Chevrolet R-20 barn door suburban - front end

Andrew Mackey

I have replaced all the control arms in my R-20. It is a Silverado version 3/4 ton 'bus'. 2 WD with the 454 and towing package. They were from Moog, and sold thru NAPA. I bought them because they were US built, not Chinese crap. Cost about 75% more. Now for the problem: Upper control arm bushings on both sides have backed out of the arms! The left side has now come apart 3 times, the right twice. The rear bushings seem to be the ones backing off. Moog has replaced the arms but won't cover labor. At 150 a clip, it is getting ridiculous, as for replacement cost! Anyone got any ideas? I cannot align, as I was told the arms have to break in for about 250 miles so they can be set. CANT even get that before the darn bushings back off! The back off has now wiped out the front tires as well :crazy: HELP! :rant: When the bushings back off, a loud 'CLUNK' is heard and felt thru the chassis, and steering wheel spoke location changes (movement is causing steering changes). Has anyone else run into this? The truck is a rust bucket, but the frame, engine, and running gear are in excellent shape except for this damn control arm issue.

These are NEW control arms, with NEW bushings, mounts and ball joints already installed. The bushings are metal, not the push in rubber ones used on the 10 series. They are heavy duty, and look like the ones that were removed. They are supposed to be in 'bolt on' condition. The original GM units wee worn out, as were the ball joints, thus the complete replacements. NO suspension mods, bone stock suspension. All new steering componants, new box, pump, relay rod, pitman arm, tie rod ends, you name it, it was replaced. The tires were balanced, and new brakes recently done. Rims checked for true (none bent). No vibration while driving either. truck rides well except for the darn control arm issue.

Doug Tallman

2 thoughts on this. I've never heard about control arms having to seat in before they could be aligned. that could contribute to them coming apart.

Second, I would question if they are being tightened right. You need to have the weight of the vehicle on the suspension before you tighten the through bolts that hold the control arm to the vehicle. If you don't, you are putting extra stress on the bushings and they won't last long.

I believe Moog has a help line. Might try calling them. Are you sure you're not getting Dorman ones? I've been having problems with a lot of their stuff lately.

Andrew Mackey

Dormans are Chinese. I have heard of problems with them. The ones I got were definitely Moog. The new control arms come as a complete assembly, only thing you have to do is install the ball joint pin into the spindle and put the mount onto the frame with the caster camber shims. The bushings come already assembled onto the mount shaft - no adjustment. The bushings are 2 part - inner bolted to the mount arm, outer threaded into the control arm itself. It is the outer section that is backing off, allowing the control arm to move on the mount shaft. For my 1988 R-20, these are a special order item - takes them a week to get in.

The last time the left hand upper control arm was installed, the mechanic let me try and move the installed arm before he installed the ball joint into the spindle. It was a bit stiff but moved freely, without binding. The arm being replaced had about 1/2" of play, as the bushing had backed out and wore out the threading in the arm. All 5 arms have come apart in the same way - the bushing is backing out of the arm. :mad:

When the first one came apart, (left side rear bushing) the mechanic thought it was a fluke, and tightened the outer side of the bushing back up into the control arm. 2 days later, it was loose again! This time he used a 2 foot breaker bar and a 3 foot cheater to tighten it. It came apart again in 4 weeks! We contacted NAPA and they said replace it, it was defective. Now, 5 bad assemblies??? Less than a thousand miles between all 5 arms:rant:


New member
Andy: L/h upper & r/h upper control arms are still in stock

lh# 12383505
rh# 12383506

$225.00 each

you get what you pay for !!!!!!

Get back with me been with gmc truck since 1982

big charlie

J.B. Castagnos

Active member
No reason the alignment can't be done immediately, these bushings don't have to be tightened in place like a rubber bushing. If I were installing them I would use the mig and spot weld them in several places so they couldn't unscrew.

Tom Wahl

New member
Andrew - My brother has never had problems like that, however when he buys new control arms, he buys "everything else" new also and everything comes completely assembled and under full warranty.

Andrew Mackey

JB, I might end up doing that (weld). Akuna, the 88 3/4 ton R-20 Silverado Suburban is part specific - only made that year. It is a 9 passenger vehicle, and the State considers it a bus. Ones earlier or later won't fit. The shop working on the truck has done work on it for me for the last 25 years. I bought the parts, because my son gets the parts for cost. When you are on SS Disability (like I am), you need to cut costs when you can. I did not skimp on the parts, I thought I was buying a quality product, instead of what I knew was Chinese crap parts. I was told Moog was US built, so that's what I bought. Maybe Moog isn't good anymore???:eek: They used to be the best! As for being the wrong part - When I originally ordered the control arms, they sent ones for the 1/2 ton version. Completely different! They had to order by the truck VIN. Then the items were matched to the originals in the truck, before dis-assembly. Thanks Charles, the local Chevy dealer told me part is NLA - guess he didn't want to look it up, after all it is a 29 year old truck! If the new ones come apart again, I guess I will have to bite the bullet and see if you can get them for me. I guess I will know in a month or so, how the new ones work out! Tom, I did get everything new, as I posted above. No rebuilt for me - the rebuild guys nowdays are only parts changers. They won't look for the reason a part failed, they just chuck in the minimum and throw it back out there, hoping it won't come back! been there done that too many times. By the way, the original control arms lasted 225,000 miles! Got my money's worth out of them!:D One of the reasons I think they finally wore out - the new soap complex grease that is used today. Water tends to wash it out, and make it caustic. Not only that, but most of todays parts are throw away. No grease fittings. Cheaper to toss and replace than to rebuild. 'Programmed Obsolescence' at its best! Don't fix it, just replace it! When I first looked at repairing the front end, I had looked up the ball joints. NO grease fittings! They were 'sealed'. Not for me, I like to keep things lubed. Last year, I had to replace the driveshaft universals. First set was Chinese, and had no grease fittings! Next set, better quality, cost more, but they had grease fittings!


Active member
Andrew, Paying for alignments over and over is a waste.
You know better.
Go to a major tire dealer and get a "lifetime alignment".
I happen to use Firestone because they are close, but others offer it. Costs less than one dealer alignment, and you can have it checked and aligned for free as often as you want. They recommend every 6 months.

They align almost everything they sell tires for.

Their alignment rack is newer and better that what dealer has, and is almost idiot proof.
Not like when we did them.
Punch in year, make, model and machine tells tech what to do.
Spin the wheels. if transmitter is not centered on wheel, or rim is bent, machine tells tech.
Out of alignment?
Machine shows picture of part and how to adjust it.
Toe- tells you which way to turn adjuster and how much so steering remains centered.
Same with camber/ caster- if they are adjustable.

Customer gets before and after printouts of all 4 wheels.

Andrew Mackey

And the saga continues! Got the right upper Moog control arm replacement today. Nice blue box says Moog Performance Parts. MADE IN CHINA :rant: The whole idea for buying Moog was that the materials were made in USA. Does this mean that Moog is also now outsourcing to china? If so does that mean that these are now crap, thus the failures? NAPA says Moog stands behind their product, but still won't make good on the labor :shrug: I got new tires, and when putting on the truck, now find the left upper is coming apart for the 4th time. Not even 2 hundred miles since installation! No info on how to contact Moog in the box. I guess a call to one of the local news shows and a complaint about shoddy parts may get some relief. Maybe a call to the NTSB might also get some results. Guy at NAPA has had other complaints now - same problem - the control arm bushings backing off. :mad: :crazy:

I like oldstuff

Moog components have gone to crap. Despite labeling a lot of it is now offshore sourced, Singapore, Malaysia Chin etc. My local store delights in sending things back to them replete with nastygrams.

Andrew Mackey

I found Moog's home website and left a post about my problem. No answer yet. They do have a phone #. maybe a call will get answers, otherwise Linda Baquerro will be getting a call! Linda has a news help line on channel 4 - NBC. She gets results when a person gets the stall from businesses. Nothing like national bad press to get results!