on/off without removing the compressor:

59370 Stretch Belt Remover / Installer

Combination Removal and Installation Tool for Most Stretch Belt Applications Found on Many Accessory Drive Systems.

www.lislecorp.com

It ain't pretty, but it works. Did it on my 2010.

 

[Flachzwilling]

Concerning the neverending quest for the right bump stops in the rear: Having ordered the same wrong, short stops as Rayra, I had a closer look at the longer, deteriorated OEM parts. They say "15200990", which decodes as "Coil Spring" for "Smooth Ride Suspension. Z71 susp. 1/2 ton, z71-off road pkg " on Cadillac Escalade ESV, MY2017 thru 2020.
Of course that's rubb(er)ish, I have the truck ('05 Suburban Z71, hecho en Mexico) since 2016 and the stops look like 2005. IMHO the whole GM parts catalogue is notoriously bad for identifying parts.
That said, perhaps someone could use this info...

 

[Jacobm]

Question for the group: For those who've had ABS/EBCM issues, has anyone ever sent theirs for repair or bought a remanufactured part? My mechanic quoted me $1500 for replacement with new, but offered installation and coding if I provide a less expensive part. It seems there's a variety of vendors offering repair or remanufactured units for around $150 plus shipping, with claims of a lifetime warranty. Seeing as I'm having a ton of deferred maintenance and front end work done for just $2,000, another $1500 just to have ABS working again is a tough pill to swallow. For the price I might try out one of the reman units from eBay, hopefully PayPal could help if it's a dud but most of the sellers have good feedback.

 

[vintageracer]

Jacobm,

I see only 1 issue with using the reman part and that is a LABOR WARRANTY from your mechanic installing and coding that reman ABS unit he did not provide.

If the reman ABS unit is installed and your ABS system still does not work properly was it a problem with the reman ABS unit OR an installation problem caused by your mechanic?

Fewer and fewer mechanics will install customer provided parts these days. From your post you state your mechanic will. I would want to know what happens if the system still does not work? Sure you have a warranty from the reman ABS unit supplier however they are not going to pay labor to replace a defective unit. All the ABS supplier will do is replace the defective ABS unit IF that truly is the problem.

Who pays your mechanic to remove and re-install all the parts if the problem is the reman ABS unit. Remember any problem with customer supplied parts is never the mechanics fault!

Personally I would go with the reman ABS unit and take my chances.

 

[Jacobm]

I'm lucky that my mechanic is very reasonable and honest, and we did have the discussion about used parts. I think I'll risk a used unit, and possibly install it myself and see what happens, and if it needs coding I can take it to him. I might try some of the DIY fixes like checking the grounds (probably fine, nothing ever rusts in Idaho) and potentially opening the unit and resoldering the relay myself, if that doesn't ruin my chances of getting a reman unit.