Bob K

I'm getting ready to press the lower control arm bushings on to the control arms. The lower control arm shaft has some play when I insert it into the bushing (prior to pressing the bushing into the control arm).

Is this ok, will be bushing tighten up on the shaft when pressed into the control arm? Or are the shafts worn and need to be replaced?

Bob K.

Mooser

For rubber bushings:
The shafts should just fit into the bushings, there is about .005"-.010" difference in size between the shaft and the bushings uninstalled.

When in and not tightened, you should be able to pretty much hold the arm out sideways with the shaft.
When you give a swift down or up the arm should move on the shaft.

With the bolts tightened it shouldn't move (hence the tighten with that car on the ground spec)

Poly bushings are oversize and non of that applies
M

Bob K

Mooser,

Thanks!

Bob K.

Mooser

The "teeth" on the end of the sleeve bite into the shoulder of the shaft so make sure that area isn't undercut or otherwise compromised. If it is, carefully file off the lip and give it something square to contact.

And if you want to get them to fit real snug you can get the shafts knurled and make them a very slight interference fit into the bushings
M

SwissVette71

Hi Mooser. The O.D. of my lower shafts are .730" and the I.D. of the bushing is .745", a .015 difference which is outside of the .010" tolerance mentioned in your reply. Is this too much? Do you know what the O.D. of a new shaft should be?

20mercury

Same question for me, I had some old shafts that I wanted to reuse. Also had some new shafts that I later sent back.

Lost the piece of paper, ha, but pretty sure the new shafts for LCA were 0.735, and my 3 old shafts on 6 ends between 0.731 and 0.735. I used a couple of the old shafts and they worked just fine. I think a few thousands here is of no consequence. Also in addition to the above, make sure you torque the shaft end cap bolts to spec after the Corvette is on the ground and you bounced the front suspension a few times to center the rubber bushing. Hope this helps.

Aggitated Monkey

If your installing poly bushings make sure you locktite the end bolts before torquing. The pollys wont allow the clamp up like the rubber does. Without the locktite they will come loose. Bad experance. About 20 years back I didnt know this and my left upper bolt came out allowing the A Arm to walk forward and off the shaft. Lucky it was at a low speed and no damage. I corrected this; resistalled the A arm, and locktite & torqued all 8 shaft bolt. No more problem.

Mooser

According to the notes I have from several guys with new sets of shafts
Upper shaft .670-.676
Lower shaft .738-.742

I cheated and knurled the shaft ends to snug then up a little more than normal while still allowing them to rotate prior to tightening the end bolts

HIH
M

arklacat

Share details plz.

Mooser

Since the inner sleeves "lock" into the arm when the bolt is tightened, even if the shafts are undersized the sleeve will still lock in place but the teeth on the sleeve are designed to prevent turning, not sliding sideways, if there is excessive play between the sleeve and shaft the sleeve can start to work sideways and effectively "loosen" itself up by wearing away the shoulder on the shaft (don't believe it happens, look at an old shaft and see it's been undercut by the sleeve)

Anyway, since I'm paranoid and had everything apart anyway, a few minutes on the lathe and they shafts are a light press fit but still allowed to rotate under minimal pressure (until the bolts are tightened with the suspension at ride height)

Probably never notice but it eliminated one more variation
M

SwissVette71

Thanks everyone for your advice. Looks like I have a few things to do before I assemble the control arms. Fun and safe driving to you!

SwissVette71

I have a crazy question. If the teeth are designed to prevent turning of the inner sleeve, could a beer can be used for shim stock to take up the slack between the bushing and the shaft? I cut up a beer can and made some sleeves to wrap around the shafts. The beer can has a thickness of .005" so when wrapped around the shaft it increases the shaft diameter by .010". The result was a nice slip-fit between the bushings and the shafts. Does anyone have any thoughts regarding the high-tech beer can solution? I know it sounds crazy but what is the down side?

Mooser

Reducing play between the bushing and shaft can only help things. I see no downside to installing a shim (beer can) since the worst thing that can happen is it wears out (which could only happen if the sleeve spins which it shouldn't) and your back to where you are without it.
Make sure the shoulders of the shafts are in good shape
M

ctuinstra

Loctite has a special compound for filling small gaps like that. I've never used it, but I wonder if that would fill and lock the bushing to the shaft. This is assuming of course a guy could get it loose in the future without too much hassle. Thoughts?

SwissVette71

My only thought is that it would solidify before you get the car back on its feet preventing the internal sleeve from turning . My understanding is that you want the sleeve to be able to turn until the weight of the car is on the suspension at the ride height. At this point you torque the end caps to the specified amount which causes the teeth of the internal sleeve to bite into the shaft which prevents the sleeve from rotating relative to the shaft from this point on. My guess is that the weight of the car would cause the locktite to release. This might be OK as it may still provide gap filling properties. Please correct me if my assumptions are incorrect.