LCA rebuild

Mattias · Aug 19, 2019

Hi,
I’m planning to rebuild the LCAs. I think I will go for the P.S.T ”deluxe” rebuild kit with stiffening plates and polygraphite bushings.

My question is:
There is some play in the inner ”sleeve” where the pivot shaft is installed. The play is between the ”sleeve” and the two LCA halfs that is riveted together. I guess the axial play will be fixed when I weld in the stiffening plates but what about the radial play? Is it normal with radial play in this position? Will this be rigid anyway once the LCA and torsion bar is installed?

/M

Jerry Hall · Aug 19, 2019

If I am understanding you right, that should go away with the new bushings.

wahya · Aug 19, 2019

My neighbor is hopefully rebuilding most of my front end on Saturday. I've had a set of lca's for a couple of months now and for one reason or another, the rebuild has been delayed. Neighbors shop is closed Saturday, so hopefully it will get done before the rain starts,as his lift is outside.
The pivot shafts were fairly sloppy feeling, but since installing new pst shafts and rubber bushings, they feel better,but not perfect. There is just a bit of what you described outside of the "sleeves" like maybe less than a sixteenth of a inch. The halves are not tight on the sleeves either. My neighbor (mechanic) says that once the arms are installed and pressure put on TB's it will be fine and he doesn't think I should bother with welding the plates on,since I don't race the car, I won't be able to tell the difference. I'm hoping he's right, because I have the plates, just not sure I have enough of a welder.

Mattias · Aug 20, 2019

Jerry Hall said:
If I am understanding you right, that should go away with the new bushings.

Sorry if my explanation was unclear. I’m afraid the play I tried to describe is not going away by change the bushings. In the pics you can see the part I describe as ”sleeve” for the pivot shaft. This part is not tight in the control arm...

Mattias · Aug 20, 2019

wahya said:
My neighbor is hopefully rebuilding most of my front end on Saturday. I've had a set of lca's for a couple of months now and for one reason or another, the rebuild has been delayed. Neighbors shop is closed Saturday, so hopefully it will get done before the rain starts,as his lift is outside.
The pivot shafts were fairly sloppy feeling, but since installing new pst shafts and rubber bushings, they feel better,but not perfect. There is just a bit of what you described outside of the "sleeves" like maybe less than a sixteenth of a inch. The halves are not tight on the sleeves either. My neighbor (mechanic) says that once the arms are installed and pressure put on TB's it will be fine and he doesn't think I should bother with welding the plates on,since I don't race the car, I won't be able to tell the difference. I'm hoping he's right, because I have the plates, just not sure I have enough of a welder.

Thanks for your reply.
I hope your mechanic is right about that this radial play will stiffen up when the torsion bar is installed. Anyway I don’t like to leave a part without action when I’m not sure it’s 100% good...

Jerry Hall · Aug 20, 2019

Mattias said:
Sorry if my explanation was unclear. I’m afraid the play I tried to describe is not going away by change the bushings. In the pics you can see the part I describe as ”sleeve” for the pivot shaft. This part is not tight in the control arm...

View attachment 820834 View attachment 820835

And it won't necessarily be tight until tension is applied to the torsion bar. Some will be tighter than others, but that has to be able to move freely. If it doesn't you are subject to front end squeaks.

wahya · Aug 20, 2019

Think I'm probably going to go with it the way it is.

hunt2elk · Aug 20, 2019

wahya said:
View attachment 821067
Think I'm probably going to go with it the way it is.

As long as you are at this stage, why wouldn't you weld on the plates? Very easy and makes the lca nice and solid. I put them on all my cars.

wahya · Aug 20, 2019

hunt2elk said:
As long as you are at this stage, why wouldn't you weld on the plates? Very easy and makes the lca nice and solid. I put them on all my cars.

Point taken. Does clamping down on the lca halfs get rid of the lateral or sideways motion of the pivot without pinching down on the adjusting blade.

hunt2elk · Aug 21, 2019

wahya said:
Point taken. Does clamping down on the lca halfs get rid of the lateral or sideways motion of the pivot without pinching down on the adjusting blade.

Yes. You will want to put them in a vice and lightly squeeze the 2 parts together. Remove as much slop as you can without getting any binding. Start by tacking one side and then the other - back and forth while checking movement of the arm before welding solid.

wahya · Aug 21, 2019

These two arms are slightly different in the amount of pivot movement and the spread. I bought the pst kit, which included the torsion adjusters. The right arm, which has more movement,accepts the adjuster easily. The left arm adjuster is tight and wont fit unless I force it, which would also tend to spread the halves apart very slightly. If I clamp (with a welding clamp) at the point just above the adjuster on the right arm, the amount of movement in between the two pivots is almost identical. Wondering if I should grind a little off one of the adjusters, so it will not bind in the left arm.

Mattias · Aug 21, 2019

hunt2elk said:
Yes. You will want to put them in a vice and lightly squeeze the 2 parts together. Remove as much slop as you can without getting any binding. Start by tacking one side and then the other - back and forth while checking movement of the arm before welding solid.

Are you doing anything to the radial play or do you leave it as is?

Jerry Hall · Aug 21, 2019

Mattias said:
Are you doing anything to the radial play or do you leave it as is?

Do as said, and use them. The pictures you posted with the new bushings installed look good. I think you are making this harder than what it is. Please don't kill it by over thinking.

Wietse · Aug 22, 2019

Mattias said:
Are you doing anything to the radial play or do you leave it as is?

My LCA arms had the same radial play, all of them will have it.
As far as i could see there is not precise machining done on both parts.
The 2 plates that make the arm are stamped, hole punched so there would have never been a nice "tight" radial clearance.
As the guys mentioned, when welding the reinforcement plate on clamp the end in a vice to remove some of the axial play.
I only clamped it slightly and left most of the axial play as i did not want to distort the arm too much.

Mattias · Aug 22, 2019

Wietse said:
My LCA arms had the same radial play, all of them will have it.
As far as i could see there is not precise machining done on both parts.
The 2 plates that make the arm are stamped, hole punched so there would have never been a nice "tight" radial clearance.
As the guys mentioned, when welding the reinforcement plate on clamp the end in a vice to remove some of the axial play.
I only clamped it slightly and left most of the axial play as i did not want to distort the arm too much.

I will do as you say...
Thanks!
/M

Wietse · Aug 24, 2019

Did you make any progress?
Not sure if you already ordered the parts, but when i was doing this some recommended to stay with an OEM style rubber bushing for the LCA.
This is due this bushing gets a lot of pounding to handle, therefore you are getting some cushioning from the rubber instead of a near solid polygraphite.

Mattias · Aug 25, 2019

Wietse said:
Did you make any progress?
Not sure if you already ordered the parts, but when i was doing this some recommended to stay with an OEM style rubber bushing for the LCA.
This is due this bushing gets a lot of pounding to handle, therefore you are getting some cushioning from the rubber instead of a near solid polygraphite.

I’ve ordered the parts but not received them yet. I red your thread before ordering but decided anyway to go for the polygraphite. I prefer a more firm ride before comfort. Hope I did the right choise, it will take some years before I know the answer...
/M

66 Sat · Aug 25, 2019

Don't worry, you made a good choice. I went with the PST deluxe polygraphite and the car rides great with no squeaking. I think the higher sidewall with small diameter wheels on these old cars gives a lot of cushioning. My Plymouth rides way better than my modern car. I was also worried about the play in the LCA's but the clamping/welding removed some, and once it's all in place with the torsion bar it isn't a problem. Call it 1960's production tolerances...

Islandkent · Aug 25, 2019

What did you use to get the cosmoline look? Paint?

66 Sat · Aug 25, 2019

Islandkent said:
What did you use to get the cosmoline look? Paint?

It's Dulux Metalshield, Hammered Finish, in Bronze. I bought a tin and sprayed it through my spray gun, but it comes in a spraycan as well. It wouldn't satisfy a concours judge I'm sure, but it looks pretty good to my eyes.

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