19 replies to this topic

[mini_cru786]

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!

cheers

[Bluemini]

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.

[Tucker SP]

Hi ya,

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 :cheese:

You are going to take the oil out anyway so get your self a new sump gasket and sump, puckker job :cheese:

Others may disagree.

Tucker

[Sam]

I'd try and repair it without having to change the sump, as if you change the sump it means the engine has to come out.

[Tucker SP]

Doh...forgot about that

[mini_cru786]

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.

[dklawson]

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.co...s/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.

[mini_cru786]

cheers! ive had a look at the helicoil kits. but i cant find a garage who knows what tap size to use? what tap size will i need for my mini?


waj

[dklawson]

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...h_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.

Web Sites to check (companies to contact):
http://www.armstronghelicoil.co.uk/
http://www.wti-faste...o.uk/frames.htm

Brand Names to look for:
Recoil
WTI Fasteners
Perma-Coil
HeliCoil

Size you'll need: 5/8-11

[Woody]

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 .

[dklawson]

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.

[adam c]

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??

[siggy]

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.

PS I agree with DKs comments on 'glue'

Siggy

[Woody]

Woody the stuff your talking about is called Belzona, very expensive.



Siggy

thats exactly the stuff i was on about mate :grin:
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 .

[siggy]

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.

Siggy