Morris Minor Owners Club

hi
does anyone know of a magazine or such that has covered doing a disc conversion yourself and not buying a pricey off the shelf jobby ??
cheer's
Chris<br><br>

marina and midget

Search for "disc brakes for under £100" in useful tips. Posted Nov 2007.
Uses existing hubs (skimmed slightly) and VW Golf/Polo discs and calipers. Mounting bracket cut from 10mm steel plate. You won't get much cheaper than that!!

Here's the link: http://www.morrisminoroc.co.uk/index.ph ... brakes+100

linearaudio wrote: Uses existing hubs (skimmed slightly) and VW Golf/Polo discs and calipers. Mounting bracket cut from 10mm steel plate. You won't get much cheaper than that!!

Hmm, disc brakes on std roller bearings, think I'd save up for a proper kit

Hmm, disc brakes on std roller bearings, think I'd save up for a proper kit

I'd go for a proper kit too, but I am intrigued as to why standard roller bearings should be considered unsuitable. Jonathan, could you please post a a brief analysis of why standard bearings are unsuitable. I stress that it's no criticism of your opinion, I just genuinely cannot see why, and would like to know. I also stress that I agree with you: with brakes a "proper" solution must be used. Thanks.

As I understand it the roller shape allows much higher thrust loads to be withstood in addition to the radial loads,due to the larger contact area and are ideally suited to wheel hubs.due to the avoidance of rapid wear and greatly reduced rolling friction.

Could the same argument be applied if you are using larger drum brakes, their claimed greater power applying higher stresses to the hubs? If they are stressing the hubs it's a good reason to go the whole hog and buy roller bearing hubs (which of course kills the cost advantage stone dead). On the other hand if they don't neither will discs and a modified Minor hub is back on which is not much more than careful disc spacing to centre it on a ford caliper.

Arnie wrote:Could the same argument be applied if you are using larger drum brakes, their claimed greater power applying higher stresses to the hubs?

The cars the bigger drums originally came from (Wolseley 1500/Riley 1.5) had the exact same hubs/bearings as the Minor, so the original factory designers obviously didn't think it was a problem.

In all my years with Minors - I have never known the front wheel bearings to give any problems. Adding discs should not make the slightest difference to the bearing loads. Only increased cornering speed/loasd will do that - I've tried and failed so far to make the bearings give up!
Be aware if fitting discs - you need to strip out the master cylinder and remove a little seal - the pedal load will likely also be high so you may want a servo (which in turn means re-piping the rear brakes so they are fed through the servo) - and you may want a remote fluid reservoir! Phewwww! There is a much easier way to get better brakes !

I've tried and failed so far to make the bearings give up!

just fit them the wrong way round like i did! Mind you Even then they lasted 40 miles and needed a darn good hairpin to shake them loose!

Standard Midgets don't have servos, but have disk brakes. The pedal is acceptable and not too heavy. I'm not sure the car is a whole lot lighter than a Minor?

They also have a very similar front bearing arrangement to a Minor. They have ball bearings and a spacer piece. I don't think it's identical, but it is very similar.

They also have lever arm dampers. Very similar really. Just with disks.

Andrew

The main premis of fitting discs is to 'improve ' braking over the standard set up.
There are two reasons for this demand, either folk are used to driving 'modern' cars which all use discs, or they find that the Minor brakes are insufficient for their driving style.
For std 1098 or below cars I'd suggest using the solid disc kit, for 1275 or above go for the standard vented kit or if the powerplant is a Fiat or similar then go for the RS turbo spec. We have opted for Cosworth 500 Sierra discs with AP racing 4 pot calipers with a servo, on our development track car.
The degree of improvement ie solid vented or large vented depends entirely on your driving style. If your car is std and you drive it at sub 50mph speed then the std set up in top order is fine, if you are more enthusiastic then go for the disc kit that best compliments your demands.
As with all mods these improvements cost, but kits can be sold to fulfil a total conversion with detailed instructions, to enable 'home' fitting. If you are not mechanicaly minded then I have outlined the possible costs.
What you buy with a disc kit and associated parts is a replicable unit for which spares are readily available. A system that has been tried and tested and one which fits in neatly should the Minor be a second car and the owners used to modern braking systems.
The larger drums suggested by BM are surely a cost effective upgrade on the original system, this cannot be disputed, however the parts for these are not easy to find and by nature this upgrade has a very limited life and spares supply where as the disc kits will provide a future proof upgrade.

Midgets do have discs (small and fairly useless really!) and the pedal load is not too high (but not low either) because the master cylinder is sized appropriately. The wheel bearings are same as Minor as far as I know - and yes - they do need to be installed right-way-round!

So, just to clear a couple of points up, with all due respect to Jonathon, I feel the bearing size could be a bit of a red herring. Yes I'm sure bigger bearings are a sensible improvement, but not a "must" as was inferred.
The initial query was regarding a cheap disc route, and I believe that the response was correct to that. Obviously, as with any engineering works, if you are not competent to carry out the work then you shouldn't get involved. I would say that applies to buying a comprehensive off the shelf kit, you still need to be capable of doing the work to produce a safe result.

Spot on la! Here here!

If fitting discs to a std Minor then yes the std bearings might cope. As stated the Midget uses similar hubs to the Minor, but also use smaller discs and calipers so what fitting larger discs would do to this set up I do not know.
As no one has actually produced data on the suitability of fitting Polo discs to a Minor hub I'd be tempted as a customer to buy a system that has these qualifications.
Ideally taper bearings should be used especially on modded cars (fast) heavier. and if designing a kit from scratch then it would seem sensible to fit the correct (suitable) bearings for the potential of that kit. Its not the bearing size that is the issue here though its the bearing contact area which is vastly increased with taper bearings.
LA your response to the initial question was appropriate, but only covered part of the reason why commercially available kits carry a significant costing over the 'home brewed' approach. This is where I have tried to put our case and as part of this the bearing issue was highlighted.
I totally agree re the customers level of competance on both this matter and many other such safety critical areas like welding. The latter unfortunately has gained the status on here as 'well have a go' fine if there is a level of competance and the novice follows sound advice offered or is prepared to follow basic proceedures. (however thats a new topic I don't want to get embroiled in at the mo)

Well said too Jono - I agree about the Polo conversion - don't fancy it at all! But fitting Spridget discs was a once popular notion - and relatively easy to do - but exactly what improvement in braking was achieved is very dubious indeed due to their diminutive size!!

eastona wrote:
Standard Midgets don't have servos, but have disc brakes. The pedal is acceptable and not too heavy. I'm not sure the car is a whole lot lighter than a Minor?

I've been swapping between Sprite and Traveller recently depending on the weather and the Sprite feels about half the weight! (It's actually around 660kg vs. 850kg)

RIGHT!
One last point that seems to get overlooked by a lot of upgraders is the need to have a balance between front and rear. Ie: just putting discs OR larger drums on the front (depending on which brake cylinders you use, I add, before Mr E starts on that one again ) can end up with all the force going to the front and the rear brakes doing nothing.
I am certain that Jonathons comprehensive kit addresses this, but feel some people only see the money as going on the front brakes, therefore why not use a cheaper "fix"?
I maybe should have added that to my first reply, as the sub £100 "fix" could well leave you out of balance.
As with a lot of subjects raised on this most excellent forum, the whole picture only seems to come in dribs and drabs. I have said before that I feel a "sticky" (frank, without axe grinding) on this subject would give an all time clear picture of the options and pitfalls of brake upgrades. Another on putting the 940 head/ free flow manifold etc would be good, and one on 5 speed versus overdive versus diff ratios.
Get them sorted and we will have precious little left to bicker about. (but that might spoil the fun for some of us!!)
All the above intended in good faith and spirit

The only balance problem I have ever had was when I fitted an ital axle with it's bigger rear brakes that caused rear lock up under really hard braking, hence the use of the bigger rs turbo discs and calipers (over the sierra/240mm combo) which balance it back out again. No cold performance problems with a decent road spec pad and no corrosion problems despite it often being left for weeks while the owner drives his minis.