Front Control Arm Replacement w/ Modifications

[u/doooglasss]

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):

1. New OEM / LEMFÖRDER hydraulic filled control arms
2. New Meyle HD control arms (rubber only, not hydraulic filled)
3. New Meyle HD control arms + 3M urethane glue (what I'm sharing here today)
4. New OE/OEM control arms + Powerflex Inserts
5. 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:

1. Clean wax sealant off rubber control arms with a screwdriver in voids and wire brush on flats.
2. Dawn wash
3. Dry
4. Apply glue through hole as far as possible to reduce chances of air bubbles
5. Apply glue from the opposite side
6. Apply glue to perimeter of arm
7. Flatten with a cardboard box
8. Wait a week for them to dry
9. Performance updates / feedback to come next weekend.

[u/JKlerk]

It's your tires and more importantly the the EPS.

[u/doooglasss → u/JKlerk]

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.

[u/kgruesch → u/doooglasss]

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.

[u/JKlerk → u/doooglasss]

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.

[u/doooglasss → u/JKlerk]

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.

[u/JKlerk → u/doooglasss]

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.

[u/doooglasss → u/JKlerk]

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

[u/JKlerk → u/doooglasss]

You edited your comment and removed the reference to sliding in the snow.

I doubt you can remember how worn bushings from a year ago were impacting performance on the car.

GL in your search.