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MG Midget and Sprite Technical - Brakes, or rather, no brakes

So, on replacing my shoes, I discovered that they weren't as worn as I thought they might be.

That may be something to do with the fact that they don't actually have working cylinders.

Both sides have leaking cylinders and one side has a huge hole in the seal (see attached), plus a massive amount of black gunk(!) in the drum.

No wonder my brakes were 'spongy'! So, no driving this weekend....




Rich Amos (1330cc Blaze Red '72)

Well the hole is not in the seal, that is only the dust cover. However if you believe the cylinders have leaked or indeed they are stuck then new cylinders are cheap and plentiful.

Sometimes the gunge that accumulates in the brake drums is due to axle oil leaking from the hub, difficult to determine by the inexperienced eye.
Bob (robert) Midget Turbo

No, believe me, it's the seal, too! When you push the brakes, brake fluid now happily pours out.

I remember a while ago there was an axle oil leakage which was fixed by a garage before I got my hands dirty with the car, so maybe this mess is remnants of that + some brake fluid....
Rich Amos (1330cc Blaze Red '72)

I agree with Bob. It looks as if the seals have failed and the dust covers shown in your photo will swell and tear to follow. New cylinders are dirt cheap, so just fit another and bleed. This is the job you read about where everybody has difficulty in securing the cylinder to the backplate (plenty in the archive on that!) and I find an ordinary circlip works best in place of the E-clip provided. The job is easiest if you remove the half-shaft and take the backplate off the axle. Then you can get the shoes back on with all the springs in their proper place (the shoes will need cleaning or replacement - but they're cheap too), and what about checking that the adjuster is still moving properly while you're at it. A good investment in time is to do the other side when you've finished, as you then have all the proper tools to hand, plus all the experience from doing the first one.

G
Gus Gander

When/if it stops raining I will need to get the drums off Lara, cos when I took her out last night I had the familiar "when's the pedal gonna start to work" feeling. Coupled with the handbrake suddenly needing pulling right up into my armpit, I rather expect a similar sight to be on view.

But not fair, 1500 or so miles since I was last in there.
Bill

Tell me about it Bill. The adjustment of the rear brakes is crap. That is why I am presently engineering rear disk brakes. I have had enough of poorly adjusted brakes
:-)
Just need to check out Peter May's proportioning valve, :-) Anyone know does this simply go into the rear brake line and adjusts the rear brake pressure? Think it is listed at 35 knicker.
Bob (robert) Midget Turbo

Been there with the leaking cylinders. And replacing soaked linings, with very little wear, since I'd just put them in a few months earlier.

I rebuilt one rear cylinder, but later replaced them both with new ones.

The one thing that surprises me is how often I have to adjust the things. I seem to remember somebody saying that the new environmentally-safe lining compounds wear more rapidly.

-:G:-
Gryf Ketcherside

I have seriously considered going to Ford brakes, hubs, axles and disks with the stupid nonsense these very old technology BMC brakes present us with.

Ford's 13" Rostyles wouldn't give away the game too readily to the purist brigade either.

So much to do and so much time in which...

but disks are still a very much better idea instead.
Bill


Anyone ever considered going to Mk2 Golf GTi brakes all round inc the rear discs with handbrake mechanism?

Vented front discs and all should fit within the 13" rims.
Bob T

Bob... have you got a death wish....?

Golf GTI brakes were always CRAP....!

Mark.
Mark T. Boldry

Of all the poorly designed things on my car, i think the rear brakes are the worse (vote for second place is canister oil filter).

Don
don g

""Anyone ever considered going to Mk2 Golf GTi brakes""

Everyone who has ever wanted rear disks Bob T. :-))

And the reasons are simple, To operate a handbrake the motor manufacturers adopt 2 basic types.

1 Brakeshoes inside the rear disk, This is by far and away the most popular option but is not really practicle for the Spridget rear axle mod.

2 Handbrake mechanism on the rear caliper. So far the only tyes like this that I have identified are the Volkswagon and the Rover 25/45s. I believe also that the Ford sierra was like this but they appear to be a bit thin on the ground in Scapyards.

Therefore the choice of parts is distinctly limited, but with the right parts the mods should be very simple. :-)

Bill who are the purist brigade? Thought most of them owned MGAs.
Bob (robert) Midget Turbo

Bob, do you think the standard rear bearings are up to the job if you fit rear disks? It's one of the things bothering me about trying a conversion.
Bob T

I thinks so but would not swear to it. I would say this however. The braking efficiency is determined only by grip, thus it is the tyres and footprint which would stress the wheel bearings not really how we brake the wheel. Wouldn't that be the case Bob?
Bob (robert) Midget Turbo

Bob and Bob T,

I think one of the problems a rear disc conversion and the standard bearing may be the movement allowed under cornering pushing the pads off the disc so when you hit the brakes next you have to make up that movement. I think it is this reason that makes the dual bearing hubs a common fitment when fitting rear discs.
David Billington

Saab 9000

Blooming big calipers and disks sadly but the handbrake is within the caliper, adjusts via a 2mm (ish) allen key inside the blanking plug'ole

If my old Sayab hits the dust there are quite a few bits that won't get as far as China on her.

Purists? Good point Bob, not many of those around OUR world are there?

And all of the MGA owners I know are as likely to be into non-period fettling as I am.

I had the car up in the air this morning, brakes ONLY (pshaw!) needing adjustment, no nasty dampishwettishoilygreasyish bit inside thank God.

But as usual the half shaft carrier has neatly sliced into the dustcover...

damned rubbishy design, nearly Not Fit For Purpose

There really does have to be a better way


Bill

This tread sure makes the RX7 rear-end option look more and more appealing

BTW Rich....that black Gunk in your master clyinder resivoir is the "Natural" rubber seals in your MC desolving Due to the petroleum based brake fluid.....change out the rubber stuff in the MC with "Ray Bestos" rubber parts....there the only kit (IN the USA) that are made from petrolium based and are compatiable with petrolium based brake fluid.

prop
Prop

Bill.

My Sister has just stopped using her Saab 9000 and I'm loathed to take it for scrap. In fact, I'm sure it would pass the MOT again with little trouble. It's not practical for her and with ever increasing fuel costs, it has to go. It's got the 2.0 Litre 16 valve engine with a recently new Red ignition pack on it, good tyres etc, in fact, no disrespect Bill, but the body work is also in very good order, perhaps it would be better coming down to you or anyone else who would like it for a small fee (I know these are reaching up to £200.00 now in scrap metal value alone...!). The Ignition pack was close on that figure!

Anyone interested, even for the rear brakes...?

Mark.
Mark T. Boldry

I have a couple of doors in mind but there is nowt on the later lump that's very compatible with mine
I have a distributor rather than the red pack.

Someone may like to play with the rear callipers though, maybe with midget sized disks. There's room for all sorts of disks between the pistons

The handbrake setup needs setting carefully but is certainly a better thing than a combined disk/drum unit

I am still thinking Ford axles and brakes myself, but I'm very loath to retire my lurveley Peter May half shafts though.
Bill

Winner's Circle of Cleveland, Ohio, USA has a disc brake set-up using Wilwood (or Wildwood not sure)calipers. A parking brake would be a problem but rear disc cars have somekind of E brake.
J Bubela

the only problem with rear drum to disk brake conversion from winners circle is the cost....I dont remember exactly but between $600 - $800

prop
Pro P

Saab sold to Pikies today. RIP.

Mark.
Mark T. Boldry

For rear discs with handbrake
operating directly on pads try Bendix as used on Renault R8,R10,Alpine110 and some Seats.
Rupert

Rupert,

I had thought of mentioning Lancia Beta as these used Bendix calipers with integral handbrake since the early 1970s, and alloy bodies, but I think Bob (Robert) was looking for current models or at least not so current models that would be easy to find in a breakers yard. Having said that I would suspect any FIAT/Alfa Romeo with rear discs would have the required sort of calipers.
David Billington

I have a pair of rear calipers with a manual handbrake on the piston. Might have to leave it in gear on a hill though just in case. They are moderns, audi or VW I think.
Tarquin

I'm interested in some from of cost effective rear disk conversion. My FTO has handbrake on the caliper too.

Whats the chance of finding a combined disk/drum that will fit over the standard midget rears and still have enough clearance to squeeze a caliper in too? Just a thought.
Nick

Yep that's right David, to do any of these conversions it is always desirable to find a readily available source of parts that helps keep prices down. It is no point trying to find exotic calipers for this modification. Rover or VW appear to be favourites Alternativel pay frontline 500 quid for a complete kit.

Nick Disks are not a problem I have a book with hundreds in that the desired disks will be readily identifiable and will require probably redrilling for studs and maching to reduce diameter.
Bob England

Pretty sure my Alfa 156 used simple cable operated levers onto the rear disc callipers. They should be easy enough to find in scrapyards.

It was a lovely car....sob!
Guy Weller

Bob, I don't suppose the disks are filtered by PCD are they? I have a pair of Maestro (3.75" PCD, same as Triumph) front disks for the rear of the V8 TR8 axle, but they are 13mm thick whereas my calipers (and probably most rear calipers) will only take 10mm thick disks. I'd rather use a standard 10mm thick disk rather than skim a 13mm to 10mm.
Tarquin

maybe I didn't describe my idea properly bob (it might be mad anyway)

I meant to find a disk from a car with OEM disks/calipers & handbrake shoes at the back (toyota etc) that happens to fit over the existing midget shoes, i.e. that the drum part of the disk is the same diameter as a midget drum. Then to drill for the 4" PCD and use the disk / caliper for the brakes and the shoes only for the handbrake. getting this all into a 13" minilite might be trickey.
Nick

Nick,

What are your reasons for wanting a disc/drum type unit rather than a disc caliper with integral handbrake. I've had the integral handbrake calipers on 2 Lancias and they always worked and the spridget is a much lighter car.
David Billington

It's not for the just for the handbrake more the ease of a conversion. Was just thinking if you could get a disk/drum like i mention, it would be a case of whack it over the shoes and then mount a caliper (don't know how yet!) and reroute the brake line. Hey presto instant rear disks.
Nick

Rear disc handbrakes can let go when the disc cools, though, can't they? I remember a story that the bloke who bought the last mga twin cam ever built left it on his sloping drive after a bit of a thrash, and later found it wrapped round a lamp post (or something).
Nick

Nick,

Never encountered it myself but usually let a car cool down after a thrash before parking up and turning the engine off, like having a turbo car even on my old Lancia Turbo with watercooled turbo I wouldn't just turn it off after hard use. Is there anything more than anecdotal evidence for the handbrake loosening, I've heard it for years but never knew anyone to suffer from it. Some said the brakes didn't work well but I haven't encountered that on my cars.
David Billington

Hey presto rear disks? :-)

I think that sounds like a little more than hey presto Nick :-) I think the disk part would be very large and prohibative and one of my concerns is that the Spridget hand brake is crap. Autotesters will know what I mean :-)

It is a far easier option to use a handbrake caliper, naturally IMO.

Sorry Matt the pcd is not displayed so I can not search with that value, but looking at the Maestro disk it does have a lot going for it although the 13mm is not good as you rightly point out.

I have left word with a couple of local scrappies to save me some VW and Rover rear calipers, but will also check out fiats.
Bob (robert) Midget Turbo

Maestro/Monty discs come in 2 thicknesses, plain and vented, have you looked at both? And what about MGF rears, same 3.75 PCD?
David Smith

Dave we were talking about the solid disks, the Maestro vented is worse and is 22mm.

However I do not have a drawing of the MGF/TF rear disk but the dimensions suggests that it is only 10mm wide and only 240mm diameter, a good candidate for you Matt if it is fitted on the MGF over the studs. In fact it is a good candidate for me with a bit of machining.
Bob (robert) Midget Turbo

If anyone is still in the slightest bit interested in this thread I have decided to have a go with the MGF/TF rear calipers.
The arc of these is at max 240mm the smallest I have found, and on top of that I have found a company supplying these fully reconditioned for 65 quid each with no exchange! Now I think that is pretty good.
Bob (robert) Midget Turbo

Bob, are they alloy calipers?
The ones I have are cast, and are a bit heavy. If I could get some alloy ones that would save some weight to help offset the axle weight.

I bought my calipers a couple of years ago at Stoneleigh. There was also a pair of good used alloy ones, I could only afford one set so went for the new cast pair, I should have borrowed some money and got both!

I'm only concerned now about clearance for the caliper, as I bet the MGF discs are quite shallow. But we shall see.

Matt
Tarquin

hmm didn't know they were available in alloy. Not sure I could afford them either. The ones I can get are definately cast.
Are you building these onto a Midget axle or something else?
Bob (robert) Midget Turbo

A narrowed Triumph TR8 axle.

the alloy ones were off a different car, Audi I think.
Tarquin

I now have a pair of mgtf rear disks for my TR8 axle. The PCD is correct but the hubs need to be turned down to fit inside the disks.
Tarquin

This thread was discussed between 21/06/2008 and 02/07/2008

MG Midget and Sprite Technical index

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