Im in the process of rebuilding the front suspension of my '47. The front lower A arm bushings at the mounting shaft are very difficult to install. The removal of the originals was hard, but I did get them out using an impact gun. I notice that there is not alot of thread depth on the bushings or the arm itself. They are a course thread but not much "bight" to them. The old bushings on the left, of the 1st photo,both have what appear to be crushed or stripped threads on the center of each of the flats of the nut ends. (The new ones are on the right). I think if they stripped, the threads would wrap around more & not just in the center of the flats of nut. The lower bushing of the knuckle support in photo 2, has the same crushed pattern yet it threads back in easily. None of the threads that these bushings go into appear stripped (photo 3). There were no metal particles that came out with any bushings either. I have the torque specs, 200 ft lbs for the arms & 150 for the knuckle support. Are these supposed to be this tight going in? I tried to assemble them with a breaker bar & socket but it just dosen't seem right that they are so difficult when barely half way in. Thanks,Bob.
Not sure why the photos didnt post, they were uploaded. I'll try again.
The 3rd photo is of the threads in the A arm. They aren't stripped.
Hi Bob, The threads on the inner lower A arms are just for locking the bushing to the arm, kind of like a threaded interference fit. The inner treads that go on the shaft have to match at both ends so the outer ones are not really threads like a bolt but rather a way of securing the bushing in the arm. You still twist it in but that"s about it. I hope this helps you , Tim
Hey Bob,
Tim is correct. I've done this on my 56, which is nearly the same design as yours, just the upper arms are a slightly different shape.
These are the same design as what GM used on their trucks when they went to an independent suspension.
The nuts thread onto the shaft, but are an interference fit in the arm itself.
What you want to do is to start both sides by hand so that one will hold pressure for/against the other. Mount the shaft in a vise so it can't rotate, then using a wrench, (not sure the exact size), or you can use a large Cresent wrench that will fit it, and turn each nut, alternating between the two, until they are both in place. The shoulder of the nuts, just below the hex, should be against the arm at this point.
You should be able to rotate the shaft once the nuts are installed. Rotate it all the way into one of the nuts, then counting the turns, rotate it back into the other nut. Then rotate it half way to center it in the arm. (It may not come out exactly centered once you turn it so the mounting ears are in the right place, (if they are not symmetrical), but this will help when it comes time for an alignment. You can affect the caster adjustment with the shafts if they aren't centered. If there's not enough room for adjustment in the normal places, then it can be augmented with the shafts if they'll turn far enough.
I've never had to try this as centering them beforehand has always worked for me.
Another tip, if the nuts don't turn with just your wrench, use a cheater pipe over the end of your wrench.
Hope this is helpful, and good luck with your project.
Rick
Thanks guys, I appreciate that. I did get them about ½ way in. I thought it might be esier to tighten them after mounting the arm back on first, since I have to get to 200 ft.lbs. plus I already painted them & would like to avoid scratching them, if I can. But based on your experience, if you think putting them in a vice is best, I will heed it! Let me know what you think.
On a side note. I instslled the bushings in my knuckle, then realised my king pins didnt fit! I looked on you tube about replacing king pins. Truck bushings are reamed so they are perfectly centered. I made a few calls to a couple of long time Cadillac owners, & to my surprise, none have heard about reaming them. I thought about trying to do it myself, but I didnt have the tool & didn't want to try with a hone or flap disc in my drill. I knew they probably wouldn't align well enough.
I brought them to a local truck repair shop & for $40 bucks, the guy was happy to help when I told him it was for my '47 Cadillac ! They fit perfectly! I appreciate the help.
Bob.
Hey Bob,
You can also install it on the car first if you want to do it that way. I have myself. I just found it easier to tighten the nuts using a cheater when it's in the vise. Plus then I can center the shaft before I mount the arm on the vehicle.
If you mount it first, then tighten the nuts, if the shaft is not centered, you wouldn't know it unless you dismount the arms and check. It is possible for one nut to push the arm over the other nut if the second one has enough wear in the hole it goes in. If this happens, the nut can bottom out on the shaft, and you could possibly crack the end of the nut, which would cause a grease leak when you lube it. If that makes sense to you.
But that's just how I do it. There's no set method, and maybe someone else has another way that works for them.
Just be careful if you do it on the car. There's less room to work in, and you'll have the car on jackstands most likely.
Rick
Yes Rick, I do have it on jack stands & am a little leary about that. I'll heed your advice & do it in my vice. Thanks for the help! Bob.
I know that when I was installing the new shafts and nuts on my truck, it definitely took more than 200 foot pounds to get them all the way in.
I have noticed that on arms that had the shafts replaced at least once before, it was a little easier to tighten them.
But I use a 4 foot long pipe that fits over the end of my largest crescent wrench when I do these. It's just easier for me that way. Too many back surgeries to mess around with short wrenches, lol!!
Good luck with your repairs.
Rick
Hi Rick, I have some more questions for you, if you don't mind. The arm is in and my next task is to install the coil then knuckle & support. My 1st photo is my new lower bushing & threaded pin on top of a copy of the exploded diagram from my master parts book.This diagram & the similar photo in my shop manual,show the interference bushing is threaded into the steering knuckle support from the front, with the threaded pin & washer screwed in from the rear. See the arrow to the text in photo 2, which instructs to do the same. Now my question is, does it really make a difference if the order is reversed? The next photos show my disassembly of these parts the other day. They were clearly in the reverse order from the manual, with the nut towards the rear & the threaded pin going in from the front. The front passenger side is the same. I drove this car when I first got it about 20 years ago, but I stopped because the insulation on the wiring was crumbling off everywhere. I didn't notice any issues with the steering at the time & there is a lot of grime underneath to show it has been this way for many miles. Thanks for your time, Bob
This last photo was not uploading.
Hey Bob,
I looked at mine when I got new parts for it as well trying to figure out which way it went. The book says the shaft goes in from the opposite end as the large nut does, and I had to think about why, because they don't mention the reason. What I came up with is this, if you install the shaft from the same side as the large nut, then your locking nut is free to come off the threaded end of the shaft with nothing to stop it except for the lock washer.
If you put the lock nut and washer on the shaft first, then install it from the opposite side as the large nut, if the locking nut should ever loosen up, it cannot come off the end of the shaft.
Plus, if the shaft were to be installed from the same side as the large nut, then only a small part of it is going through the opposite side of the arm where the lock nut would be. Once the lock nut comes loose or even off of the shaft, that shaft only has to turn a small amount before it comes out of that side of the arm.
Whereas when it's installed from the opposite side as the large nut, if the locking nut were to come loose, then the shaft would have to turn much farther before it ever comes out of the larger nut, much less the arm itself.
I think I explained that correctly. Does this make sense to you?
Rick
Hi Rick, I'm not quite sure what you mean to install the loch nut first? Mine are installed in the same order as the parts book shows in the first photo, it's just that the order is 180° from the book. The photo from the shop manual does not show the bushing unfortunately.
Hi Bob,
I'm going out to have a look at my control arms to verify something before I go farther into this.
Get right back to you soon.
Rick
Ok, I see where I went wrong with my thinking on this.
That larger nut doesn't actually pass through the lower control arm, it's threaded directly into the knuckle, and your threaded shaft then passes through both, going through one side of the arm first, then the knuckle, and then out the other side of the arm. Then you install the lock washer and locking nut to keep everything in place.
From appearances, I guess it wouldn't matter from which side you install the shaft. The only consideration that I can see is how easy it is to get to the fitting to lube it once everything else is installed and in place. The steering arm might get in the way, that's the only thing that I can see.
Well, other than maybe when an alignment is being done, it might be helpful if the hex end of the shaft were on the rear just because the Technician would be working from that side to adjust the toe-in and camber and caster. That's the only thing I can think of Bob.
Maybe it was easier for the last person who had replaced those to install it opposite from what the book says, or they just didn't care. Who knows?
I hope that clarifies things some.
Rick
Ok, I was thinking thet too. As long as the components are in the correct order it probably won't matter. It might be the case of the mechanics that actually worked on these cars found it a bit better to do it this way than the engineers upstairs doing it on paper. I appreciate your time & patience with me! Thank You, Bob.
Is yours done the opposite way, or as the manual says? Just curious.
Mine isn't all together yet. Only partially assembled so far. I've got another set on the car just for now so I can move it around when I can get to work on it.
I'd have to look at my other 56 since I haven't touched it yet. But that would be later today.
I've got a few things to do in town this morning.
Once I get a look at it I'll let you know what I find.
Glad to help.
Rick
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Hi Bob, Rick, So here is one thing I found when dismantling my 46 front end. Everything was 180 out from the shop manual. Even the upper arms/shocks were flipped right for left! I think that maybe something was going on at the assembly plant at Cadillac as I have heard this story before. Tim
Hi Tim, thats interesting. Were you having issues with your front end, or is she just in need of some new parts?
If these cars could talk?
I guess it doesn't matter much which direction it goes back together, as long as the parts are in the correct order.
Hey Bob,
I'm still in town, having lunch, and I was just looking at the pictures you posted, and on the second one it looks like the shaft is installed from the front. The picture in the book also appears that the shaft goes in from the front.
Were the grease fittings in the front before you started on this?
The fitting is on the "head" of the shaft from what I see in both pictures.
Are you trying to put the shaft through from the rear instead?
You are right, from what I can tell, it doesn't matter which way it goes in, as long as it's all there.
Just curious, I'll still check my other car.
Rick
I think what would matter more is which way you install that large nut, or bushing I think they are calling it.
The book shows that part going into the knuckle from the rear. Why that would make a difference is because of the thickness of the hex part of it. Installed the other way and it shifts the knuckle to the rear, adding a lot of caster to your suspension.
What do you think?
Rick, I see your phone # in the directory here. Would you mind if I call you?
Bob,
Yes, if you'd like to call that's fine.
But I think the number listed is wrong now. If it's a 520-307 number, it's wrong.
Email me if that's listed in here, and I'll send you the correct number.
Rick
I was having my upper arms/shocks rebuilt as one was in need of replacing because of structural damage and the other just leaked badly. When the rebuilder said my right shock wasn't repairable we got into a hot discussion as to which was the right and left as the left/drivers side was the one that flopped and rattled for years and he kept calling it the right. Then he showed me the part numbers and we came to agree my car was assembled backwards. Tim
Hey Bob,
I was out back of the garage yesterday and took a look at both the 55 and the 56 parts cars, and they both had the pins installed from the front with the grease fittings in front.
Sorry I didn't get back to you sooner about this, I just happened to remember to look when I saw the cars.
Rick