S1 Original brake performance

Talk about the E-Type Series 1

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Granthar
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#1 S1 Original brake performance

Post by Granthar » Wed Sep 28, 2022 9:40 pm

Deal all

I have just acquired a set of S1 front calipers and pistons from a fellow member. My 1965 ots came with cooperkraft front calipers. I am considering going back to stock and would appreciate your experiences.

I have just finished reconditioning the rears with new discs, girling pads and seal kit, as well as the handbrake.

I am keen to achieve good front rear proportioning to make the most of the braking performance. I drive fast on the road but no track time for this car planned.

I would appreciate your experience or redirection to previous threads

Ps what color are the pistons and Calipers originally?

Many thanks
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1965 S1 4.2 OTS. Opalescent silver blue. 1E 10786

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DWW
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#2 Re: S1 Original brake performance

Post by DWW » Wed Sep 28, 2022 10:48 pm

Hi, what was wrong with the Cooperkrafts apart from not looking the part. I personally upgraded mine to 4 pot calipers and vented discs from Fosseway Performance and find the braking and balance excellent, a great improvement from stock.


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But if originality is what you are after....
Danny

1962 S1 3.8 FHC (1012/1798)
2015 Range Rover Sport SVR

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dlgis
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#3 Re: S1 Original brake performance

Post by dlgis » Thu Sep 29, 2022 9:09 am

DWW wrote:
Wed Sep 28, 2022 10:48 pm
I personally upgraded mine to 4 pot calipers and vented discs from Fosseway Performance and find the braking and balance excellent, a great improvement from stock.
Danny did you upgrade all round or just the fronts? I have brakes on my to do list :?:
Darryl
1964 S1 FHC 3.8 opalescent maroon
2007 XKR convertible

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christopher storey
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#4 Re: S1 Original brake performance

Post by christopher storey » Thu Sep 29, 2022 9:55 am

If you revert to standard after having had Coopercraft front brakes you will find a definite deterioration in braking performance . It is not that the front brakes were not up to standard at the time : it is just that the performance of modern disc brakes is now in a different league. The most noticeable occasions when this is apparent is in what I call the "rejected takeoff" scenario : one starts to accelerate hard to overtake another vehicle, and then decides for whatever reason to abandon the manouevre . With the originals, there is then a noticeable hesitation before deceleration starts, whereas with moderns such as Coopercraft, there is no feeling of inadequacy at all

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DWW
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#5 Re: S1 Original brake performance

Post by DWW » Thu Sep 29, 2022 12:27 pm

"Danny did you upgrade all round or just the fronts?"

Just the fronts.
Danny

1962 S1 3.8 FHC (1012/1798)
2015 Range Rover Sport SVR

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caveman
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#6 Re: S1 Original brake performance

Post by caveman » Thu Sep 29, 2022 7:52 pm

Nothing wrong with my Coopercraft front callipers after 22yrs and 6k miles use so far.
Last edited by caveman on Sat Oct 01, 2022 9:36 pm, edited 1 time in total.
Steve
1965 S1 4.2 FHC

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Granthar
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#7 Re: S1 Original brake performance

Post by Granthar » Sat Oct 01, 2022 8:17 am

DWW wrote:
Wed Sep 28, 2022 10:48 pm
Hi, what was wrong with the Cooperkrafts apart from not looking the part. I personally upgraded mine to 4 pot calipers and vented discs from Fosseway Performance and find the braking and balance excellent, a great improvement from stock.


Image

But if originality is what you are after....
Hi, thanks for your reply

I live in Switzerland where modifications are only allowed with certification so I anticipate problems when I next have inspection. I have noticed severe front bias to braking, causing the fronts to lock very easily. I have reconditioned the rears to ensure they are not the problem, I also notice uneven wear on one front tyre so need to set the alignment before I can test the bias. Does anyone have braking effort measurements for f/r?

Finally of course I would like originality as long as this doesn’t strongly compromise driving experience, I will always drive like a 20 year old.

Rob
1965 S1 4.2 OTS. Opalescent silver blue. 1E 10786

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Granthar
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#8 Re: S1 Original brake performance

Post by Granthar » Sat Oct 01, 2022 8:22 am

christopher storey wrote:
Thu Sep 29, 2022 9:55 am
If you revert to standard after having had Coopercraft front brakes you will find a definite deterioration in braking performance . It is not that the front brakes were not up to standard at the time : it is just that the performance of modern disc brakes is now in a different league. The most noticeable occasions when this is apparent is in what I call the "rejected takeoff" scenario : one starts to accelerate hard to overtake another vehicle, and then decides for whatever reason to abandon the manouevre . With the originals, there is then a noticeable hesitation before deceleration starts, whereas with moderns such as Coopercraft, there is no feeling of inadequacy at all
Thanks for the opinion, I guess I should try to drive an original set up. A friend has an original s2 which is not the same setup but closer to mine than Coopercraft
1965 S1 4.2 OTS. Opalescent silver blue. 1E 10786

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DWW
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#9 Re: S1 Original brake performance

Post by DWW » Sat Oct 01, 2022 11:25 am

Didn’t realize that you still have to have inspection on classic cars, here in the UK they are exempt. There is also a different attitude to modifications here they are not covered by the MOT.
Danny

1962 S1 3.8 FHC (1012/1798)
2015 Range Rover Sport SVR

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#10 Re: S1 Original brake performance

Post by Granthar » Sat Oct 08, 2022 7:00 pm

Thanks for the replies. I am however surprised that with my rebuilt original 1 3/4 rear calipers the rear locks before the Coopercraft fronts. If the Coopercraft provide greater breaking than stock wouldn’t I expect them to lock first? As it stands the balance of the car is not good I prefer the fronts to lock just before the rears.

Anyone had similar experience?
1965 S1 4.2 OTS. Opalescent silver blue. 1E 10786

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abowie
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#11 Re: S1 Original brake performance

Post by abowie » Sun Oct 09, 2022 1:36 am

Granthar wrote:
Sat Oct 08, 2022 7:00 pm

my rebuilt original 1 3/4 rear calipers the rear locks before the Coopercraft fronts
If this is the case you need to fix it as it is dangerous. If you brake hard while turning and your rears lock you will spin.

The stock brake bias on the E type is pretty close to 2/3 front 1/3 rear.

I don't know what it is with the aftermarket brakes you have fitted, but you can work it out it by calculating the piston area of front and rear calipers.

Personally I would just fit the original front calipers, assuming they are in serviceable condition.
Andrew.
881824, 1E21538. 889457. 1961 3.4l Mk2. 1975 XJS.
http://www.projectetype.com/index.php/the-blog.html
Adelaide, Australia

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Granthar
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#12 Re: S1 Original brake performance

Post by Granthar » Mon Oct 10, 2022 9:26 pm

Based on areas of the pistons the ratio is 45:30 f:r or 3:2. Based on 2 1/8 f and 1 3/4 rears

My plan is to fit the originals and see

Thanks
1965 S1 4.2 OTS. Opalescent silver blue. 1E 10786

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DWW
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#13 Re: S1 Original brake performance

Post by DWW » Tue Oct 11, 2022 1:56 am

Will definitely be interesting to see if that improves the balance or indeed make it worse.
Danny

1962 S1 3.8 FHC (1012/1798)
2015 Range Rover Sport SVR

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#14 Re: S1 Original brake performance

Post by bitsobrits » Tue Oct 11, 2022 3:17 am

Granthar wrote:
Mon Oct 10, 2022 9:26 pm
Based on areas of the pistons the ratio is 45:30 f:r or 3:2. Based on 2 1/8 f and 1 3/4 rears

My plan is to fit the originals and see

Thanks
When determining a basic force ratio, wouldn't you also need to take into account the area of the brake pads?

Something like comparing (pressureXarea) for both front and rear.
Steve
'65 S1 4.2 FHC (early)

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Jeremy
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#15 Re: S1 Original brake performance

Post by Jeremy » Tue Oct 11, 2022 9:33 am

DWW wrote:
Thu Sep 29, 2022 12:27 pm
"Danny did you upgrade all round or just the fronts?"

Just the fronts.
I upgraded my brakes with Zeus - a moderate and unobtrusive upgrade with cast iron twin front calipers and new rear cylinders (no vented discs or sharp-edged alloy calipers). The man at Zeus emphasised the importance to me of keeping front and rear braking effort in the correct ratio for safe and effective braking. He specifically said, if you upgrade the fronts, you must also do the rears.
Jeremy
1967 S1 4.2 FHC

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1954Etype
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#16 Re: S1 Original brake performance

Post by 1954Etype » Tue Oct 11, 2022 10:13 am

How are the brakes plumbed into your servo. On the early 4.2 cars, the rears came on before the fronts. Check your plumbing.
Angus 67 FHC 1E33656
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Granthar
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#17 Re: S1 Original brake performance

Post by Granthar » Tue Oct 11, 2022 10:11 pm

bitsobrits wrote:
Tue Oct 11, 2022 3:17 am
Granthar wrote:
Mon Oct 10, 2022 9:26 pm
Based on areas of the pistons the ratio is 45:30 f:r or 3:2. Based on 2 1/8 f and 1 3/4 rears

My plan is to fit the originals and see

Thanks
When determining a basic force ratio, wouldn't you also need to take into account the area of the brake pads?

Something like comparing (pressureXarea) for both front and rear.
The brake clamping force is the product of the piston area multiplied by the hydraulic line pressure. As the friction force is the product of the clamping force multiplied by the coefficient of friction of the pad/disc combination I would expect the pad area would affect the coefficient of friction (bigger pads bigger coefficient), and hence the braking force. I have the same brand of pads; Bendix f and r.
1965 S1 4.2 OTS. Opalescent silver blue. 1E 10786

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Granthar
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#18 Re: S1 Original brake performance

Post by Granthar » Mon Oct 17, 2022 5:00 pm

Granthar wrote:
Sat Oct 01, 2022 8:22 am
christopher storey wrote:
Thu Sep 29, 2022 9:55 am
If you revert to standard after having had Coopercraft front brakes you will find a definite deterioration in braking performance . It is not that the front brakes were not up to standard at the time : it is just that the performance of modern disc brakes is now in a different league. The most noticeable occasions when this is apparent is in what I call the "rejected takeoff" scenario : one starts to accelerate hard to overtake another vehicle, and then decides for whatever reason to abandon the manouevre . With the originals, there is then a noticeable hesitation before deceleration starts, whereas with moderns such as Coopercraft, there is no feeling of inadequacy at all
Thanks for the opinion, I guess I should try to drive an original set up. A friend has an original s2 which is not the same setup but closer to mine than Coopercraft
I have installed the original setup as I do notice an initial bite compared to the Coopercrafts. I am definitely locking the rears before the front which is both dangerous and suggests another problem. Could the slave or master cylinder be at fault?
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1965 S1 4.2 OTS. Opalescent silver blue. 1E 10786

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Andyp_67E
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#19 Re: S1 Original brake performance

Post by Andyp_67E » Wed Oct 26, 2022 7:56 pm

How old are your tyres? Old tyres that have gone hard but with lots of tread will give the impression of brakes easily locking up as they are frequently the overlooked part of braking performance on an E Type.
Andy
Andy
1967 Series 1 4.2 OTS
Leicester, UK

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Granthar
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#20 Re: S1 Original brake performance

Post by Granthar » Sat Nov 12, 2022 6:26 pm

Just replace all 4 tyres with a new alignment and bleeding. I’ll see what affect this has.

Looking in the service manual there are 2 ways to connect the servo; for “early “ S1 4.2 cars the rears connect to the first circuit connection with “later” cars connecting first the front circuit. I have currently the early setup, but have had advice to switch to the later setup as per the diagram below

Anyone have experience with this?

Many thanks


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1965 S1 4.2 OTS. Opalescent silver blue. 1E 10786

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