Issue with BMR lower control arm bearing kit bk055

[Radiation Joe]

I'll add my contribution to this thread. I've been riding on my BK055s for about 3 or 4 weeks. Initially, the rear suspension felt bound up tight; particularly on the passenger side. I also experienced the clicking/grinding sound with any movement of the car. During this period, I put the car through it's paces on a 300 mile drive that included 70+mph on I95 between Philly and Wilmington. For those unfamiliar with the current condition of that stretch of road, lets say it will use most to all of your suspension travel.
The binding has minimized, but the noise continues. If I run the car through a car wash, or it rains, the noise disappears for a day or two. When the noise comes back (washed yesterday) I'll try the de-torque technique and report back.
On a related topic, I didn't replace the toe bushing at the knuckles when the BK055s were installed. The rear seems to go through significant toe changes under load with suspension travel. Is it more important to change to the toe bearing at the knuckle once the BK055s are installed?

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[Robottrainer]

I've been reading this with interest. I put a post asking about people's experience with these and whether others are having problems-longevity on the street before I invest any time and aggravation.

I have these loose and I can confirm a couple of things. The length of the straight section of the bushing is .675". The overall length is 1.293" on one and 1.280 on the other (.013" difference probably a machining error). The width of the bearing is 1.373". This leaves rough a .020" gap between the two bushings.

The only way I see this working is when the bolt is torques it squeezes the inner ball between the two bushings which causes the outer race to rotate and pivot around the inner ball. If the bushings are touching (too long) and you torque them to spec, it will not trap the inner ball between them. What happens then is the inner ball can pivots around the bushing, given how stiff the bearing is, and the bushing can also pivot around the bolt which would make alot of noise and would explain why the noise would go away when you loosen the bolt or spray lube into it (and why that is a temporary fix). The center ball should remain stationary and the other race/housing pivots around the ball

I also noticed that one of the bushings is a tighter fit than the other. I would think it would be more beneficial to have the bushing as a light press fit.

The total width of the bushing installed is 2.59" The opening in the subframe has to be at least that much for it to fit. Not sure where BMR is getting the 1.31" dimension from.

 

[jmeiers]

I've been reading this with interest. I put a post asking about people's experience with these and whether others are having problems-longevity on the street before I invest any time and aggravation.

I have these loose and I can confirm a couple of things. The length of the straight section of the bushing is .675". The overall length is 1.293" on one and 1.280 on the other (.013" difference probably a machining error). The width of the bearing is 1.373". This leaves rough a .020" gap between the two bushings.

The only way I see this working is when the bolt is torques it squeezes the inner ball between the two bushings which causes the outer race to rotate and pivot around the inner ball. If the bushings are touching (too long) and you torque them to spec, it will not trap the inner ball between them. What happens then is the inner ball can pivots around the bushing, given how stiff the bearing is, and the bushing can also pivot around the bolt which would make alot of noise and would explain why the noise would go away when you loosen the bolt or spray lube into it (and why that is a temporary fix). The center ball should remain stationary and the other race/housing pivots around the ball

I also noticed that one of the bushings is a tighter fit than the other. I would think it would be more beneficial to have the bushing as a light press fit.

The total width of the bushing installed is 2.59" The opening in the subframe has to be at least that much for it to fit. Not sure where BMR is getting the 1.31" dimension from.

Thanks for the update on this thread and the measurements. I tried reaching out to BMR over a year ago and also gave my receipt and they were supposedly going to send a better replacement. Never got a response and have given up on them fixing this shit! Fortunately, my car is not a daily but the lower bolt torque 120 ft lbs. vs 166 ft lbs. is still keeping it mostly quiet.

I am dreading it but I may pull both bearings out completely and go with the Steeda setup. Although, I may try and pull the driver side and machine the spacers and see if I can torque them down all the way without the noise.

 

[moffetts]

My Steeda bearings are silent, for what it is worth. I would definitely go that route if you are going to go through the effort of pulling them.

 

[Robottrainer]

Thanks for the update on this thread and the measurements. I tried reaching out to BMR over a year ago and also gave my receipt and they were supposedly going to send a better replacement. Never got a response and have given up on them fixing this shit! Fortunately, my car is not a daily but the lower bolt torque 120 ft lbs. vs 166 ft lbs. is still keeping it mostly quiet.

I am dreading it but I may pull both bearings out completely and go with the Steeda setup. Although, I may try and pull the driver side and machine the spacers and see if I can torque them down all the way without the noise.

That's a lot of money and aggravation to have them not honour the warranty. Everything I wrote is just my theory. Its alot of grief to prove or disprove it.

 

[shogun32]

This leaves rough a .020" ...
The center ball should remain stationary and the other race/housing pivots around the ball

So there's a couple schools of thought on this. If the straight shank portion are "perfect" you get no noise from the slop of them sliding back and forth in the 'eye' of the inner bearing. It also means there is little/no pinching of the bearing and so no distortion and little tendency to impart a rotating moment from the shank into the bearing.

The other is to design them to be slightly short (say 0.1mm) and thus to do the opposite of above. We don't need for it to rotate axially just twist and take up mis-alignment. It is perfectly acceptable to grease the straight shanks and shoulder so at least some of the rotation is independent of the heim bearing and it's teflon-derived race material.

That there is a 0.020" (0.5mm) gap between the ends means there is tremendous side-loading on the bearing shell depending on fastener torque, and opportunity to distort it. This is IMO serious design fail. I would go buy shims from McMaster and shim it to 'zero' (or smidge under) preload.

I also noticed that one of the bushings is a tighter fit than the other. I would think it would be more beneficial to have the bushing as a light press fit.

that's a side-effect of machining tolerance and anodize thickness. A slip fit or *very light* tap with a hammer should send them effortlessly to the shoulder. Less than 0.05mm undersize.

The total width of the bushing installed is 2.59" The opening in the subframe has to be at least that much for it to fit. Not sure where BMR is getting the 1.31" dimension from.

the chassis opening is probably 2.6+ and for whatever reason it seems BMR quoted you 1/2 distance.

I'm guessing on the sizes but https://www.mcmaster.com/shims/ring-shims-7/id~14mm/ is probably what you need.

 

[Robottrainer]

So there's a couple schools of thought on this. If the straight shank portion are "perfect" you get no noise from the slop of them sliding back and forth in the 'eye' of the inner bearing. It also means there is little/no pinching of the bearing and so no distortion and little tendency to impart a rotating moment from the shank into the bearing.

The other is to design them to be slightly short (say 0.1mm) and thus to do the opposite of above. We don't need for it to rotate axially just twist and take up mis-alignment. It is perfectly acceptable to grease the straight shanks and shoulder so at least some of the rotation is independent of the heim bearing and it's teflon-derived race material.

That there is a 0.020" (0.5mm) gap between the ends means there is tremendous side-loading on the bearing shell depending on fastener torque, and opportunity to distort it. This is IMO serious design fail. I would go buy shims from McMaster and shim it to 'zero' (or smidge under) preload.

that's a side-effect of machining tolerance and anodize thickness. A slip fit or *very light* tap with a hammer should send them effortlessly to the shoulder. Less than 0.05mm undersize.

the chassis opening is probably 2.6+ and for whatever reason it seems BMR quoted you 1/2 distance.

I'm guessing on the sizes but https://www.mcmaster.com/shims/ring-shims-7/id~14mm/ is probably what you need.

Maybe if the the BMR tech could chime in on this. If the intent is for the bearing to just pivot and compensate for irregular movements of the control arm I would agree. After all the rear bushing is in fact a smaller spherical.

If the bearing ball is meant to be free floating, not pinched between the bushing, then yes the bushings should be slightly longer than the width of the ball, however that would mean any rotation that occurs would have to be between the ball and the bushing sleeves or the ball/bushing/bolt. The ball would not rotate on the race but would pivot to take up misalignment. In my opinion this isnt desirable either as this means there would be steel (ball) on aluminum (sleeve/bushing), and aluminum (sleeve/bushing), on steel (bolt). The other problem in all this is there is no way to lubricate it other than taking it apart every once an awhile.

The question is, what was the design intent? It starting to look like that for a mostly street driven car the SuperPro Poly bearing is probably the better way to go.

 

[Robottrainer]

So a little experiment with the BK055s I have. Take the scenario where the spacer/bushings touch inside the ball. This would mean when the bolt is torqued, there is minimal force clamping the ball between the bushing/bracked. When the control arm moves, the ball would move with the race and rotate around the bushings like a plain bearing, except being steel on aluminum would eventually damage the the bushings.

Next, if the bushings dont touch but not enough torque is applied or the bolt stretches so, again, not enough clamping force. A new stiff bearing would move lock step with the race as the control arms move, but in this case cause the bushing to rotate with them and would damage the large face that sits between the mounting tabs. Eventually it would wear and reduce the clamping force further. Also, at the rated torque, is there enough clamping force to hold the ball so it doesnt slip between the bushings and allow the race to move around it when the arm moves (if the ball is an extremely tight fit to the race)? These situation are most likely the cause of any creaking, groaning, or clicking.

I went out and bough two Grade 8 5/8" X 3-1/2 bolts, 4 hardened washers and 4 fender washers (1 set per bearing. I stood up one of my press v block and sandwiched the bearing between the other. I applied about 1000lbs of force to hold the bearing in place which would simulate it in the control arm (the forces to press it into the control arm and in operation would be much greater). I then torqued the bolt to rough 140lb/ft (in practice it should be tighter but tough to do as the bearing wants to pivot). This is enough to clamp the ball. As you can see with a long ratchet, it moves fairly freely and will loosen over time. This makes a good point that in order to have it noise free, and working properly it is important that the bushing do not touch in the center, that proper fasteners are used (makes a good point for buying new bolts), and that everything is torqued correctly.

Also, the majority of the manufacturers state not to use any lubricant as it may degrade the PTFE coating. The PTFE, with pressure and heat from movement deposits itself on the ball much like wax when you wax you car. Lubricant may prevent this from happening or may react adversely with the PTFE. Lubricants also attract dirt. Probably the best thing to do, if you can do it, is to run a boot over the bearing. I'm going to try it. I bought some Seals It #56 boots. I'll see how they fit.

 

[WildHorse]

This makes a good point that in order to have it noise free, and working properly it is important that the bushing do not touch in the center, that proper fasteners are used (makes a good point for buying new bolts), and that everything is torqued correctly.

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[Robottrainer]

Last thought. If the bearing/bushing/LCA combo is narrower than the inside of the two mounting tabs, there may not be enough clamping force applied to the bushing to clamp the ball even torqued to 160lb.ft. This could also cause noise and may need shims to solve it

 

[jmeiers]

Update:

After over 2 years with the BK055 bearings, I finally got to the root cause of the snapping/clicking noise. On my car, I isolated the noise to the driver side and I previously explained earlier in this thread that I stopped the noise backing off bolt torque from the the 166 ft/lbs. to only about 120 ft/lbs or in other words just enough to take out any space. All this time, I have driven it this way and no issues with the bolt backing out but I have always wanted to figure out the real problem.

Fast forward to 9/10/2022, I finally had a spare day and decided to pull the RLCA out. I verified that the bearing spacers were in fact touching each other within the bearing and that when the bolt is fully torqued down, it was causing the noise. I do not have a lathe so I carefully used my angle grinder with a cutoff wheel and cut off about 1/8 inch from both spacers. After this, there is now plenty of room between the spacers and no way they can touch regardless of bolt torque. Happy to report that the bolt has been fully torqued down to 166 ft/lbs. per spec and there is no noise.

Anyone still having the noise with the BK055 bearings should definitely try this fix. Anyone planning to install these bearings should check the spacer clearance BEFORE putting the RLCA back on the car.

 

[Robottrainer]

Update:

After over 2 years with the BK055 bearings, I finally got to the root cause of the snapping/clicking noise. On my car, I isolated the noise to the driver side and I previously explained earlier in this thread that I stopped the noise backing off bolt torque from the the 166 ft/lbs. to only about 120 ft/lbs or in other words just enough to take out any space. All this time, I have driven it this way and no issues with the bolt backing out but I have always wanted to figure out the real problem.

Fast forward to 9/10/2022, I finally had a spare day and decided to pull the RLCA out. I verified that the bearing spacers were in fact touching each other within the bearing and that when the bolt is fully torqued down, it was causing the noise. I do not have a lathe so I carefully used my angle grinder with a cutoff wheel and cut off about 1/8 inch from both spacers. After this, there is now plenty of room between the spacers and no way they can touch regardless of bolt torque. Happy to report that the bolt has been fully torqued down to 166 ft/lbs. per spec and there is no noise.

Anyone still having the noise with the BK055 bearings should definitely try this fix. Anyone planning to install these bearings should check the spacer clearance BEFORE putting the RLCA back on the car.

Update:

After over 2 years with the BK055 bearings, I finally got to the root cause of the snapping/clicking noise. On my car, I isolated the noise to the driver side and I previously explained earlier in this thread that I stopped the noise backing off bolt torque from the the 166 ft/lbs. to only about 120 ft/lbs or in other words just enough to take out any space. All this time, I have driven it this way and no issues with the bolt backing out but I have always wanted to figure out the real problem.

Fast forward to 9/10/2022, I finally had a spare day and decided to pull the RLCA out. I verified that the bearing spacers were in fact touching each other within the bearing and that when the bolt is fully torqued down, it was causing the noise. I do not have a lathe so I carefully used my angle grinder with a cutoff wheel and cut off about 1/8 inch from both spacers. After this, there is now plenty of room between the spacers and no way they can touch regardless of bolt torque. Happy to report that the bolt has been fully torqued down to 166 ft/lbs. per spec and there is no noise.

Anyone still having the noise with the BK055 bearings should definitely try this fix. Anyone planning to install these bearings should check the spacer clearance BEFORE putting the RLCA back on the car.

Glad you solved it

Update:

After over 2 years with the BK055 bearings, I finally got to the root cause of the snapping/clicking noise. On my car, I isolated the noise to the driver side and I previously explained earlier in this thread that I stopped the noise backing off bolt torque from the the 166 ft/lbs. to only about 120 ft/lbs or in other words just enough to take out any space. All this time, I have driven it this way and no issues with the bolt backing out but I have always wanted to figure out the real problem.

Fast forward to 9/10/2022, I finally had a spare day and decided to pull the RLCA out. I verified that the bearing spacers were in fact touching each other within the bearing and that when the bolt is fully torqued down, it was causing the noise. I do not have a lathe so I carefully used my angle grinder with a cutoff wheel and cut off about 1/8 inch from both spacers. After this, there is now plenty of room between the spacers and no way they can touch regardless of bolt torque. Happy to report that the bolt has been fully torqued down to 166 ft/lbs. per spec and there is no noise.

Anyone still having the noise with the BK055 bearings should definitely try this fix. Anyone planning to install these bearings should check the spacer clearance BEFORE putting the RLCA back on the car.

Glad you solved it! I proved that if the bushings touch in the middle, the spherical bearing won't be clamped so instead of the combination of the ball/housing turning on bushings which will make a hell of a noise. The ball is very stiff for a few hundred miles making a bad situation worse. I hope BMR has addressed it. Seems like a tolerance stack up issue.

 

[S550 Recon]

Almost looks like that KellTrac dude knew what he was talking about. Shocker?

 

[Jeepwx03]

We have tested multiple sets of the BK055 and none of what we have tested have had issues. However that doesn't mean that we could have recieved a bad batch. If you are having this issue please email over a copy of where you purchased them so we can get them warrantied for you.

I just installed these on Saturday and I'm having the bouncing and clicking issues. I purchased them directly from the BMR website. My hopes were purchasing them directly I would get an updated version that solved this issue.

 

[Robottrainer]

I just installed these on Saturday and I'm having the bouncing and clicking issues. I purchased them directly from the BMR website. My hopes were purchasing them directly I would get an updated version that solved this issue.

If you go back to older threads you will see this problem crops up from time to time. The issue is with the insert bushing being too long and butting together. Some were too long.

When you torque the bolts, rather than clamping the bearing, the bushing get clamped so the bearing is sliding rather than than rolling. Torquing more just butts the two ends tighter together.

This is a bigger problem with this big bearing as it is very stiff when new and you need the ball clamped hard while it breaks in an loosens up. Spaying oil or grease in there provides temporary relief of the noise.

You will have to remove the control arm and file down the ends of the bushings until there is about a .010 or more gap.

I find this alot with BMR lately. I bought the camber links and had to make new Inner bushings, as the ones supplied were too short.

If you tightened them in place they would clamp on the delrin and not the inner sleeve. The arm would have pivoted on the clamped delrin instead of the delrin pivoting on the bushing.

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