Mini Cooper 1964 coversion to S Brakes

49 comments

  1. Hi We have a 1964 std Mk1 Cooper and think of upgrading to the 7.5' brakes . Do we need the S Steering arms or will the std Mk1 cooper steering arms be ok . Regards Bruce

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    As far as I'm aware, standard Mini wheels will fit over 7.5' disc brakes.

    Problems arise when trying to fit Cooper S wheels over 7' discs or drum brakes. This is due to the inset of the S wheels resulting in fouling of the suspension.

    I guess thatis why Dunlop introduced the LP918 reverse rim, so you could get the S look on 997/998 Coopers or standard Mini's without altering the brake set up.

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    [b]Andrew1967 wrote: [/b] “As far as I'm aware, standard Mini wheels will fit over 7.5' disc brakes.

    No, they won't! Standard steels will hit the calipers.

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    [b]Mini4Ever wrote: [/b] “[b]Andrew1967 wrote: [/b] “As far as I'm aware, standard Mini wheels will fit over 7.5' disc brakes.

    No, they won't! Standard steels will hit the calipers.

    I stand to be corrected, Bart 😀

    AmI'm right about S wheels not going over drums and 7' brakes though 😕

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    Cooper S 4.5×10 rims WILL go over 7' discs, I have a set on my '64 Cooper with original 7' discs and 165×10 tyres and there are no clearance issues. Only on full lock can I hear the inside of the tyre rubbing. My Cooper has also been lowered quite abit. (soon to be raised again!)

    I have S type drums on the back with the spacers so theres no problems there too.

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    Don't see any problems with fitting any type of S wheels on 7' discs or drums at the front. Do however think that the narrow rear drums might cause problems – will check after dinner :DFitting 4.5' reverse wheels with 165 tyres on the 1/2' spaced rear drums is for sure no problem.

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    Seems that the reference book I have iswrong on this issue then. 🙁

    So if S wheels fit over the front drums, what was the point in the reverse rim?

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    I have 4.5' Cooper S rims on my 997.

    The discussion is correct about the front wheels hitting the calipers.

    One thing about the rears though is that the 4.5' rims on full spaced drums will stick out a fair bit from the arches hence the flairs on Cooper S.

    My solution years ago ended up being to use mini moke drums (13' wheel version – standard wheel ) as the spacer is about half the thickness of a normal spaced drum so the 4.5' rim wont protrude from under the arch and it clears the trailing arm.

    also, I believe the standard spaced drum could be used if the spacer part was machined down but you could only do that using the solid spaced type and not the ones with recesses on the inside.

    cheers

    RNY

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    Well, did some checks but definately didn't try all possible combinations:

    [list]
    [*]I already mentioned that standard 3.5' rims will not fit on 7.5' discs at the front as the wheels will hit the calipers
    [*]4.5' S rims with 165 tyres fit on 7' discs and drums – no problems at all. On Mk I even no problems with tyres hitting inner front wing at backon full lock. Might be a problem for later spec Mk II and on steering racks. As a result, also the 3.5' S and reverse rims will fit like a glove
    [*]As I suspected, 4.5' S rims with 165 types and also 3.5' S rims with 145 tyres will not fit on standard drums at the rear. The tyre will hit the shock absorber / hydro spring helper or even the suspension arm. 4.5' reverse rims with 165 tyres do not have this problem and will not stick out stupidly much. Solution for the S rims is fitting 1' spaced drums as I think that the 1/2' spaced drum will not provide sufficient clearence between the tyre and the shock absorber / hydro helper spring – even not for the 3.5' S rim 145 tyre combination[/list]Think that clarifies not only the intro of S rims but also the reverse version of the 4.5' ones

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    Hi 1963S- I have a question – If steering arms are matched to racks what is the difference between an S rack and a standard Mini cooper Mk1 steering rack . . My question relates to placing S hubs and discs on to a Mk1 1964 cooper .Is the rack longer , are the track rod ends different etc??

    I'm surprised that there is any difference in the racks at all- please advise. I have S hubs ready to fit to our Mk1 cooper which still has its original rack. . PS car currently fitted with 6X10 minilites

    Regards Bruce

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    Mini4Ever wrote:
    “[b]Andrew1967 wrote: [/b] “As far as I'm aware, standard Mini wheels will fit over 7.5' disc brakes.

    No, they won't! Standard steels will hit the calipers.

    I have a rolling shell in my garage with 'S' brakes and standard 3.5 inch rims on …. hadn't really thought about until this discussion started. Now I am confused. Been trying to find photos of 998 calipers/brakes in case I've been flogged a lemon (wouldn't be the first time !)
    D.

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    The wheels will go on the car. But don't try to spin them as you will damage your 7.5' calipers. Certainly don't try to start and drive the car!

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    Hi Bruce,

    Not sure when it was introduced but what I recall is the 'S' rack differs mainly by the ratio of the gears (# of teeth on the pinion to the # on the rack). The higher ratio theoretically improved the steering feel at faster speeds.

    An 'S' rack shouldreturn a shorter rotational distance of the steering wheel than a standard rack lock to lock. ie; 'fewer' turns of the steering wheel.

    Also, I think from memory the rack bar inside the housing is shorter & so not only are the arms bolted to hubs madethickerbut with a slighter steeper angle (when viewed overhead) which in turn with the higher ratio, gives a slightly smaller turning radius and improves manoeuverability. The track rods and track rod ends are all the same.

    There shouldn't be any issue fitting the 'S' hubs & brakes though to a standard steering setup.

    RNY

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    I think that if you want to improved your cooper's brakes to S specification, you should have to change the originales wheels, has i'm not shure that 7.5 disc could go inner the 4×10' cooper's wheels…I have a 1965 998cm cooper whith its original steel wheels (with 145 X 10 Sp tyres)and i'm not shure that i can simply upgrade with 7.5 disc whitout changing for wider wheels.?:?

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    Mini4Ever wrote:
    “The wheels will go on the car. But don't try to spin them as you will damage your 7.5' calipers. Certainly don't try to start and drive the car!”

    I drove my Cooper that had S brakes on it for quite some time with standard 3.5 inch wheels off my 850 mini,

    No problems with calipers fouling

    :?:?:?:?

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    That the S and reverse rims fit over 7.5' calipers is obvious. But why do my tests give different results for std 3.5' wheels??? I fitted S brakes to my 1975 Mini 850 years ago and only after doing so I discovered that the original wheels of the car hit the calipers when turning around. I actually had to take everything off again as I didn't have suitable rims at that time. So, why didn't it work for me then?

    @rodeo1968: Did you actually try to turn those std 3.5' wheels when fitted over the 7.5' calipers?

    Apparently my tests lastnight on fitting S wheels in different sizes on 7' discs and drums haven't convinced all. Should I redo them and make pictures??? Or is there maybe something different to the various sets of 3.5' S, 4.5' S and 4.5' reverse rims I have???

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    [b]Mini4Ever wrote: [/b] “Apparently my tests lastnight on fitting S wheels in different sizes on 7' discs and drums haven't convinced all. Should I redo them and make pictures??? Or is there maybe something different to the various sets of 3.5' S, 4.5' S and 4.5' reverse rims I have???

    Please don't get me wrong Bart, I am not disputing what you have tried at all.

    I can't remember where, but I have definately read in an authoratitive Mini book that S wheels do not fit drum braked cars (without spacers) and that the Dunlop reverse rim was introduced to give 'ordinary' Mini owners the S look. It's be interesting to know why they were produced if Cooper S wheels would fit straight on to lesser models.

    From what I understand, the S brake set up is slightly wider than the drum/7' brake set up resulting in thewheels sticking outfurther. If you fit reverse rims and 165/70's to a car with 7.5' brakes then the tyres stick out too far and spats are required. With S wheels, you can just about get away with it, as has been previously mentioned.

    I do remember very clearly that when I was 18 I went to buy some wide wheels for my first Mini and bought a set of reverse rims for £5 and turned down a set of S wheels for the same price as they would not fit my '72 1000, according to what I had read.:shock:

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    Don't worry Andrew, the books are absolutely correct! The problem is however at the rear and not at the front 🙂

    Now, I just went into the garage to do some more experiments. This time on a 970S which is again a different car- you never know – and tried to fit a std 3.5' rim to its 7.5' calipers. Tried to make a picture of how the rim hits the caliper, butdidn't succeed very well. Below the best picture I was able to make (rather bright though).The inner edge of the vent hole of a standard 3.5' rim hits the outside of the outer cylinder housing of the caliper. Now comes the interesting bit: if you do not tighten up the wheel, it might just work. In other words, if you remove a bit from the edges of each of the 4 vent holes, the problem is solved. Possibly also that some calipers have less flesh around the problem area and then it will work too. But it didn't work on the cars for which I tried, notwithout modifying the rims (or fitting spacers).

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    :cool:[b][color=yellow][size=7]Bright ! :cool::cool::cool::cool:[/size][/color][/b]

    [b][color=#ffff00][size=7][color=black][size=2]Your not kidding :dude:, but I am with You on this one.:D[/size][/color][/size][/color][/b]

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    apologies all for any confusion.

    There were no specific S racks. I think i was getting Mk 1 & Mk11 racks confused. Seems the rack & pinions are the same in Mk Is

    RNY

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    [b]Mini4Ever wrote: [/b] “Don't worry Andrew, the books are absolutely correct! The problem is however at the rear and not at the front 🙂

    Now, I just went into the garage to do some more experiments. This time on a 970S which is again a different car- you never know – and tried to fit a std 3.5' rim to its 7.5' calipers. Tried to make a picture of how the rim hits the caliper, butdidn't succeed very well. Below the best picture I was able to make (rather bright though).The inner edge of the vent hole of a standard 3.5' rim hits the outside of the outer cylinder housing of the caliper. Now comes the interesting bit: if you do not tighten up the wheel, it might just work. In other words, if you remove a bit from the edges of each of the 4 vent holes, the problem is solved. Possibly also that some calipers have less flesh around the problem area and then it will work too. But it didn't work on the cars for which I tried, notwithout modifying the rims (or fitting spacers).

    Just recovering from arc-eye viewing thatpicture:PInteresting investigation Bart.

    I had better have a look at the spare standard wheel in my Cooper asap and check whether it will fit the front. Just as well I haven't had a puncture.

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    “An 'S' rack shouldreturn a shorter rotational distance of the steering wheel than a standard rack lock to lock. ie; 'fewer' turns of the steering wheel.

    There is no such thing as an S rack, they are all the same.

    Steering arms are matched to the rack in as much as you need to use Mk 1 arms with a Mk 1 rack otherwise your Ackermans angle is messed up. You should use S arms with S hubs for the same reason.

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    Have done many a forest/gravel stage rally with 3.5 standard mini wheels shod with Colways on 7.5 disc set up, no problems, just the odd puncture!:)

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    Yes I did rotate the 3.5' rim and all was OK. During my tests it looked very much as though the inside of the 3.5' rim has the same dimensions as the inside of a 4.5' reverse rim. They are of course different on the outside as the reverse rim is much wider and sticks out a lot more.

    Picture attached of 3.5' standard rim with sufficient clearance (just) on 7.5' caliper.

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    [/quote]
    There is no such thing as an S rack, they are all the same.

    Steering arms are matched to the rack in as much as you need to use Mk 1 arms with a Mk 1 rack otherwise your Ackermans angle is messed up. You should use S arms with S hubs for the same reason.[/quote]

    I'm with the Meister…somewhat. A Mk I rack is a MkI rack (and a Mk II is different) . You should use the matching steering arm. I have driven cars with mixed rack/arms and they seem fine – but I wouldn't choose to do it myself.

    There are two kinds of Mk I steering arms (and Mk II); S and other. in both cases the S type is thicker but the geometry of the two holes is the same type for type. So I don't agree fully with the comment above.

    The S type is thicker allegedly to allow it to resist harder knocks but, one old time racer noted that, if you hit something hard enough to bend the arm, then it was much easier to replace the thin arm than risk the stronger arm passing the shock to the rack.

    I run a Mk II rack (because of its much reduced turning circle), Mk II standard arms and Mk I S (1071) hubs. Seems to work.

    As for wheels; (and from my experience) standard Mini rims will fit over S brakes but won't rotate fully. 4.5 S steelies won't rotate when fitted to non S drums at the back. S wheels (with 165 tyres) will fit under non flaired arches with S drums at the rear ..and the front. The wall of the tyre does bulge out a bit past the bodywork but not enough to upset the roadworthy (MOT) nazis (legal if the 'tread' is covered).

    Some people report that their standard wheels fit over their S brakes. So it seems that all brakes and wheels are not equal – so one would have to suck it and see.

    I'd be a little concerned about running 7' front brakes and spacered drums (to use S wheels) as the 7.5' discs stick out 1' a side – the spacered drum was introduced to even this out front to rear. Cooper front brakes with S rears would seem to introduce a bit of imbalance.

    Cheers, Ian

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    Well, I have just done a test with a 4.5' S rim, a 4.5' reverse rim and a 3.5' standard rim. They all fit over 7.5' discs and calipers.

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    [b]rodeo1968 wrote: [/b] “Well, I have just done a test with a 4.5' S rim, a 4.5' reverse rim and a 3.5' standard rim. They all fit over 7.5' discs and calipers.”
    As I thoughtthey would.

    I am still of the belief though thatLP882/3 Cooper S wheels will not fit on a drum or 7' disc braked car without the use of spacers.

    My 4.5' Minilife alloys would not fit on my 998 Cooper without the use of spacers on the front (and back). Now I have S brakes on it, I no longer need spacers at the front. These alloys have, I think, a similar inset/offset to an S wheel.

    Come the better weather I'll try an S rim on my 850 and then I'll know for certain

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    Some standard 3.5 inch mini wheels have rivets where the centre meets the rim, these are quite big, maybe they hit the caliper??

    Also there is more than one manufacturer of S calipers too.

    J

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    [b]ka2s4 wrote: [/b] “Some standard 3.5 inch mini wheels have rivets where the centre meets the rim”
    That would be early Mk I rims.

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    At least we don't need sunglasses to view it :DBut it looks like your std rim is different from mine. Was only aware of differences between early Mk I std rims and later ones. Is yours an early Mk I?

    PS.: Sorry Bruce for hijacking your thread – two discussions in one thread 😕

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    My rule with Minis is to 'never say never'. Things that you would swear are 'A' will be proved by someone else to be 'B'.

    None of the standard Mini wheels I have will fit over MY S brakes. The common denominator is my 1071 callipers. I have used different discs, flanges and CVs with always the same results. The wheels fit but won't rotate.

    I guess if you wanted to use this combination you just bolt it up and if it works, then fine ..otherwise.

    The general consensus amongst the people I know is that it doesn't work. Maybe Oz wheels are different??

    Cheers, Ian

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    I have no idea which Mk of 3.5' rim I have,which fits over a 7.5' caliper. Here is a foto. No, I am not proud of it but was thinking of cleaning it up and using it as a spare.

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    [b]rodeo1968 wrote: [/b] “and the other side (rim02.jpg)”

    Yep, that's different from what I have. And I can understand that these will work!

    A have made a picture of mine and did some photoshopping to try to show the difference in the green elipses. It's maybe a bit hard to see in 2 dimensions but on my rim the egde sticks out further inwards than on yours. Mistery solved 😎

    Now I only need a better camera to make clearer pictures and not such crap :X

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    Mini4Ever wrote:
    “[b]ka2s4 wrote: [/b] “Some standard 3.5 inch mini wheels have rivets where the centre meets the rim”
    That would be early Mk I rims.

    am looking for a pair of those rims 🙂

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    are there differnt types of hubs then (for discs)? i thought that all the hubs where the same but you guys keep mentioning s hubs??

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    masnarda wrote:
    “S hubs have a slight taper to them, apart from that they are the same”

    I thought there were only two types of disc uprights… the BTA186/187 and the later FAM something or other as pictured below (I hope)!

    Cheers

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    dgear1984 wrote:
    “there abouts is the taper? can you fit s discs with no s hubs?”

    More information. Just had a look through the parts books/fiche. The BTA 186/187 disc swivel hubs were used for all disc brake systems (7', 7.5' and 8.4') up to the early MK IV. Someway through the MK IV, the swivel hubs changed to the FAM 2390/2391 pair. If you order BTA186/187 from many of the UK suppliers, what you'll get are likely to be FAM2390/2391. Checking one of each, the physical differences are as in the picture in the previous message. The bores are the same lengths, diameters and the ridge in the middle is the same length. They are also the same dimensionally as to bore distance from the vertical axis through the top and bottom ball pin centres. So, can we say that there are no Cooper S swivel hubs; just disc swivel hubs?
    Cheers.

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    If you are out for the correct look, you will need hubs like pictured on the left in the image of the previous post. The hubs should have MOWOG on them.

    I'm not claiming that others won't fit but if you want it the correct item that's the one to look out for.

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    Did not the early hubs (the ones on the left) appear first on the 997 Cooper??

    If so, there really isn't an S hub, its more of a 'Cooper' hub.

    Serious question as I have a set of 997 hubs which I'm hoping to combine with S calipers, drive flanges, 7.5 discs etc etc…. Will it work?

    Cheers, Ian

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    Did not the early hubs (the ones on the left) appear first on the 997 Cooper??

    If so, there really isn't an S hub, its more of a 'Cooper' hub.

    Serious question as I have a set of 997 hubs which I'm hoping to combine with S calipers, drive flanges, 7.5 discs etc etc…. Will it work?

    Cheers, Ian

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    Sorry, really late input here. The standard 3.5' wheel on 7.5' S hub must be a very close run thing that depends on catsings tolerances etc. I have run standard wheels on a Moke with S disks on with no problems at all. I have also run them on a number of other saloons. Only one of which required the fitting of 1/8' spacers on the front to clear the caliper.

    M.

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    1963S wrote:
    “Did not the early hubs (the ones on the left) appear first on the 997 Cooper??

    If so, there really isn't an S hub, its more of a 'Cooper' hub.

    Serious question as I have a set of 997 hubs which I'm hoping to combine with S calipers, drive flanges, 7.5 discs etc etc…. Will it work?

    Cheers, Ian”

    Do they have BTA186 and BTA187 cast into them? If so, the answer is yes…
    Cheers, Keith

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