Newbie bit off more than can chew (suspension trouble)

[ogatrulle]

Getting these LCAs onto the ball joint studs can require a great many cuss words. I did the job for the first time only about six months ago after reading various posts on this site. Here are some things I did:

1. The stud on the bottom of the ball joint can be moved around. In hindsight it's forehead-slappingly obvious, but while I was wrestling with the LCA trying to line it up under the ball joint, I forgot for a while. Monkey mind.

2. In addition to the main ratchet strap pulling the control arm down, I also had two more smaller ratchet straps, one fore and one aft of the rotor, hooked to wheel studs and running across the underside of the car. The idea was to limit the fore/aft motion of the knuckle while I jacked it up a little.

3. I did unhook the steering rod at the knuckle. That yielded a lot more freedom to move things around. NB you'll need to hold the stud while loosening the nut to keep the boot from turning.

4. I did have a problem with the rotor turning when I jacked it. I like the suggestion above of wedging a bolt in to stop it from turning; wish I'd thought of that at the time.

[precopster]

The rollers move back and forth over a range of about 50mm whenever the car's suspension travels. Once they have been inserted they can slide back and forth over that 50mm range. That's why they came out in the first place; the CV shaft was pulled past the insertion point when you were working on the strut.

The key is to get them back in and secure the boot with a clamp ASAP

[GoldCO]

I assume then that range is all contained within the cage? I'll snap a photo in the morning...

The rollers move back and forth over a range of about 50mm whenever the car's suspension travels. Once they have been inserted they can slide back and forth over that 50mm range. That's why they came out in the first place; the CV shaft was pulled past the insertion point when you were working on the strut.

The key is to get them back in and secure the boot with a clamp ASAP

[mrbrian200]

I assume then that range is all contained within the cage? I'll snap a photo in the morning...

Yes. On FWD vehicles the axle shaft requires a provision to lengthen/shorten with suspension travel, not unlike a driveshaft on a solid axle RWD truck which you would be familiar that allows the yoke at the transmission to slide in and out. Limits imposed on suspension travel (bump stop, strut extension limit) keep it in the safe zone. Because the angle the shaft needs to bend is greater (short + turning the wheels/steering), a U-joint would last about 1 minute so they use this type of joint.

[GoldCO]

success! ...well, at least it is all 'together' -- now need to go back through and tighten/torque everything. i've had to do "questionable" things before while wrenching, but this was pretty sketchy at times... ratchet strap just waiting to snap, strut springs 'kinda' compressed (tool didn't really fit inside the towers), jacking up hub and then basically push it, teetering, into place. whew! no wonder the shop wanted $750.

i was able to get the CV joint pushed back together (shoved a few fingers full of grease around for good measure). the boot seems okay -- the clip holding it on came apart; is it re-useable? looks like it would snap back together but i'm guessing there is a special tool and/or method to do so? don't suppose a large zip-tie would work?

did i read to wait and final torque everything once the wheels are on and back on the ground? that won't be much fun i'm sure for access, but at this point (knock on wood) the hardest part is behind me.

thanks, all, for the help.

[precopster]

If the clamp around the boot is OEM and the boot brand is GKN the clamp will have a fold in it which was tensioned with an Oetiker clamp tool. You won't be able to re-use this type without a considerable amount of effort and an Oetiker clamp tool.

You can use a very large zip tie but they do tend to leak a small amount as you can't get them tight enough before they break. Buy 3 zip ties for one job in case they break while tensioning them.

[mrbrian200]

Just installed some Meyle HDs, will see how long those last.

Those might be ok. Meyle is a big enough company if they tweaked the bushing design or material properties they would have access to in-house computer aided engineering to model multibody dynamics/kinematics to make sure changes didn't upset the system. The ones I had trouble with were a concoction IPD came up with (more virgin rubber/less recycled etc). In addition to fiddling with the tensile/elongation properties of the rubber, they also changed the physical design of the front bush (looks like they were trying to tighten steering response/dynamic toe error), changing either too much or not enough depending how you look at the problem. Geometry of the suspension on these lends to a much more delicate balance between materials/properties than many other cars . Enthusiasts looking to apply 'generic principals' to upgrade the handling/dynamics which may work on a variety of other vehicles are more likely to upset the birdcage on these. Running/tweaking changes with the aid of computer modeling and extensive real world testing is absolutely essential. Inexpensive aftermarket bushes are just asking for trouble.

[mrbrian200]

Another note regarding aftermarket LCAs which I have become aware. Talking about the actual control arm, not the bushes.

Volvo engineered this setup so in a severe frontal impact, particularly small overlap, the wheel breaks away from the vehicle instead of remaining attached/pushing into and contributing to the compromise of passenger compartment integrity. Provisions include the metallurgy/alloy composition of the LCA itself (break away, not bend in a collision yet hold during everyday driving/bombcrater potholes at highway speeds etc). Note these are severe collisions every vehicle on the planet would be disabled/towed away on flatbed whether the wheel remains attached or not. You'll see this behavior in IIHS crash test videos. Some of the worse performing vehicles (not Volvo ) in area are vehicles where the wheel remains attached and exasperates intrusion into front footwell areas increasing the risk of foot/leg injury and entrapment.

You don't necessarily know with aftermarket parts what they used and how it will behave in such a scenario. None of these aftermarket LCAs specifically say that the metallurgy conforms to Volvo crash safety provisions. Volvo has some TSBs regarding aftermarket LCAs that mention vehicle crash safety (but aren't very specific about what and why). Something to think about.

Goldco, even though we aren't sure about the particular bushes you used, you kept the OE LCAs and pressed new bushes into them instead of replacing the entire LCA with some cheap aftermarket. Though you probably took this route to save money, it is from a safety standpoint probably the smartest approach.

[GoldCO]

good to know, thanks...
yes, saving money was a factor, but also just the idea of replacing a part (arm) that was perfectly fine seemed a bit wasteful. yeah, it was a bit of a pain to take them to a shop for the press, but it worked out.