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MG Midget and Sprite Technical - Midget Mk1

I am new to this site and would welcome any advice from members.My car is a 1962 Mk1 midget.

I am in the process of trying to remove the rear axle complete. The bolts holding the radius arm in place should be knocked out using a hammer and drift!! I have tried this without success. I have applied some heat and plusgas - still no joy.

Can anyone help please?

Regards

Tony
A D Lane

Hi Tony,

Welcome!

Have you tried spraying penetrating fluid on the area and leaving it for a while?

Other than that, more heat and hammering I’m guessing is the only way forward.

I’ve a MK2 so different setup on the rear suspension

Good luck

James
James Paul

Hi, welcome Tony.

PlusGas and time and patience.

Apply plenty of PlusGas and leave to soak in a minimum of over night then soak again and use the hammer bolt head side to loosen rust grip then hammer and drift on other side.

If you have a helper they could try turning the bolt head with a snug fit spanner whilst you use the hammer and drift other side.

If this doesn't work then apply plenty of PlusGas again and leave to in soak a minimum of over night again and then repeat as above.

PlusGas and time and patience.

Usually only two attempts are required but if you need three, so what.
Nigel Atkins

Welcome to this great bbs!

In my experience, Plus gas *often* works but, for something really stuck and frozen, you need heat which always works. Keep away from the fuel tank of course!
Bill Bretherton

Using heat on the radius arms is going to burn out the rubber on the metalastic bushes. But perhaps your radius arms are kaput anyway?

Which end of the arms are you attacking?
GuyW

Welcome to the BBS!

Have you got a compressor and a rivet gun or similar? Brilliant tool for getting things like that to move.

If not then it’s just perseverance with all the other suggestions!

I’m in Lincoln and also have a 1962 Mk1. If you need to look at a similar car for any reason then let me know.
John Payne

Thank you one and all for your comments.

I will try and reply to the comments you have made.

I have been using lots and lots of plusgas and hitting the nut end (with a nut partially on). I have also applied some heat where I can and then hitting again. Where is the best place to apply the heat? On the end of the radius arm nearest the body there is a bolt head and I have had a socket on there and tried to turn it - no joy - rounds off the bolt head!! The other end does not have a bolt head!!!

Hi John - I also live in Lincolnshire. In the village of Helpringham, near Sleaford and would be interested in seeing your 1962 Mk1 sometime. You can contact me using my email if you would like to: shellback1945@gmail.com.

I am also a member of the MGOC but nobody has a Mk1 either!

My last resort is to cut through the radius arm and remove the back axle, then sort the arms out when I have more space. I am trying to avoid cutting if possible. I do have two new radius arms ready to install. Maybe keep applying plusgas and using the heavy hammer.

Thanks agsin
Regards
Tony

A D Lane

Hello again

I have been reading my comments again and thought I would ask what type of heat application is best? I have been using my butane torch but wonder if something hotter would be the answer like oxy/acetylene?

Regards
Tony
A D Lane

I would suspect that at the axle end at least, the bolt has rusted into the metal sleeve inside the rubber bush. When hit with a hammer the rubber will be absorbing the shock, and when turning the bolt the sleeve will just turn with it. Actually if the correct bolts are used they have a flat on the "head" so won't turn anyway.

Since you have replacement arms to fit I would attack it with an angle grinder and slitting disc and just cut through the arm part way along to release it. Much easier to then deal with it off the car.
GuyW

You are right Guy, hammering doesn't work because the rubber absorbs the shock. I ended up drilling mine out as far as I could, which is difficult because there isn't room to line up the drill properly. Once a lot of the metal had been removed, the sides of the pin collapsed inwards slightly and relieved the adhesion. I then used an old pin to drift the remains out. Amazingly I was able to preserve the radius arm, which is actually an original one AFAIK. The pins are fitted with copper grease now.
Les Rose

Hello Tony,

I'm no expert, I've only had my Midget for four months, however I have had very good results with a product called PB Blaster which I got from Amazon.
I don't know if it's better then Plus Gas but it was powerful enough to free up a seized lawn mower engine.
Might be worth a try if you can get some.
Roger D

Good point about the hammering, I totally forgot and didn't think about bushing so it would be twisting with a very snug fit spanner or 6-sided socket, perhaps less effective if the headed rounded. It's a case of cracking a start most times and slowly working an item out back and forth.

Unless you're a race competitor torture equipment are last resorts.

Nigel Atkins

Thanks again for all your comments.

I resorted to cutting the radius arm near the bulkhead end and removed the back axle. I then used the angle grinder (with difficulty) to cut the bolt where the nut is and then cut a slot in the top of the radius arm. (Difficult to get at). I then prised open the slot and dropped the remainder of the radius arm out. The next job was to cut the bolt head off and the bracket then came away. The bracket was rotten at the rear so will need a new one to go with the new radius arm. The bolts on the drivers side came out easily!!!

I now need to finish off the drivers side.

The next big job is the remove the front suspension - this is also a difficult job I believe. Any suggestions before commencing would be helpful.

Regards

Tony
A D Lane

Hi Tony,

I wouldn’t say it is difficult remove the front suspension. You do have to be careful removing the spring.

Here’s a link to a video that shows a method to refit the springs reasonably safely, so you can do this in reverse.

https://youtu.be/L82Y8s9Hcp8

To be honest I didn’t follow this method and undid the kingpin top nut and steering column bolt and let the wishbone drop and pulled the spring out. But looking back it wasn’t a great idea.

I’ve got quite a few pictures and posts on my blog that might help you.

https://www.mgmidgetrestoration.com/

Removing all the old rubber bushes can be a pain, just depends how old and rusted they are.

Cheers

James
James Paul

Tony,

It can be difficult to get the fulcrum pins out of the inner ends of the wishbones. Don't spend hours with heat, hammers and bad language, just cut through the fulcrum pins with a hacksaw blade - it is MUCH quicker in my experience.

Good luck :-)
Jonathan Severn

Observing of course the general principle to make sure you can get (and preferably have got in your possession and have verified quality thereof) a replacement before destroying any part.
AdrianR

The outer fulcrum threaded pin can be difficult to remove. If it won't move and the threads feel worn when you move the kingpin fore and aft you might want to or have to replace the wishbone. Also, I've found the shock absorber pinch bolt tends to seize and will shear if you force it, making it difficult to remove. Be careful with the bearings - they come apart, which you don't really want as you can re-use them if no play. Others might give more / better detail about this.
Bill Bretherton

Thank you all once again for your valuable comments.

I have seen the video on YouTube, James - interesting. There is another video by a guy from Canada, calle econobox, and he uses four bolts to remove the spring.

I will keep you all posted when I start to remove the front suspension, missing out the swearing of course.

Regards

Tony
A D Lane

As James says, you can remove the spring by allowing the wishbone to gradually drop on a jack (with the kingpin nut removed and weight of car on front cross member jack) until the spring can be pulled out. That's what I did anyway. Replacing the spring can be done with two long bolts. These are comparatively small cars with smaller springs - spring compressors aren't required.
Bill Bretherton

No doubt someone will correct me if I've got this wrong, but I have a feeling you can't let the wishbone down gently on a jack if you have uprated springs, as the stronger spring will be too eager to push the rest of the car upwards. Standard springs on a Midget Mk1 are presumably fine to remove with the jack method.

Can anyone clarity this for the sake of future BBS archive searchers?
Jonathan Severn

Jonathan, I think if you still have the engine and gearbox in the car then controlled compression and lowering of the spring pan is still possible, even with uprated springs. If however you are doing this with the engine out then the answer is an Attractive Assistant is needed to perch on the wing, above where you are working.
I secure the car on axle stands placed under the main front chassis rails and then use a small bottle jack with the screw part extended up inside the cone of the spring seat. That way it is secure and the jack cannot slip away from the spring. The other thing is to also partially slacken the nut on the top of the kingpin, but keeping it fully engaged on the thread, to relieve some of the spring tension. It's a much quicker way than the 4 bolt method.
GuyW

Guy, Are you sure that your method won't launch your Attractive Assistant if things go wrong?
C Mee

Might do, but where's the downside in that!😁

Actually, no, the spring is fully enclosed at the top. If it were to escape, it would be downwards to then bounce up off the floor into your face, but with using a bottle jack inserted up into the spring pan inverted trumpet thing it cannot do that either. And actually the difference in length between the compressed 'at rest' length and its fully released state is surprisingly little. Releasing this compression in a controlled way with a hydraulic bottle jack is very simple.
GuyW

If like me you're not of mechanical bent like many of the chaps here and are just removing the front road springs the the "bolt" method is by far the easiest, if I can do it anyone can.

I am NOT suggesting anyone else do it but I only used two set screws and IIRC that was also on uprated rated springs. The set screws were metric, forget what length, used with washers and two very short offcuts of copper pipe to make getting the deep socket on easier. I threw the setscrews and nuts away after each pair of use.

Nigel Atkins

I prefer the bolt method too. Its nice and controlled and allows it all to go together sweetly. It is the factory suggested way but I suppose that doesn't really matter........
Bob Beaumont

I bought a coil spring compressor especially for the Sprite: it doesn't fit so it's never been used.

I use the bolt method but tend to err on the side of caution and use four long bolts instead of the two suggested in the manual.

My 400lb springs are shorter which makes them much easier to remove than the original ones as there is a lot less nut/bolt turning required.
C Mee

Nigel

I think two bolts are sufficient (you probably do mean bolts rather than set screws) providing they are of sufficient diameter and the nuts are a decent fit.
Bill Bretherton

A long bolt is unlikely to have sufficient thread to release the load,a setscrew in this context is a continuously threaded 'bolt'.
I use threaded rod with captivated nuts on one end.
richard b

Richard

I wouldn't have thought of a larger bolt threaded to its head as a set screw. I'd think of a set screw as a smaller "machine screw" e.g. M4, M5, M6 say being used to clamp something to another surface using a threaded hole in that surface. I'd always call a larger diameter screw a "bolt", say M8, M10 (or imperial equivalent) nomatter how much thread.

But, of course, I stand corrected if I'm incorrect.
Bill Bretherton

Bill, when I started working for a combat vehicle manufacturer I was picked up on my incorrect use of the word bolt when it was a set screw that was required and vice versa. I subsequently came across safety issues on these vehicles where incorrect fasteners had been used.

I'm more careful these days but am far from infallible. I should have said that I use four long (M6 x 150mm) set screws!



C Mee

Bill,
IIRC when I tried looking it up before I concluded that a set screw has the thread from top to bottom, there was nothing about width/gauge. But of course this being language and engineering where everyone has their own favourite standards a bolt, that has an unthreaded portion, can also have the threads going all the way from top to bottom.

I say tomahto, you say tomayto, it's a mixed up, muddled up, shook up world, except for Lola.

IIRC I used M8 set screws, 4" long. 😁
Nigel Atkins

Colin, Nigel, Richard

I've read up on bolt definitions and it does seem, generally, that a "set screw" is taken to be a "bolt" threaded along its entire length as you all say. So I was wrong! And I'm supposed to have an engineering background (electrical, but did machine shop stuff as well). But it also seems that a more precise definition of (any) fastener is its ISO definition, as you might expect.

Sorry for "thread" drift Tony.
Bill Bretherton

People who insist that hexagon headed bolts are screws should be made to demonstrate how to undo them with a screwdriver :)
AdrianR

These are the ones I used. M8 150mm long
Thought I’d add the two bolts just to be extra careful


James Paul

"There is no universally accepted distinction between a screw and a bolt."

A propeller is also a screw.

"a device having a revolving hub with radiating blades, for propelling an airplane, ship, etc."

But read on.

"A screw is a combination of simple machines: it is, in essence, an inclined plane wrapped around a central shaft, but the inclined plane (thread) also comes to a sharp edge around the outside, which acts a wedge as it pushes into the fastened material, and the shaft and helix also form a wedge at the point. Some screw threads are designed to mate with a complementary thread, called a female thread (internal thread), often in the form of a nut object with an internal thread. Other screw threads are designed to cut a helical groove in a softer material as the screw is inserted. The most common uses of screws are to hold objects together and to position objects."

"A screw will usually have a head on one end that allows it to be turned with a tool. Common tools for driving screws include a screwdrivers and a wrench."

There is no universally accepted distinction between a screw and a bolt. A simple distinction that is often true, although not always, is that a bolt passes through a substrate and takes a nut on the other side, whereas a screw takes no nut because it threads directly into the substrate (a screw screws into something, a bolt bolts several things together). So, as a general rule, when buying a packet of "screws", nuts would not be expected to be included, but bolts are often sold with matching nuts. Part of the confusion over this is likely due to regional or dialectical differences. Machinery's Handbook describes the distinction as follows:

A bolt is an externally threaded fastener designed for insertion through holes in assembled parts, and is normally intended to be tightened or released by torquing a nut. A screw is an externally threaded fastener capable of being inserted into holes in assembled parts, of mating with a preformed internal thread or forming its own thread, and of being tightened or released by torquing the head. An externally threaded fastener which is prevented from being turned during assembly and which can be tightened or released only by torquing a nut is a bolt. (Example: round head bolts, track bolts, plow bolts.) An externally threaded fastener that has thread form which prohibits assembly with a nut having a straight thread of multiple pitch length is a screw. (Example: wood screws, tapping screws.)[5]

This distinction is consistent with ASME B18.2.1 and some dictionary definitions for screw[6][7] and bolt.[8][9][10]

The issue of what is a screw and what is a bolt is not completely resolved with Machinery's Handbook distinction, however, because of confounding terms, the ambiguous nature of some parts of the distinction, and usage variations.

https://en.m.wikipedia.org/wiki/Screw




anamnesis

I believe that the proper term in this context is machine screw, not just screw, which has a wider and much less specific definition.
GuyW

I've just looked on the Namrick website to see what they call them. So, a bolt threaded all the way is a "setscrew". A machine screw has a slotted or posidrive head typically up to 1/4" dia. I make no judgement but that's what they call them.
Bill Bretherton

Bill

I remember in 'O' level engineering my tutor saying a set screw was threaded its length but a bolt had a proportion of plain shank. Its how I have always understood the difference but hey who really cares!!!
Bob Beaumont

Bob

You're right, it doesn't matter! As long as we all know what we mean.

So, you need longish threaded things to get them there springs on.
Bill Bretherton

My understanding is as Bob's.
Full thread = screw; blind shank (unthreaded section) = bolt.
Who knows? Maybe it's not that simple.
Greybeard

Ah, but, some wood screws have a full thread and some don't. And you can get wood screws with a hex head and increasingly commonly with a torx socket head!
;-)
GuyW

Try and get a screw driver to drive this in.


anamnesis

That's a coach screw. You'll need a coach driver for that.😀
C Mee

And if it's a really big coach screw then, an hgv driver, but they are in short supply. 😉 .

anamnesis

There should be a fastener in the attached image to fit most requirements :)


S Holt

WOW.

Lots of comments on bolts - I get the idea!!!!

I like the different bolts image.

Tony
A D Lane

You'll get used to it Tony
Thread drift is part and parcel of this forum, but you do learn a lot here--it's a bit like data collecting--
and by the way--Welcome to the forum
willy
William Revit

My apprenticeship at Jaguar told me that basically

Bolt - a thing with a nut
Screw - almost anything else with a thread and no nut

May explain the build quality at the time........
Oggers

Willie

Is a thread drift a bolt or a screw?
Oggers

Presumably putting technical queries on the General forum must be cross-threading.
C Mee

We have not got even got on to discuss ‘drifts’ and ‘podgers’.

Cheers
Mike
M Wood

I remember being shown how to insert a wood screw using a hammer. I was told 'The slot in the top's just for taking them out again.'
Jonathan Severn

This thread was discussed between 08/11/2021 and 02/12/2021

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.