mk1-forum.net

Posted: **Sat Jan 07, 2023 12:33 pm**

A good friend of mine is in the early stages of restoring a 997 acquired from Pete F (the ex-Montague car).
He has two questions that he wanted me to answer but I’m not positive so thought you guys may be able to help him out.
The car has had S brakes added at some stage, he wants to
return it to the original 997 braking system.
1) are the rear 997 drums standard non-spaced or would they have had a small spacer? I always thought they were non-spacer but when he contacted the usual major mini parts suppliers to buy some he has been given conflicting information, one telling him that he should have spaced 998 drums which is confusing as we both thought that the 998 7” hubs were the same as the 997 which apparently had the same offset as the standard front drums. Wouldn’t this mean that any spacer on the rear would affect tracking?
2) will the 7” 997 hub be a straight swap for the existing 7.5” S one, using the existing S drive shafts, suspension arms etc.

Posted: **Sat Jan 07, 2023 1:22 pm**

The trouble is, is that you are asking 3rd party/3rd hand questions and this leads to ambiguities. It would seem that your pal hasn't looked at the parts lists - or hasn't got a set

A GOOD start is to look at the 997 and 998 parts list and compare part numbers

Question 2 is a good example. So far as I am aware, the disc braked hubs are interchangeable but not the guts. Once again, the parts lists will answer pretty much all you/he ask regarding the front suspension

Posted: **Sat Jan 07, 2023 1:41 pm**

The front hubs currently fitted with the S brakes are same as the Cooper. At the front you will need to fit 7 inch discs, Cooper callipers and cooper drive flanges. At front they used the same CC joints and wheel bearings as a drum brakes car.
He will also need the correct master cylinder, 4222-921 Lockheed number.
At the rear it is all as a standard 850, the spaced Cooper non S drums were only 67 on.and using 5/8 wheel cylinders. I could probably help on some of these items.

Posted: **Sat Jan 07, 2023 4:29 pm**

641071S wrote: ↑Sat Jan 07, 2023 12:33 pm A good friend of mine is in the early stages of restoring a 997 acquired from Pete F (the ex-Montague car).
He has two questions that he wanted me to answer but I’m not positive so thought you guys may be able to help him out.
The car has had S brakes added at some stage, he wants to
return it to the original 997 braking system.

2) will the 7” 997 hub be a straight swap for the existing 7.5” S one, using the existing S drive shafts, suspension arms etc.

Just to add to the reply from Smoke Grey.....
The 997 brakes will require standard drive shafts...(S has larger CV shafts)
Also, finding decent 997/998 Cooper drive flanges will be a bit of an 'experience'....997 calipers do come up on E Bay...they are different to the 998 Cooper version.

Posted: **Sat Jan 07, 2023 6:05 pm**

998 Cooper drive flanges are not a problem at all. Never understood the problem. Good used tandard 850 are easy to modify to 998 Cooper spec. That's how they were formulated - to utilise production castings to keep costs down. A good lathe and cutters and you're away. There is a thread on the tech forum showing exactly how.

Posted: **Sat Jan 07, 2023 7:19 pm**

Thanks for all the info guys.
Unfortunately Nige does not have a parts list and nor do I.
He does already have the front 7” hubs, discs, calipers and brake master cylinder (he’s been collecting parts since he bought the car over a year ago) the only thing he doesn't have is the driveshafts. Thanks to Dermot and Steve we now know that he can’t use the S driveshafts and needs to find some standard 850 shafts and non-spacer rear brake drums.
Peter, you are right, it’s a pain to be relaying third party info and being piggy in the middle. I have suggested that he joins the Forum himself as I am sure he will need much more advice during his restoration. He’s only got as far as stripping it and having the shell soda blasted ……it needs a lot of work!
Cheers,
Martin

Posted: **Sat Jan 07, 2023 7:37 pm**

Peter Laidler wrote: ↑Sat Jan 07, 2023 6:05 pm 998 Cooper drive flanges are not a problem at all. Never understood the problem. Good used tandard 850 are easy to modify to 998 Cooper spec. That's how they were formulated - to utilise production castings to keep costs down. A good lathe and cutters and you're away. There is a thread on the tech forum showing exactly how.

Peter, not exactly that easy!!!!...as you know I have made some from 850 flanges....there is a lot of machining....not all that easy and not for the faint of heart!

I posted pictures on the thread showing how it is done.

Posted: **Sun Jan 08, 2023 9:36 am**

Why can't you use "S" driveshafts? You should be able to just swap over the CV joints. The "S" driveshafts might not be 100% correct but they should be dimensionally equivalent.

Posted: **Sun Jan 08, 2023 8:59 pm**

Don't 997's have that odd brake intensifier bolted to the driver's inner wing? I don't know much about them tbh other than they didn't work very well. I thought 998 Cooper brakes were 'a bit' marginal.

Posted: **Sun Jan 08, 2023 9:24 pm**

Hi Steve, yes, the 997 did have that wonderful intensifier....not all of them...
The 998 brakes are better than the 997 but not great.
Spent a couple of hours in the shop playing with an old 850 flange......it is hard on the lathe due to the stud holes...
This was just a rough cut at it....would need more refining.

Posted: **Sun Jan 08, 2023 10:05 pm**

Brake Intensifier was only on early 997,s best i know ?
Properly set up 7inch Disc Brakes on a 997 Cooper will do the job.. then thought "Do i have the confidence that 7inch Discs will stop the car in todays traffic or a fast downhill " .. that is why i fitted 7.5 inch S brakes onto my 997.

Posted: **Sun Jan 08, 2023 10:15 pm**

Polarsilver wrote: ↑Sun Jan 08, 2023 10:05 pm Brake Intensifier was only on early 997,s best i know ?
Properly set up 7inch Disc Brakes on a 997 Cooper will do the job.. then thought "Do i have the confidence that 7inch Discs will stop the car in todays traffic or a fast downhill " .. that is why i fitted 7.5 inch S brakes onto my 997.

Hi Norman, I had a 997 way back...brakes faded in a few seconds of hark braking...even the twin leading drum brakes are better than the 997.agree with you....7.5 only way to go.

Posted: **Mon Jan 09, 2023 3:44 am**

I posted a version of this BMC Australia Service Liaison Summary previously but thought it might be useful here.

SLS 043 p1.jpg

SLS 043 p2.jpg

Posted: **Mon Jan 09, 2023 11:51 am**

Can anyone on the forum point me in the direction of an authoritative article based on verifiable data that states quite clearly, mechanically and scientifically proves that well/properly set-up TLS brakes are more efficient, thermally greater or superior, more worthy, an improvement or in any way better than an equivalent, well/properly set-up set of 7" Cooper discs?

I have NEVER seen an authoritative article to substantiate this claim in my very few years of mini cooper ownership. I have asked the same question MANY times. They're not as thermally efficient as the bigger and later Cooper brakes but they're certainly superior to TLS's in every mechanical and thermal way.

Steel helmet on of course and hope that my forthright view/engineering opinion here doesn't rattle the moderators. If you are a 7" properly set-up Cooper user and happy with your lot, feel free to chip in

ADDED LATER. And also bear in mind that within a few pounds weight, but VERY relevant to the stopping weights, the cars weigh the same

Posted: **Mon Jan 09, 2023 12:18 pm**

Peter Laidler wrote: ↑Mon Jan 09, 2023 11:51 am Can anyone on the forum point me in the direction of an authoritative article based on verifiable data that states quite clearly, mechanically and scientifically proves that well/properly set-up TLS brakes are more efficient, thermally greater or superior, more worthy, an improvement or in any way better than an equivalent, well/properly set-up set of 7" Cooper discs?

I have NEVER seen an authoritative article to substantiate this claim in my very few years of mini cooper ownership. I have asked the same question MANY times. They're not as thermally efficient as the bigger and later Cooper brakes but they're certainly superior to TLS's in every mechanical and thermal way.

Steel helmet on of course and hope that my forthright view/engineering opinion here doesn't rattle the moderators. If you are a 7" properly set-up Cooper user and happy with your lot, feel free to chip in

I’ve wondered this too. Maybe there’s some contemporary detailed road tests that show braking distances and pedal effort for the Cooper 997/998 and the Mini 850..

Posted: **Mon Jan 09, 2023 1:24 pm**

i've run two Coopers on 7 inch brakes, once id come to setup they were excellent. Won rallies on them. There is another member on here who was struggling to get the brakes sorted, i gave him the spec and he said it was night and day compared to before.

Posted: **Mon Jan 09, 2023 2:13 pm**

641071S wrote: ↑Sat Jan 07, 2023 7:19 pm Thanks for all the info guys.
Unfortunately Nige does not have a parts list and nor do I.
He does already have the front 7” hubs, discs, calipers and brake master cylinder (he’s been collecting parts since he bought the car over a year ago) the only thing he doesn't have is the driveshafts. Thanks to Dermot and Steve we now know that he can’t use the S driveshafts and needs to find some standard 850 shafts and non-spacer rear brake drums.
Peter, you are right, it’s a pain to be relaying third party info and being piggy in the middle. I have suggested that he joins the Forum himself as I am sure he will need much more advice during his restoration. He’s only got as far as stripping it and having the shell soda blasted ……it needs a lot of work!
Cheers,
Martin

Lots of PDF parts lists here:

https://mk1-performance-conversions.co. ... _lists.htm

Posted: **Mon Jan 09, 2023 2:30 pm**

Can someone post a link to the original article giving details on modifying drive flanges, cos I'm buggered if I can find it.

M

Posted: **Mon Jan 09, 2023 3:03 pm**

Peter Laidler wrote: ↑Mon Jan 09, 2023 11:51 am Can anyone on the forum point me in the direction of an authoritative article based on verifiable data that states quite clearly, mechanically and scientifically proves that well/properly set-up TLS brakes are more efficient, thermally greater or superior, more worthy, an improvement or in any way better than an equivalent, well/properly set-up set of 7" Cooper discs?

I have NEVER seen an authoritative article to substantiate this claim in my very few years of mini cooper ownership. I have asked the same question MANY times. They're not as thermally efficient as the bigger and later Cooper brakes but they're certainly superior to TLS's in every mechanical and thermal way.

Steel helmet on of course and hope that my forthright view/engineering opinion here doesn't rattle the moderators. If you are a 7" properly set-up Cooper user and happy with your lot, feel free to chip in

ADDED LATER. And also bear in mind that within a few pounds weight, but VERY relevant to the stopping weights, the cars weigh the same

It really depends on the type of driving you do or if you've ever needed to do a real emergency stop. Personally speaking I find my standard 998 Cooper system to be perfectly adequate but I'm never doing repeated hard braking so can't say how they perform under duress. I have driven it down some Alpine passes and never felt I was in danger of losing efficiency but again, I wasn't exactly throwing it around.

Posted: **Mon Jan 09, 2023 4:06 pm**

mk1 wrote: ↑Mon Jan 09, 2023 2:30 pm Can someone post a link to the original article giving details on modifying drive flanges, cos I'm buggered if I can find it.

M

Mark,
It was my posts on the how to....I included pictures etc.
I can't find the thread....
I remember it started out as a want ad. for cooper drive flanges. I made a few sets and sold them.....that was a few years ago.
I did one yesterday to refresh my memory of how it is done.
Let me take a look to see if I have any old pictures.
D

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