13 replies to this topic

[JonnyAlpha]

Hi,

I need to do a drum to disc conversion when upgrading my 1982 998 HLE 1000 to 1310.

The best priced complete kit is £360, but this will have standard Calipers and Bearings.
I have been keeping an eye out and contemplating refurbishing second hand parts or using a mix of new and refurbished.

I have spotted a set of what are supposed to be Cooper S 7.5 Calipers with hubs and flanges for £120.

Questions:
1. How do I tell if they are genuine Cooper S?
2. What are the benefits of using Cooper S over others?
3. Is it worth returning the hubs (new ball joints etc) or just buying new ones.
3. What would be a reasonable asking price for second hand Cooper S Calipers, Hubs and Flanges )separate prices)
4. Where the Cooper S Hubs different and would they fit?
5. What’s the cost of refurbish Calipers?


I was contemplating getting a conversion kit but asking for Timken bearings and no Calipers or maybe hubs and using SH Calipers and Hubs.

I am happy to refurb (I use Citric Acid on Rust - Comes up like new (less any putting of course), but need to find the most cost effective route as budget is almost gone!!!

[Ethel]

Cooper "S" refers to 7.5" discs that were used with 10" wheels. If you look on Minspares website you should be able to spot the differences:

 

The main one is that flange is on the outside of the "bell" that connects it to the disc - note the attachment by small countersunk screws because the studs pass through similar to drum brakes.

 

The calipers are harder to identify without a direct comparison to 8.4" discs, but the pads are retained differently and that shows if you look at the flanges the retaining pins fit through.

 

Original ones will be 40 years old any flogged 2nd hand are as likely to be reproduction, not that it should matter much. See if you can get  photos with the bleed screws removed, if they're seized they have a habit of shearing off.

[DeadSquare]

ONE

Even if your were going to go circuit racing, it would not be necessary to use Cooper S parts.

 

TWO

Buy something from someone who knows what they are doing.  If your brakes are not up to scratch, you might kill someone else, and that's not nice.  Buy something from someone who knows what they are doing.

 

THREE

I don't want to be unkind, but if I thought that you had replaced the seals in your calipers, I'd walk.  Buy something from someone who knows what they are doing.

[JonnyAlpha]

OK so the opinion on refurbishing Calipers is a no then

 

So if buying new calipers what are the performance differences in the standard 7.5 Cooper S Copies and the Genuine AP versions:

 

https://www.minispar...ic/27H4657.aspx

 

Expanding on this subject a little more, I have been looking at the comparison between SH and new for a long while and today priced up all the parts for a conversion using Non Genuine Calipers but Timken Bearings. Came out around £530 before discount (using Mini Spares as a source of info.

 

WRT Disc Hubs, to refurb a set of Hubs would cost about £60 using budget bearings and about £130 using Timken bearings, this does not include, degreasing, soaking in citric acid for a week, and cleaning up.

 

Huddersfield Spares sells a built up new Hub for £115 (so £230 for a pair), but probably using budget bearings 

 

So, based on the above, if you could pick up a pair of hubs for lets say £40, add the cost of recon using budget bearings as a comparison, would cost £100 all in, so that's a saving of about £130. Probably worth it.

 

So you have a set of hubs but now need the rest of the kit, you can pick up an 8.4 to 7.5 kit with MiniSpares Calipers for £185, so we are now up to £285, but you still need the CV Joints. A pair of CV Joints is £63 so that's a total of £348, nearly the same as buying a kit! (And Iv'e missed a few essentials like Hub Split Rings).

 

Not sure about Drive Shafts - IIRC you should be able to re-use the old Drum ones, but may as well renew them!!

 

This is not a racing Mini, more a fast (ish) road car, maybe a once a year track session at Castle Combe (but if you know me I am not a fast driver!!

 

Once I can afford to get the cylinder head done it will be a Stage 2 head, Stage One Kit 1310 with an AC RS Cam, with a standard set of rockers should pull about 80 lb/ft Torque.

[nicklouse]

OK so the opinion on refurbishing Calipers is a no then
 
So if buying new calipers what are the performance differences in the standard 7.5 Cooper S Copies and the Genuine AP versions:

They are the same. 

[nicklouse]

 

Not sure about Drive Shafts - IIRC you should be able to re-use the old Drum ones, but may as well renew them!!

 

The drive shafts are the same. No point in changing them unless the C clip rings are damaged.

[Cooperman]

Budget bearings may last as long as half-an-hour.
If you are happy with 12" wheels just get a pair of 8.4" discs.
If you ar interested I have a pair of good 8.4" discs and callipers which can be yours for a small consideration.
PM me if interested. I have just done a 12" to 10" wheel conversion.

[unburntfuelinthemorning]

If your brakes are not up to scratch, you might kill someone else, and that's not nice.

 

Well put.  In fact it would make you a total rotter!

[alex-95]

When I was doing the same from drums to discs I bought the minispares 8.4" to 7.5" conversion kit (don't need the AP calipers) and bought a 8.4" disc set with driveshafts for not a lot of money. Then just refurbished it all along with new cv joints and bearings (ended up swapping them to timken after a few hundred miles.

 

 

 

Not sure about Drive Shafts - IIRC you should be able to re-use the old Drum ones, but may as well renew them!!

 

The drive shafts are the same. No point in changing them unless the C clip rings are damaged.

 

Drum drive shafts are smaller diameter looking back at my photos, unless it was a while after they changed to disc that the diameter changed, I guess the splines are the same.

Edited by alex-95, 04 January 2020 - 08:30 PM.

[nicklouse]

When I was doing the same from drums to discs I bought the minispares 8.4" to 7.5" conversion kit (don't need the AP calipers) and bought a 8.4" disc set with driveshafts for not a lot of money. Then just refurbished it all along with new cv joints and bearings (ended up swapping them to timken after a few hundred miles.

 

 

 

Not sure about Drive Shafts - IIRC you should be able to re-use the old Drum ones, but may as well renew them!!

 

The drive shafts are the same. No point in changing them unless the C clip rings are damaged.

 

Drum drive shafts are smaller diameter looking back at my photos, unless it was a while after they changed to disc that the diameter changed, I guess the splines are the same.

Correct some were thinner but the fittings are all the same ( pot and X types excepted)  but then again many were the same thickness.

[Ethel]

If you're up to doing the engine mods you ought to be capable of servicing a set of calipers in my opinion. 

 

Fitting 'em would offer more opportunity to stuff up dangerously.

[JonnyAlpha]

Budget bearings may last as long as half-an-hour.
If you are happy with 12" wheels just get a pair of 8.4" discs.
If you ar interested I have a pair of good 8.4" discs and callipers which can be yours for a small consideration.
PM me if interested. I have just done a 12" to 10" wheel conversion.

A very generous offer but I do love my 10’s they make the car I think ?

[JonnyAlpha]

When I was doing the same from drums to discs I bought the minispares 8.4" to 7.5" conversion kit (don't need the AP calipers) and bought a 8.4" disc set with driveshafts for not a lot of money. Then just refurbished it all along with new cv joints and bearings (ended up swapping them to timken after a few hundred miles.

Not sure about Drive Shafts - IIRC you should be able to re-use the old Drum ones, but may as well renew them!!

The drive shafts are the same. No point in changing them unless the C clip rings are damaged.

Drum drive shafts are smaller diameter looking back at my photos, unless it was a while after they changed to disc that the diameter changed, I guess the splines are the same.

I might be able to get a set of hubs cheap, but they’ll still need new bearings etc. But even then it’s not much of a saving?

[sonikk4]

As Cooperman said, budget bearings, you may as well burn your money, it will be wasted one way or the other.

 

Timken is the only decent way to make things last. Standard drum driveshafts are fine for what you need. I still have mine fitted with a 7.5 S conversion. Not sure if they will cope with my 1293 7 port conversion though.

 

The one thing on a car you want to make sure its 100% and that is the braking system. No point in trying to cut corners or go cheap. Ultimately its not just your life but everyone else in your car and on the road.

 

I get the whole budget thing but it may be worth just waiting a little longer to save up to buy decent kit.