lower control arm replacement - Mazda 5

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I was doing the winter-to-summer-tire changeover on our '09 Mazda 5 Saturday, did the standard brake inspection (looking for lots of meat left on the pads) all around, and finally, on the front, checked for side-to-side & up-and-down play. CLUNK, CLUNK, CLUNK! What the ... ??? Definitely not normal, and present on the driver's side only. My first suspicion was outer tie rod ends. Indeed, some play there. I gingerly drove over to the dealer, and picked up both sides. Installed the one on the driver's side. Clunking attenuated, but still present. OK, more detective work req'd. (Something loose in the manual transaxle? GAH! Hopefully not! CV joint? Likely not, boot not torn, and no clicking.) Hey, it's the ball joint (which doesn't look to be replaceable.) Phoned the dealer, and confirmed that the ball joint is an integral part of the lower control arm. No stock, but they're due in Tuesday or Wednesday. (I'll replace both sides.) I don't drive the 5 often, and was so glad neither the ball joint or tie rod end had failed while my wife was driving. I should have caught it earlier.

Anyway, the car's parked for a few days - I consider the ball joint play severe enough to be unsafe. There are various YouTube videos on this topic, some of them very good. (They're typically of the Mazda 3, but the 5 shares the same platform, and everything looks pretty similar.) Anyway, most of them show the long nut that goes through the pivoting bushing not being tightened when the wheel is hanging. It is inserted under no load, but is not tightened until the weight of the car is on the suspension. Makes sense. So here's my question - although it's not shown in the FSM, should I lube the bolt when reassembling things? To me this would put less stress on the bushing when the LCA pivots. (Or should the bolt be 'grabby' on the rubber?)

I'm not surprised that the ball joint & tie rod end are shot - we've had a crazy winter with unusual freeze-thaw cycles, with the resultant severe potholes. The car has 131K km on it - about 80K miles.

Any input much appreciated!
 
moms 10 fusion needs all 4 lower arms w/ ball joints. (102k) one is loose and the other ones clunk and squeak. got to drop the rear sub frame to do tht. not looking forward to it.
 
Originally Posted By: Number_35
So here's my question - although it's not shown in the FSM, should I lube the bolt when reassembling things? To me this would put less stress on the bushing when the LCA pivots. (Or should the bolt be 'grabby' on the rubber?)


I don't know about you specific application, but on many bushings the bolt is supposed to clamp them in place and then the bushing twists as the suspension compresses and releases.

That's why you torque it when the vehicle is on the ground (or simulating that position), so the bushing isn't twisted during the vehicle's normal sitting position. If you torque it in the air, then the bushing will be significantly twisted when the vehicle is just sitting on the ground.
 
I would check a Mazda / Ford specific forum to see what are the common problems and which brand / model is good. I haven't heard much about lubing the LCA bolts but definitely preload the bushing before tightening (lower the car to rest on tire, or jack the control arm so the control arm is supporting the weight just like you are on the ground). Not doing so will over twist the bushing and it will die prematurely.

I personally wouldn't save a few bucks to have the old bushing cut and burnt to replace just the bushing, because I am afraid of damaging the control arm. To me it is not worth the savings, especially if I am not planning to sell the car right after.
 
Originally Posted By: stephen9666
Originally Posted By: Number_35
So here's my question - although it's not shown in the FSM, should I lube the bolt when reassembling things? To me this would put less stress on the bushing when the LCA pivots. (Or should the bolt be 'grabby' on the rubber?)


I don't know about you specific application, but on many bushings the bolt is supposed to clamp them in place and then the bushing twists as the suspension compresses and releases.

That's why you torque it when the vehicle is on the ground (or simulating that position), so the bushing isn't twisted during the vehicle's normal sitting position. If you torque it in the air, then the bushing will be significantly twisted when the vehicle is just sitting on the ground.
Quite so. I understand that, and my question was/is whether the bolt is, by design, supposed to grab the rubber bushing (with the bushing acting as a bit of a torsion spring), or whether it's acceptable to lube the bolt (which will obviously minimize the wear on the rubber bushing due to twisting, but may defeat the purpose of this type of connection).
 
The bolt doesn't twist on the bushing. It passes through the sleeve. When you tighten the bolt, the sleeve is locked in position by being pinched between the two parts of the frame. This is why you want it to be set up with the rubber relaxed in the neutral position while the car is at rest with weight on the suspension. When you go over bumps, the sleeve stays in position while the rubber twists back and forth.
 
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Originally Posted By: PandaBear
I would check a Mazda / Ford specific forum to see what are the common problems and which brand / model is good. I haven't heard much about lubing the LCA bolts but definitely preload the bushing before tightening (lower the car to rest on tire, or jack the control arm so the control arm is supporting the weight just like you are on the ground). Not doing so will over twist the bushing and it will die prematurely.

I personally wouldn't save a few bucks to have the old bushing cut and burnt to replace just the bushing, because I am afraid of damaging the control arm. To me it is not worth the savings, especially if I am not planning to sell the car right after.
Agreed, I went with a dealer part. Likely a bit more money, but we could have this vehicle another 10 years. I learned the hard way (with $22 tie rod ends on a previous vehicle) not to cheap out on certain parts. (They only lasted about 20K km.) Given that I'll get a $100 alignment after replacing the LCAs & tie rod ends, it doesn't make sense to cheap out on the parts. Agreed, replacing just the ball joint is a real hassle, and then the LCA still would have the old bushing w/ eight years of wear on it.
 
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