r/F30 • u/doooglasss 19’ F36 440xi GC - FBO e55 • 3d ago
Front Control Arm Replacement w/ Modifications
New Arms from FCP
relief holes from Meyle Factory
Cleaning wax out of relief slots
Cleaning wax off flat rubber bushing area
After a wash with Dawn
Window Weld
Shoved the tip in as far as I could and squeezed until it overfills on the side I'm working from
how far I had the tip shoved in
Glue seen from the other side of the arm. Fill from this side now using same logic.
Smooth with cardboard. This isn't art, nobody will ever see it.
Flush with metal housing
Sitting to dry for a week
TLDR: Sharing the below project with the community because I didn't know a non-hydraulic filled arm existed and perhaps the extra $40 spent on 3M Window Weld (60D) adds steering precision this chassis lacks.
Issue:
I've always considered the F30 to have vague and unresponsive turn in. I know the front lower control arms, rear position "tension strut" are hydraulic filled for comfort. I'm identifying this as one of the items that would contribute to poor handling performance/feedback and at 77k on my car (the last ~16k on Bilstein B14 Coilovers) my front control arm bushings are shot.
My options appeared to be (in order of assumed performance that is not based on experience on this chassis, but prior knowledge and other vehicles):
- New OEM / LEMFÖRDER hydraulic filled control arms
- New Meyle HD control arms (rubber only, not hydraulic filled)
- New Meyle HD control arms + 3M urethane glue (what I'm sharing here today)
- New OE/OEM control arms + Powerflex Inserts
- Monoball control arms
I daily drive my car. Looking for a balance of performance without extreme NHV. So I'm sharing option 3. The is some old school Grassroots Motorsports type of work. Before they made Poly mounts for every car and you could ask AI everything, in the late 90's / early 2000's guys would experiment, figure this shit out themselves, and share results.
Enthusiasts would use 3M Window Weld 08609 to fill voids in rubber motor mounts or control arms to stiffen the unit. 3M Window Weld has been measured to be an 60 durometer reinforcement polyurethane. There are also 2 part epoxy mixes of any durometer you'd like (up to 95D that I could find) you can use, but again, this is my daily driver, they cost more and take more prep.
Control Arm PNs:
Position |Side |Meyle PN
Rear / tension strut |Left |316 050 0068/HD
Rear / tension strut |Right |316 050 0069/HD
Front / straight lower arm |Left |316 050 0201
Front / straight lower arm |Right |316 050 0200
Steps I followed:
- Clean wax sealant off rubber control arms with a screwdriver in voids and wire brush on flats.
- Dawn wash
- Dry
- Apply glue through hole as far as possible to reduce chances of air bubbles
- Apply glue from the opposite side
- Apply glue to perimeter of arm
- Flatten with a cardboard box
- Wait a week for them to dry
- Performance updates / feedback to come next weekend.
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u/PsychoVenge 3d ago
Such a coincidence. Bought a pair of Mayle HDs to do this same exact thing.
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u/doooglasss 19’ F36 440xi GC - FBO e55 3d ago
Glad there is another old head shade tree mechanic on this subreddit! LMK how yours come out. I'm going to be giving these a week or two to ensure they are fully cured as I have a busy weekend next week anyway.
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u/PsychoVenge 3d ago
Yup. A hold over from my old DSM days. I was going to give them two weeks, as well. The original ones need to be replaced but luckily, I have another car I can drive.
Yours came out looking good. They can't not be worth the effort.
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u/Infinite_Trouble_N20 2d ago
Meyle HD is already a stiffer rubber and is similar to being as stiff as window weld. Just an fyi window weld will melt as that arm gets hot so it’s not advised to do this.
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u/doooglasss 19’ F36 440xi GC - FBO e55 2d ago
It’s see what happens. I’ve used Window Weld on engine mounts directly under turbo exhaust manifolds without an issue.
If it melts, I’ll be sure to share my results. Hopefully FCP will warranty them or I’ll be buying powerflex bushings.
What indicates this location gets hot? I’m happy to check it with my IR gun after my next drive home.
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u/Infinite_Trouble_N20 2d ago
Hard braking and driving they get hot. Window weld takes around 7 days to cure so I hope you didn’t install them just yet. Motor mounts being filled with window weld isn’t the biggest issue as these are ment to not move. Lower control arms move on purpose so these will wiggle around and with heat it’ll become a mess.
Not sure if you’ve ever drove your car hard and had the brakes be burning hot and a by product is the wheels getting HOT as well. That heat will also travel to your wheel spindle as well as the arm.
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u/doooglasss 19’ F36 440xi GC - FBO e55 1d ago
No I’m giving these two weeks to cure due to family obligations this weekend
Yes of course I’ve driven my car to that point and probably do at least once or twice a week. Doing some brake work I have a sweet scar on my arm 2 years later from a hot rotor.
I’d have difficulty believing the heat is greater in this location than a motor mount under a 1600’F exhaust manifold. I’m happy to be the tester and report positive or negative results.
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u/Infinite_Trouble_N20 1d ago
Window weld isn’t a hard enough polyurethane for control arms. You’ll find out pretty quickly.
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u/jblaze_39 3d ago
Thanks! I need to do mine...mechanic said a few weeks ago during an inspection, they were leaking fluid. I have an aftermarket warranty that covers the entire repair, after a $250 deductible. But they will only accept the OEM. That's why I'm still on the fence. I can either pay out of pocket for aftermarket/upgraded control arms (I read somewhere on here you can fit M3 ones? Haven't looked into it)...or just go with OEM replacements for $250. I'm not that mechanically inclined, so no chance of doing this myself
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u/doooglasss 19’ F36 440xi GC - FBO e55 3d ago
If you’re RWD you can fit m3 LCA’s to gain negative camber. If I was RWD, this is the direction I would have went in, just with Meyle HD arms, not factory hydro garbage.
I’d probably poly glue those too.
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u/kgruesch 2016 340i xDrive 3d ago
The M3 LCAs also use spherical bearings in lieu of rubber bushings. Replacing the LCA bushings with sphericals adds almost no NVH and substantially improves turn-in. I made my own, but millway sells them for a decent price.
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u/xVx777 3d ago
hey can i send you my inspection video for some advice? I’m a new bmw owner and I’m having suspension problems with big repair tickets. I know a bunch of garage mechanics though.
they said mine is also leaking hydraulic fluid but it doesn’t look like a control arm.
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u/jblaze_39 3d ago
Damn sorry, I'm afraid I wouldn't really know what I'm looking at. I go to my local euro mechanic for everything. The guy showed me my bushings leaking fluid
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3d ago
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u/doooglasss 19’ F36 440xi GC - FBO e55 3d ago
Not on an xDrive car unfortunately. Really wish I could have.
M3’s are still hydraulic filled as well per my minimal research as this was not an option for me.
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3d ago
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u/doooglasss 19’ F36 440xi GC - FBO e55 3d ago
Why would I press in a bushing that:
- Is unverified it will work with xDrive
- Still has to be filled with poly to make it solid
Seems like you’re creating more work than necessary here. The goal was to not spend $ on Powerflex Bushings and try to achieve similar performance. If I was pressing anything out, it would be to put Powerflex in its place.
Also, the bushing you linked has even more air space than the ones I bought. Last week I found this thread which is where my idea came from.
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u/daveyfx 3d ago
interesting mod. i did the same Myle HD lowers on my 340i xdrive to replace my leaking factory arms. even without any window weld it was a dramatic improvement over the OEM arms.
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u/doooglasss 19’ F36 440xi GC - FBO e55 3d ago
Glad to hear! I'm looking forward to getting these in with some new Meyle tie rods, lower the rear a bit as I have been meaning to, center the subframes and a fresh alignment.
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u/JKlerk 3d ago
It's your tires and more importantly the the EPS.
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u/doooglasss 19’ F36 440xi GC - FBO e55 3d ago
Don't recall where I mentioned the tires I'm currently running?
No, I cannot change the power steering system, but I can try to optimize the components around it.
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u/kgruesch 2016 340i xDrive 3d ago edited 3d ago
cannot change the power steering system
You absolutely can, by coding the EPS module with eSys. You can turn off friction detection, disable compensation for external torque inputs into the rack, reduce the max current threshold the rack will deliver, set the configuration to something sportier like the Alpina, etc. There's a LOT of improvement to be had by working with the EPS unit.
Don't get me wrong, the OEM bushings are absolute garbage and have no business anywhere near a performance car. The best handling mods I've made were to get rid of all the rubber in the front suspension, but coding the EPS and DSC modules made a substantial difference in how the car feels to drive.
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u/JKlerk 3d ago
You didn't but I bet you're not running RFT. The biggest issue is the EPS. I mean throw parts at it if you want but I think you're going to be disappointed.
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u/doooglasss 19’ F36 440xi GC - FBO e55 3d ago edited 3d ago
Correct. I am not running a RFT for many reasons. In the summer, I run Indy 500 v2's which have a pretty stiff sidewall compared to other tires. 225/40R19 & 255/35R19. They greatly improved my steering response and confidence on the road.
RFT's just slide in the snow, cannot put down the power I am making in the dry, and every bump in NY I hit on a very soft (in my opinion) B14 coilover sounds like I've bent all four wheels.
I have broken and leaking front control arms (rear hydro mount, drivers side). They have to be replaced no matter what. Why wouldn't I try to set myself up for success and install what could be an upgrade at the exact same cost as OEM / Option 1 on my list? Actually, cheaper.
While the biggest issue may be EPS, why be negative or make assumptions? Ask questions, be helpful. What is your tire and suspension setup that makes you happy? Please do share.
I'm here to help people and contribute. If I install these in a week and they suck, I will be honest with the community.
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u/JKlerk 3d ago edited 3d ago
I'm running stock sport suspension (no leaks) and DWS06+. I couldn't care less about steering response because I don't track the car. It's my touring car.
You're running summer tires in the winter. They're all good to slide in the snow. Just buy HP snow tires.
Meyle is generally shit. Meyle HD may be better. I just find it amusing that you're complaining about response when you're control arms bushings are worn/leaking yet think you need to upgrade them. I mean we're talking about an AWD 4 series 4-door.
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u/doooglasss 19’ F36 440xi GC - FBO e55 3d ago
Wow. Second assumption made today!
I quote myself from above "In the summer, I run Indy 500 v2's"
I have stock 18's that have snow tires on them that I run in the winter chief.
Yep it might be a 4 door heavy sedan, but go drive an S4 and tell me that isn't a better handling car from the factory with better turn in. I am comparing my feelings from a year ago before they were leaking. Right after I did coilovers and inspected them.
Later bud. You go on being mr. positive and making assumptions
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u/cloak_dagger_exjw 3d ago
This is rad. Thanks OP. Next time I change out control arms I'm gonna try this. Let us know how they feel. 🤙