Help! Bumper Troubles.
 

Guys,

I'm having a real hard time fixing the rear bumpers to the chassis. I've just spent the afternoon drilling holes (which I assumed where straight) into the chassis and the bumper tube (which I tried to keep level by clamping it steady) - only to find that after tapping the bumper tube and bolting it up it all goes to cock, and out of true.

I've tried three times on both sides now, and I just can't get them to sit level. I've even tried using ali shims, and that didn't work either.

Any tips? If I drill any more holes the chassis will look like swiss cheese. :(

Used ali shim on mine drilled a hole all the way from the bottom to the top then welded a nut to the top of the chassis and put a long bolt all they way though.

I found me left side was wonky so drilled out the hole on the bumper till it would sit straight.

The ali shims where added to stop the wobbling.

To stop it twisting I put a hole in the side of the chassis - no hole in the tube behind. I tapped the and put a bolt in which stops it turning (one for each side).

So one bolt top to bottom to stop it pulling falling out then one in the side to steady it.

It is a bit of pain getting the side bolts in with the tub on but it made all the difference.

I hope that helps :)

One of mine is slightly wonky but you can't see them when your driving!! :lol:

I found the ali shims were solid enough (ie required a mallet to get the bumpers fully in) so that it didn't move when you drilled the hole. Maybe use slightly thicker ali??
Or could you wedge a block under the bumper with a jack to keep it straight??

I drilled a m4.5 hole through both chassis and bracket, then tapped the hole in the bracket to m5 and enlarged the hole in the chassis to about 5.5m.

This gave some room for adjustment as you could rotate the bracket slightly, then I squirted silicone sealant into the hole, lined it up and did the bolt up tight. Seems OK so far.

1. Shim out the bumper tubes first so they cant move within the chassis. I wrapped a piec of copper (from a copper tube) round mine as it happened to give the best fit. I pop-riveted the shims to the bumper tubes to stop then getting "lost" in the chassis rails.

1a. Fit the bumpers to the chassis. I clamped a long staight edge accross the two to make sure thay were square.

2. Drill a pilot hole (3mm ish) right through the chassis and bumper tube.

3. Remove bumper.

4. Drill out the hole in the chassis and tap. I tapped mine to 6mm.

5. Now the trick.... Get a couple of longish 6mm screws (30mm>) and file a taper on the end where it will pass through the bumper tube. Leave just enough thread on the rest of the screw to screw into the tapped hole on the chassis. (Crap explanation but I think you will get what I mean...)

6. Open up the hole in the bumper tube so that it is just big enough to take the fattest part of the taper. Probably about 5mm will do.

7. Slide in the bumper and roughly align the holes. Screw in your tapered screw - it should pull the bumper tube into exactly the right position as it goes.

If it's any comfort I had to do mine twice before I came up with this trick....

Robin

Thanks guys - I'll give it another go after the hols. :)

Martins clam a bar across the two if them worked - they're straight now, thank god! :)

thanks again, and happy Christmas