7 mm thin-wall tube spanner or hex socket
 

Hello All,

I am attempting to take the voltage regulator off a Lucas "style" alternator. The issue is that my sets of Kincrome, Sidcrome, Trojan a some "no name" mini sockets feature socket walls that are too thick. The three 7 mm hex head bolts are in a deep and very thin recess which none of my sockets can fit into.

I spent hours today going to four specialist tool suppliers; an autoparts store; and a hardware store. I also took the alternator to a local auto electrician. All without success. The options I was given were to: 1) get a die grinder and make the recess wider in the voltage regulator casing so a socket will fit; 2) grind down a 7 mm socket until the wall is thin enough to fit into the recess; or 3) do a combination of both.

The details about the alternator: it is known as either a Land Rover part number: RTC5084; or a Lucas code of LXA119; or A127 Type alternator. They fit everything from Land Rovers including my ex-Army Series 3; Land Rover Defenders; Massey Ferguson tractors and some Fords to name a few. So it is not a "rare" part.

The voltage regulator has a parts code of YR-818 or alternatively UCB150

Does anyone know of a supplier of thin-wall 7 mm hex nut tube spanners or hex sockets?

I also went to an electronic parts store and their hex nut drivers only go up to 6 mm - sigh! :bang:

I need to change the brushes and reassemble the alternator. I had to split it into half so I could clean it properly after it was subjected to years of being sprayed by a faulty power steering pump on a farm. It was just one chunk oil laced grot, grime and cow manure. I just need to change the two brushes - or get the whole voltage regulator.

The Catch 22 situation is that to reassemble the two halves of the alternator I have to take the voltage regulator off so the brushes do not get damaged. Then fit the voltage regulator as the final step before re-installing the alternator back into the vehicle. To do this I need to be able to get the bolts off and put them back on.... Catch-22 .... Argghhh!

I included an image of the alternator's voltage regulator.

Imaged accessed 11th November 2021 from, https://www.ebay.com/itm/311909551662...

No the company does not sell tools - I emailed them and other suppliers of the part!

Kind regards
Lionel

Have you considered taking a deep socket and having it turned down to fit the deep recess ?

Hello James,

Thank you for the suggestion James. However, as I do not have a lathe it would need to be done professionally. If I could find a local company who would accept such a "small job" it would cost the same in labour as buying a new alternator.

It also annoys the hell out of me that such a common and inexpensive part; at 20 Australian dollars, would be machined so it requires such a secret squirrel tool.

Kind regards
Lionel

Hello All,

I had thought of buying a cheap 7 mm socket and fitting it to a 1/4 inch extension bar. Putting the extension bar into a battery operated drill's chuck. Then using a bastard file on the rotating socket until the socket fits the recess space.

Rough as guts I know. What irks me is that it is something that is a consequence of poor design.

Or maybe it is a case of deliberate engineering. Where people cannot readily take the bolts out so they just give up and buy a whole new alternator. Something that I will not be doing.

Kind regards
Lionel

Hello All,

Another option could be to measure the outside diameter of a 7 mm socket and match it to a drill bit. Centre punch the 7 mm hex head bolt and drill it out while enlarging the recess hole at the same time. The thickness of the voltage adaptor should allow enough length of the bolt to use some vice-grips on to undo. It means sacrificing three bolts which will need to be replaced.

Again this is something that should not have to be done just because of poor design.

Kind regards
Lionel

Grind
 

The drill and file method you mentioned is ok but very slow. You could use a angle grinder instead of the file but be super careful , wear face protection and rotate the socket slowly. The socket will want to fly off so it needs to be firmly jammed onto the extension.

Buy a little lathe, every vehicle restorer needs one !

Mount the socket directly in the drill Chuck and grind one half then turn it around grind down the other half.

https://m.youtube.com/watch?v=iPa0jFlFW70

I'd do it with a bench grinder and eyeball.

You will need a 1/2" chuck drill (think of that as a "mini lathe") and a angle head grinder with a flap wheel to do this trick, put the deep socket in the drill chuck and while running both, work the flap wheel along the socket till you bring it down to the desired size that will fit in the recess. I would replace the 7mm bolts with allen headed caps (as they should have in the first place).

I am not sure why there is mention of deep sockets above but surely it is possible to grind the outside of a 1/4" drive 7mm socket until it fits. This could easily be done by eye, holding the socket by a long 1/4" drive extension and using either a bench grinder or an angle grinder held still by someone else or even ratchet strap it to a pallet (for example). Just go slow and don't try to take too much off quickly. It doesn't need to look pretty, just work.

David

I agree that safety should be a factor in this operation. Consider the relative motion of the part being turned down (socket) and the "cutting tool" (file, grinding wheel, flap disk...) and try to arrange it so that the forces push the socket onto your holder (extension rod, mandrel, ...) rather than trying to make it fly to the far corner of your shop (through you).
I also agree that it would make so much sense if manufacturers would design assemblies to make service easy rather than hard, particularly if they are selling the repair/replacement parts (rather than leaving it to the aftermarket). Perhaps designers should have a mandatory month working (hands on, not observing) in repair shops each year to keep this in their minds...

If the depth is what you are showing in your photo of the regulator, run a dremel cutting disc over each screw putting a slot on them and remove them with a screwdriver. Don't be afraid to go into the old regulator if need be.


Grinding down your cheapest 7mm socket to a tapered point would not be hard to do either. I would use an angle grinder myself with a sanding disc after fixing the socket on an extension and running it in the drill press.

How about a nut driver screw driver......
 

I have a set of cheap ones ...hand held screw driver handle with a permanent socket at the end..........each driver is a different size.......and the walls are very thin/cheap but mine are Imperial ..... may be they have similar in Metric.

Some deep sockets are already quite thin-wall, especially the multipoint drive ones. Other possibilities are a 'Jubilee' clip driver or take some suitable thin-wall tube, file a taper on a 7mm bolt and use it as a broach to make your own box spanner.

'thinning' a socket using a bench grinder might be an option, too (assuming single sockets are cheap) - mount the socket on a 1/4" hex to square adapter in an electric drill and gently apply it to the grinding wheel (making sure the socket and wheel are rotating in opposite directions). Gloves and eye protection are mandatory for this operation!

Best regards,
Chris.

Mount a flap wheel/sanding disk or whatever its called where you are on a angle head grinder and take a pass at using a bench grinder wheel. This is what you want for a clean polished look.

https://www.princessauto.com/en/10-p...t/PA0008908808

Hello Bob,

I was trying to buy some of the hex nut drivers that you describe locally and did not manage to. The closest I came was a set which only went up to 6 mm.

I can buy sets online like this one in the photo. However I do not know how thick the walls are. I could be waiting for them to arrive in the post only to find that the walls are too thick.

Well, one eBay order for the set of nut drivers at $26 Aus including postage has just been placed. I have to take the gamble that they fit I suppose. A set would come in handy anyway even if it does not fit the alternator.

Kind regards
Lionel

Hello Mike, Bruce, James, David, Grant, Rob, Bob, and Chris + All,

Thank you for all your different suggestions of options to solve the machining issue with bolt access for the alternator. Also, thank you for the safety precautions as well - they are greatly appreciated.

As mentioned in the message immediately before this one, I have ordered a set of hex nut drivers online.

Last night I also contacted a fellow member of an Australian Land Rover forum. While we live two states away from each other they do own a metal lathe, rotary grinder and a milling machine. They very kindly agreed to machine the socket down for me. I will post down a socket and an old voltage regulator that the auto-electrician dug out from a pile for me yesterday. The regulator must have been easier to find then their adapted socket.

So between the hex socket driver order and the interstate machining task I should have all bases covered.

I will just need to be patient. Sigh.

I will let you know how I go. Thank you again for all the replies.


Kind regards
Lionel

Hello All,

Just a quick update on the thin wall socket. I did buy the set of nut drivers mentioned in an earlier post. Their 7 mm one's walls were too thick for to gain access to the alternator bolt head. While I was waiting I bought two types of 7 mm socket: a normal sized and a deep socket. I asked a fellow member of a Land Rover forum if they could use their lathe to turn the sockets down for me. I sent them the sockets and the voltage regulator with a pre-paid return envelope. Gavin turned the sockets down and bought a socket to turn down for himself for future use.

I had also bought a new voltage regulator from the UK. As it turned out the new voltage regulator and the interstate posted modified sockets arrived at home within two days of each other. The modified sockets worked! Thank you Gavin!

I have since used the nut driver set on other projects and they are a versatile tool. So it was an investment not a loss.

Kind regards
Lionel