Upper control arms

[Julifin]

I’m buying new upper control arms for my 620. I found some new ones online but the new ones don’t have threading inside where the spindle screws in. But the old ones do. I guess I need to know why the new ones have no thread. Is it because they are torqued so high that it forces the spindles through and creates threads? And if so, should I get new control arms or can I use the old ones. 

[datzenmike]

 Perhaps your old ones are just worn. The UCAs have to be free to move while the upper link spindle is stationary. There are grease nipples on the ends of the upper link bushings that screw onto the upper link spindle.

[Julifin]

Thank you

[Julifin]

@datzenmikehttps://share.icloud.com/photos/0e2i6KfnGZWvCbrT1Gt_A9cjQ 

here are pics of what I’m asking about. The part on the yellow background is the old one. It has threads. 
The pic of the ad seems not to. 

[Crashtd420]

6 hours ago, Julifin said:

@datzenmikehttps://share.icloud.com/photos/0e2i6KfnGZWvCbrT1Gt_A9cjQ 

here are pics of what I’m asking about. The part on the yellow background is the old one. It has threads. 
The pic of the ad seems not to. 

Yes it needs the threads....

It almost looks like a protective sleeve inside but I can't tell for sure....

 

 

 

Better to be safe, just email the seller and ask...

 

Edited August 18, 2023 by Crashtd420

[Crashtd420]

What's wrong with your control arm... the threads dont look bad... maybe it's just not visible but I just see old dried up grease....

 

 

Edited August 18, 2023 by Crashtd420

[datzenmike]

I think that may be a bushing? Picture of the new one?

[banzai510(hainz)]

arent those a coarse shallow thread?

 

maybe the other part wore out I had to find spares for my 521 they where shot

Edited August 18, 2023 by banzai510(hainz)

[Julifin]

4 hours ago, Crashtd420 said:

What's wrong with your control arm... the threads dont look bad... maybe it's just not visible but I just see old dried up grease....

 

 

The threads on them are worn down. Almost nonexistent on other side. I sent email to seller. No answer yet

[datzenmike]

3 hours ago, banzai510(hainz) said:

arent those a coarse shallow thread?

 

maybe the other part wore out I had to find spares for my 521 they where shot

 

42 minutes ago, Julifin said:

The threads on them are worn down. Almost nonexistent on other side. I sent email to seller. No answer yet

 

It may be just grooved to spread and hold the grease. Not really threads just looks kind of like them.

[Crashtd420]

16 minutes ago, datzenmike said:

 

 

It may be just grooved to spread and hold the grease. Not really threads just looks kind of like them.

I never like to disagree with you but I believe they are actually threads.....

The part that threads in is torqued at a very high rate.... it move with the arm..... 

I believe it pivots on the cross shaft....

 

[banzai510(hainz)]

40 minutes ago, Crashtd420 said:

The part that threads in is torqued at a very high rate.... it move with the arm..... 

I believe it pivots on the cross shaft....

I like to know this myself as mine was worn out bad and had to calculate the movement as when it when up iarm  tighten.

 

on the lower below the king pin thos e2 big Caps that have the grease fitting on I seen mine wear threw the threads and had to get new ones. I never knew the torq value. or are those really just grease caps for that Fulcrum pin

Edited August 18, 2023 by banzai510(hainz)

[Crashtd420]

20 minutes ago, banzai510(hainz) said:

I like to know this myself as mine was worn out bad and had to calculate the movement as when it when up iarm  tighten.

 

on the lower below the king pin thos e2 big Caps that have the grease fitting on I seen mine wear threw the threads and had to get new ones. I never knew the torq value. or are those really just grease caps for that Fulcrum pin

Both the fulcrum and the upper inner have those big caps with grease fittings.. if I remember the torque is over 100lbs.... they lock onto the control arms.... the caps pivot on the fulcrum and the upper inner crossbar..

[Julifin]

2 hours ago, Crashtd420 said:

I never like to disagree with you but I believe they are actually threads.....

The part that threads in is torqued at a very high rate.... it move with the arm..... 

I believe it pivots on the cross shaft....

 

Yes, that’s it. It is torqued very high. The spindles actually screw in here. 

[datzenmike]

4 hours ago, Crashtd420 said:

I never like to disagree with you but I believe they are actually threads.....

The part that threads in is torqued at a very high rate.... it move with the arm..... 

I believe it pivots on the cross shaft....

 

 

Good enough for me. FSM says torque the 'screw bushing' to 253-398 ft lbs!!!! So it moves with the upper links, but the spindle inside must remain stationery bolted to the frame.

 

The spindle ends are threaded, so what does it screw into???  Seeing as the spindle is stationery and the screw bushing rotates with the upper links????? The spindle inserts into the screw bushing so what's inside it??? Is there a bushing in there that the spindle sits in and why there is grease???

[Crashtd420]

All I know is it is threaded on the inside of those spindle ends....

When I did my coilover conversion I had that spindle out with the two arms attached... 

You could screw the spindle in and out of those caps easily.... I actually found it easier to set the spacing to proper spec off the truck.... 

As long as the spindle ends are torqued you can rotate the arms screwing them in or out, one at a time to set it to the proper measurement and put the assembly back in....

I assume the grease is for the threads its rotating on....

[mklotz70]

I know this is an older thread.  This vid helps to explain the lower fulcrum pins and their bushings.  The "waves" inside the arm are actually threads. The "nuts/bushings" have a similar thread on their outside.  The inside of the nut is a coarse thread and it's actually the bushing surface for the fulcrum pin's threads.

 

[banzai510(hainz)]

soemone on here says these are same as 521. I had to sawzall mine out as they were stuck. Now Im out of spares.The end caps also.

 

https://mossmotors.com/661-900-pin-fulcrum-lower-link-outer.  end caps are different for this 300-6

[datzenmike]

The lower link is the same for 521 and 620 through '77 when everything changed for disc brakes

[mklotz70]

I'm nearly positive that the UCAs will interchange between the 520 and 521....even 620 king pin ones.  The 320 should work, too, but I don't remember if the towers are a bit narrower on the 320.  If so, the arms might be a bit narrower, too.  To be clear, it's the complete arm assemblies that will swap.  The nuts are shorter on the older(?) arms so the cross shaft is probably a bit shorter too.  

[datzenmike]

My info shows the right side 54533-20500 520/521 the same. The 620 ones are 54533-B5000 for the right side. On the books they don't show they interchange but we all know lots of parts will. 

[mklotz70]

Are those numbers for the entire assembly?  They'd have to be swapped as an entire assembly.  The mounting holes in the cross shaft maybe a different size on the 620 ones.  

[datzenmike]

No, only for one of the two on the right side for comparison of part numbers. I can look up a single part number and it will show me every Datsun/Nissan that used that part from mid '60 to mid 2,000s. Although they might fit it's not an exact parts match by the numbers.