hi, i just recently brought my mini. it is a 1986, 998cc mini. i would like to service it as soon as possible yet i have a problem. the last person who owned the car cross threaded the sump bolt on the bottom of the engine where you drain the oil from. at the moment the bolt is being held on by the last 2 remaining threads. and tends to leak when the car is parked over night. It isnt a very big leak, however id like to solve this problem.
I was told i would have to buy a new engine or sump cover but i was also told by a local mechanic i could re-thread the sump with some kind of tool? is this possible and if so what is this tool called? i know i will have to get a new bolt for my sump to match the new thread which will be created.
please could someone point me in the right direction!
Best thing to do is contact your local engineering shop and ask them if they can do it for you, this will save you having to buy the tools do it yourself.
You can get a kit that will re-thread it but I would say that it is more hassel than wahts its worth. I would get a new sump, save any problems in the future
You are going to take the oil out anyway so get your self a new sump gasket and sump, puckker job
Thanx for your help lads! only 1 more question what is the size of the sump bolt(MM) on my mini? i was told i will have to use the next size up to make the new thread.
In the U.S. the idea of “just getting a new sump” (a.k.a. transmission casing) is out of the question. There simply aren’t a lot available. The method used here is to re-tap the drain plug hole and insert a “HeliCoil”. HeliCoils are thread inserts that resemble a spring made of diamond shaped wire. ( http://www.emhart.com/products/helicoil.html )They are routinely used for repairs (in all industries) and they are also used to increase the strength and reliability of tapped holes in aluminum.
Call around and find a shop in your area that can use this method to repair your drain plug (call shops that specialize in Minis and/or transverse engine A-series cars). If you find a shop that already has the tap, the repair can be done with the engine in place and all you’ll pay for is the insert itself and the labor (figure at least 1/2 hour). This is a very fast, cost effective, reliable repair.
The HeliCoil you need will be for a 5/8-11 thread. You don’t use a “standard” tap for a HeliCoil… it is a special sized tap to work exclusively with the insert. While Mini Mania in the U.S. sells the kit with inserts (Tap drill, tap, inserts, installation tool), Mini Spares does not appear to list it. I also didn’t find it at Mini Sport or DSN which are the other suppliers in the U.K. whom I buy from. If you get desperate, check out Mini Mania at their search page http://www.minimania.com/Search\_Inventory.cfm
and enter TOOL08 for the part number. If you had to you could buy it from them but shipping would be a killer. I’ll continue to search and see if I can find a U.K. distributor for HeliCoil or one of their competitors. If I find anything I’ll post it here.
EDIT:
I did a short Google search and found the following. Look for “free running” inserts/kits. Free running means that when the bolt is installed it isn’t “locked” by the thread insert. Sorry, but beyond this you’ll need to send some emails or make some telephone calls over there. Let me know how successful you are.
Another idea is to build up the inside of the damaged thread with a resin based repair stuff (cant remember what its called ) and then re-tap the original sized thread back in and use the original sized sump plug .
The stuff i am on about has "molecular bonding " on the tub , it comes in two tubs (one orange, the other black) and you mix them together .
A mate gave me some , he worked in a nuclear power station and they use this stuf to repair broken castings , it is possable to use it to repair cracked gearbox casings (and i am told the repair is stronger than welding !) and also cracked engine blocks .
the only thing is you would have to remove every trace of oil from the repair area , but it should be possable to do in place .
I don’t wish to in any way insult your friend or the product he provided you samples of. However, “molecular bonding” is a fancy way of saying “glue”. Glue, even metal filled epoxy, is not as strong as the metal used for the castings they are “repairing”. The statement that this product is used in “a nuclear power station” implies that somehow it is super stuff. However, if you press your friend I’ll bet you discover they only use it on secondary, non-critical, non-nuclear components… like rain water sump pumps. Your nuclear regulatory agency would NEVER allow glue to be used on any critical components. Never.
In the U.S. there is a “good ole boy” product called J.B. Weld which is used to fix castings, and things like you’re describing. It is touted as “drillable, machineable, tappable, etc.” The fact remains it is not as strong as the base metal you’re trying to fix and if the area is subject to shear loads (like a bolt), glue in all its forms is a poor choice. It will strip out almost immediately.
By all means you can try the glue, but remember it is IMPERATIVE to get ALL the oil off of the area you’re trying to fix or it won’t adhere. If and when the glue does fail you can always tap the sump for a thread insert. However, using the glue will just be postponing the later fix.
by the way, there are other types of thread inserts you can use but typically they require tapping the sump to 7/8-9 and installing the insert with thread sealant on its outside. This may compromise the washer/face seal on the drain plug. This is why the HeliCoil is the preferred method over here.
Don’t know whether this is any use to you but have just seen that morspeed in leicester do a “5/16 sump fixing” for £25. (see advert on pg.102 mini magazine)
Not sure how they do it but maybe you could ring them and ask??
JBs weld wonderfull stuff. Had an 820 rover that boiled good style and I used it across the crack in the head across 3 cylinders. Worked a treat. You can/could buy it in Halfords.
Woody the stuff your talking about is called Belzona, very expensive.
> Woody the stuff your talking about is called Belzona, very expensive.
Siggy
thats exactly the stuff i was on about mate
If its expensive its probs not the best option then !
Helicoil would seem to be the best option , I have used them to redo threads on moterbike barrel and head bolts and had exelent results .
A helicoil would be the best option, but I have never seen one with the right size thread, You will be able to get one the right diameter, but then you need to find a suitable sump plug. Also not too sure if there enought room with the engine in situ to actually use one.
i agree that there probably wouldn’t be room to get the helicoil tool in, but its not hard to undo the engine mounts and just lever the engine over a little to drop the sump plug down low enough to use the tool
if you’re not in a rush, i’ve seen a lot of helicoil stuff at autojumbles, and the local army surplus yard has lin-bins full of them.so it might be worth shopping around, this might be the cheaper option as i think the insert tool and the tap aren’t exactly cheap.
Getting the HeliCoil in the U.K. is probably the biggest problem. The HeliCoil does NOT change the size of the threaded hole. The process involves re-tapping the hole oversized to accept a spiral wire insert that becomes the “new” threads. Typical kits include the proper drill, tap, inserts, installation tool, and a tang breaker. The tang is a little bit on the insert used to “drive” the insert into the re-tapped hole. Once the insert is in place this tang must be broken off to leave the hole clear. The end result is a strong threaded hole of the correct size. You will use a STANDARD sized drain plug.
The kit is available from Mini Mania for about $50 U.S. (by the way, this is an EXCELLENT price for a HeliCoil kit. They are usually MUCH more!) Shipping to the U.K. would be expensive. However, why not contact Mini Spares and see if they can’t get you this kit from Mini Mania. The two companies have a relationship and they must ship parts back and forth. Frankly I’m surprised they don’t sell this kit in the U.K.
The following is from the Mini Mania web site:
****************************************************
HELICOIL KIT DRAIN PLUG
The tranny drain plug on the Mini is large and robust but we have all seen them where the threads have been stripped out. No reason to change gearboxes just because of the drain plug. While the threads and the diameter and not very standard we have found a “helicoil” kit that allows you to simply install new threads and restore the box to stronger than new. While it is best done on a workbench (box does not need to be taken apart), it can be done while still in the car!
Fits the Following Cars: MINI
TOOL08 Categories: [GEARBOXES] [TOOLS]
Price: $49.95
Hey, i had the same problem and got a tapered sump plug which is the bizz. no new threading or any kits or any of that messing. bought it from minisport london
Tapered plugs were once common in cast iron transmission and differential housings. They do work, particularly with sealant on the threads. However, if you go this route be careful not to “over tighten” the plug. They are a very powerful wedge and can easily split the tapped aluminum hole you’re putting it in when used on a Mini.
On an old Honda of mine I put a tapered pipe plug in the sump after an oil change place ruined the stock plug/sump. I chose to use nylon pipe plugs for drain plugs and they worked very well. However, if you use this in the Mini there won’t be any magnet to catch debris in the sump. You could easily make your own custom plug like this though by adding a magnet.
I’ve just had the job done properly on a Cooper ‘S’ engine/box I’m building. There is a Helicoil exactly the correct size, but I don’t know for sure what that size is. Ask a good engineering shop, or take the sump plug into an engineering parts stockist.
When I had the problem with a Mini 30 a few years back I got a 3/4"Whitworth bolt, a tap to suit and borrowed the right sized tapping drill. The entire job cost me about £12-00. You drill out to the right tapping size making sure you go in absolutely straight and in line with the existing hole. The tap and fit the new bolt with a big copper washer. It’sas simple as that, soi long as you choose the right tools. Don’t forget to get all the swarf out of the bottom of the box before filling with fresh 20/50 ‘Valvoline Racing’ oil (the best IMO for all Minis).
