Replacing lower control arm - The 1947 - Present Chevrolet & GMC Truck Message Board Network

GMC Guy · 11-01-2010, 05:50 PM

my driver side lower control arm is bent and may be causing my vibration problem. i'm going to pull a LCA off a truck at pick n pull and have a shop press in new bushings and a ball joint. what's the easiest way to swap out the LCA? things to watch out for?

i was thinking, remove the tire, break the ball joint loose from the spindle, unbolt the LCA, and reverse the process? i need to tackle this project within the next couple days.

benoit454 · 11-01-2010, 06:00 PM

I think you got it right but you gotta do something with the spring, chain it down, meaning run a thick chain through it with the trucks weight on it, and bolt it solid so it can't spring out, use some spring compressors, something because it loaded and when unbolted it will come out.

You could be careful with a jack under the control arm and let it down slow, but to be safe I'd use something, chain or compressor somerthing. That way it don't your teeth out or worse.

You need to pul the cotter pin, remove the nut, take the sway bar off or loose from it, if you have one, let it down and get the spring out, remove the 3 bolts that hold it in, and remove it.

Usually you need a pickle fork to hammer in between the ball joint and knuckle to seperate them. You might not even need to remove the tire but it'd give more room to work, same for the entire knuckle/spindle.

GMC Guy · 11-01-2010, 06:21 PM

is it possible to strap the coil spring to the upper control arm or something, that way the spring stays in the same place? also, any tricks to re-assembly?

benoit454 · 11-01-2010, 06:36 PM

It may be if you had a heavy duty strap and a way to secure it good.

I don't really think there's any real tricks to getting all of it back in. Not real sure though.

GMC Guy · 11-01-2010, 06:42 PM

is there a certain way the spring sits on the LCA?

kelsfine69 · 11-01-2010, 07:56 PM

Yes you will see the dent in the bottom. I am going to tackle this in the spring . I have my LCA already from a donor truck. I would put the front on stands(frame) Then put the jack under the pocket on the LCA. Remove tire brake caliper, swaybar pin, and nut from lower ball joint. leave nut on the last few threads to prevent a breakaway. Break the jont from the spindle and remove the nut totaly and using the jack, lower LCA till the spring is loose ( go slowly). Once the spring is loose then push the LCA down and pull the spring out.Remove the ubolts and done. Putting a small chunk of 2x4 in between the UCA and the frame hepls hold the spindle and stuff out of the way once the spring is broke free.

GMC Guy · 11-01-2010, 08:05 PM

thanks, every little tip and trick helps!

kelsfine69 · 11-01-2010, 08:10 PM

You might want some ubolts cause Im thinking the old ones might have to be torched from all these years. I got a set from GM and another off ebay. Im doing both sides..

Slonaker · 11-02-2010, 01:29 PM

Quote:

Originally Posted by GMC Guy

is there a certain way the spring sits on the LCA?

Sort of, but the upper actually locates the spring. The upper has a "D" shaped protrusion that fits into a similarly shaped bend at the top of the spring. If you look up inside the pocket in the upper you'll see what I'm talking about.

Slonaker

tucsonjwt · 11-02-2010, 02:00 PM

Just curious - what are you going to pay for the used lower control arm? Is it priced low enough that a new one is not competitively priced?

GMC Guy · 11-02-2010, 04:18 PM

i can pull one out of the yard for around $25-30 rather than a new one being around $150.
also, is there a difference between 1/2 ton and 3/4 ton control arms?

and does $93 sound right to have a shop press in new bushings and a ball joint?

benoit454 · 11-01-2010, 10:38 PM

It's been along time since I had one apart, and all the above is great info.

I would soak those bolts for a few days before trying to remove them, mainly the u bolts for it. I hear a 50/50 mix of acetone and atf works better then any penetrating oil you'll ever buy.

We're getting ready to work on the front of dad's 84, but we're not taking the control arm off, but are still going to have to work with the springs, since we're doing ball joints, a new upper control arm, tie rods, and an idler arm, parts should be here tomorrow, should be starting on it soon. We were gonna do as mentioned, raise, jack stands, jack under the LCA, and safety chain the spring, let down slow and take it out. Tried to talk my old man into cutting a couple coils while we're at it.

benoit454 · 11-10-2010, 12:23 AM

wow that much to do a ball joint and bushings? You can rent the ball joint tool from a local chain parts store for a hundred, then once done get your money back. We're getting ready to do that. As for the bushings, not sure I think it should be cheaper to press 2 out and 2 back in them. I don't think it was much worth it to do it on one side and not the other.

Yezzi · 01-26-2011, 06:36 PM

what did you do to stop the rubbing?

1LowToy · 01-26-2011, 09:55 PM

GMC guy You have us very curious. We need to see that control arm and where you ground off too much. And what kind of wheels are you trying to put on the truck.

GMC Guy · 01-27-2011, 02:59 AM

ah man that control arm is long gone...

i'm running 15 inch wheels with like 5 or 4.5 inch backspace. not sure

the inside of the wheel would rub the lip of the control arm, soo i started cutting. i ended up getting carried away on the driver side out of frustration, i made more of a straight cut across the control arm lip. instead of following the natural shape of it. basically i took so much off that it weakened and bent from the weight of the truck.

it would be sooo much easier showing you guys...but the lesson here i guess is if you're running 15 wheels, use an grinder if you need to shave down the control arm, don't use a cutting wheel and go crazy lol

oh plus i added a 1/4 inch spacer and i haven't had rubbing issues since. i just need wheels with less backspace.

1LowToy · 01-27-2011, 08:15 PM

A picture would tell a thousand words. I just trimmed mine back too and I now wondering if I took too much off too. Which wheels are you running and where did you find 1/4" spacers? Don't be afraid to admit defeat because it will salvage the rest of us hackers.

Yezzi · 01-27-2011, 09:05 PM

Quote:

Originally Posted by 1LowToy

A picture would tell a thousand words. I just trimmed mine back too and I now wondering if I took too much off too. Which wheels are you running and where did you find 1/4" spacers? Don't be afraid to admit defeat because it will salvage the rest of us hackers.

Tell me about it I trimmed some off mine and now after seeing this thread I'm freaking out. I would love to see that picture.

1LowToy · 01-28-2011, 10:59 PM

I guess I better add more infor here. I trimmed mine as I will have the 3" drop spindle and 15x8 chevy ralley wheels. The 15x7 ralley wheels don't have clearance issues (So says the forum). I just hope I didn't make a perfectly good lower control arm a paper weight.

1LowToy · 01-31-2011, 10:29 PM

GMC Guy Did I screw mine up too ^^^^^^^^^^^^^??

GMC Guy · 02-01-2011, 01:07 PM

i need spme side angle pictures. but from the top angle, i don't know if i'd install it on my truck

1LowToy · 02-02-2011, 12:31 AM

I cut back about 1.5" on the forward edge and only about .5" on the rear of the ball joint area. What lowering spindle and wheels are you running and where did you find them rubbing the lower control arm. Did the wheel spacer cure all your issues?

The last pic is someone elses instructional pic of how to that I followed.

I thought then that it should be reinforced. Let me know if you need more pics.

GMC Guy · 02-02-2011, 12:57 AM

it looks fine to me, that's how trimmed mine the second time. i'm running 3in drop spindles with 15in rims. and yes the 1/4 spacers did give me a little extra clearance.
and even if you install them on the truck and need to trim a little more, just whip out the angle grinder. be sure to only take off little bits at a time.

78cheyenne292 · 02-03-2011, 01:32 AM

you asked if a 1/2 ton and 3/4 ton are different.. i have an 83 1/2 lca on my 78 3/4 its built a little diffrent but the truck sits level and it bolts up fine but the balljoints are thicker on the 3/4 ton but the 1/2 lca actually looks beefier could just be cause its a newer model

11-01-2010, 05:50 PM	#1
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Replacing lower control arm my driver side lower control arm is bent and may be causing my vibration problem. i'm going to pull a LCA off a truck at pick n pull and have a shop press in new bushings and a ball joint. what's the easiest way to swap out the LCA? things to watch out for? i was thinking, remove the tire, break the ball joint loose from the spindle, unbolt the LCA, and reverse the process? i need to tackle this project within the next couple days. __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

11-01-2010, 06:00 PM	#2
benoit454 Chris Join Date: Nov 2004 Location: Monaville, WV Posts: 3,737	Re: Replacing lower control arm I think you got it right but you gotta do something with the spring, chain it down, meaning run a thick chain through it with the trucks weight on it, and bolt it solid so it can't spring out, use some spring compressors, something because it loaded and when unbolted it will come out. You could be careful with a jack under the control arm and let it down slow, but to be safe I'd use something, chain or compressor somerthing. That way it don't your teeth out or worse. You need to pul the cotter pin, remove the nut, take the sway bar off or loose from it, if you have one, let it down and get the spring out, remove the 3 bolts that hold it in, and remove it. Usually you need a pickle fork to hammer in between the ball joint and knuckle to seperate them. You might not even need to remove the tire but it'd give more room to work, same for the entire knuckle/spindle. __________________ Chris GIT R DONE!!!!!! Check out all our rides, http://www.cardomain.com/id/benwa454

11-01-2010, 06:21 PM	#3
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Replacing lower control arm is it possible to strap the coil spring to the upper control arm or something, that way the spring stays in the same place? also, any tricks to re-assembly? __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

11-01-2010, 06:36 PM	#4
benoit454 Chris Join Date: Nov 2004 Location: Monaville, WV Posts: 3,737	Re: Replacing lower control arm It may be if you had a heavy duty strap and a way to secure it good. I don't really think there's any real tricks to getting all of it back in. Not real sure though. __________________ Chris GIT R DONE!!!!!! Check out all our rides, http://www.cardomain.com/id/benwa454

11-01-2010, 06:42 PM	#5
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Replacing lower control arm is there a certain way the spring sits on the LCA? __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

11-01-2010, 07:56 PM	#6
kelsfine69 18 Till I Die Join Date: Mar 2005 Location: Alberta, Canada Posts: 1,522	Re: Replacing lower control arm Yes you will see the dent in the bottom. I am going to tackle this in the spring . I have my LCA already from a donor truck. I would put the front on stands(frame) Then put the jack under the pocket on the LCA. Remove tire brake caliper, swaybar pin, and nut from lower ball joint. leave nut on the last few threads to prevent a breakaway. Break the jont from the spindle and remove the nut totaly and using the jack, lower LCA till the spring is loose ( go slowly). Once the spring is loose then push the LCA down and pull the spring out.Remove the ubolts and done. Putting a small chunk of 2x4 in between the UCA and the frame hepls hold the spindle and stuff out of the way once the spring is broke free. __________________ 2011 GMC Acadia 1969 GMC BBC LS7 2007 GMC Crew Duramax 1987 Camaro Iroc 350 Tuned Port Injection 42000Km 1987 Chevrolet Silverado 350 TBI 1987 Chevrolet Silverado 350 TBI(yes 2) Take me drunk, I'm too home... Last edited by kelsfine69; 11-01-2010 at 08:07 PM.

11-01-2010, 08:05 PM	#7
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Replacing lower control arm thanks, every little tip and trick helps! __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

11-01-2010, 08:10 PM	#8
kelsfine69 18 Till I Die Join Date: Mar 2005 Location: Alberta, Canada Posts: 1,522	Re: Replacing lower control arm You might want some ubolts cause Im thinking the old ones might have to be torched from all these years. I got a set from GM and another off ebay. Im doing both sides.. __________________ 2011 GMC Acadia 1969 GMC BBC LS7 2007 GMC Crew Duramax 1987 Camaro Iroc 350 Tuned Port Injection 42000Km 1987 Chevrolet Silverado 350 TBI 1987 Chevrolet Silverado 350 TBI(yes 2) Take me drunk, I'm too home...

11-02-2010, 02:00 PM	#10
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,188	Re: Replacing lower control arm Just curious - what are you going to pay for the used lower control arm? Is it priced low enough that a new one is not competitively priced?

11-02-2010, 04:18 PM	#11
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Replacing lower control arm i can pull one out of the yard for around $25-30 rather than a new one being around $150. also, is there a difference between 1/2 ton and 3/4 ton control arms? and does $93 sound right to have a shop press in new bushings and a ball joint? __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

11-01-2010, 10:38 PM	#12
benoit454 Chris Join Date: Nov 2004 Location: Monaville, WV Posts: 3,737	Re: Replacing lower control arm It's been along time since I had one apart, and all the above is great info. I would soak those bolts for a few days before trying to remove them, mainly the u bolts for it. I hear a 50/50 mix of acetone and atf works better then any penetrating oil you'll ever buy. We're getting ready to work on the front of dad's 84, but we're not taking the control arm off, but are still going to have to work with the springs, since we're doing ball joints, a new upper control arm, tie rods, and an idler arm, parts should be here tomorrow, should be starting on it soon. We were gonna do as mentioned, raise, jack stands, jack under the LCA, and safety chain the spring, let down slow and take it out. Tried to talk my old man into cutting a couple coils while we're at it. __________________ Chris GIT R DONE!!!!!! Check out all our rides, http://www.cardomain.com/id/benwa454

11-10-2010, 12:23 AM	#13
benoit454 Chris Join Date: Nov 2004 Location: Monaville, WV Posts: 3,737	Re: Replacing lower control arm wow that much to do a ball joint and bushings? You can rent the ball joint tool from a local chain parts store for a hundred, then once done get your money back. We're getting ready to do that. As for the bushings, not sure I think it should be cheaper to press 2 out and 2 back in them. I don't think it was much worth it to do it on one side and not the other. __________________ Chris GIT R DONE!!!!!! Check out all our rides, http://www.cardomain.com/id/benwa454

01-26-2011, 06:36 PM	#14
Yezzi Registered User Join Date: Dec 2010 Location: Phoenix Posts: 1,176	Re: Replacing lower control arm what did you do to stop the rubbing?

01-26-2011, 09:55 PM	#15
1LowToy Registered User Join Date: Nov 2009 Location: Sonora California Posts: 860	Re: Replacing lower control arm GMC guy You have us very curious. We need to see that control arm and where you ground off too much. And what kind of wheels are you trying to put on the truck.

01-27-2011, 02:59 AM	#16
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Replacing lower control arm ah man that control arm is long gone... i'm running 15 inch wheels with like 5 or 4.5 inch backspace. not sure the inside of the wheel would rub the lip of the control arm, soo i started cutting. i ended up getting carried away on the driver side out of frustration, i made more of a straight cut across the control arm lip. instead of following the natural shape of it. basically i took so much off that it weakened and bent from the weight of the truck. it would be sooo much easier showing you guys...but the lesson here i guess is if you're running 15 wheels, use an grinder if you need to shave down the control arm, don't use a cutting wheel and go crazy lol oh plus i added a 1/4 inch spacer and i haven't had rubbing issues since. i just need wheels with less backspace. __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]



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01-27-2011, 08:15 PM	#17
1LowToy Registered User Join Date: Nov 2009 Location: Sonora California Posts: 860	Re: Replacing lower control arm A picture would tell a thousand words. I just trimmed mine back too and I now wondering if I took too much off too. Which wheels are you running and where did you find 1/4" spacers? Don't be afraid to admit defeat because it will salvage the rest of us hackers.

01-28-2011, 10:59 PM	#19
1LowToy Registered User Join Date: Nov 2009 Location: Sonora California Posts: 860	Re: Replacing lower control arm I guess I better add more infor here. I trimmed mine as I will have the 3" drop spindle and 15x8 chevy ralley wheels. The 15x7 ralley wheels don't have clearance issues (So says the forum). I just hope I didn't make a perfectly good lower control arm a paper weight.

01-31-2011, 10:29 PM	#20
1LowToy Registered User Join Date: Nov 2009 Location: Sonora California Posts: 860	Re: Replacing lower control arm GMC Guy Did I screw mine up too ^^^^^^^^^^^^^??

02-01-2011, 01:07 PM	#21
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Replacing lower control arm i need spme side angle pictures. but from the top angle, i don't know if i'd install it on my truck __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

02-02-2011, 12:31 AM	#22
1LowToy Registered User Join Date: Nov 2009 Location: Sonora California Posts: 860	Re: Replacing lower control arm I cut back about 1.5" on the forward edge and only about .5" on the rear of the ball joint area. What lowering spindle and wheels are you running and where did you find them rubbing the lower control arm. Did the wheel spacer cure all your issues? The last pic is someone elses instructional pic of how to that I followed. I thought then that it should be reinforced. Let me know if you need more pics. Attached Images

02-02-2011, 12:57 AM	#23
GMC Guy Registered User Join Date: May 2009 Location: Sparks, NV Posts: 913	Re: Replacing lower control arm it looks fine to me, that's how trimmed mine the second time. i'm running 3in drop spindles with 15in rims. and yes the 1/4 spacers did give me a little extra clearance. and even if you install them on the truck and need to trim a little more, just whip out the angle grinder. be sure to only take off little bits at a time. __________________ Greg 1974 GMC 1/2 Ton SWB Fleetside L33 5.3/4l65e .................__ ............._____l __\__ ..............l_(O)_ l___(O)]

02-03-2011, 01:32 AM	#24
78cheyenne292 Registered User Join Date: Nov 2010 Location: Tavistock Ontario Posts: 79	Re: Replacing lower control arm you asked if a 1/2 ton and 3/4 ton are different.. i have an 83 1/2 lca on my 78 3/4 its built a little diffrent but the truck sits level and it bolts up fine but the balljoints are thicker on the 3/4 ton but the 1/2 lca actually looks beefier could just be cause its a newer model

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