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MG MGA - Drain Plug for 5-Speed Conversion

I am finishing a 5-speed conversion to the T-9 gearbox. those who made the conversion know that there is no drain hole in the tranny. I've read a couple threads where folks have put in a drain hole. Can some of you give me an idea of where to put the drain hole and what size plug to use? I figured it be better to do this now while I'm still putting the gearbox in, rather than later. Also, are there any good methods of adding oil once the gearbox is in?
J Butler

There are two places people put them. This is where Peter Gamble has them, on the aluminium flange behind the cast iron casing

See the black bolt head centre right - mine is here. This is said to be the best place because in others the casing is too thin to get a solid thread in the hole


dominic clancy

And this is the other. The bulge is to hold a magnet inside the casing, and the magnet has a hole in the centre



dominic clancy

Add the oil the same way as for the rear axle, with a bottle of the correct oil which should come with a cap and a tube that fits to the cap. Put the end of the tube in the filler hole and squeeze the bottle hard to force the oil up the tube. Best done with the car *safely* jacked up high or on a lift. The oil is not the same as for the rear axle!
dominic clancy

I was told that the (very expensive) Ford oil is for life.
gva guido

I was under that impression too. Mine has done 15 years to date!

Steve
Steve Gyles

Ah yes! But life for an MGA might be considerably longer than that anticipated for a Sierra. Shane
Shanerj

Drilled mine in the magnet area.Used a 1/4 inch pipe plug with a allen socket recess. Seals well. Made a right angle end for the hose on an inexpensive qt bottle pump to fill from underneath.
Dan Craig

Dominic

I am considering putting a plug in as shown in your first photo. Do you know if there is anything immediately above that hole or is it an empty void? I would not not wish to hit anything with my drill! I plan on a small pilot hole first to avoid an arm full of oil! What thread did you tap? - fine or coarse?

Steve
Steve Gyles

Steve
My gearbox came with the drain already installed ( on request) and as I don't know where it came from (Chris Betson may have obtained it elsewhere and not from Peter Gamble) I suggest you look in the gearbox manual and you should be able to see from that. It is only a thin thread, maybe M5 or M6, and as I have never taken it out I have no idea if it is metric or UNF !
Dominic
dominic clancy

Thanks Dominic. I guess I will be governed by what suitable tap I have in my collection.

Steve
Steve Gyles

Is it really necessary to buy a specific drain plug or would any suitable length set screw and copper washer do the job?

Steve
Steve Gyles

Steve,
A set screw and (annealed) copper washer would work but how are you going to remove any swarf from inside?

regards
Colin
Colin Manley

Colin

Just thinking about it all at the moment. I have no reason to do engine and gearbox removals at the moment so it's a chance I may take. Drill slowly etc. I guess the oil flow outwards with the first pilot hole drilling will bring the swarf with it.

As the system is supposedly sealed for life and not causing any issues, even after 15 years, I am not in a rush.

Steve

Steve Gyles

Not sure how it works in the UK, but under the US warranty law, if the manufacturer specifies that their proprietary oil must be used in order to maintain warranty coverage, then the manufacturer must provide that oil to the vehicle owner at no cost. In order to get around that, they say that their special synchro lube for manual transmissions is a "lifetime" lubricant.

What that actually means, is that "lifetime" really only means "greater than the period of warranty coverage". My daily driver calls for one of the proprietary lifetime transmission lubes... I run an aftermarket synthetic, and change it out every 30 or 40 thousand miles. So far, so good.

-Del
D Rawlins

Hope this might help the discussion. When I did my drain hole in a T9 gearbox conversion job, I followed Peter Gamble's advice which was to drill and tap a hole in the lower central bulge (Dominic's second photo above). M5 from memory. Re swarf - he said to just drill slowly and carefully so as not to penetrate inside very far and it will all run out with the oil. Likewise gently with the tap to avoid swarf. Then a bolt with copper washer and don't over-tighten as the casing is not that thick at that point. No problem and a simple job.
Bruce Mayo

Steve, if you need any taps, drills etc. let me know. I have a very good selection and would gladly lend you them Just post them back when finished. Paul
p anderton

Paul

Thanks for the offer. I have plenty, including some dating back to the 30s!

Steve
Steve Gyles

Engineering question for you experts. I was browsing sump plugs last night (very sad way to spend an evening). A number of plugs were advertised with fibre washers. Is there a very good reason for using copper washers or are fibre ok? I have both.

Steve
Steve Gyles

My T9 5-speed came with a drain plug. However, I understand that HiGear Engineering did not always provide them with drain plugs. If it will help, I will post a picture of mine later in the week. I will not be back home until Thursday.

Jim
JL Cheatham

Steve to answer your question, maybe this will help. Paul
http://www.oldclassiccar.co.uk/forum/phpbb/phpBB2/viewtopic.php?t=13160
p anderton

Thanks Paul. Makes sense. Others have said that the Type 9 wall thickness is not great and be aware of overtightening, so it seemed to me that a fibre washer was perhaps the sounder option. I will probably also smear with a bit of Wellseal gasket compound.

Just trying to pluck up the energy to get the car up on my hoist and do the job.

Steve
Steve Gyles

I have just put the camera under the car to look at the two locations for the sump plug as per Dominic's photos. Couple of questions:

1. As arrowed in my photograph and also evident in Dominic's first photo, is that a plate joint where the plug is located or a casting seam? If a joint, does it make any particular difference such as increasing the chances of a leak?

2. The other option, is the position of the sump plug critical to locate within the hole of the magnet? Dominic's second photo shows two bolts. I wondered what the reason is of the second, smaller round headed slotted machine screw?

I just want to clear things in my mind before committing to drilling.

As an aside, Ford specify SAE75W-90 semi synthetic. Lots of discussion in various forums with some people saying go for the fully synthetic version, whereas others suggest this could cause syncromesh rings to slip. Any thoughts?

Steve

Steve Gyles

Steve
Just over from the midget & Sprite area.
In your photo you seem to be indicating the join line and not the casting flash (see pic attached).
If you drill in the position shown you will hit an internal web. The pros have the advantage when the box is apart to relieve the web so that it does not snag the drill nor tap.

If you drill into the centre of the magnet it is apparently possible to dislodge the magnet.

You can drill opposite the magnet but in most places the casing is thin. I have previously done it and tapped UNF then used a bolt with copper washer.

BGH Geartech, who allowed me to watch a T9 strip down and rebuild, recommend Comma semi synthetic 75/90 without additional additives.

Alan
www.masckent.org

Alan Anstead

Thanks Alan

Getting my orientation to match your photo, I think you are saying I should drill in the position shown in my attached photo?

Steve

Steve Gyles

Steve, Not sure what age your gearbox is, but I have been told not to use a GL5 spec oil in gearboxes and diffs with yellow metal (phosphor bronze) as there's an additive in GL5 which eats it away. I use GL4 spec. Not sure what semi synthetic spec is.
Paul
p anderton

Steve
You're on it.
Alan
Alan Anstead

Paul

The gearbox is circa 1997/8 I think. I got it from a pranged Sierra in a Blackpool scrapyard for 50 in 2000. It had about 40k mileage. I have had the correct semi synthetic in it for the last 15 years so will refill with the same.

Alan. Many thanks.

Steve
Steve Gyles

Steve
I am contactable at
enquiries at midgetandspriteclub dot co.uk
Alan
Alan Anstead

A good way of controlling tapping swarf is to use a tapping lubricant grease, applied to the tap,then regular withdrawing of the tap to clean and recoat traps the swarf within the tap voids.

R.
richard boobier

This is going to be fun with the unit installed. I have the car on the hoist and, on inspection, there is precious little room to use the standard length tap and tap holder without fouling the gearbox support plate. Some innovative use of other tools required here. I will report back!

Steve
Steve Gyles

Steve,
Couple of possibilities :-

If its an M8 tap often you can invert a 1/4" socket extension and use a tap wrench on the squared end.

Another option possibly is to select a suitably tight socket for the tap and grind a bit off the opposite ends of two of the four sided drive end of the tap, so it goes in the socket and grips on two edges, then you can use the socket set to turn the taps.

R.
richard boobier

Richard

Thanks for the suggestion. I forgot I had an alternative tap wrench that will do the trick.

Quite amusing when I drilled the pilot hole. The drill body acted like an archimedeam shaft and sprayed oil all over the place! The oil was quite murky so it is a job worth doing after 15 years!

Steve

Steve Gyles

Plug done. Very straightforward in the end. Filling up with oil though is another a game. I had wrongly assumed the plug was on the right hand side. That cost me half an hour! We are quite a mad lot with these old cars, modified to some modern standards. I spent the next hour (not finished yet, just taking a break) with a squeezy bottle and tube trying to force 1.9 litres of thickish oil up hill and into the box. I may leave the next oil change for another 15 years!

As an aside, that oil has a pungent smell. I had left the drained oil in a tray overnight. The garage reeked this morning.

Steve

Steve Gyles

Job done and not leaking. I got thinking why sump plugs are generally quite large. My conclusion is that it is purely for the benefit of professional servicing shops who want a quick turn round. When I drilled my pilot hole using a 2mm bit, the sump drained in about 90 minutes which is probably acceptable for an enthusiast's workshop. I could then have simply plugged the hole with a self tapper. However, I did go larger with an M8 because I had the kit at hand to do it.

Lessons learnt: Thinking about adapting my Eezibleed to pump the oil up hill in future! Got a headache and arm ache from lying on my back squeezing bottles.

Steve
Steve Gyles

Steve,
Did you warm up the unopened oil container in a bucket of hot water? It makes it easier to pump uphill.

Colin
C Martin

Did you use the correct oil?: The genuine Ford stuff is not a thick hypoid
dominic clancy

Dominic

Yes, SAE 75/90 semi synthetic. I was speaking in relative terms about pumping heavy oil up hill. It's not like filling the back axle when you can get the bottle almost to the hole level. Unless you use a metre and a half of tubing routing up through the engine compartment and allowing gravity feed from the bottle it's a constant hard squeeze for an ageing bloke on a bottle to push the oil 40 to 50 cm uphill.

Colin. No I did not think of warming it. I used to have a concertina oil bottle, but the wife sorted my garage out a while back and I suspect she may have binned it! I have only just found my ear defenders that she relocated - I now have 2 pairs.

Steve
Steve Gyles

You should be able to buy them in the UK, but a suction oil gun, shaped exactly like a large grease gun. You just add a small piece of plastic tube on the nozzle, suck the oil out of the container, put the tube in the gearbox/diff hole, and press the plunger. Do that until fill.
Gary Lock

What Gary said.
Andy Bounsall

I have just been for a run post modification and the car felt much smoother throughout the drive train. I am therefore happy to concede that an oil change after 15 years was definitely worth the effort despite the 'sealed for life' tag that supposedly goes with these boxes. If there are others without this drain plug I would strongly recommend you fit one.

Happy days. Now on to the next job!

Steve
Steve Gyles

I used one of the plunger guns mentioned by Gary and found it was fairly easy to pass clear plastic hose attached to the nozzle from the engine compartment above the filler hole level and fill the box.Not so hard on the arthritis...
Neil Ferguson

Guy's
Just wanted to say thanks or the discussions on the drain hole. I started this thread and it I will definitely put a drain hole in the tranny before the finished body goes back on. Next couple weeks, I hope. Again many thanks.
Jack
J Butler

This thread was discussed between 17/03/2015 and 09/04/2015

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