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Re: 1974 1800 Magnum on the mot trail

PostPosted: Sat May 27, 2017 11:36 pm
by 1972nail
Lower on the driver's side - This can be caused by weak springs front or rear (usually rear) or both front and rear, worn inner front suspension bush on the bottom arm and/or weak shocks.

To check the springs, set the car on level ground. Use a trolley jack dead centre under the front subframe to raise the car up very high. This will load the rear suspension and exagerate any weakness in the rear springs. Do the same to test the front springs by placing the jack under the diff.

Try swapping the rear shocks over side for side. The less worn and hence stiffer passenger side rear shock may be enough to lift it up sufficiently.

I did these checks on my Bro's saggy Sports Hatch last year and simply swapping one rear spring for a good 2nd hand one was all that was needed. We swapped the shocks over as well.

Re: 1974 1800 Magnum on the mot trail

PostPosted: Sun May 28, 2017 7:32 am
by cooperman
Well done for getting so much done in such a short time, it's looking really nice, keep up the good work

Re: 1974 1800 Magnum on the mot trail

PostPosted: Sun May 28, 2017 10:08 pm
by 1972nail
Magnum Force wrote:Good call on the suspension test David, will give it a try :goodideasign:


You're working on the back brakes next, so here's another tip! Well more specific, the handbrake.

The self adjusting brakes work fine but the handbrake tends to become mediocre over time. The pivot points in the mechanisms wear, cables stretch and there's very little or no adjustment and you tend to find that there is a temptation to move the axle cable clevis pins to the inner holes of the connectors to tighten everything up.

Yes it works but it reduces the leverage and therefore the efficiency. I replaced my cross axle cables with 4mm SS threaded rods with nylocks. I covered the exposed length of the rods with shrink wrap tube to look like cables. This allows you to have adjustability and efficiency. It costs less then new cables too!

Re: 1974 1800 Magnum on the mot trail

PostPosted: Tue May 30, 2017 11:00 am
by 1972nail
Good news. :)

Re: 1974 1800 Magnum on the mot trail

PostPosted: Fri Jun 02, 2017 11:09 pm
by 1972nail
Later Magnums had Cibie halogens as standard and they work OK. Relays are a good idea, even for the standard lights. The headlight system doesn't have a fuse, but instead it has a thermal overload cutout. This is rated at something like 28A but as it tires with age and heat it can start cutting out on main beam - no lights till it cools down.

The main worry on the Magnum is the switch and wiring in the centre console (7 dial dash). The contacts are small and can get dirty/pitted, this causes a bit of over heating, melting the insulation on the wiring. Dismantiling the switch for cleaning isn't difficult and well worth while for peace of mind. I assume the twin dial dash switch is probably just as prone to to this problem too.

Re: 1974 1800 Magnum on the mot trail

PostPosted: Sat Jun 03, 2017 8:17 am
by 1972nail
I believe that they are all the same. You'll need to open the switch to get at the internal contacts. Use a proper electrical greae or Vaseline as a lubricant on reassembly.

Re: 1974 1800 Magnum on the mot trail

PostPosted: Sat Jun 03, 2017 6:38 pm
by droopsnoot
If you're putting rear wheelarches on, a sill isn't a terribly difficult thing to bend from flat steel plate IMO. The complicated bit of the sill is only at the back end - and the arch has that bit.

Re: 1974 1800 Magnum on the mot trail

PostPosted: Sun Jun 04, 2017 7:24 am
by lord13
Looks like my estate arches . . . don't be disheartened, it's actually not to bad, rear arches can be bought from expressed panels i believe and, as someone said earlier, sills can be made out of sheet steel.

Re: 1974 1800 Magnum on the mot trail

PostPosted: Sun Jun 04, 2017 8:21 am
by 1972nail
lord13 wrote:Looks like my estate arches . . . don't be disheartened, it's actually not to bad, rear arches can be bought from expressed panels i believe and, as someone said earlier, sills can be made out of sheet steel.

If buying from Expressed Panels don't forget to ask for VVOC membership discount :wink:

Re: 1974 1800 Magnum on the mot trail

PostPosted: Tue Jun 06, 2017 2:48 pm
by Fred Dukes
Expressed Steel Panels have my pair of HC outer sill skins which they are supposed to be making a patter from - must find out what their intentions are! As Mike says if you are using their rear wheelarch repair panels which have a complete arch to the bottom of the sill you don't need the frilly bit on the end of the sill :roll: :wink: