22 replies to this topic

[mini_pooper]

Hi all!

 

I have a question regarding the way the pads are mounted in the 7.5 inch Cooper S style brakes. I fitted this conversion to my car a few years ago (originally drums all round), and it struck me that there were no pad retaining springs in the kit, the ones that look like a butterfly between the pads and the retaining split pins.

 

 

Question one is, did the 7.5 disk setup ever use a spring clip?

Over time, in the absence of a spring clip putting tension on the split pins, I can imagine the split pins wearing where they pass through the calliper since they are loose and free to vibrate. Since the pins hold the pads in place on their own, they do a very important job keeping the pads located in the caliper. Does anyone have or know if there should be a spring clip on 7.5 inch calipers? I can't see any listed anywhere, no parts diagrams or anything, so the information and my gut feeling are conflicting a little! 

 

 

Question two is, should there be any return spring on the pads to keep them from rubbing on the disk?

It looks like I have some glazing on both disks, hence the question. Picture attached, not the best image as I was just taking a "general" picture and not focusing on the disk.

 

I haven't taken the pads out to look at the faces, but looking through the top of the calipers, all pads look brand new in thickness and I can still see some red where it meets the disk, I assume this is the bedding in material (or what remains of it). I'm surprised the bedding in material is not gone, but I don't use the brakes very much (does anyone in a mini?) 

 

Of course, if the pads are constantly just slightly touching the disk, they will not wear, but the contact faces will get a glaze from friction. So, should there be a form of return spring holding the pads away from the disk?

 

 

Let me know your thoughts   A job for the summer is wheels off cleaning all the suspension, incredible how much dust gathers under the wings!

 

John

Attached Files

•  Photo 28-03-2019, 18 24 42.jpg   74.38K   0 downloads
•  Photo 30-03-2019, 12 26 16.jpg   83.84K   0 downloads

Edited by mini_pooper, 02 April 2019 - 01:12 PM.

[DeadSquare]

To answer Q2 first.

 

There is nothing to retract the pad from the disc, other than a deflection in the rubber seal through which the pistons pass.

 

Q1.    Long ago, I once saw an after market set of pads which included 'anti squeal' shims, (that fitted between the piston and the pad),  the front edge of which was turned up. I assumed that this might have been to add rigidity to the shims, but if the dimensions were just right, the turn up could also have provide tension that would stop the pins from rattling.

 

BMC and other well known pad makers have never used a butterfly spring.

[nicklouse]

nope nothing. only the 8.4s had anti rattle "springs".

[unburntfuelinthemorning]

When the brakes are operated the caliper pistons move towards the disc which deforms the piston seals.  When the hydraulic pressure is released the seals then pull the pistons away from the discs.  You won't find calipers with return springs for this purpose.  The pads do remain in light contact with the discs and they are designed to work like this.

[Spider]

I had to double check myself. The Anti-squeal shims were in fact factory fitted from day 1 with these Calipers

 

 

The other aspect of these Calipers is the Pistons had a small relief in them, towards the top on the side that presses up against the shim and pad. This was to help ensure the Pads wore evenly and didn't try to taper.

[DeadSquare]

I had to double check myself. The Anti-squeal shims were in fact factory fitted from day 1 with these Calipers

 

 

The other aspect of these Calipers is the Pistons had a small relief in them, towards the top on the side that presses up against the shim and pad. This was to help ensure the Pads wore evenly and didn't try to taper.

 

Now that I look at the diagram and think about it, I don't know if the anti-squeak shims that I saw would have been fitted with the turned up front edge facing in together or facing outwards.

 

I hope I don't loose sleep over it !

[Spider]

I hope I don't loose sleep over it !

 

 

Squeak !

[DeadSquare]

 

I hope I don't loose sleep over it !

 

 

Squeak !

 

 

That made me giggle.

[Cooperman]

I have never fitted them in any Cooper S I have had, and I have had a good few over the years.

[Spider]

I have never fitted them in any Cooper S I have had, and I have had a good few over the years.

 

You may have been short changed !

 

 

Best I can determine, they were standard fitment from day 1 with these.

 

I had to look them up earlier as I don't see these brakes that often these days and I couldn't recall if they were standard, a production modification or after-market thing. I know most people don't bother re-fitting them with a Pad Change.

[Fastorq]

I don’t think you will be happy with these brakes and you should sell them to me !

[DeadSquare]

I don’t think you will be happy with these brakes and you should sell them to me !

 

 

That is a very generous offer.  As a Scotsman, I'd have thought that you would have suggested they were a gift.

[dodge44]

Seem to recall the first set of S/H 7.5" disks I fitted in 1990 had thin fibre type 'shims' between the pads and pistons but no idea if they were aftermarket or original fitment. Either way, when the pistons eventually cut through what was left of them were discarded and have always just used copper ease since. It's a curious one though as many other disk brake systems from the period are fitted with stainless steel shims (Triumphs for instance)

[Fastorq]

I don’t think you will be happy with these brakes and you should sell them to me !

 
 
That is a very generous offer.  As a Scotsman, I'd have thought that you would have suggested they were a gift.

That would be a Yorkshire man
Lol

[mini_pooper]

Lots of good info here   The car is currently tucked away at a lockup so I can't pop out to take a wheel off and check for shims. Looking at the picture on MiniSpares' website, I can't see any shims in the kit so I'm going to say they don't reproduce them new and/or include them in the kit (attached picture)...

 

I haven't had a single squeak from the breaks on the car as they are now, so if the shims are not fitted, I'll say they are fine 

 

For the sake of information - MiniSpares say the GBP103AF pads actually have anti-squeal pads attached.

 

Just had snowfall here in Surrey/Hampshire 10 minutes ago, and I'm off to Norway next week, so it will be a little while before I can check my setup. After the nice weather last week and driving it every day, I'm already missing the feeling (and that stupid grin a mini makes you pull!).

 

Good news is drive it day falls on my birthday this year (April 28th), so if the weather is nice I'll be able to celebrate in the car with a stupid grin 

 

 

Another question - I've always felt the brakes are a little dull, and looking at the MiniSpares site, the kit I bought and fitted to the car (C-AJJ4028B) would have included the Ultimax Street pads (GBP103ULTIMAX). According to the site, these pads are supposed to be "very durable and great for most road usage" and produce "less brake dust". However, would standard pads like the GBP103AF or GBP103MS (by Mintex) give a more positive brake feel, especially at lower speeds?

 

I don't have a servo (and I am reluctant to fit one as I like the extra space under the bonnet), however with the current pads the pedal has quite an uninspiring/non-confidence inspiring feel even with quite a lot of pressure, almost like stone cold brakes. They do work and the car stops, it's just the feel is not as nice as I would have liked.

 

Hopefully someone here has first hand experience with these different pads on the mini. I've read the forums but a lot of the comments seem to be second hand opinions, or just opinions formed around something they have read online. I always prefer opinions that come from experience! 

 

I had a non-servo MGB before with standard pads and that had much more feel, granted the brake setup was different from a mini (a quick search shows larger discs of 10.75 inches compared to the mini's 7.5 inch). But it felt very confident and inspiring.

 

John 

Attached Files

•  image.axd.jpeg   16.93K   2 downloads

Edited by mini_pooper, 03 April 2019 - 05:11 PM.