Vintage Fox modifications

 This is an article issued by an old French magazine. The article describes the preparation of a vintage FOX to run in the modified category. These 3 modifications, (1 for the rear and 2 for the front) were tested and approved by French drivers with some A-finals in the modified category.
The modified front trains were equipped with the anti-roll bar hop up.

These modifications use BOOMERANG parts and handmade alloy and epoxy parts.


The rear drive train

You will need:

  • Boomerang gearbox joints
  • Boomerang wheel axles
  • Boomerang drive shafts
  • Boomerang rear wishbones
  • Boomerang wheel axle supports
  • Boomerang rear wheels and adaptors
  • Boomerang rear shocks
  • 4 ball joints + balls
  • 3mm threaded shaft


This is the starting point, the original Fox rear end.

The original fox rear end


These are the parts required laid out.

The parts you will need


The modification begins with grinding of the gear box joints. Make 2 flat spots on each, enabling them to fit inside the Fox differential.

Modify the gear box joints



Now you can replace the rears arms, axle supports, drive shafts etc. with the Boomerang parts. Then, you need to cut two 3x25mm threaded rods to make the upper adjustable arms. Fix them on each side with a ball joint.

For the shocks, stock boomerang with the big pre-charge adjuster is to be used.

Your rear drive train is ready!

finished modified rear end modified rear end modified rear end


Now we will modify the front suspension.
Like mentoned above, there are 2 versions: horisontal mounted shocks and the more standard vertical shocks..


The horisontal front modification

 You need:

  • Boomerang front shocks
  • 1,5mm alloy plate
  • 2mm FPR plate
  • screws, long ball joints
  • nylon stops.


First, make two u-brackets in aluminium, according to this sketch.

Lower bracket for horisontal mounting


Secure it in the place of the big screw on the upper arm using an apropriate screw.

Front bracket horisontal installation


Make the shocks support in FRP or similar according to this sketch.

Fox front tower sketch


Fix the shock support to the chassis. Use longer screws and add nylon spacers.

Front tower horisontal installation


You now need to mount long ball joints to the new damper support and mount the Boomerang shocks upside down.


Finished modified Fox front suspension Finished Fow suspension

And there you have an easy to do "competition" front suspension.

 The following second version is a little harder to do because it will involve replacing the upper arm (similar solution as the rear modofication)


The vertical front modification

You need:

  • Fox servo stay
  • ball joints (to fit the top of the front upright)
  • 3mm threaded shaft
  • aluminium plate 1,5mm
  • FRP plate 2mm
  • front boomerang shocks

First, remove the upper arm of the fox.

Mount the ball joint and the servo stay at each end of the threaded shaft, making an upper adjustable arm, replacing the stock upper arm.

Make a 3 mm hole in the servo stays to fix them to the chassis with a 38mm screw.

Fox horisontal suspension mod


Make the shock support in FRP (see sketch) and fix it to the chassis.

Fox front shock support Fox horisontal suspension mod tower


Now, you can remove the small S alloy part on each side of the lower arms and make the under alloy shocks supports which will be fixed on the lower arm in place of the S.

Fox bracket for vertical mounting


And now, mount the shocks to the lower arm and the new shock support.

Fox horisontal suspension mod tower


And there you have a "vintage" modified Fox using Boomerang parts with some custom creations. 

Fox modified horisontal suspension Fox modified horisontal suspension Fox modified horisontal suspension Fox modified horisontal suspension


 This article is a translation & adaption of an article found in the French Buggy Magazine no. 6 September/October 1988.
Original text by Regis Faucqueur, Photos by Yves Faucqueur


Translated and edited by TB member stingray-63

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