Suspension bushings

[jframe]

I am wanting to replace the bushings on the strut rods on my 65 than run from the lower control arms to the front of the frame. Will the car need a new alignment if we take these loose for replacement? Prolly going to replace the sway bar end links and frame bushings too, but that shouldn't be an issue.

[KongaMan]

Yes, you'll need an alignment, as you will be moving the lower control arms.  Since you'll have the reaction rods loose, it would also be a wonderful time to replace the lower control bumpers if needed. 

[RockinRiviDad]

I’m no mechanic like some of these guys. So please correct me if I’m wrong.

 

When I researched wheel alignment details for my 65 I was told to have the shop give me as much caster as possible. The shop couldn’t give me as much as I had hoped for. But they did said that the only way to get more caster would be to have a machine shop cut more threads into my brake reaction bars (strut rods). 

 

So, if that’s true, maybe u can add that to your list haha

[KongaMan]

That's not quite true (although it would work).  You can also trim the rear reaction rod bushing.  Either of these methods would pull the lower control arm further forward.  The risk with trimming the bushing or cutting more threads is that if you pull the control arm too far forward, it may bind or be cocked.  Perhaps more elegantly, you can also move the upper control arm shaft off center so that the upper control arm is positioned a bit rearward.  I calculated this out once, and one rotation of the shaft will give you something like 1.5-2° of extra caster.

 

But if I were tearing into the front end of a car that was presumed to still have the original components, I'd put a compressor on the spring in order to change the LCA bushing (cheap and easy) and check the ball joints.  And if I'd gone that far, I'd think seriously about taking the opportunity to change springs if needed.  Don't swap stuff just to swap it, but if it's the original bushing, it's a good bet that the rubber has degraded over the last 50 years and is no longer working as intended.  You might get lucky on the ball joints, but new lowers (which are more prone to wear) are readily available and easy to change.  The uppers are a little more dear and a bigger PITA to change, as they're welded to the control arm.

[EmTee]

There you go again -- giving that mouse a cookie!  

[telriv]

When I want more positive caster on full size Buick's & Rivs. that have the strut bar.  I ALWAYS use the poly bushings & remove about a 1/4" from the rear bushing. Been this way on my '64 Riv. now for about 30yrs.

 

 

Tom T.

[KongaMan]

27 minutes ago, telriv said:

When I want more positive caster on full size Buick's & Rivs. that have the strut bar.  I ALWAYS use the poly bushings & remove about a 1/4" from the rear bushing.

 

But again, that's something of a kludge that potentially upsets the alignment of the lower control arm.  When you trim the bushing, it pulls the arm forward.  This cocks it a bit around the bushing, which means that there are now lateral forces on the bushing.  This would tend to distort the bushing.  If you spin the upper shaft and move the upper arm back, the lower arm stays on axis and uncocked.  It seems a better approach, as the components remain aligned as intended.

[telriv]

I appreciate your thoughts, BUT it's been like this for 30yrs. & 100K miles with NO adverse affects that I can tell. Maybe it has something to do with the bushings being original with over 300K on them???  Look at how much the lower control arm moves when braking kinda hard in forward & reverse. IF IT AIN'T BROKE WHY TRY & FIX IT & MAKE IT MORE COMPLICATED THAN IT HAS TO BE???

I know you'll have something to add.

[KongaMan]

Well, if you've got 50-year-old bushings, they're probably not up to snuff in any circumstance, irrespective of maintenance. ;) Rubber deteriorates over time.  These bushings aren't immune.  Would you drive on 50-year-old tires?

 

And yes, it's true that that the control arm moves during braking (that's why the reaction rod uses bushings).  However, it's also true that there's a lot more rotational movement on the bushing in the normal course of driving than there are lateral movements from instances of hard braking.  As such, the aggregate effect constant off-axis rotation might be more damaging than the occasional hard pull.

 

Finally, I'd suggest that it may well be easier to rotate the upper shafts than to trim and swap reaction rod bushings.  We're talking about removing two bolts, spinning the shaft, then tightening it back up.  Besides, one might posit that this not more complicated, but better.

[1965rivgs]

On 5/31/2018 at 10:00 PM, jframe said:

I am wanting to replace the bushings on the strut rods on my 65 than run from the lower control arms to the front of the frame. Will the car need a new alignment if we take these loose for replacement? Prolly going to replace the sway bar end links and frame bushings too, but that shouldn't be an issue.

  That depends on where the alignment is before you replace the bushings. If your car`s alignment was previously where it should be when the bushings were good, and as a result of wear and tear the bushings have worn out, then replacing the bushings will simply bring the alignment back to where it was before. The earlier strut rods have a nut and cotter pin which would imply adjustability but the nut on the `65 rods, when removing and replacing, are simply retightened to a certain torque spec, preloading the bushings, to the same position on the rod. So if the alignment was where it should have been previously when the bushings were sufficient then replacing the bushings should simply bring the alignment back to where it was.

I have replaced dozens of sets over the years, mostly due to pulling to one side or the other during hard braking, and as long as there were no issues encountered during the road test after I left the front end adjustments alone. If one wanted to be very thorough an alignment check might be advised but I am conservative as a tech and if the car steers properly after replacement  I leave it alone. Just another opinion...

Tom

Edited June 2, 2018 by 1965rivgs (see edit history)

[Paul K.]

One should always check the front toe. It can be out causing Tire wear but the car won’t pull. Springs sag over time causing camber changes. However in the big picture, the best indicator of whether a suspension needs an alignment is tire wear patterns or if the car pulls to one side. 

Edited June 3, 2018 by Paul K. (see edit history)