Hot Rod Forum banner

offset a-arm shafts on LeMans?

1K views 8 replies 6 participants last post by  Bonneville462 
#1 ·
Last year I rebuilt the front suspension on my '67 Lemans while I've got it blown apart for engine and paint. I replaced all the bushings, ball joints, converted to disc brakes, stanhuff springs, del-a-lum upper bushings, etc. I also installed offset shafts on the upper A-arms, because the alignment shims were maxed out on the passenger side and none on the driver's side.

Since the offset shafts were 1/8" offset, I set the pass side inward and removed 1/8" worth of shim. I set the driver's side outward and added 1/8" of shims. Is this right? The difficulty is that the lower control arm bushings were wasted, so the LCAs were way out of position. The car also has a very slightly bent frame, the driver's side frame rail is about bent about 1/8-1/4" from an old rear end collision. I assume the insane shim set-up was due to the original LCA bushings being wasted.

Anybody want to hazard a guess as the best installation direction for these offset shafts? Basically, do I need to flip one over? It'll be a lot more difficult once I install the engine....
 
#2 ·
I'm not an alignment guy, so take this with a grain of salt... I would remove the springs and reassemble the front end without them. Block up the frame to the approximate ride height, and level it out as well as possible. No spring pressure will also make it much easier to remove or adjust your upper control arms. Reinstall the springs once you have made your adjustments. That should get you in the ball-park to see where you stand with all of your new parts. Final alignment after the car is complete and assembled.




Also, what did you use to convert to disc brakes up front? I have a '65 LeMans that I will be converting eventually.


Dave
 
#3 ·
It will never truly be right without having the frame straightened.....which should have been the very first thing you had done, before you even disassembled the car.

Should be an easy job for a frame shop.

One offset shaft flipped in and one flipped out is not the way to be correcting things, they are meant to be used with both flipped out., to counter the excessive negative camber these cars have.....they are not meant to correct for collision damage.

You building a nice car or just hacking a pile together for the dirt track??
 
#4 ·
Somewhere in between. It's a street/strip car with a lot of body filler. It'll run well and look good from 5 feet.

I tried to get the frame straightened but no body shop will touch it unless I bring a wheelbarrow full of money. Car isn't worth it, so hell with it.

So should I flip both of them outward and let it ride?
 
#5 ·
Of course you should have your frame straight, but as far as the front end goes if you can get the front sheetmetal aligned without resorting to anything too wacky, you'll probably get by. Do check for cracked welding and metal around the spring cup openings and where the crossmember portion of the frame attaches to the rails, looking from underneath. If there's any problem, you do have to fix that, whatever it takes.

Just stick the cross shafts in there however you think but punch the mounting studs back a half-inch first using a brass hammer or a piece of aluminum or something to protect the threads, this is to get them knocked back so the knurled portion of the studs is dis-engaged and I'm assuming you have the engine is out at that point. Fasten the cross shafts in without cranking them down and pulling the studs' knurled portion back in, and don't tighten the bushing fasteners either, just snug everything up w/ about 5 ft/lbs. Later with the whole car and engine back together, the lower a-arm bushing bolts loose and the ride height where you want it (if you needed to trim springs), AND BEFORE YOU DRIVE IT use a flat road surface and a carpenter's square to gauge camber and get it close enough to drive on (actually you can get it exact if you're patient). If you need to flip either of those cross shafts now it's easy, by supporting the car at or near the lower ball joint and pushing the cross-shaft studs back (not all the way out if you can help it), which you can do because you didn't tighten them back in all the way. Now you can manipulate the cross shaft around without having the exh. manifold or headers or whatever else tangling you up.

Don't screw around with that until you destroy the fit the knurling should have, try to go once-out, once-in, when you tighten the cross shaft studs it should pull the knurled portion back in to how they were before and you'll need to check tightness again after the first trip around the block in case there's any settling-in. If there's further fine-adjustment needed, hopefully you'll be doing it with just the shims now, the normal way.

If you or time and abuse have gotten the stud's knurling so screwed up that the studs just spin in their holes when you tighten the nuts, you can still get to them on the backside to hold them, using a u-joint socket and extension, but what a pain. Try to not have that happen.
 
#6 ·
Thanks guys, this really helps explain some things. Right now everything is installed and snugged up with engine out. What would be the best way to get the pass side loose to flip the pass side shaft outward? Do I need to compress the coil spring?
 
#7 ·
Crossmember SAG is what its called...

it comes from the leverage of the suspension pushing in on the top of the frame rail until the top is narrower than it should be... it was horrible in my 66 GTO.. i actually went to offset steel bushings produced by dick gulstrand..

years later.. i met a frame repair guru.. he showed me how to fix it.. i had him fix several of my cars..

i actually have done alignments as a tech back in the early 80s.. and actually have my own bender caster camber gauge and turn table plates.. i used to have a 4" W beam about 5 feet long.. it was leaning against the door frame in a former shop. i think a scrap guy took it.. W beams have wider top and bottom flanges than I beams. a 20 ton bottle jack.. or two.. some 4 or 6" square 1/2" thick plates to spread the load of the bottle jack top.. 2 sections of frame pulling chains with hooks on at least one end..

first step... lay fender covers across the fenders.. lay a 2x4 across the fenders directly over the upper control arms.. clamp or mount some fairly thick wire.. or welding rod... so you can measure around the motor and to the inside of the upper control arm mounting brackets.. outside of the shim packs if there are any.. 31 1/16" between the inside faces of the upper control arm mounting brackets..

if you have to bend the welding rod to get around the obstructions.. then carefully lift it off and touch a pre measured distance on the floor.

setting up... it really helps to have turn tables and wheel alignment gauges.. and a perfectly LEVEL place to work with.. you need to set both upper control arms with a minimum of 2 1/8" shims.. plus what ever you need to reach your caster.. even if the camber is way crazy..

make sure your car is level.. let a level across the core support or the cowl.

write down on the floor on each side... the exact measurements you get.. caster and camber.. jack front of the car up so there is at least 10 inches under the front tires.

check the alignment again.. make sure that you have jacked the car up and supported the frame at the kickouts under the passenger and drivers feet level. .. yes.. with the wheels dangling.. write the camber number next to the on the ground camber number. calculate the difference.. then figure out how much more you need to add to the first number to bring it to 1/2 degree camber positive left side and 1/4 positive camber right..

now.. remove the front tires.. loop the frame pulling chain middle behind the upper control arm shaft .. not pulling on the upper control arm. but pulling on the shaft and bracket.. hook the chain in a loop just off the ground.. you may need to unbolt the brake line brackets and move them slightly so you don't crush them..

slide the W beam thru both looped chains so its several inches off the ground. set the 20 ton bottle jack on top of the W beam.. directly under the cross member. place one of the square jacking plates above it..

look at the numbers you have calculated.. how far do you need to go.. which side gets more.. if you need to go more on one side.. put the jack slightly toward that side.. it will exert more force on that side.

you can start jacking.. doing it a little at a time watching the camber change on gauges.. warning it will spring back.. you don't want to go too far..

what are we doing.. put your arms straight out to the side from your shoulders.. bend your elbows so your forearms point straight up like you were flexing your arm muscles. now.. move your wrists outward slightly.. that is what you are doing.. spreading the top of the frame..

things you don't want to do.. you don't want to get the chains behind the upper control arms.. or over them.. if you pull on the arms at all.. you are going to be pulling really hard down.. you will usually pop the lower ball joint out of the lower control arm. i have seen it done..

you can.. use all thread with stacks of various sized washers thru the shock hole to hold the suspension at ride height.. while its up in the air.. gives you a better idea of what you are doing.

if you don't have wheel alignment turn tables.. you can make your own..

1 in. Roller Ball Bearing mount some of these to the bottom of a piece of 3/4" plywood.. if you have a perfectly smooth concrete floor without paint.. they might ride directly on the floor.. if you use some 12 gauge steel sheet metal.. they will roll really easily on it. allow the tires to move in and out easily.. turn left and right effortlessly.. you do have to build plywood spacers to go under the rear tires that match these fronts in height.. do them in a circle pattern.. use at least 8 on each piece.. there are 5/8 versions but they hold less weight.. so it would take more to support your car.

more measurements.

not nearly as important.. but worth checking..

between the inside of the frame rails below the lower steering box mounting bolt and where the idler arm bracket mounts. 28 1/8"

outside of the frame rails where the front bumber brackets bolt on.. 35 1/2"

i don't know if these grade 43 chains are strong enough.. 3/8 in. x 14 ft. Grade 43 Towing Chain it will take 2..

i think my frame pulling chains were grade 70 3/8"

i hope this helps.. i used to do these in my driveway.. probably took me 2 hours to set up and pull them. on a frame rack as my friend(RIP) would let me use his frame rack.. i could do it in 45 minutes.

2 to 2.5 degree negative caster... right 1/4 positive camber left 1/2 camber .. depends on the crown on the streets. i would fine tune the front toe in by having a friend drive the car down the block toward me as i worked the tie rod adjusters. so i could get almost perfect toe in. the gto was so perfect.. i could push it easily with one hand when i was done.. i have seen small cars that took many times the force to push..
 

Attachments

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top