Today's episode of the Great outer Pin Repair

[StudeRich]

Thanks much, 55prez and Alan for all your help. We borrowed a new Chuck Collins repro spreader tool from another SDC member and replaced the upper and lower outer pins on my '59 Lark VIII, actually they are going on the '59, but they are '61 Lark King Pin/A arm assembies that were already rebushed on the inner ends. I am aware that I will need to align it with close to 0 degrees instead of -2 1/2 caster with the late style king pins.
But here is the problem...the spreader holds the top of the A arms, but under what must be 250-300 ft.LBS of torque it takes to really force those outer pin caps to thread all the way flush with the A arms, the bottom pinches in .030 to .100 thou, when it should hold .015! The repair manual shows the spreader mounted on top of arm, so we mounted it there and spread it to 2.750 + .015 and wrenched away on those caps, a little at a time on each end. They are unbelivably hard to drive in. The result was that there may not be enough room to move the K/P to read 0 degrees to -1 1/4 to align it. I can see those grease seals being really flatened if it will even go that far. It would be way worse on a pre '61 where it requires up to -2 1/2 degrees caster! Has everyone who does this right had to fight this hard to do it? exhausted and dissapointed - Rich.
PS almost makes you want to put one O-those cheeseball pinto front ends in! [xx(]
quote:
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Originally posted by Alan

2.750" or 2 3/4"

added by Richthis is the correct spread of the outer end of the '51-'66 upper & lower "A" arms.)

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StudeRich
Studebakers Northwest
Ferndale, WA

[wagone]

Hey StudeRich, I've been reading these threads with interest and yesterday measured my Avanti outer top a-arms. One of mine is 2.650" and the other 2.690" (both plus or minus .003" or .004"). So I'm very interested as to what others have to say about this. On the one which is 2.690" I installed a new pin and bushings about two years ago and until now I didn't know that the measurement was supposed to be 2.750"....so I just tried (without the J2044 tool, or whatever the number is) to hold the plus .015" measurement. So the question I have is how to bend the "ears" on the end of the a-arm and can they be bent that much without damage (.050 to .100")? This appears to be a VERY critical process in doing front end work and I would love to see a poll of Stude owners as to the measurement on their cars. How many have been screwed up by sloppy mechanics at some point in the past? The lower is also to be 2.750" but it appears nigh on to impossible to measure the lower with the suspension on the car. Comments, guys, please!

wagone and the R2 Avanti

[64V-K7]

The important thing is that, in operation, the pin and cap bushings do not turn in the ear of the control arm, as one unit. The force required to achieve the specification torque has to vary. New arm = x, old arm = y ( if you follow the original threads), old arm =Y+x ( if you're cross threading the old install, etc

The spreader tool creates an artificial barrier to torque the cap bushings to. It combines the inner ramp of the pin threads and the resisitance of the outer bushing, in the ear, to satisfy the torque requirement. Once both caps are tight, the spreader is released and resulting movement frees the ramp of the inner pin threads from the torque (and bushing threads). This is what allows the pin to turn, inside the bushings.

If the spreader isn't used, the cap bushings are then torqued to the pins. In this case, the up/down motion of the suspension can only work if the rotation of the pin is translated thru the bushings to the arm. This would force the cap bushing to turn inside the ear and shortly wear it out.

[Alan]

You tell em Prez, When I measured the 2.750 I have 2 NOS still in Stude boxes arms and 4 used ones. they all measured 2.747-2.753". 2.750" plus or minus .003" now over the years things could have been crunched, banged or maulled to change the specs. On one of the used lower arms I have it is almost 1" tighter on the inside where the rubber bushings are where it appears that someone used a press to get the bushings in or out and didn't use the tool to keep them spread.

[StudeRich]

WOW thanks a lot 55Prez; that's a little deep, but I think I get it.[^] It's all about transfering the stress to the arm and not between the bushing caps and the shaft. I have aligned these myself and remember (it's been awhile) that it was not hard at all to turn the shaft (pin) with the small allen wrench.
Maybe the dimension at the end of A arm and bottom are not that critical, and they will be fine at .030 and .100 under the 2.750.
Or, I could back the bushings out, risking galling the arms too much and making the fit looser when I force them back in with a little more spread so they spring in closer to 2.750 when done. This probably would not ruin the arms THIS time, but it would be the last time!

quote:Originally posted by 55Prez

The important thing is that, in operation, the pin and cap bushings do not turn in the ear of the control arm, as one unit.

StudeRich
Studebakers Northwest
Ferndale, WA

[wagone]

StudeRich, I'm a little confused by your most recent post. At first you appear to say that your arms are OVER the 2.750" (and mine are UNDER)--but then later in your last post you seem to be saying that were you to take them apart again you might be able to get "them to spring in closer to 2.750"." I'm wondering how they might get spread apart to more than 2 3/4"? When turned with an allen wrench mine rotate easily enough, but I might try and find four arms close to 2.750" and redo the whole thing with all new parts (at least the parts that can still be purchased new). On closer read your statements do coorelate, I'm just wondering how they would be spread apart--I can see closing when the bushes are pulled in during installation if J-2044 is not used.

wagone

[StudeRich]

Wagone, you are right I changed it to say "UNDER".

Thanks, Rich

StudeRich
Studebakers Northwest
Ferndale, WA

[sbca96]

Anyone have a picture of where they are measuring at?

Tom

[StudeRich]

Tom; the shop manual shows it being measured on the end of the arm at just above the pin on the uppers and at the centerline of the pin on the lowers. They measure the outside, but we have been going from the inside measurement that Alan gave us, which is very consistent with everyone's NOS arms. Too bad the manual does not state the actual dimension. I guess they knew it would vary a bit, so they went with something like: "spread it .015 from where it was".

Update:Added 3:56PM PDT I tried measuring the OUTSIDE of my upper A arms like the manual and came up with 3.475 and 3.490 these are the original "build", I have not removed anything since we rebuilt them yesterday. I think they are supposed to be 3.500 but no way to be sure, since there are no specs. That does not sound so bad though
-.010 and -.025 maybe I should just "GO FOR IT" and throw it together like the alignment/front end shops probably did, I gotta be closer than them if they never used the spreader!!![^][:0]
Rich.

quote:Originally posted by sbca96

Anyone have a picture of where they are measuring at?
Tom

StudeRich
Studebakers Northwest
Ferndale, WA

[gordr]

For what it's worth, I have changed the outer bushings before without a spreader tool (didn't have one, do now). I have never experienced the binding problem, where the bushing cap seats on the pin. But I was always VERY careful to try to make the new bushing line up with the "threads" in the arm itself. If that is done, the bushing will usually screw in quite easily.

I have seen them become so loose in the arm that they have been tacked in by a little weld, either by myself or a previous worker. Not a recommended procedure, but it can get you by until a proper front end rebuild can be done. Less call for that sort of thing now, but when Studes were being used as daily drivers by relatively poor people...

The shop manual assumes that the work is being done in a well-equppied dealer shop with an ample supply of new parts and all the special tools. It tells you the "right" way to do things, but it does not tell you what you can get by with when resources are scarce. (Nor should we expect it to.)

Gord Richmond, within Weasel range of the Alberta Badlands

[wagone]

It is now past 11 pm here in the midwest. Tomorrow I intend to measure the outside of my a-arms as StudeRich has done and report back on this thread with my measurements. I'm hoping that we can generate some discussion on what minimum dimensions might be encountered and not expect to have a problem. As has been stated earlier, neither StudeRich nor I have any frictional or binding problem with the pins when turning them with the allen wrench as one would when doing the caster/camber alignment. Is that a fair assessment as to whether or not a problem can be expected between the male and female threads of the pins and bushings? It would appear that being able to turn the pin without binding would indicate that alignment (pin and bush alignment--not suspension alignment)is pretty good--assuming no appreciable wear of the threads that is. As stated earlier I replaced one of my outer upper pin and bushings about two years ago and that a-arm measures 2.690" (1/16" approximately under spec)--replaced with NEW parts. I have no binding when turning that pin with an allen wrench. The other side (left in this case) is 2.650" and the pin doesn't bind in that one either but there may be a fair amount of wear in that pin and or bushes. I replaced the right upper pin and bushes because my suspension had (still has) a knock somewhere and the washer type "gaskets" at that location were SHOT--funny thing is that pin and bushes (the threads) do NOT seem unduly worn. Anyway, I'd like comments (and perhaps StudeRich would also--after all this is his "thread") on any of the above. Thanks.

wagone and the R2 Avanti

[Mike]

Comments:
I have a couple of used pins from a '57 Hawk. I think they are original Stude parts.
The grooves on the outside of the caps are definitely spiral threads; not just parallel ridges.
I counted the number of threads on the outside of the caps, and on the pin. There is the same number of threads per inch on both. I had half expected to find divergent threads; but that is not the case.
The cap has to enter the "A" frame at the same rate as it screws onto the pin. I guess the spreading tool is just to keep the "A" frame from deflecting; as the threads on the pin pull the cap into place.
Is it possible to make the joint bind, and maybe not take grease, by tightening the caps so they pull against each other, on the pin. The .015" preload from the spreader would make that worse. Backing off one cap may help.
Mike M.

[wagone]

Mike M. But backing off one cap or the other (or both I suppose) would make it (them) short on torque, wouldn't it? We (I, at least) need an expert. AND who do you trust as an "expert" after 40 plus years?

wagone

[studegary]

quote:Originally posted by wagone

Mike M. But backing off one cap or the other (or both I suppose) would make it (them) short on torque, wouldn't it? We (I, at least) need an expert. AND who do you trust as an "expert" after 40 plus years?

wagone

40 plus years ago, I was working full time in a garage that actually fixed things like front ends and rebuilt engines, but my memory doesn't lend anything to add to this thread.

Gary L.
Wappinger, NY
1954 Commander Starliner (restomod)
1959 DeLuxe pickup (restomod)

[Alan]

Rich, I measured the outsides of the 6 I have around here the measurements were all over the place, between 3.480-3.525" the cover of the arm that the pads are spot welded to tapers and at the end where you would put the spreader is the most bent out of shape. Since there is no hard and fast diminsions in the Stude shop manuals I would say you are trying to make a mountain out of an a-arm.