Rear Bumper Mounting Bolts?

[GTO]

2 weeks ago I had a young women rear end me at a traffic light, I think she was playing on her phone!
My rear bumper has 4 bolts each set are welded to a plate 1 bolt on each side sheared and the bumper dropped, last accident I had on this vehicle was in 2010 it was also a rear ender and the bumper did the same thing in that accident the other vehicle hit at a slow speed so other than the bolts shearing there was no damage to my 2.4SRX.
This time left rear light and number plate light were taken out and the bottom area where the lights sit was pushed in a bit, exhaust was slightly damaged from bumper dropping.

I fitted new bolts but I was thinking wouldn't high tensile bolts be better or would that cause more damage?

Also is welding bolts to plate necessary?

[Tim86]

If you don't want the bolts to shear easily use Grade 8.8 (usually anodized black) with a shank (unthreaded portion near bolt head) to increase the cross sectional area. Looking at your sheared bolt you would need a shank length of about 10-15mm and if the nut bottoms out on the shank add an extra washer on the nut side. My favourite CT spot for special bolts is TopFast in Paarden Eiland.

You don't need that plate - use good thick washers that fully cover the oval holes in the chassis rails. I have however previously implemented additional plate on the inside of the chassis rails through which the bolts pass to stiffen up the rails as they thin out towards the rear of the vehicle and turn into 'C-sections'.

You would need considerable rear end force to buckle the chassis with the rear bumper properly fixed to the chassis - for a standard rear end scenario a properly fixed bumper will eliminate those small irritating damages. Let the foam bumper of the modern vehicle behind absorb the impact.
If the bumper is used as a towbar I would feel much happier with proper strength bolts too.

[GTO]

Thanks very informative, will try the Bolt It in Diep River

[GTO]

Let the foam bumper of the modern vehicle behind absorb the impact.

That Mini definitely absorbed most of the impact.

Radiator was a goner, fenders etc

Airbags didn't go off though.

[niclemaitre]

I've added U-channel to the inside of my chassis rails and enlarged the bolts that hold the bumper on (also got a custom bumper - similar to the original though). I think the U channel was a 400mm section of 75mm U-channel with I think M14 HT bolts

[GTO]

Bearing Man don't do this particular bearing,went to few different places eventually was told to go to Zhous Enterprises they are the agents for Nachi bearings no stock in CT has to come from JHB will get it early next week, R 115.

[GTO]

Sorry posted on wrong thread

[pietpetoors]

I welded flat bar (angle iron will be better) on the inside of the bumper bracket underneath the chassis. This prevent the bumper bracket from moving up when you hit the tow bar on the ground.

See
https://www.hilux4x4.co.za/towbar-mod-I ... /index.php

[Dowe Koos]

Hi Stephen, I agree with Tim and Pieter. It's the best way what they suggested.