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MG MGB Technical - Harness / Loom Fitting

I want to fit a replacement loom to my 71 model GT as the existing one is damaged, butchered, unwound, etc. And I want to make some modifications eg relays. I read somewhere that there's a problem getting the new loom through the firewall/bulkhead. Has anybody had any problems in this regard?
Thanks, Neil
Neil22

Neil,

No problem getting the loom through. As far as I can remember it goes from the car to the engine compartment feeding it gradually piece by piece until you have got it into the correct position. Good luck.
Iain MacKintosh

Hi Neil, I am just about to do the same with my roadster. One piece of advice that I got at Silverstone was to cut all the existing connections rather than disconnecting them - this makes reconnection a lot simpler as you can swap wires like for like. This advice came from Danny Waters - owner of the Green MGB reg MG1800 as seen in Clausager's book. I believe that Danny used to rebuild "new" MGs that had been written off before delivery. Yours, Dave
DM Gibson

Thanks Ian. Have you done it yourself, as it looks a tight squeeze!

Thanks too Dave; I've read that somewhere else, seems sound advice!

Neil
Neil22

I removed the loom from my engine bay at the weekend, feeding it into the cockpit, as my engine bay is undergoing a repaint.

It went through the bulkhead relatively easily and I don't see why it should be any worse feeding it back in.
Dave O'Neill 2

Neil,

Yes I have done the job myself and it wasn't too bad. Remove the speedo and the tacho to give you more access and you will get on just fine. You can just sit on the seat and work away at it. You may have to remove the steering wheel cowl dependant on where the connector is.
Iain MacKintosh

Out of interest what would an auto electrician charge to put a new loom in?
c cummins

Thanks Ian; I like to know whether knowledge comes from experience! From what you say, I'm assuming that you didn't remove the dashboard... which makes me happy!

Neil
Neil22

The later the model the harder it is as there are more wires i.e. it is thicker. On a 1980 I taped the spurs off the new harness that would end up in the engine compartment some forwards and some backwards such that the thickness of the harness was relatively constant. If you leave the spurs trailing you could end up with too much thickness to pull through the hole. You need to put split sleeving round the edges of *both* holes in the bulkhead to avoid sharp edges nicking wrapping tape and insulation on your new harness. The vast majority of wires on the harness are self-explanatory as they split off by the component to which they are connected. Chopping wires and leaving the tails on (horrible practice) is only as good as any how all the POs have left it. You really need to know what connects to where as wire colours can be subtly different through age, dirt and a different shade. The only head-scratching I had was two in-line fuse by the fusebox connected green to green on one and white/brown to white/brown on the other, whereas they should both be green to white/brown.
PaulH Solihull

No Neil, didn't remove the dash my car is 72 metal dash. Once you get into the job the problems will go away the worst part is thinking about it.
Iain MacKintosh

I reinstalled my loom some 4 years after it was removed from my '72 Roadster. There was no dash or precious little else at the time so access from within the cockpit was easy.
I did much as the others have suggested but I pulled the spurs close to the main loom with cable ties to minimise the diameter, then sheathed it in one layer of polythene to give it a more slippery surface. All went pretty easily although I made use of my 'beautiful assistant' when both pulling and shoving were required. Don't forget to thread the large bulkhead grommet onto the loom at the beginning as it can be a bit awkward to fit once the loom in place.
Richard Coombs

This thread was discussed between 26/07/2011 and 29/07/2011

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