Lower Control Arm Pivot Shaft Grease

1970FuryConv

Old Man with a Hat
Joined
Aug 8, 2014
Messages
5,739
Reaction score
5,436
Location
Richmond, VA
Firm Feel offers these greaseable pivot shafts. I haven't installed a lower control arm in a while, but I remember using wheel bearing grease in the cavity through the front subframe. FSM wasn't much help.
What grease are you using?
Is there any reason to have the Firm Feel pivot shafts if the car is only driven occasionally?
'65-'73 C-body Greaseable Lower Control Arm Pins
GPIN_f5e7d5a9-d493-44d2-8774-6295797b5e1e_600x.jpg

My 1971 lower control arms. No grease in subframe cavity, but car not driven since 1978.
PXL_20221003_211905107.jpg
 
Original bushings where non lubricated rubber type bushings, these shafts are for nylon or polyuretan bushings, like they say in FF website. Grease need to be suitable for materials.
 
Unless you are worried about squeaks, there is no reason to install the after market shafts with grease fittings and nylon/poly bushings. Replace the stock bushings and clean up the pivot shafts and call it good. A lot of the after market nylon/poly bushings are much harder than the stock units. That will give you a marginal improvement in handling but at the cost of having the vehicle ride like a truck. The stock units were soft rubber for a reason.

Dave
 
Yeah, I wouldn't install those in an occasional driver - not worth the cost.
Not sure I'd install them in a daily driver either for the harshness that Davea Lux mentioned.
 
Do you use grease in the cavity through the front subframe? The cavity is honed and feels like it's fitted bore to the pivot shaft. FSM does not mention using grease in that cavity/honed bore.

I thought the rubber bushing acts as a shock absorber between the lower control arm and the pivot shaft to lessen the impact of bumps, potholes etc, but that the pivot shaft still has to turn against the bore in the engine cradle. I assumed grease is required in that honed bore. (Maybe I don't understand control arm operation and the pivot shaft does not turn inside the engine cradle portion of the subframe. But then the bushing would have to turn on the pivot shaft which is impossible because it's a press fit.)
 
The tapered part of that shaft, the part that goes thru the cross member requires no grease, as it does not rotate in the cross member. If you look, the small hole in the ones pictured, is where the bushing in the lower control arm rides. That is where the grease comes out. Use a light coating of anti seize on the tapered part when reassembling, makes life a little easier if it has to come apart again someday.
 
Unless you are worried about squeaks, there is no reason to install the after market shafts with grease fittings and nylon/poly bushings. Replace the stock bushings and clean up the pivot shafts and call it good. A lot of the after market nylon/poly bushings are much harder than the stock units. That will give you a marginal improvement in handling but at the cost of having the vehicle ride like a truck. The stock units were soft rubber for a reason.

Dave

In my opinion, the only place I see the need for improved bushings would be the front sway bar and strut rods, if available in urethane. The stock rubber ones are flimsy. I also see FF has what looks like an improved rear shackle kit too, that might be a nice upgrade with minimal ride comfort sacrificed....?
 
Last edited:
The tapered part of that shaft, the part that goes thru the cross member requires no grease, as it does not rotate in the cross member. If you look, the small hole in the ones pictured, is where the bushing in the lower control arm rides. That is where the grease comes out. Use a light coating of anti seize on the tapered part when reassembling, makes life a little easier if it has to come apart again someday.
Thanks for the tip on the tapered shaft not turning. Edit: today 1/31/23 I verified this with my 1970 Fury convertible. I put it on jackstands and has an assistant use my hydraulic jack to move the left front wheel up and down while I watched. Pivot shaft does not move. Control arm pivots on the immobile shaft. It's hard to see the bushing because I have to watch between the lower control arm and the engine cradle of the subframe. End Edit. Anti-seize is a good idea.

Are the small grease holes visible in the pictures? Not sure where we are talking about or how the grease is applied to the lower control arm bushing. Thanks. FSM 2-1 1971, Front Suspension chapter (also 1970 & 1973): “Rubber bushings should not be lubricated at any time.”

I thought the tapered shaft is press fit into the lower control arm without grease. If the tapered shaft doesn't move, would the bushing allow the up and down movement based on the flexing of the rubber insert between the inner and outer shell of the bushing?

Rear
PXL_20221005_190519207.jpg
 
Last edited:
In my opinion, the only place I see the need for improved bushings would be the front sway bar and strut rods, if available in urethane. The stock rubber ones are flimsy. I also see FF has what looks like an improved rear shackle kit too, that might be a nice upgrade with minimal ride comfort sacrificed....?
I agree with staying with rubber bushings so it does not ride like a truck. I read some old Mopar Muscle articles. Steve Dulcich does not use poly lower control arm bushings in his A-body builds. He uses rubber bushings on upper and lower control arms. MM May 1999, A-Body Suspension Article.

As far as the strut and sway bar bushings, I have new rubber bushings already because they don't usually come in the rebuild kits. Hope they hold up!

I agree with looking at a shackle kit when I get to the rear springs. The car is not a roller, so main focus is on rebuilding the front suspension. Then working on front steering and brakes.
 
Last edited:
Maybe some of this is a repeat of other comments, but I'm typing it to make sure I articulate my meaning because I think there is an unanswered question on the bushings still.

The LCA pin is fixed into the subframe and tightened down - it does not pivot. Smear some type of lube for future disassembly purposes and rust prevention.

The LCA bushing is vulcanized to the inner and outer shells, which is then pressed into the LCA.
As the LCA is ~16" long (or whatever) the amount of suspension travel at the wheel requires only a few degrees of rotation at the bushing. So the outer bushing shell rotates with the LCA, the inner shell is stationary with the pivot pin, and the bushing gets squirmed to make it all happen. The overall design is such that the holding force of the rubber to the shells is sufficient that the rubber gets pulled but does not slip. OR it is all such a press-fit of rubber in the shells, with further pressfit when installed in the LCA, there there is no vulcanization, and the friction of the rubber on the shells performs the function.

So it would seem that a poly bushing is a totally different mechanism. From all the notes I saw years ago, the bushings stated that inner and outer shells needed to be re-used. So I suspect the bushing now functions as a bearing surface, and there is slip between bushings and shells. Certainly DIY people would not be able to assemble these bushings with the consistent pressfit (across all hobbyists) that OEM factory machinery would do in a production run, but slip-fit would certainly be a practical approach for DIY. And as it still has few degrees of rotation, the required lube is more for squeak prevention.

Other notes:
1. B-body strut rod bushings fit our cars. I have used a poly set in a car and I'm pleased with them. It really sucks how much disassembly is required to change them, the engineers should've made some type of drop-out feature for the front bushing setup.
2. B-body spring-eye and shackle bushings also work. There is a 1.5" and 2" OD for the front eye bushing, I believe the 1.5" is for Hemi cars, as the smaller bushing would give less squirm.
3. For our rear shackles, the poly bushings are not a 100% fit, because the flanged surface is flat and not domed like the OEM rubber. However, I have used these with OEM shackles and not noticed any issues.
4. For the FirmFeel shackles - these can be readily be made at home with some suitable flat steel from Mcmaster.com. (due to the small amount needed and online credit-card ordering, going to a steel house is likely not worth the few dollars saved.) I have made a set like this in the past - and no problems.

For all the shackle work - I used 9/16" bolts to fit the bushing IDs and then drilled shackle holes to match. Bolts with a long unthreaded section for the bushing to ride on would be elusive and pricey (they would be like shoulder bolts at that point). I used standard Grade5 or 8 bolts, so yes, some of the bushing is riding on the threads. Have not noticed any problems, and when I changed 1 set of OEM shackles with bolts/poly bushings to the heavier flat-steel shackles, the bushings were fine and I reused them. Those bushings surely had 50k miles on them, I put them in ~20 years ago.
 
And also, when reassembling, bushing fasteners/bolts should not be fully tightened until the car is on it's wheels at rest (or at least supported by the LCAs.)
This prevents tightening in a pre-load that would theoretically reduce bushing life.
Probably the LCAs are the most critical for this.

I read this in FCBO a few years ago, long after I did 2 my front end rebuilds. I fear I did NOT do that right. Loosening the LCA pivotpin nuts should ease that, though? (and re-tightening, of course)
 
The LCA bushing is vulcanized to the inner and outer shells, which is then pressed into the LCA.
As the LCA is ~16" long (or whatever) the amount of suspension travel at the wheel requires only a few degrees of rotation at the bushing. So the outer bushing shell rotates with the LCA, the inner shell is stationary with the pivot pin, and the bushing gets squirmed to make it all happen. The overall design is such that the holding force of the rubber to the shells is sufficient that the rubber gets pulled but does not slip. OR it is all such a press-fit of rubber in the shells, with further pressfit when installed in the LCA, there there is no vulcanization, and the friction of the rubber on the shells performs the function.
This is the part I got concerned about when the other poster said that there are small holes that the grease comes out. I agree that the LCA bushing does not use grease.

I agree also that the LCA bushing doesn't turn on the inner shell. The rubber bushing would be destroyed in a few miles of driving. The bushing needs to be of excellent quality to absorb that twisting force as well as the twisting force from the torsion bar. THANKS!

I suspect Rare Parts has the best LCA bushing, but I take correction easily.
 
And also, when reassembling, bushing fasteners/bolts should not be fully tightened until the car is on it's wheels at rest (or at least supported by the LCAs.)
This prevents tightening in a pre-load that would theoretically reduce bushing life.
Probably the LCAs are the most critical for this.

I read this in FCBO a few years ago, long after I did 2 my front end rebuilds. I fear I did NOT do that right. Loosening the LCA pivotpin nuts should ease that, though? (and re-tightening, of course)
FSM states that the lower control arm (LCA) shaft nut should not be final tightened until the full suspension is installed and the weight of the car is on the garage floor with tires installed. Basically, it is the last thing tightened before the car is aligned
 
Just to be clear, the holes i mentioned are visible on the Firm Feel shaft that was pictured. Those are to lube the lower control arm bushings if you replace them with poly units, not oem style rubber bushings.
 
Just to be clear, the holes i mentioned are visible on the Firm Feel shaft that was pictured. Those are to lube the lower control arm bushings if you replace them with poly units, not oem style rubber bushings.
That makes sense. I thought you were talking about the control arms. Thanks!
 
Back
Top