[WileyCobra]

HI FFfriends,
I’m considering converting my completed MkIII 4-link to a 3-link to improve handling for autoX and road courses. Has anyone done this? Is there a source for a conversion kit, or plans, or am I fooling myself about the wisdom of this course?

Thanks in advance for input.
Eric

 

[Michael Everson]

Factory five has the kits to do this. If your Mark 3 is new enough, it might already have the upper link mount welded in place.
Mike

 

[WileyCobra]

Factory five has the kits to do this. If your Mark 3 is new enough, it might already have the upper link mount welded in place.
Mike

Thanks Michael. I had been told that FFR offered the kit, but I’m also interested to know if anyone else has done it or has input on the advantages of the end result.

 

[MauiKarl]

I did it years ago, a pain to do but well worth it! It’s more planted in corners especially if there’s bumps. I autocross it regularly and do well. I had to cut out part of the back wall behind the passenger seat to access the Bolt in bracket, and buy a drill extension to drill from underneath. I recommend it.

 

[CraigS]

Absolutely do it. The difference is amazing. The only difficult part is the frame mount for the 3rd link. It goes very near where your right hand 4 link attaches. On my MkII I had to cut away part of the 4 link mount. Compare this pic of 4 link
4-Link Rear Suspension - Factory Five Racing
to this pic of 3 link
3-Link Rear Suspension - Factory Five Racing
I only removed what I needed to of the 4 link bracket and actually used the remainder as reinforcement for the 3 link bracket. Plan to remove the passenger seat and cut an access hole in the aluminum panel. It makes all the difference. The kit 3 link bracket comes w/ holes in it to bolt it to the underside of the cross tube. I cut a plate w/ matching holes, dropped a couple of G8 3/8 bolts through and welded the heads to the plate. I pushed that bolt plate into the open end of the frame tube and maneuvered it so the bolts dropped through the holes. Another note; you can install the banana bracket, the panhard bracket, and the new axle brackets, while still driving the car as a 4 link. I did that so I could do it in stages and still drive the car. The final stage was removing the top 4 links, doing the 3 link frame bracket, and installing the panhard and 3rd link. BTW a close enough set up for pinion angle is, before removing the 4 links, look at the clearance from the rear surface of the banana to the diagonal panhard tube. It is about 3/8" so adjust your 3 link to the same gap. I drove mine for months that way before actually measuring pinion angle.

 

[WileyCobra]

Excellent info. Thanks very much!

 

[nsisaac]

I completed this upgrade in 2018, one year before I sold my Mark III. Grinding and drilling was the most time consuming part.

Here are the parts, sources and 2018 prices:

Breeze: $857.95
(#21108) Spanner Wrench Set for QA1 Proma-Star Coil Over Shocks 1
(#70676) 3-Link Rear Shock Kit, Single Adjustable, w 250lb/in Springs 1
(#70730) Rod End Rear Lower Control Arm Kit 1

VPM: $210
Vintage Performance Motorcars: Both items
Banana Bracket Support Brace Kit
Frame Bracket Support Brace Kit

Factory Five: $650
#13181 - 3-Link Retrofit Assembly
#15237 Traction Lok Bracket Set (free)
(#5974 had older 4-Link style Traction-Lok Brackets, so FFR provided the upgraded bracket set for free)

Trunk view (had to relocate FFMetals battery box from trunk center to left side)

Left side view (blue tape to remind me to torque bolts to spec)

View from passenger seat into access hole (towel soaked with water to reduce hot sparks)

Right rear view

Good luck and enjoy the upgrade.
Nate

Sold Fall 2019
FFR #5974 BRG (PPG-Subaru Green), 306, 93-GT-40 heads, E-cam, Hypereutectic D&D rebuilt T-5 trans, 3-link, 3.73 rear, North Racecars A/C, Firewall Forward and expanded footboxes, Kirkeys, CobraEarl Trunk, wipers/washer, Custom Tonneau cover (Phil & Kay), FFR Softtop, and 15" Cooper Cobras.

 

[WileyCobra]

Thanks for all the great info and pics! Very helpful.

 

[johnnybgoode]

2X on Mark's QA1's and rod-end LCA's. These two mods significantly improve the ride quality of a three-link car in my opinion. Scott