SC and 3.2 disc differences

[Busybee]

Hi guys. Trying to do a complete refresh of brakes on my 84 3.2 Carrera. 

Ordered discs, pads, pins, clips and sensor cables from @Type911. 

Went to fit today and the front discs won’t fit in the throat of the calipers. Luckily I had some new sc discs so sorted that. Sensor cables are different too. Matt sent 2 each of two types. 2 fit but the other two won’t. 

The rear discs go on but I can’t get them to align properly. They are on the wonk. Will spin but then hit the throat of the calipers. Tried fitting them 3 times, wound in the handbrake shoes but still no joy.

What’s the difference  between SC and 3.2 rear discs if anything? Guessing as the car is an 84, it might have SC brakes? 

Edited February 10, 2022 by Busybee

[Ian Comerford]

Matthew will reply I am sure but from what I think I know the main difference between SC and 3.2 discs is that the 3.2 ones are thicker.  The 3.2 calipers have a spacer inserted between the two halves to enable a thicker disc.  Not sure what your problem is though

[Jon Miller]

Only difference is the thickness, perhaps you have SC calipers. Both SC and 3.2 calipers have spacers but the 3.2 version has a thicker spacer.

[Leicestershire]

SC are 290mm x 20mm thick.

3.2 are 290mm x 24mm thick.

SC calipers (ATE) have smaller pistons and spacer. They also require a different 'J' pipe.

Very similar main casting and take same pads.

[Busybee]

Big problem at the rear is why the disc won’t seat flush on the hub. It’s on a wobble. Fits in the throat of the rear caliper but rotate it and it catches on the caliper 

The fronts were definitely the thinner sc ones 

Edited February 10, 2022 by Busybee

[Type911]

Haith, you did not get all that from me

You got pin kits, brake caliper pipes and bolts

Where did the calipers come from?

[Busybee]

Ahh sorry, must’ve been d911. I bought bits from you and from them.
Calipers were the original ones refurbished. 

Just now, Type911 said:

Haith, you did not get all that from me

You got pin kits, brake caliper pipes and bolts

Where did the calipers come from?

 

[Busybee]

6 minutes ago, Type911 said:

Haith, you did not get all that from me

You got pin kits, brake caliper pipes and bolts

Where did the calipers come from?

Is there a seating difference on the rear discs for an sc and 3.2 Matt. Any way to tell what I have/should have had?  

[SilverWT]

32 minutes ago, Busybee said:

Is there a seating difference on the rear discs for an sc and 3.2

Shouldn't be, quite common to upgrade SCs to 3.2 discs and calipers.

Mark

[Type911]

Take some pics of the calipers close up

 

[Type911]

10 hours ago, Leicestershire said:

SC are 290mm x 20mm thick.

3.2 are 290mm x 24mm thick.

SC calipers (ATE) have smaller pistons and spacer. They also require a different 'J' pipe.

Very similar main casting and take same pads.

Correct although only on the rears, the fronts are the same size with same size pipes

SC spacer between the halfs is about 7 or 8mm  3.2 are about 4mm wider to allow the thicker disc

[Leicestershire]

Check if you still have the proportioning valve fitted on the rear circuit.

This was fitted with the move to larger rear pistons and is not required with SC calipers.

With new discs, check the park shoes are clearing the 'drum'. 

[Type911]

Why has a 3.2 Carrera got SC brakes fitted?

Hardly an upgrade is it!

[Wingnonut]

have they sent you back your old callipers? Sure they haven't exchanged them and exchanged the wrong ones?

Also, as I said last night are you sure you haven't dislodged something when you have pulled the old disc off? Easy to knock one of the shoes  off its peg slightly so not seated properly.

[GaryH]

14 hours ago, SilverWT said:

Shouldn't be, quite common to upgrade SCs to 3.2 discs and calipers.

Indeed

(and also not to use the rear proportioning valve leaving you open to criticisms of altered brake bias )

 

Edited February 11, 2022 by GaryH

[Busybee]

I just spoke to the refurb guys. She tells me the n/s front caliper had a smaller spacer. Wonder if in the cars history, someone has put an SC caliper on my car. Just one front one. 

21 minutes ago, Wingnonut said:

have they sent you back your old callipers? Sure they haven't exchanged them and exchanged the wrong ones?

Also, as I said last night are you sure you haven't dislodged something when you have pulled the old disc off? Easy to knock one of the shoes  off its peg slightly so not seated properly.

They seem pretty certain it's the same set.

I'll check the rear shoes 👍

3 hours ago, Leicestershire said:

Check if you still have the proportioning valve fitted on the rear circuit.

This was fitted with the move to larger rear pistons and is not required with SC calipers.

With new discs, check the park shoes are clearing the 'drum'. 

Will do

[Type911]

So it had an SC caliper on the front left and a 3.2 one the front left?

Is this the car you bought from Fat Fuchs? If so no way he would have bodged it, something stinks.............................

[Busybee]

8 minutes ago, Type911 said:

So it had an SC caliper on the front left and a 3.2 one the front left?

Is this the car you bought from Fat Fuchs? If so no way he would have bodged it, something stinks.............................

Exactly so. Front left side is sc and right is a 3.2 carrera jobby. Or so they say. I'll measure in a bit.

Yes, @fat fuchs Andy's old car. I agree. Can't be Andy's work. 

[Type911]

No way he sold you that car like that................................no way

[Busybee]

49 minutes ago, Type911 said:

No way he sold you that car like that................................no way

I agree. He may have never known.

Just looking to get it right to be honest. Have you got a refurbed front N/S 3.2 Caliper in stock? 

[SilverWT]

Why don't you confirm what is going on at the front by measuring the width of both the old discs and the new ones. If the old discs are both thick 3.2s they would have had to have had 3.2 calipers.

 

Mark

[Nige]

I think Mark is the wisest one amongst us, I'm sure we test his patience on a daily basis! 😃

[GaryH]

8 minutes ago, SilverWT said:

Why don't you confirm what is going on at the front by measuring the width of both the old discs and the new ones. If the old discs are both thick 3.2s they would have had to have had 3.2 calipers

Wise words mate

[Busybee]

59 minutes ago, SilverWT said:

Why don't you confirm what is going on at the front by measuring the width of both the old discs and the new ones. If the old discs are both thick 3.2s they would have had to have had 3.2 calipers.

 

Mark

I’ve just measured the throat width on both front calipers. 28mm and 24mm. So we have a difference.
Old discs measure at 21mm. As do the sc ones just fitted. New Carrera ones supplied measure at 24mm as expected. 
 

Have a set of pagid new Carrera 3.2 rear discs and they’ve just popped on perfectly. No seating issue or wobble. 
 

Now what to do with the front calipers? 

[Type911]

Ask the mob that refurbed them if you can have your correct one back?