Out of spec? Control arm & superpro poly mysteries

***EDIT: Mystery solved, see bottom post. /EDIT***

I recently purchased (genuine) volvo part numbers 1229925 and 1229923 from GCP, which are 240 control arms with reinforced plates on them that were found on police and taxi models.

Upon inserting the front control arm front poly bushings and sliding in the sleeve for test fitment, it's apparent that something's out of spec. Either the welded sleeve is too long, or the lip on the superpro bushings is too thick in the axial direction. I know the superpro inner sleeve isn't too short because the bushings don't 'meet' in the middle of the CA outer sleeve (see pic 4). Both genuine volvo and superpro are reputable manufacturers, so looking for some guidance on what I should do? These CAs are pricey so I wanted some consultation from the forum gurus.

My options appear to be to:
1. Cut down the CA welded metal sleeve (outer bushing sleeve), in the event that it's too long... but then, which side??
2. Throw the poly bushings on a lathe or something and cut the inner shoulder back towards the outer face of the bushing to allow it to seat further.

See pictures:

1. Both CA sleeves measured about 50.25mm


2. Bushing face-to-face length installed was 65.73mm


3. Bushing face-to-face uninstalled was 61.91mm


4. 4mm inner gap (surely not supposed to be this way...?)


5. Inner sleeve measures 64.54mm


6. Inner sleeve sits recessed on both sides by ~0.6mm



Anyone have access to some control arms or superpro kits that can check or confirm? Is this supposed to be this way? I feel like it isn't, because the poly would unnecessarily compress during install...

Install them and get the car aligned.

Just measured the M12 poly bushing on my ipd panhard rod. Inner sleeve 50mm, poly bushing face-to-face 48mm. That's how it should be. Dunno what's going on with CA/poly, maybe gsellstr can chip in with some measurements?

Sorry guys, I don't have stock on those or a car to measure, but here's some input from my end of things...

Do you have a stock bushing inner sleeve? How does the length on that compare to the length on the Superpro inner sleeve?
What is the width of the pocket where the control arm fits into on the car side? How does that compare to the width of the bushing face to face when installed and to the length of the inner sleeve?

My initial thoughts are that the control arm shell may be slightly wider than the original arms. Do you have an old set of arms to compare against?

Having said that, I've seen a few different poly sets where the inner sleeve was slightly shorter than the bushing face to face dimension, or bushings where there was a slight gap between halves. What you've shown for pics doesn't seem severe enough to not run them, though I would certainly make sure the inner sleeve is well greased, the outer shell and bushings are well greased before sliding in, and the faces are greased when you install, since there will be some contact with the steel around the pocket.

Sorry I don't have more specifics, it's been ages since I've installed a set of those on a 240.

Please do post up any of the other stuff I suggested. If this is a potential manufacturing variance in the arm's or in the bushings, that would be good info to have. I can use pic's and dim's to pass along to my contact for further research if it looks like a bushing issue, but I have no contact on the GCP side of things if it's an arm issue.

A 1.2mm discrepancy?

SEND IT

...or get a grinder and SAND IT

kyote said:

A 1.2mm discrepancy?

SEND IT

...or get a grinder and SAND IT

Click to expand...

Send it... yeah that 1.2mm equates to about 10% compression strain (which could mean a few hundred psi of stress) on the urethane if I were to install it as is, since only the exposed 7.5mm shoulder would compress. Considering this bushing's sole function is to handle forces in a compressive manner, the bushing could easily wear out & break prematurely because you've got double compression- one from install, one from applied forces. That extra compressive stress also increases the normal force between the face of the bushing and chassis 'ear', which means any sand or dirt that gets in there will eat up the face of the bushing.

Sand it... I might do that. Gotta check to make sure the inner sleeve isn't out of spec with the original bushings that are on the car currently.

Have you had a chance to check the stock control arm shell length yet, to see if the new arms are out of spec or the bushing is a tad long?

Honestly, that 1.2mm doesn't concern me enough to worry about it but that's just me. I've had to compress various bushings before to get them into place...

It is caused by the coating inside the arm where the metalistic bush would normally be pressed in. The slightly tighter bore stretches the bush out a bit.

I would not worry about it tbh

IansPlatinum said:

...which means any sand or dirt that gets in there will eat up the face of the bushing.

Click to expand...

Self clearanceing bushing you say?

gsellstr said:

Have you had a chance to check the stock control arm shell length yet, to see if the new arms are out of spec or the bushing is a tad long?

Honestly, that 1.2mm doesn't concern me enough to worry about it but that's just me. I've had to compress various bushings before to get them into place...

Click to expand...

I'm going to try to get in there and get pictures today...
Depending on the application, bushing compression may or may not be a big deal. In this application, the bushing has to be compressed a non-negligible amount before the bolt & chassis mounting snugs down on the inner sleeve. Who knows if it's a big deal or not. But this scenario isn't how they bushing was designed for optimal use. Yeah it'd work. But the chassis tangs might grip the poly too much, and force the bushing to rotate within the CA shell (AKA outer sleeve), which is not what I want because I'm drilling and tapping zerks to grease the inner sleeve.

classicswede said:

It is caused by the coating inside the arm where the metalistic bush would normally be pressed in. The slightly tighter bore stretches the bush out a bit.

I would not worry about it tbh

Click to expand...

I'm going to try to get measurements of the stock bushing today. The coating is hardly inside the sleeve, and the bushings can be pretty easily pressed in and removed by hand. Poisson's ratio wouldn't come into play, because the radial strain is very negligible.

I'm worrying about it because this is my OCD car. I'm trying to buy the nicest equipment available and do this thing 100% right. If it were going on my 850, not a care in the world.

kyote said:

Self clearanceing bushing you say?

Click to expand...

Lol. That's quite the break in period, but arguably less effort

Call super pro and ask their opinion.

That type of behaviour has been on all poly bushings that I've installed in to my cars.

I'd say it has to be because the sleeve isn't attached to poly like rubber is. If the sleeve is longer than the bushing, the control arm moves more easier back and forth.

I'm an ME also, and you are seriously overthinking it. I have these bushings also, and there needs to be preload to eliminate play, since the bushing material is not bonded to the sleeve the way the OE bushings are. Install it, and see how freely the arm pivots.

Mystery solved.

Short answer: It's supposed to be this way, for a reason I didn't realize.

That reason: the cross member mounting tabs aren't flat & parallel as I assumed they were... (pretty sure they are parallel flat plates on my 850's front CA bushing tabs....)
Here's some pictures.



Really hard to tell from the pictures alone but the tabs have a slight bevel to them which meets the inner sleeve without stressing the bushing.
Checked OEM inner sleeve, superpro is in spec. Volvo control arm sleeve is also in spec. Not sure why superpro decided to leave a 4mm gap in the middle of the two bushing upon install, as it caused my original concern and suspicion. Superpro (from the measurements I took from this set) has awesome tolerancing, and they could easily make the middle of these two bushings 'meet', which would reinforce the notion that it's supposed to be this way. Wonder if there's a reason for the gap...? To hold grease, maybe?

I ended up only notching a bit of the bushing to clear the zerk (~6mm diameter), was expected to notch a half circle into each bushing, had they met in the middle.
I also sanded the outer sleeve on the CA to see how much paint there was... only about 0.2mm as I suspected. Not gonna do that on the other CA.





I installed it and it rotates nice & smooth.
I also did a visual check on the CAs for colinearity with a giant M12 through rod and a bolt on a coupler:
They're just slightly off, but good enough that I don't think there will be any problems.

Greg Wong said:

I'm an ME also, and you are seriously overthinking it. I have these bushings also, and there needs to be preload to eliminate play, since the bushing material is not bonded to the sleeve the way the OE bushings are. Install it, and see how freely the arm pivots.

Click to expand...

My original thought was that the inner sleeve needs to be slightly longer than the bushing but this doesn't make sense. It should be as close to flush as possible, and erring on the side of pre-compression, but I thought 10% strain was a little unnecessary. Turns out, hardly any strain, because those mounting tabs are slightly beveled as shown above. It's installed now and works great. Just a little confusing because the mock-up looked wrong.
Also, overthinking is my middle name, man. Can't say there weren't a bunch of volvo engineers that 'over-engineered' their products too. That's why they were the safest on the road for a long time.

Hahaha, nice. Can you post a pic showing the boxing plates? How much were they?

Greg Wong said:

Hahaha, nice. Can you post a pic showing the boxing plates? How much were they?

Click to expand...

~$350 for the pair shipped from sweden

One thing I've noted on the Superpro stuff for a very long time is their tolerances are pretty damn nice, glad you found they were very close as well. Having worked with them a little on the R&D side over the years, they put a lot of research into stuff before they roll it out. Sure, stuff can happen on the line from time to time but they seem to be pretty good at watching for it.

Glad you're up and running with the new goods!

Not to scare anyone but keep them bushings lubed:







Those were in use for quite a few years but still. This had a very noticeable effect on suspension travel... Effectively preventing movement.

Made some new bushings from stainless steel, problem probably solved.

JW240 said:

Not to scare anyone but keep them bushings lubed:

Those were in use for quite a few years but still. This had a very noticeable effect on suspension travel... Effectively preventing movement.

Made some new bushings from stainless steel, problem probably solved.

Click to expand...

Careful, you might get some galvanic corrosion at the point where the stainless meets the crossmember. I'd rather my sleeves corrode rather than my crossmember! Greasing the assembly will prevent that...

It's all about the zerk lyfe- join the grease gang