Are all factory A-arms the same?

I searched but all I got was info on aftermarket A-arms.

I am asking because when calling multiple junkyards they want to know if the car had 14", 15" or 16" wheels on it.

I was under the assumption they were all the same. Am I wrong?

 

i though i heard once that the 1le cars had a slightly different a-arm, but other than that i though they were all the same too.

I have a set i just took out of my car if you are interested, they have poly bushings, but they need balljoints, i blew the grease caps when i took them apart

 

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JamesC

 

There's a wheel stop welded onto the side of the a-arms that is likely placed differently for different radius wheels. Conjecture on my part, though.

 

Does anyone have a picture of the wheel stops? What do they do?

 

I think the only differences in A arms were the bump stops, circled in yellow, and the "wheel stops", circled in red. Both "stops" are slightly different depending on what size wheel your car came with on the assembly line.

 

What I would like to know is what other cars do these arms fit? G-body? C-body? They must interchange with something or they wouldn't have a shock mount on them.

 

Shock mount? The wheel stop is an interesting idea; however, I have a difficult time believing that GM would go to the expense.

JamesC

 

From my measuring, they are the same shape as the s10 truck of the era. However, the truck had different bushings.

 

I remember getting one from a jy and the one bushing was a lot thinner then the one on the car. Not sure if it was from the wrong car or what but everything else was the same.

 

The bushings are slightly different between 1982-mid83 cars found that out due to my conversation with global west on their del-a-lum bushings.. Judging that poly bushings are universal I am not sure how big of a difference this really is.

I also know the wheel stops are different, my car originally came with 14s, then had 15s, 16s, and now 17s.. When you could still get new a-arms for these vehicles there was a difference in stops with different wheel sizes and I compared the two. The only trouble I have had with using my original stops/a-arms is that with LS1 brakes the wheels turn far enough to almost hit the caliper banjo bolts at full lock.

IMHO the best best is simply to get one from a car that is in your general year range.. the thirdgens had a few years with minor (but annoying) changes, 82-83s are the same, 84-87 similar, etc.. any time that the cars changed visibly the mechanicals had the tendency to change slightly also..

 

There's a shock mount inside the spring pocket. IIRC S10 and G-body arms are the same or interchange, and it wouldn't surprise me if GM used them on F-bodies too.

 

a 3rd gen spring will fit in a s10 and g body a arm.
it lowers the front an inch or so, and has a higher spring rate for taking corners over other factory springs.
the a arms may be the same casting, other than the bushings......

 

Ok, now i am confused. I don't how many posts i have read on here when researching about going to 16" wheels from 15" that the "stops" are in the steering box, and that is what stops the wheels from rubbing?

 

There's both. All steering boxes have stops in them. The cars that came with 16" wheels had different stops in them that restricted the travel of the pittman arm more than in the other cars. There is also a steering stop on the control arm that differs depending on what size wheels/tires came on the car.

 

The 82-97(?) S-10, 78-88 A/G-body & 82-92 F-body LCA's all have different bushing sizes.

Moog makes high durometer (think 1LE) rubber bushings for the G-arms. Obviously 1LE bushing from GM work on the F-arms. I can't remember if they do for the S-10 LCA's.

Off-topic but S-10 and G upper a's are the same bushings / arms.

I did an install w/ a friend on his 85 SS w/ F LCAs and 1LE bushings. I can't remember if the stops were any different.

 

I am still confused . If you have stops on the control arms in a different spot, why on earth would the cars with 16" rims have a different steering box with different stops from those with 15" (the ones that had the performance tight ratio)? The stops on the control arm effectively eliminate the need for different stops in the box and end up reducing the travel of the pitman arm (since the wheel can't turn any further).

 

The stops placement inside a steering box is not to limit the turn radius, it is to limit the geometry of the pitman arm from going to an angle of no return so the tierod does not flop outward (If you have even experienced a go-kart doing this you will know what I am talking about). They extend too far if you make contact and you have to get out and kick the tierod back into the articulation path

The stops on the A-arm are what limit the turn radius. THis is the important one so you do not rub the fenderwheel. THe 16" cars restricterd the turn radius bbecause the wheels were wider and would rub the inside fender at full lock.

You can put any a-arm on the car, just learn not to turn the wheel so far as to rub. If the factory had not done this, then there would be comsumer after consumer bring their car in complaning the wheel rubs rather than using common sense and just not turning the wheel that far.

 

Hell, this stuff takes a novel to explain. If you were standing in front of me I could explain with my hands in 10 seconds.

just don't worry about the steering box stops, they are irrelevant. Pretend they do not exist.

Htere is actually another benefit of the steering radius reduction that is not talked about, but has become my experience. When you put 16" factory wheels onto an original 15" wheel car and the fatter tires swivel in ackerman angles, the fatter wheels will fight eachother whent he ackerman angles go to hell at full lock. The 15" tires were skinnier and did not suffer as noticibly as the wider tires do when the ackerman angles extend far enough to fail and scrub. THe 16" wheel stops aid the prevention of breaching the ackerman- in other words, the car will lift and shutter when u-turning too sharply.

The narrower the tire, the less an ackerman breach will show.

 

thanks for the detailed description Vetruck, much appreciated.