Jump to content

Upper control arms


Julifin

Recommended Posts

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. 

Link to comment
  • Replies 20
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

 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.

  • Thanks 1
Link to comment
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....

 

Screenshot_20230818-081541_DuckDuckGo.thumb.jpg.38004228e4e2423436d35f9b3cb88950.jpg

 

 

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

 

Edited by Crashtd420
Link to comment
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....

 

 

Screenshot_20230818-081528_DuckDuckGo.jpg

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

  • Like 1
Link to comment
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.

Link to comment
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....

 

  • Like 1
Link to comment
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 by banzai510(hainz)
Link to comment
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..

  • Like 1
Link to comment
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. 

  • Like 1
Link to comment
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???

  • Like 1
Link to comment

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....

  • Like 1
Link to comment
  • 5 months later...

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.

 

  • Like 1
Link to comment

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.  

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.