Rear LCA experiences over the years

Unexplodedcow

Member
Joined
May 23, 2011
Posts
52
Reaction score
17
I have own a 2010 GT since 2012. Shortly after getting it, I decided to get J&M polyball rear LCAs. Never had a problem that I knew of.

Around 2017 or so, I lowered the car, changed out the sway bars, and added in LCA relocation brackets. Steeda sport springs, Maximum relocation brackets, and UMI upper, lower, and panhard bars with rotojoints and poly. Here are my thoughts about all that.

The OE LCAs use very large crush sleeves. In the torque box, they have small, .5mm textures to hold it in place at the body, and the OE torque is high (probably from having to torque through the bolt, and not the nut).

The J&M arms say to torque to OE (129 ft. lbs). The UMI arms say to torque to 72 ft. lbs. That's a large difference. So, what could happen with that torque spec?

Well, I've had the arms on my car about 1500 miles tops, mostly cruising, a few medium/hard launches on a slightly modified car (canned tune, 1 piece driveshaft), and even on stock tires sometimes. The J&M arms never had an issue with things, and never loosened up.

The UMI ones, however, have been extremely problematic. Some people say they clunk. Yup, they do...when the crush sleeves are hammering the bolts from sliding back and forth. I have been under the car to torque the bolts about 30 times in a few years, barely driving it.

I finally took the time (about a week) to really shakedown the car and trace the cause. The bolts were not loosening. I noticed problems at both ends. Elongated (wallowed-out) holes at both the chassis torque box, and in the relocation brackets, and hammered bolts/sleeves.

The body side is worse, particularly at the inner hole, where the stock bolt uses threads. The hole is probably 5/8 diameter (16mm). and not overly elongated. Ford used too large of a hole, IMO. Each aftermarket arm has crush sleeves that are much, much smaller, around 19mm outside diameter. This causes the sleeve to torque up fine, but partially extrude itself through the hole, and tear it up, along with the threads. The J&M clamped in just fine. UMI seems to use a stainless steel sleeve that kept getting worse and worse, losing about 3mm of length as it was pushed *through* the chassis hole. Increasing torque only made things worse.

I had some 1" OD, and 9/16" ID crush sleeves sitting around from a spare front control arm bushing (Prothane 6-218). They were a bit long, so I cut them down to 50mm and drilled out the poly front bushings to fit. I went with slightly upsides hardware (9/16" 18 thread) and used large flange washers on the inside (late 90s Humvee lug nuts, actually). The shank end fit well, while about 1/16" slop remained for the 9/16" threaded end. Torqued to OE spec 129 ft. lbs. and the arm does not move. Larger sleeves and hardware solved the issue.

The axle end is another story. UMI specs 72 ft. lbs on the roto joints. They can go slightly above this, to about 90 ft. lbs, but will otherwise collapse if torqued to 100+. The rear LCA bolt holes were also damaged, more on the shank sides. Larger 9/16" hardware and flange nuts again, and that worked, but the roto-joint collapses under higher torque is still a problem. Torquing to UMI spec will, 100% of the time, result in clunks. This is the roto-joint slipping in the LCA bracket, and hammering the bolt (not a good idea).

I even tried without the relocation brackets. Same problem exists, except worse. A shorter lever imparts higher loads on whatever is pushing against it, so the stock axle tabs are a shorter lever than with an LCA relocation bracket. Clunks were worse, and torque beyond 90 also collapsed the roto-joint. Yes, I ordered additional hardware and rebuilt the joints.

How is this fixed? Larger sleeves are needed front and back, so they can take the pressure without collapsing or extruding through/damaging the hole. Despite the massive ends on the OE hardware, those don't have issues with moving around. The downside to them is massive wheelhop.

Future plan is to expand the holes and weld in chromoly stepped washers to prevent the problem from happening again, while still using larger sleeves. I have no fix for the roto-joints, and am going to let UMI know my findings. I'm doubtful one random person will make a difference, but with the problems I've experienced with movement and yielding, I can't recommend the UMI rotojoint arms.

The panhard bar and UCA both use larger joints, by the way, and were able to handle higher torque loads to stop moving. I will say their bracket fit the stock 14mm bolt *tight* that it had to be seated in place with a small hammer. It moved slightly under UMI torque spec, but I increased torque without issue. It's holding well, and has been the entire time. The differential bushing is a BMR multi-piece urethane type. While difficult to get in the car with the axle in place, it's also worked out fine. The panhard bar simply works, and has given zero issues. The roto-joints themselves are built tightly, and I've seen zero wear inside. They do require good greasing, while assembling, and after, through the zerk fitting.

The quality of the UMI part is good. It's not like it's a cheap piece, or sloppily designed, but it comes down to failing to hold torque due to collapse and extrusion.

So, moral of the story: if you're having clunks and think it's a normal part of the joint or suspension design, it certainly is not. Something is loose, and requires tightening. If it fails under tightening, it's not a viable part.
 

MasterofDisaster

Senior Member
Joined
Jun 10, 2019
Posts
1,067
Reaction score
1,797
Location
Michigan
I installed UMI LCA in 2015 on my 08 GT. The instructions said to torque to 100ftlb. I think I went with Ford b/c I didn't use new bolts, so I applied 129ftlb. I do have a squeak that may be from the LCA, but no clunks I've noticed.
 

Unexplodedcow

Member
Joined
May 23, 2011
Posts
52
Reaction score
17
Are you using the Rotojoint version? If so, you may want to check for collapse or something loose.

I pulled the axle from my car about a half hour ago to make room for installing the weld washers, as well to get better eyes and measurements on the LCA brackets. Might do a few deadlifts for fun while it's out. I also still need to call UMI and let them know the issues. Much fun.
 

Juice

forum member
Joined
Aug 24, 2017
Posts
4,652
Reaction score
1,922
This is the result of getting rid of the "soft" bushing LCAs. That soft bushing absorbs a lot of shock. I had zero issues with the stock 2013 LCAs that came with the 8.8 axle assembly. And they are a bit lighter than the 07 V6 ones.
 

Midlife Crises

Senior Member
Joined
Jul 20, 2019
Posts
1,887
Reaction score
1,300
Location
Fairbanks, Alaska
This is the result of getting rid of the "soft" bushing LCAs. That soft bushing absorbs a lot of shock. I had zero issues with the stock 2013 LCAs that came with the 8.8 axle assembly. And they are a bit lighter than the 07 V6 ones.
I’m more inclined to believe its because of mismatched parts and or improper installation. The center tube in poly bushings is not supposed to rotate or wobble in the hole as the suspension moves. Just like the stock bushings, if they were run loose it would eat the mounting holes in no time. Another thing I have seen is an SAE bolt in a metric hole. Great way to make the UCA klunk.
 

skwerl

tree hugger
Joined
Aug 6, 2011
Posts
16,209
Reaction score
1,157
Location
central Florida
Stock Ford bolt has a slightly larger diameter collar to fit the hole. Aftermarket bolts are standard size, so some manufacturers use sleeves to make up the difference for the hole size. Others ignore it. Been a decade ago but I think I ended up using the Ford bolt to attach the relocation brackets. And my first setup on my first Mustang was UMI, had no issues with it once I figured out the difference in bolt size. Second car I used BMR, also no issues.

If you've buggered up the bolt holes, the brackets can be welded in place.
 

Norm Peterson

corner barstool sitter
Joined
Feb 5, 2011
Posts
3,615
Reaction score
317
Location
RIP - You will be missed
I’m more inclined to believe its because of mismatched parts and or improper installation. The center tube in poly bushings is not supposed to rotate or wobble in the hole as the suspension moves. Just like the stock bushings,
Not supposed to, but if the polyurethane pieces are longer than the inner sleeve you're not going to get the necessary amount of clamp load through the sleeve to prevent it from moving or rotating under load. Quite a bit of your installation torque gets wasted compressing the poly. Keep in mind that the sleeves supplied with aftermarket bushings do not feature the 'toothed' arrangement of the OE sleeves.


FWIW, I've gotten years of excellent service out of a set of rear LCAs made by Currie, though I did grind a little off of the ends of the poly to make sure that the sleeve would be the only points of contact in the chassis-side brackets. No squeaks or clunks, and only a bare minimum of periodic re-lubing (about once a year in a year-round, daily-driven car). Not sure they're making them any more, though.


Norm
 

Unexplodedcow

Member
Joined
May 23, 2011
Posts
52
Reaction score
17
So, I checked the diff. bushing, and it was internally shredded. How did this happen with a urethane BMR piece? No idea. The arm had been torqued to OE spec, and shouldn't have been a problem. The diff. was smacking against the UCA, and made a couple small dents in it, so that bushing was moving way too much. It's not moving now.

I spent the latter part of today pressing in a Steeda spherical bearing, 'cause why not at this point. Pull the axle from the car, did the work, installed it again.

I highly doubt it's the upper arm at this point, but yet again, one good launch, and the thing clunks with jiggling the car back and forth with the parking brake on. It does not do that prior to driving it, but every single time I drive it, that happens.

Been using the UMI upper arm, torqued the arm in the UMI bracket while in a vice, preloading it inward (since the mount hinges in slightly, and always has), but this has never been a source of noise to my knowledge. I'm hearing more overall noise with the Steeda bearing in the diff. and that's not surprising.

The weld washers went in over last weekend, to press-fit holes in the torque boxes, and since I have no way of welding, I went with a hard solder (better than an epoxy method). J&M arms with large front crush sleeves to fit the modified bushings. I can torque on these things all day, they seem to hold. The weld washers took the hole size back down to an M14 size. Arms were actually torqued closer to 140 ft. lbs than 129.

The swaybar bushings are tight and seemingly trouble-free. Hellwig rear bar, though I could put the stock one back on. My only other thought is that something is up with the MM relocation brackets, and that they're minutely shifting. I know a weld is cracked on one side from initial installing, and them hinging, but did not suspect it, as the bottom weld has held.

At this point, I am out of ideas, other than a bolt is losing torque somewhere, but it never measures that way when checking, loaded or unloaded suspension. I have gone through every bushing, checked every bolt, pulled and checked the axle itself. Nothing looks off, and the only questionable part was the BMR diff. bushing that shredded itself in about 1,000 miles, and the UCA bolt hole was slightly enlarged, by about .4mm (it can fit a 9/16 bolt now instead of only M14).

I have no answers; only questions, and am fed up to the point that I am seriously considering selling the car and ridding myself of this headache. Something is loosening, likely in the LCA area, after one good bit of acceleration and tire spin (stock tires), yet every single bolt torque checks out, and I can't find any movement. Literally no change from the messed up urethane bushing to the spherical, other than I can hear the clunk/knock better.

I have been testing with the car in neutral, parking brake engaged. Jiggle it, and it clunks. I can also hear a difference between coasting/mild decel, and mild acceleration when hitting bumps. Under load, the suspension sounds solid. When coasting or in decel, the knock sounds hollow. Something is shifting. I may try the OE LCAs next, or remove/replace the LCA relocation brackets.

After about 30 times being under the car, and close to 100 hours chasing this, I am pretty done with the thing.
 

Unexplodedcow

Member
Joined
May 23, 2011
Posts
52
Reaction score
17
I’m more inclined to believe its because of mismatched parts and or improper installation. The center tube in poly bushings is not supposed to rotate or wobble in the hole as the suspension moves. Just like the stock bushings, if they were run loose it would eat the mounting holes in no time. Another thing I have seen is an SAE bolt in a metric hole. Great way to make the UCA klunk.

I would normally suspect this, as well. Following the UMI spec torque, as well as an already large inner hole, which was originally not elongated, didn't work. Ford bolts, SAE bolts, other metric bolts. All were tried, nothing worked, though I did get slightly longer time to clunk using a 9/16 - 18 bolt with mostly shank. It fit very nicely. After the weld washer install for the inner holes, I've only tried the Ford hardware again, but no change. I think the 72 ft. lbs. torque spec from UMI was the cause at both ends, though torque box hole damage was more severe. For what it's worth, if a flange bolt/nut is used, metric or fractional wouldn't matter between M14 and 9/16, as there is about 0.4mm difference in diameter between the two. 18 thread SAE would have larger diameter shank and be capable of greater torque holding.

If I remember fastener torque limit, a class 10.9 M14 bolt with 2.0mm thread (what Ford used), would be capable of holding ~ 150 ft. lbs. of torque, while a 9/16 - 12 bolt would rate for about the same, and a 9/16 -18 would rate for around 170. The primary concern would be in using flange bolts and not cap bolts; worst case would be a cap bolt with a tight-fitting washer to act almost as a flange bolt (minus microscopic compression I'd guess).

What's curious is that only the inner holes of the torque boxes did this. The outer holes had no issue, while the outer holes on the LCA brackets show minor elongation and the inner ones are tight. Swapping to larger crush sleeves on the torque box end seemed to prevent any wobbling, though it didn't solve the clunk, regardless of hardware used.
 

Unexplodedcow

Member
Joined
May 23, 2011
Posts
52
Reaction score
17
Not supposed to, but if the polyurethane pieces are longer than the inner sleeve you're not going to get the necessary amount of clamp load through the sleeve to prevent it from moving or rotating under load. Quite a bit of your installation torque gets wasted compressing the poly. Keep in mind that the sleeves supplied with aftermarket bushings do not feature the 'toothed' arrangement of the OE sleeves.


FWIW, I've gotten years of excellent service out of a set of rear LCAs made by Currie, though I did grind a little off of the ends of the poly to make sure that the sleeve would be the only points of contact in the chassis-side brackets. No squeaks or clunks, and only a bare minimum of periodic re-lubing (about once a year in a year-round, daily-driven car). Not sure they're making them any more, though.


Norm
I had checked to be sure the poly wasn't wider than the sleeves, but might check this again to see if anything creeped. I didn't find any LCAs for the S197 on Currie's website, so I'm guessing they're no longer made. I've wondered if the lack of "teeth" on the sleeves might be an issue, but it's not causing an issue in the panhard bar or the UCA to body bracket.
 

Norm Peterson

corner barstool sitter
Joined
Feb 5, 2011
Posts
3,615
Reaction score
317
Location
RIP - You will be missed
I had checked to be sure the poly wasn't wider than the sleeves, but might check this again to see if anything creeped. I didn't find any LCAs for the S197 on Currie's website, so I'm guessing they're no longer made. I've wondered if the lack of "teeth" on the sleeves might be an issue, but it's not causing an issue in the panhard bar or the UCA to body bracket.
That certainly could be contributing, especially if any lube found its way between the ends of the sleeves and the inner sides of the brackets. It's at least theoretically possible that torqueing the poly sleeve down flattened the upsets in the brackets enough for the poly to start stealing clamp load, which again would make clunks more likely.

I suppose you could try contacting Currie directly to see if they could help you in any way.


Norm
 

Unexplodedcow

Member
Joined
May 23, 2011
Posts
52
Reaction score
17
I didn't notice any deforming of the torque boxes beyond bolt hole damage. They match from one side to the other.

I may get more sleeve material and make a few more, but with "teeth" this time. I'll also check the brackets to see if something is indeed shifting at that cracked weld. Rear shocks will be re-checked at the tops. I doubt these are the issues, but perhaps.
 

Pentalab

forum member
Joined
Mar 5, 2013
Posts
5,228
Reaction score
1,108
So, I checked the diff. bushing, and it was internally shredded. How did this happen with a urethane BMR piece? No idea. The arm had been torqued to OE spec, and shouldn't have been a problem. The diff. was smacking against the UCA, and made a couple small dents in it, so that bushing was moving way too much. It's not moving now.

I spent the latter part of today pressing in a Steeda spherical bearing, 'cause why not at this point. Pull the axle from the car, did the work, installed it again.

I highly doubt it's the upper arm at this point, but yet again, one good launch, and the thing clunks with jiggling the car back and forth with the parking brake on. It does not do that prior to driving it, but every single time I drive it, that happens.

Been using the UMI upper arm, torqued the arm in the UMI bracket while in a vice, preloading it inward (since the mount hinges in slightly, and always has), but this has never been a source of noise to my knowledge. I'm hearing more overall noise with the Steeda bearing in the diff. and that's not surprising.

On a side note, Kelly Aiken at BMR advised me, that if using poly at the front end of the UCA, NOT to use their BMR poly at the axle end of the UCA. Poly to Poly is bad news in a UCA, at least one end has to be able to rotate on it's axis a bit. Kelly highly recommended using the STEEDA spherical bearing at the axle end of the UCA. ( I was using the BMR adjustable UCA on my 2010, the one with POLY at the front end). The other option was to use the BMR adjustable UCA, that has a spherical at the front end, then the BMR POLY could be used at the axle end of the UCA. The oem ford rubber bushing at the axle end is still intact, so have not swapped it to the steeda unit.

Currently, I'm using HD BMR boxed LCA's (poly at both ends)..and BMR LCA relocate brackets.

I also had BMR adjustable PHB and mating phb brace in years ago, which was dead simple to adjust, after the rear was lowered 1.25". That was replaced with a whiteline watts link..( + eaton tru-trac LSD).

Zero clunks anywhere, with either config.
 

Unexplodedcow

Member
Joined
May 23, 2011
Posts
52
Reaction score
17
I'll likely end up buying different brackets in that case. In the MM relocation brackets, the inner laminate is welded top, middle, and bottom with long spot welds. The top weld cracked on the passenger side one, while middle and lower remained. This was caused, I believe, by the hinging of the bracket, where the front is closer together than the rear of the bracket. I had tried a crush sleeve as well, but it didn't help; no perceived difference. When contacting MM about it, they blamed the crush sleeve use. I haven't driven the car much since then; roughly 5 years. So, about 300 miles a year, mild cruising 90% of the time. Not a hard life, and I haven't seen the cracks expand, but also have not kept the closest eye on them.

I've debated on the Ford brackets or J&M, as I don't need a serious drop on the LCAs (not drag racing), and greater potential ground clearance around the tire may be useful. Strength, obviously, is critical, and since I have no access to a welder (either myself, and have zero confidence in local shops) bolt-in still seems the most logical, despite the greater potential for movement.
 

Unexplodedcow

Member
Joined
May 23, 2011
Posts
52
Reaction score
17
On a side note, Kelly Aiken at BMR advised me, that if using poly at the front end of the UCA, NOT to use their BMR poly at the axle end of the UCA. Poly to Poly is bad news in a UCA, at least one end has to be able to rotate on it's axis a bit. Kelly highly recommended using the STEEDA spherical bearing at the axle end of the UCA. ( I was using the BMR adjustable UCA on my 2010, the one with POLY at the front end). The other option was to use the BMR adjustable UCA, that has a spherical at the front end, then the BMR POLY could be used at the axle end of the UCA. The oem ford rubber bushing at the axle end is still intact, so have not swapped it to the steeda unit.

Currently, I'm using HD BMR boxed LCA's (poly at both ends)..and BMR LCA relocate brackets.

I also had BMR adjustable PHB and mating phb brace in years ago, which was dead simple to adjust, after the rear was lowered 1.25". That was replaced with a whiteline watts link..( + eaton tru-trac LSD).

Zero clunks anywhere, with either config.
I have a UMI roto-joint UCA, basically spherical at the body, and now spherical at the diff. side, too, as the BMR bushing was really torn up, split, partly shredded at one end (may have pinched, but not sure). It had cocked itself in the bushing shell, and I opted to just pull the whole thing.

My LCA were UMI Poly at the chassis end, and Rotojoint at the axle end, with MMR relocation brackets. Currently, J&M poly/polyball is on the car, as that's what I ran about 9 years ago on it, no issues. I didn't want poly on poly due to binding, and the car being mostly road, with a desire to track it. Zero interest in drag race.
 

crjackson

Member
Joined
Nov 28, 2015
Posts
625
Reaction score
315
Location
Midgard
So, I’ve been following this thread and I want to upgrade my rear LCA’s with the Billet Roush part. When I do the swap, I know the suspension needs to be loaded at ride-height when tightening.

If I back the car up on ramps, and start the removal, will the axle-housing and chassis slip out of alignment so as to make instilling the new part a challenge?

I’m planing to complete 1 side at a time to make sure one LCA is always locked in.

Oh, and for a future upgrade, I’ve decided (so far) to go with the Steeda UCA and bracket.

I really wanted the Roush Upper, but I’m just not confident about using the older version that’s not intended for my car (2014).
 

Unexplodedcow

Member
Joined
May 23, 2011
Posts
52
Reaction score
17
If using spherical joints or poly, then the suspension does not necessarily need to be loaded, as those bushings are not bonded, and free to rotate. The idea is that the center sleeve is what's compressed, with the bushing free to rotate. I used levers and/or ratchet straps to pre-load the control arm bolts in the holes, but it didn't do anything more than regular aligning and assembly.

Ford OE arms *must* be torqued with the suspension loaded (preferably level) due to the bushing rubber being bonded to the center sleeves, and those sleeves are "toothed" or knurled to resist rotation.

I also spent some time on the phone today with both UMI and J&M, just to get a feel for their designs. The J&M relocation brackets reminded me of the MM design, which seems to be quite strong. However, J&M said they had seen some that were crooked, possibly sprung from the welding process (I cannot validate this, but have seen pieces spring from jigs before), with the holes being crookedly drilled.

In speaking with UMI, they're looking at larger center sleeves for me, and possibly thicker walled roto joint balls that won't collapse under OE torque. They further suspected that the arms may be skewed from where they should be, and asked if non roto-joint arms lined up between location bracket and the torque boxes; they do not. Given the outer hole in the location brackets being slightly ovaled, and inner hole in the chassis side, I may have a crooked set of relocation brackets (possible theory).

Again, the UMI UCA and Panhard bard have been flawless, aside from a funky diff. bushing that seems to be resolved with the Steeda bearing in place. The primary difference is the 2011+ cars use a longer UCA than previous years if memory serves, and slightly different mount in the bracket. I'd suggest a matching bracket, or at least "anti-clunk" stepped washers for an aftermarket UCA.

I'm debating between the J&M or Ford relocation brackets to replace the MM ones, to see if they really are crooked, or if my axle is FUBAR from the factory, which would then force me back to stock height/LCAs.
 

crjackson

Member
Joined
Nov 28, 2015
Posts
625
Reaction score
315
Location
Midgard
Ford OE arms *must* be torqued with the suspension loaded (preferably level) due to the bushing rubber being bonded to the center sleeves, and those sleeves are "toothed" or knurled to resist rotation.

Yes, that’s my understanding. The billet Roush LCA’s use a rubber compound and to my understanding they’re manufactured with a different compound than stock. Even if that’s not correct, I need to replace my noisy stock parts, so I may as well upgrade them in the process, and ditch the stamped steel.

I used levers and/or ratchet straps to pre-load the control arm bolts in the holes, but it didn't do anything more than regular aligning and assembly.

So in your opinion, would I be able to lay on my back, and with the use of a pry bar, install these alone, and without major difficulty? I really don’t want to go to a shop unless it’s beyond what I can do without help.

When I do the UCA, I’ll get a shop to install probably. Would you stick with the supplied Steeda parts (UCA & Matching bracket/bushings), or would you go ahead and replace the Diff bushing with the spherical part?

I don’t really want to order the UCA that puts a spherical joint oat the chassis mount. From what I’ve read, putting the spherical joint on the diff, and poly or rubber on the front keeps the noise transfer at a minimum.
 

Unexplodedcow

Member
Joined
May 23, 2011
Posts
52
Reaction score
17
I installed mine with the car face-down, butt-up on jackstands, and have done so at least 30 times as I've taken things apart and repeatedly checked them. As long as the car is high enough, it's honestly not a bad job; height is needed to make room for a torque wrench.

The spherical bearing will absolutely make for a lot of noise in the cabin, regardless of location. It's a stiff setup. OE makes for the least noise, and anything beyond that is going to up the noise. The arm should pivot as the axle does, so a spherical at the body side makes sense, and is why I chose that way. The arm needs to move in an arc. With a poly body bushing, it can't move nearly as much. The diff. side doesn't need to flex as much.

The compromise is the rotojoint or (if J&M) poly-bushed spherical, which they quote as 88 durometer (assuming Shore D given other urethane bushings). That will still allow for movement, but less noise than a regular or delrin lined spherical.
 

Support us!

Support Us - Become A Supporting Member Today!

Click Here For Details

Sponsor Links

Banner image
Back
Top