New rear bumper for Rooies.

Discuss modifications on your 1979 to late 1998 SFA 4x4 Hilux here.
Post Reply
User avatar
niclemaitre
LR 4WD Full Lockers
LR 4WD Full Lockers
Posts: 695
Joined: Mon Jun 13, 2011 2:44 pm
Town: Stellenbosch
Vehicle: 87 DC 2.8D
Real Name: Nic
Location: Stellenbosch

Wed Sep 20, 2017 10:53 am

The 30 year old stock rear bumper on Rooies was very tired and rusty. It also had no way to use it for recoveries. I was beginning to become worried that a trailer might break the hitch point off. So it was time for a new one.

With some input from my engineering mates I designed a new one that has recover points, is directly inline with the chassis rails and looks somewhat stock.
Rear Bumper Plate Solid hole move.jpg
Stress caluculations
Rear Bumper v2.jpg
10mm plate laser cut by TFD in Strand.
WhatsApp Image 2017-09-05 at 16.30.37.jpeg
Happy trails
Nic

SFA '97 DC affirmatively shopped
SFA '87 DC "Rooies"

User avatar
niclemaitre
LR 4WD Full Lockers
LR 4WD Full Lockers
Posts: 695
Joined: Mon Jun 13, 2011 2:44 pm
Town: Stellenbosch
Vehicle: 87 DC 2.8D
Real Name: Nic
Location: Stellenbosch

Wed Sep 20, 2017 10:57 am

Cut the holes in the rear valance and test fitted the new brackets.
WhatsApp Image 2017-09-09 at 17.17.31.jpeg
Test fitting and tacking the tubes. Going to need to move the number plate...
WhatsApp Image 2017-09-09 at 13.10.40.jpeg
Also got some 3x38x76mm channel to add support inside the chassis rails.
Happy trails
Nic

SFA '97 DC affirmatively shopped
SFA '87 DC "Rooies"

User avatar
niclemaitre
LR 4WD Full Lockers
LR 4WD Full Lockers
Posts: 695
Joined: Mon Jun 13, 2011 2:44 pm
Town: Stellenbosch
Vehicle: 87 DC 2.8D
Real Name: Nic
Location: Stellenbosch

Wed Sep 20, 2017 10:58 am

WhatsApp Image 2017-09-19 at 17.43.31.jpeg
WhatsApp Image 2017-09-19 at 17.43.17.jpg
And done.
Happy trails
Nic

SFA '97 DC affirmatively shopped
SFA '87 DC "Rooies"

User avatar
coetzer94
Low Range 4WD
Low Range 4WD
Posts: 217
Joined: Tue Nov 18, 2014 9:13 pm
Town: Pretoria
Vehicle: Hilux Xtracab 3.0 D-4D 4x4 2014
Real Name: Vian

Wed Sep 20, 2017 11:18 am

Looking good!!
--------------------------------------------------------------------------------------------------------------------------------

Working on my bucket list only makes it longer

User avatar
coetzer94
Low Range 4WD
Low Range 4WD
Posts: 217
Joined: Tue Nov 18, 2014 9:13 pm
Town: Pretoria
Vehicle: Hilux Xtracab 3.0 D-4D 4x4 2014
Real Name: Vian

Wed Sep 20, 2017 11:18 am

What load did you apply for the stress analysis?
--------------------------------------------------------------------------------------------------------------------------------

Working on my bucket list only makes it longer

Mars
LR4WD, Lockers, Crawler Gears
LR4WD, Lockers, Crawler Gears
Posts: 1286
Joined: Mon May 07, 2012 12:33 pm
Town: Pretoria
Vehicle: Toyota Hilux Dakar 2.8 GD-6 DC 4X4
Real Name: Marnus
Location: Pretoria Oos
Contact:

Wed Sep 20, 2017 11:25 am

Very neat. How are the pipes attached to the brackets?

User avatar
niclemaitre
LR 4WD Full Lockers
LR 4WD Full Lockers
Posts: 695
Joined: Mon Jun 13, 2011 2:44 pm
Town: Stellenbosch
Vehicle: 87 DC 2.8D
Real Name: Nic
Location: Stellenbosch

Wed Sep 20, 2017 12:00 pm

I don't know what load was applied for the stress analysis, I can find out it you want though.

The pipes were (badly) fillet welded to the tubes. I suck at fillet welds, but I can use a grinder
Happy trails
Nic

SFA '97 DC affirmatively shopped
SFA '87 DC "Rooies"

Mars
LR4WD, Lockers, Crawler Gears
LR4WD, Lockers, Crawler Gears
Posts: 1286
Joined: Mon May 07, 2012 12:33 pm
Town: Pretoria
Vehicle: Toyota Hilux Dakar 2.8 GD-6 DC 4X4
Real Name: Marnus
Location: Pretoria Oos
Contact:

Wed Sep 20, 2017 1:21 pm

:laugh2:

You know what they say. "If you need to grind your welds then your'e a grinder not a welder!"

Still looks good though.

User avatar
coetzer94
Low Range 4WD
Low Range 4WD
Posts: 217
Joined: Tue Nov 18, 2014 9:13 pm
Town: Pretoria
Vehicle: Hilux Xtracab 3.0 D-4D 4x4 2014
Real Name: Vian

Thu Sep 21, 2017 10:10 am

It would be a interesting discussion topic: Do these recovery holes take into account the load of the vehicle as well as the forces experienced during a recovery?

Lets say for a recovery the forces are 3x the weight of the vehicle (sucking thumb here) and add to that a safety factor of 2?

Your calcs should look something like this:

Vehicle 2000kg
Dynamic weight during a recovery: (x3) 6000kg
Safety factor of 2: 12 000kg

you can halve that value if you recover from 2 point at once, but for peace of mind i would analyse them for the total load on a single point.

I'm not sure about any of these numbers, but its just to get the conversation started?
--------------------------------------------------------------------------------------------------------------------------------

Working on my bucket list only makes it longer

User avatar
niclemaitre
LR 4WD Full Lockers
LR 4WD Full Lockers
Posts: 695
Joined: Mon Jun 13, 2011 2:44 pm
Town: Stellenbosch
Vehicle: 87 DC 2.8D
Real Name: Nic
Location: Stellenbosch

Thu Sep 21, 2017 10:13 am

You're not actually moving the weight of the vehicle, you're overcoming the friction between the surface and the vehicle, so it's a bit more complicated than that.

Anyway, these are mounted far more securely than the old one was. The bumper itself is attached to the channel and chassis rail with two M12 grade 8.8 bolts (normal recovery points are two M10 bolts). The channel is attached to the chassis rail with one M14 8.8 bolt right through the top and bottom of the chassis rail and another M10 8.8 bolt through the top of the chassis rail.
Happy trails
Nic

SFA '97 DC affirmatively shopped
SFA '87 DC "Rooies"

Post Reply

Return to “1979 to early 1998 Hilux (Gen 3&4 aka SFA 4x4)”

  • Information
  • Who is online

    Users browsing this forum: No registered users