Rear Alignment - Rear Suspension End Play

[larsend]

OK sports fans!
The Rush SR Baseline Setup recommends 0.25mm of toe in on the rear.
I've tried and tried to get a consistent suspension setup but, each time I setup the car the toe and to a lesser extend the camber changes.
So, today I took things apart and measured them.

First I pushed/pulled and the 3 and 9 o'clock positions and found ~1.25mm of play

Removed the tire and noted this when looking from underneath the car looking at where the rear trailing arm connects to the hub/upright

Stuck a feeler gauge in the gap and came up with ~0.43mm

So then I measured the width of the opening on the upright

Then the rod end spacers

and the width of the center of the hiem joint

So.....
Opening on the upright ~23.85mm
The hiem joint width ~13.90mm
It would appear that the rod end spacers are a bit undersize ~4.75mm and ~4.78mm............. each of these needs to be 5mm not undersized.......

So for my car I could do with two set of rod end spacers that are 5mm in width.

I'm also going to replace all of my hiem joints with Aurora Bearing with the PTFE lined bearing surface as my current ones have excessive wear.

I looked for Rod End Spacers with a 10mm inner diameter and a 5mm length with no luck.......anyone have a source?

Hopefully with new hiem joint ends and proper sized rod end spacer I'll be able to get a repeatable suspension setup!

P.S.

this is where I have additional end play, but I understand these are "wear" items and need to be inspected and replaced when there's end play...

 

[David Hosie]

Spec on the hime joint width is 14.00 +0/-.25. Don’t see any grease in the photo. They will last a lot longer if you grease them.

 

[larsend]

Spec on the hime joint width is 14.00 +0/-.25. Don’t see any grease in the photo. They will last a lot longer if you grease them.

I grease them, only cleaned it up for photos....what about the rod end spacers? 4.75mm or 5mm?

 

[John H]

How much play is in the rod end? The side to side can't be responsible for much of the play. From memory mine are a pretty tight sandwich, I'll take a look later today. You can just use some precision washers on the outside of the conical spacers.

On this joint, put threadlock in the hole instead of on the bolt. If you put it on the bolt you have a good chance of locking the washers/heim to the bolt making it a pain to remove. I would also use a nordlock washer (these wouldn't stay tight for me), but depending on your thread engagement you might need a longer bolt to accommodate the thickness.

Also, whys your car so clean in the first pic. I wipe mine down but evceryones cars "engine bay" looks detailed in their pictures.

 

[larsend]

How much play is in the rod end? The side to side can't be responsible for much of the play. From memory mine are a pretty tight sandwich, I'll take a look later today. You can just use some precision washers on the outside of the conical spacers.

On this joint, put threadlock in the hole instead of on the bolt. If you put it on the bolt you have a good chance of locking the washers/heim to the bolt making it a pain to remove. I would also use a nordlock washer (these wouldn't stay tight for me), but depending on your thread engagement you might need a longer bolt to accommodate the thickness.

Also, whys your car so clean in the first pic. I wipe mine down but evceryones cars "engine bay" looks detailed in their pictures.

Good call on the precision washers! Didn't think of that.
Just ordered these.

Right on, ref the lock washers, I use these;

Belleville Spring Lock Washers for Socket Head Screw​

These washers have smaller outside diameters than standard spring lock washers to fit neatly under socket head cap screws. Also known as conical washers, these have a slightly cupped shape that gives them spring-like flexibility to grip tighter than split and tooth lock washers. They minimize loosening from wear, temperature changes, and vibration. Serrations on the top and bottom provide extra gripping power. Load-rated Belleville disc springs are also available.
18-8 stainless steel washers have good chemical resistance and may be mildly magnetic.

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[John H]

So I just checked, mine are totally tight. I couldn't even fit a .005 feeler and there was no tactile movement. They are however, brand new.

I can confirm nordlocks do also fit this bolt hole.

 

[larsend]

So I just checked, mine are totally tight. I couldn't even fit a .005 feeler and there was no tactile movement. They are however, brand new.

I can confirm nordlocks do also fit this bolt hole.

I can get a .43mm feeler in there......

 

[John H]

I can get a .43mm feeler in there......

You said as much, I was just giving you a data point to utilize in your decision making process.

 

[Rush Mx - Marcelino]

Im believe the suggested toe in its 25mm no 0.25mm

 

[David Hosie]

Im believe the suggested toe in its 25mm no 0.25mm

25mm would be rather a lot?

 

[John H]

That made me question my entire existence for a moment.

 

[Rush Mx - Marcelino]

25mm would be rather a lot?

View attachment 407

Yes my mistake, say 2.5mm like a 1/10 inch maybe works because 0.25mm are 1/100 inch ….

 

[larsend]

Yes my mistake, say 2.5mm like a 1/10 inch maybe works because 0.25mm are 1/100 inch ….

Here's a screen shot for the RUSH SR baseline setup from the resources page "rear 0.25mm In".......