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MG Midget and Sprite Technical - Brake decisions

I keep coming up against these decisions and for some reason really struggle. Its not that I cannot decide, but that every time I decide I get a different answer! It must be an age thing!

I am assembling the front suspension on the Frog. Lower wishbones, dampers and king pins all attached, springs ready and waiting in position. I cannot assemble any more without fitting the swivel hubs, and there lies the rub.

I have the original 7" drum equipment that I am not using, but those swivel hubs could be used and take the 8" twin leading shoe drums that I have. They are quite sturdy and "look the part". They would retain the original drum brakes all round design but give a significant improvement over the tidly little 7" ones.

OR, I have a full set of normal discs and calipers just begging to be fitted with their different design of swivel hub.

The car is intended as a "back to the 50's motoring" so I am not going for all the bells and whistles available as are often discussed on the BBS. It will have a 1098 engine in standard spec, and retain a standard 4 speed box. It isn't a track car and although I drive with enthusiasm, its intention is for use on the lanes and empty by-ways of the North Country. Of course its on these lanes with their blind brows and high walls that you need sharp brakes for when you meet a flock of sheep. Or a bull, tractor or some such hazard.

So should it be the uprated drums or the discs?
GuyW

Discs, without a shadow of a doubt.
Much safer especially with a larger than standard engine.
Jeremy MkIII

I would go with the discs, that's what I did when I got my frogeye on the road and didn't know about the potential issues with using the drum master cylinder but never had any issues. Whatever you decide to do I would say swapping either way is straightforward so if you change your mind it's no big deal if you keep the other parts.
David Billington

Guy,I decided on discs some time ago and renovated the calipers I had acquired. Have also had new bushes reamed for kingpins so commited now. I intend to use the original Frogeye coil springs as they are a different rest height than the later disc ones.
W Bretherton

Discs for me too. That's what I'm doing to my Mk1 though mostly for the ease of maintenance than the stoping ability. Like you I already have the parts so it seems the right thing to do. I don't think it will effect the value/originality unduly because people were doing disc conversions as soon as they were introduced in 1963. I think most people would regard them as a sensible upgrade for modern roads.

John Payne

In some ways I suppose it was a silly question. Sensible answers should be based on personal experience and do deserve to be respected. But of course the upgrade using discs is far more readily available than sourcing the 8" drum parts. So that will be directly reflected in the "vote".

As far as I understand from information gleaned, the 8" drum is very effective and as powerful as a standard disc upgrade. There are two differences. The discs, though not more powerful, do dissipate heat faster so are less prone to fade but as I am not racing this shouldn't be too much of a disadvantage.

The other difference of course is that discs are self adjusting, whereas the drums would need regular attention.

I do like the comment from David, that either choice can be readily reversed.
GuyW

Were the 8" discs from an A40 or Riley/Wolseley?

Didn't the A40 use the larger kingpin, like the disc brakes midget?

Obviously, if you're fitting discs, you'll need the larger kingpin to match the stub axle.

Do the 8" brakes fit the standard Frog stub axle? If so, is the kingpin up to the job?
Dave O'Neill 2

Guy... i perder brain fart over calling myself an idiot

But i completel. agree with the crowd that just jumped off the bridge... disc and calipers, rhere not orginal but neither are our roads from 1960

There safer and fewer problems... i deplore drums, and would never use them exceot on a car that will necer be driven on the road and is a queen additikn in a mancave piece of art

Prop
1 Paper

Another vote for discs. I did mine many years ago and have never regretted it. I also have a 1965 Ford Econoline E100 van that came with drums. I could never get them adjusted to the point where they didn't pull to one side or the other and I've owned it since 1971 so I'm not a beginner. About 3 years ago I converted to discs and it transformed the car. Stops straight every time. And up here in western Washington state we get a wee bit of rain and with the drums I'd get one side or both wet and you prayed a lot if you had to stop quickly. Discs give you some peace of mind in the stopping department.
Martin

ISTR the Wolseley 1500 fronts were 9" drums ? the Riley was similar but wider linings and different makers.
I had the Wolseley 1500 ones on my Morry Minor many many years ago, along with 5 1/2J 13" wheels !

R.

richard b

Guy
I can see you really want to fit the 8" drums
Is it on wire wheels or steel wheels
How about drums with some cooling holes drilled in the face--they look a bit period racer specially if it's through wire wheels
If you are on steel wheels no-one is going to see them really so discs would probably be best choice I guess
willy
William Revit

I had drums on my Mustang and they worked very well considering the weight and power of the car. In fact when I converted it to discs the initial bite was less than the drums. The discs were obviously better from a fade point of view, drums faded badly after a couple of big stops.

Do you drive regularly in the hills Guy? That might be another consideration, being able to use the brakes without worry on big decents is nice.
John Payne

Although I see the point of fitting drums to a car that had them originally surely the 8" drums would make it non-original anyway, but then so does the 1098 engine I suppose.

Is there not the potential problem with front drums that, if one is more out of adjustment than the other, then the car would pull to one side which, in the event of harsh braking at the bottom of a hill on a damp road (maybe there's a sheep round the corner), could be interesting.
W Bretherton

Hills and rain in Cumbria so I wondered if drums get wet and it seems that on Martin's Ford they do - do they on UK cars, can't say I've noticed but I've only really had drums on the rear.

Hills and rain and brake fade.

Spirited driving and brake fade, and hills.

Discs the standard change on the vehicle.

Seems to point towards discs but you seem to want to the drums and have the all the parts and the willingness to be adjusting the brakes as much as necessary so why not give the drums a try as you can always change to discs later if you want.
Nigel Atkins

If you like adjusting the brakes on a regular basis then drums are for you. They are tricky to get the bake balance right,especially if the drums have much wear. And if you cost up the price to have them machined and add new cylinders it will be an expensive option. I've just replaced the 8 inch drums for discs for that very reason.
f pollock

I did have the 8" drums for a while but found the discs far superior. They don't fade, are more responsive and don't need adjustment. The downside is you get brake dust on the ventilated frogeye wheels which is a bit unsightly.

You do of course need to change the master and the rear cylinders. The king pin is larger than the original Frogeye one so you will need this as well.

If you want originality and be really cool(!) then you could try and source some Girling discs as available as tuning option by Donald Healey Motor Co. Bit hens teeth though.

If your not going to rag it then the original set up is 'just' about ok but maybe not for avoiding tractors!
I kept the old set up along with the matching numbers 948 engine so it can always be swapped back.
Bob Beaumont

Another discs vote here, I appreciate the originality thing, but they are so much easier to live with I don't see the sense in giving yourself another job to add to the perpetual list which you can avoid.
It is not as if the standard disc set up is exactly 50 years more modern than the drums !
P Bentley

Re. Bob's comment:
"You do of course need to change the master and the rear cylinders".
Might be better to say:
"You may want to change...".
As I have stated on here before, in my experience, there is no need, you just end up with a heavier brake pedal.
Simon
Simon Wood

Bought my Frogeye in 1969. It was Shorrock supercharged in those days and fitted with 8" drums. The Supercharger is long gone but it has retained the 8" drums.
Kingpins are Std Frogeye.
Master cylinder is Std (7/8") Frogeye.
Slaves are Austin A40 Farina & others.
The shoes are Std A40 Farina / Morris Minor but you can upgrade lining spec.
In 48 yrs of ownership I experienced brake fade only once traversing the Austrian Alps. The car car has been driven around every major GP circuit in Europe, & many lesser known circuits, across the Swiss Alps & Italian Stelvio Pass, Czech Republic & Hungary & more.
And I am not forever adjusting the shoes.
Alan
Alan Anstead

The quality and wear on all the components and parts, related and associated components parts and their matching could make a difference plus driving style particularly the amount of breaking.

I say that not knowing anyone's here Spridget brake set up condition or driving style or abilities, personally I don't use my brakes much but I'm not a particular good driver and would be slow around any track even if it wasn't my car and have actually been told I'm too slow by a track driving instructor on a classic car track day, my mate on the other hand was asked to slow down a bit.
Nigel Atkins

Do what you want to do, Guy, and don't pay heed to any of us. I wouldn't expect to get a 50s driving experience with discs, but it's what you experience that matters.

I drove my Frog for 10 years, twice to Le Mans, summer tours of Britain, and lots of Autotests and rallies, sometimes with a family team of three drivers, so constant hard braking, and I love the 7" drums. They're sharp, and they stop you quickly with a lot less leg than discs require, so ideal for 17 year-old daughters.

No brake fade so far, and if I'm enjoying a 50s drive down a long hill, I shall do what the 50s Highway Code said, and use my gears.

And for unexpected sheep, drums for me.
Nick and Cherry Scoop

Well, I made my decision (again!) and opted for the larger 8" drum version. Partly I like a challenge. More because every car I have driven for the last 40 years has had discs and I wanted a change and to regress to drums for the different style of braking. And the larger than standard, though not original, will give better braking whilst remaining nearer to the original style of the car.



So I went to the garage and collected together the parts to start assembly. They were in various boxes as received from the PO who dismantled the car. On trial assembly I find the swivel hubs have been rebushed, but not yet reamed, and that the king pins with them are in poor, worn condition.

So, for now at least - its going to be discs, at least for now. I have already renovated the parts for the disc brake set up, with new kingpins, new (reamed) bushes and even the hubs all assembled with new adjusted FWBs (the correct ones!) and painted. They just need to be fitted as units to the car. The only thing that needs modifying is to match the steering arms to my early Sprite TREs

Pragmatic outcome!
GuyW

I'm glad you want to use drums Guy, one does what works for one, as Nick says.

Speaking of steering arms, I'd assumed, via the Moss catalogue, that the BTA648/649 arms can be used from Frogeyes right through to 1971/2 Spridget. I've built up my hubs with the arms that came with them from a later Spridget, but haven't mated them up to TREs yet.
W Bretherton

Guy

Hmmm, i thought there were only 2 rack and pinions an early and a later ... thae later came out in 72

So the TRE you have should fit as normal,

Are you saying you used the later triumph rack instead of the orginal ?

Or did i miss something

Prop
1 Paper

Good decision, Guy, as you're obviously getting the car onto its wheels now, before you've saved up for new kingpins. Will you keep it on the rotisserie to do other assemblies, or is it time for right way up on the garage floor?
Nick and Cherry Scoop

Prop,
Its a Frogeye, with the early Sprite rack. But it is now fitted with the disc brake components that I bought for it some years ago complete with stubaxles and fitted steering arms. As I don't know the age of Midget that those components came off its possible there is now a mis match. It just needs checking that the tapers in the steering arms match the TREs

Not sure how long it stays on the rotisserrie Nick. Its getting noticeably heavier as I add bits. I should put in the fuel and brake lines, but might leave fitting the diff itself and do that the old fashioned way, lying on my back.


GuyW

Guy

Alan would be best person to advise on this, but if going down the A40 front drum upgrade route I would be looking here for some of the bits: http://www.earlpart.co.uk/catalogue%20a30.pdf

(as well as Past Parts http://www.pastparts.co.uk, Coasting Ltd http://www.coastings.co.uk and Powertrack Brakes http://www.powertrackbrakes.co.uk)

Best wishes
Mike
M Wood

Thanks Mike,
Yes, Alan posted earlier. Its partly based on his experience that I favour the drum kit ( Taraa!)

I would still like to use the A40 drums that I have, but for the time being I am fitting the discs as they were complete, bolt on assemblies. I keep getting waylaid by things and the priority at the moment is to get some running gear on it so I can get it off the rotisserie, on some wheels and manoeuvrable!

The alternative A40 set up needs new(early) king pins, the stub axles reamed and probably a new set of wheel cylinders. And that's before I delve into the M/C issues, for either set! So for now it will have discs, but I have saved those links for future parts sourcing.
GuyW

This is definitely thread drift, but its my thread so I am allowed!

Nice little Sunday morning job cleaning up and fettling the tank sender unit ready for fitting the tank to the upside-down boot floor. Fettling in this case involves following John Davies' advice in his recent excellent MASCot article and adding an extra internal earthing lead to the sender. By all accounts this will avoid erratic fuel gauge responses in the future. The sender will also get an external earthing wire to extend clear of the tank when installed, so its not dependant on earthing solely through the tank, various bolts and the body tub. Hopefully his will also make testing and fault finding easier in the future.
GuyW

Yes, the additional earths sound like a good idea Guy.
W Bretherton

This will probably get lost with the wrong message title, but what do we think of this? (Photo)

Having anded my wiring for the fuel sender unit and installed it in the tank, I then sealed over it in its depression with a good quality waterproof Gorrila tape. The idea is to keep dirt out and I have always thought the depression had the risk of filling up with water. So its now fully sealed.

BUT, I then wondered if there was a risk of gathering petrol vapour in the now sealed cavity, with no possibility of it wafting clear away on the breeze. Perhaps its not such a good idea after all?

Paranoid?


GuyW

Assuming the sender is completely sealed to the tank on its gasket, could vapour really escape? It wouldn't worry me but, if there's doubt, maybe remove the tape and coat it in grease or waxoil.
W Bretherton

looks good to me -bit of an overkill but I suppose the cleaner you can keep the connections the better,there shouldn't be any vapour there anyway
If it's going to leak vapour it's going to leak fuel
William Revit

Tank all installed. No one spotted the error that I found when I offered up the tank? The cork strips need to match the ribs in the floor. Neat and tidy they may look on the tank but every one missed its corresponding floor rib and needed realigning!.

Anyway, now that is in, where does the sender unit wire enter the inside of the body tub on a Frogeye? (wires, plural in this case as I am adding a loom earth) There may have been a grommet hole and I may have welded it up. The boot floor is a modified 1500 one - they are much the same as the Frog but the 1500 has lots of extra holes. Or it did until I got going with the MIG!

Where do I reconstruct a wiring hole? I know it isn't important and I could choose my spot, but as I have the choice it may as well be where it ought to be.
GuyW

Smack in the middle, dropping through a hole at the extreme rear end of the boot. The loom for the rear lights etc. runs along in the fold of the boot floor/rear body junction, and the tank sender wire drops through and is secured by a clip about four inches forrard of the hole.

Anyway, that's where mine was. You can see where I've taped it up out of the way.

Nick and Cherry Scoop

Thanks Nick.
Mine may vary from that.
GuyW

Oh that's what it's for! My shell has the hole in the location described by Nick.

So thanks Nick and thanks Guy for asking all the questions I'd have had to ask in a few months time! Of course I'll have to remember the answers or remember where I've written them down!

Bill
W Bretherton

If you want the authentic driving experience stick to drums in the knowledge that the accident will be fully authentic too!
Graeme Williams

ha ha ha Graeme lol
You'd get a laugh out of what I've been doing for my little project then
MGB spindles for strength I hope with 10"x2" drums fitted to them just to keep in period with the rest of it-----(unfinished)

William Revit

Guy, let us know when you decide where it goes, and I will circulate the information to all the councours judges.
Nick and Cherry Scoop

Concourse is about as far from my intention as one can get. But since l have to drill a new cable access hole l may as well do it in the proper place. Having already fitted and removed the tank 3 times, it would just be lazy not to do it once more!
GuyW

This thread was discussed between 03/08/2017 and 08/08/2017

MG Midget and Sprite Technical index

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