BMW E46 M3 Rear Wheel Arches Rusting
The 2nd most common E46 enquiry we receive (after RACP work) is 'Rear Arch Rust'.
All E46 Rear Arch corrosion starts from the Inner Arch area.
Regardless if you can only see a small blister on the Outside Arch area.
We can guarantee you that the epicentre is hidden under Seam Sealer on the Inner Arch area.
This means if you aren't tackling the Inner Arch area then the corrosion will return.
Regardless if you can only see a small blister on the Outside Arch area.
We can guarantee you that the epicentre is hidden under Seam Sealer on the Inner Arch area.
This means if you aren't tackling the Inner Arch area then the corrosion will return.
We've been tackling E46 Rear Arch corrosion for many years now and if you've followed us on our YouTube channel, and Facebook/Instagram pages you would have seen several of our repairs.
2X Rear Arch Flares with Inner Flange (+55mm) Complete Rear Bumper (For Side Exhaust setups) Optional Extras: 2X Rear Bumper Flares, For Those Wishing to Retain OE Rear Bumper and Exhaust ($500 off) Carbon Fiber Front Lip with Chassis Mounted Brackets ($1200) E46 Race Dash in FRP or Carbon (Starts at $995) M3 GTR Hood Vents in Carbon ($500). E46 NFS GTR Wide Arch Bodykit To Fit Coupe And Cabrio Only This kit will fit the saloon and touring but rear arches foul the door so modification will be needed Inspired By The E46 GTR Featured In The Popular Need For Speed Video Game Consists Of Wide Front Bumper And 4 Bolt/Rivet On Arch Extensions Designed To Work With The Original BMW Sideskirts and Rear Bumper Adds 50mm a side at the front and 90mm. Chassis Panels & Sheet Metal for BMW 3-Series E46 (1999-2006): Fenders and Support Parts.
Redish offer 2x different E46 Rear Inner Wheel Arch Repairs:
- New BMW Metal Inner Wheel Arch Panels £2895.
or - 3M Panel Bond Adhesive (aka CSL style) Inner Wheel Arches £1595.
(Prices are for both sides, and include all paints/materials/labour, and VAT).
By far the most popular version is our 3M Panel Bond Adhesive (aka CSL style) modification.
This is where we remove a section of the Inner Wheel Arch Panel - especially the 'U shape channel' which removes 99% of E46 Inner Arch rust.
We leave this cut as that's how it is on the CSL Wheel Arches.
Once all the remaining loose corrosion has been removed/cleaned from the Outer Wheel Arch 'U shape channel' we treat any bare metal with a chemical to stop it further corroding.
We then improve tyre-to-arch clearance by gently closing some of the Outer Wheel Arch 'U shape channel' (all hidden on the inside of the arch system).
Then the area is thoroughly dried and inspected before we protect it with Etch Primer.
Then we carry out our pioneering-repair to bond the Inner and Outer Wheel Arch Panels together using 3M Panel Bond Adhesive - just like a CSL.
We also ensure the remaining Outer Wheel Arch 'U shape channel' is not only completely filled with continually-joined 3M Panel Bond Adhesive, but also envelopes the entire front face of the 'U shape channel'.
This means the vehicle retains it's strength of the 'U shaped channel' but it's completely flat and therefore water/salt/mud cannot collect and instead simply slide down the newly created vertical line and fall onto the ground.
Once cured we further protect the repaired area (Inner Arch area) with High Build Primer, Sprayable Seam Sealer (textured), and 'Redish E-coat' OEM colour.
Finally we treat the internal hidden sections to copious amounts of high performance Cavity Wax for total protection.
This is where we remove a section of the Inner Wheel Arch Panel - especially the 'U shape channel' which removes 99% of E46 Inner Arch rust.
We leave this cut as that's how it is on the CSL Wheel Arches.
Once all the remaining loose corrosion has been removed/cleaned from the Outer Wheel Arch 'U shape channel' we treat any bare metal with a chemical to stop it further corroding.
We then improve tyre-to-arch clearance by gently closing some of the Outer Wheel Arch 'U shape channel' (all hidden on the inside of the arch system).
Then the area is thoroughly dried and inspected before we protect it with Etch Primer.
Then we carry out our pioneering-repair to bond the Inner and Outer Wheel Arch Panels together using 3M Panel Bond Adhesive - just like a CSL.
We also ensure the remaining Outer Wheel Arch 'U shape channel' is not only completely filled with continually-joined 3M Panel Bond Adhesive, but also envelopes the entire front face of the 'U shape channel'.
This means the vehicle retains it's strength of the 'U shaped channel' but it's completely flat and therefore water/salt/mud cannot collect and instead simply slide down the newly created vertical line and fall onto the ground.
Once cured we further protect the repaired area (Inner Arch area) with High Build Primer, Sprayable Seam Sealer (textured), and 'Redish E-coat' OEM colour.
Finally we treat the internal hidden sections to copious amounts of high performance Cavity Wax for total protection.
Once cured our repair is rock-solid, and will not allow corrosion to form.
This is a repair which Redish Motorsport have pioneered after years of experience with the E46 chassis and especially chasing corrosion, as well as having utter confidence to open up BMW chassis's to component metal form and produce adequate solutions to common problems.
We are soon-to-release a brand new video detailing our 'Rear Arch modification aka CSL style'
In the mean time please feel free to watch our old way of the repair using New BMW Metal Arch Panels:
Bmw E46 Rear Arch Repair Panel
I actually didn’t take a single photo of this entire process, but about a week ago I set aside the whole weekend to do the rear arch rolling. I knew this was going to be a little changeling, not because of the arch rolling itself, but because BMW decided to pack the inner lip of the rear arches with some kind of sealant to help prevent rust. That’s a good thing – I like their idea behind it – but it’s a nightmare if you want to roll the arches!
I did a lot of reading about the procedure, and the majority of what I said was take it slow, use some heat, and swear a lot! That’s pretty much exactly what I did. A combination of a couple of various chisels, a blowtorch, and a LOT of patience, and finally they were done. After over 1 whole day, I may add!
Finally though, my new wheels are now fitted – all around. The fronts just fitted straight away, no issues at all, it was the rears that caused all the headache
I’m really pleased with it though, looks fantastic. Completely transformed the car
E46 Rear Ashtray
And then fast-forward to yesterday, after about a week since the new wheels have been on, I went for alignment. I spaced out fitting the new wheels & alignment by a week or so to make absolutely sure that I was happy with how the car was sitting.
I knew the alignment would be a quite badly off, but -9 rear toe on one side! That’s impressive!
The man himself working his magic. Always highly recommend The Wheel Alignment Specialist in Southampton
Final results
Not exactly what I was hoping for on the rear. We had a look into it and it seems there must be something bent causing so much negative camber (drivers rear). I’m yet to investigate that further, or if I will, but the excess camber is causing toe-in problems too.
I’m hoping it might be a bent upper rear wishbone (as that’ll be the easiest to change). A bent trailing arm is fairly unlikely as they are solid cast, so I think I’ll try a replacement upper wishbone first — but this is fairly low on my todo list, it’s not causing any untoward characteristics
A few more photos again, now with the alignment done. Sitting nicely!