Now that I have the engine running, I want to shorten the original BMW engine wiring loom. A couple of the connectors are multi-pin ones that have the pins sealed into the body of the connector and are quite expensive to replace like for like.

I only need to shorten the wiring on one of the two ends in each case and I don't particularly want to cut the loom to take a section out of the middle and have to solder the ends together or add an additional connector.

Is there any reason why I cannot reuse one of the original connectors by drilling out the existing pins, connecting new pins to the shortened loom and then araldite them back into the connector block?

If you can rebuild the connector to be as robust and reliable as it is now then I can't see why you should not reuse it. But if it was me I would cut a section out the loom and solder and heatshrink the joint or buy new connectors maybe these would be suitable
http://www.ebay.co.uk/itm/6-Way-Genuine-AMP-Superseal-Waterproof-Electrical-Wiring-Multi-Connector-/140938481537?pt=UK_CarsParts_Vehicles_CarParts_SM& amp;hash=item20d0968f81

I haven't done a Bmw but Ford, Vw , Audi, Peugeot ect that I have done all use a fairly standard type of connector. Some are easier to re-use than others.

A set of extraction tools helps with some plugs but not others. Some come to bits with just a small awl.



I have re used connector's as you have suggested but I find the best way is to leave the connectors well alone and shorten the wire itself. I prefer mechanically twisting the conductor with minimal solder and covered with glue lined heat shrink for single joints and glue lined heat shrink crimps on multi spurs.

I also prefer minimal connectors so wouldn't use two extra pairs of connectors to add or take length.

the main issue with reusing factory connections is the machine crimped terminals, they are almost impossible to uncrimp, and youll be very lucky if any terminals that are widely available happen to fit the factory ones.
IMO, you're better off cutting the standard loom and re-connecting, depending on if external (engine bay) with some superseal, (super cheap in bulk on ebay) or if internal (behind dash), with some uninsulated butt crimps (possibly solder, although its sometimes frowned upon for automotive use) and heatshrink. both will give a more reliable, robust connection than bodging the terminals in the original connectors.

Thanks for the advice. I normally use Vehicle Wiring Products as they are local, but they didn't have what I need. However, I've now found these guys on line and it turns out that they are just down the road from me as well.

Seem to be reasonable prices for a decent product so I'll give them a go.

Connectors

ebay for real cheap if you can wait from hongkong, or just cheap if you select uk items
http://www.ebay.co.uk/sch/i.html?LH_BIN=1&_sop=15&_sacat=0&_from=R40&_nkw=waterproof+connectors&_pgn=6&_skc=125&rt=nc />
[Edited on 25-8-13 by loggyboy]