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Improving the cars Brakes


Eric JS

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Hi guys, I am looking for opinions about brake upgrades

My Standard 8 currently has 7 inch drum brakes all round, I feel getting the brakes upgraded is a must but I have only been able to come up with two costly options.

The options are:

1: Keep the rear drums and carry out the same upgrade some of you may have done to your Heralds and that is fitting front discs.

2: Remove all of the 7 inch drums and fit new 8 inch drums, back plates etc. 

As my Standard 8 has an 1147cc Herald engine fitted and is smaller than the Herald and I would guess a little lighter - we should get good road speeds.

If I can get the differential I want, I am planning to replace the original unit with a newer/better ratio unit.

Four questions: 1: Which brake upgrade option would you go for, 2: If you say Drums - where to buy from, 3: Fit new remote servo, 4: Fit bigger master cylinder in lieu of a servo.

Your opinions would be appreciated because I feel even though I lean towards fitting discs, a bit of me wonders if discs might not be needed.

Ric

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Obviously discs would be nice but I wouldnt write the drums off. Wheeler Dealers did a Volvo PV544 and found the brakes quite acceptable with uprated shoes and well adjusted - of course it also does depend on how you want to drive it... 

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I suspect finding a disc brake conversion will be easier, and is probably a well trodden path. Rear brakes will be fine as they are, the car is light and the last thing you want/need is too much braking at the rear.

One of the biggest issues is friction material. The usual "white box" (or stuff bearing the name of a company that used to make quality stuff) is not very good at all. I have found NOS asbestos pads/shoes to be much much better. Mintex 1144 are probably as close as you can get to those but in asbestos free material. 

Of course, it is well worth trying the brakes as they are, but checked over, adjusted and so on. But I do remember my first car (avenger) and that had drums all round. I experienced brake fade many times, but always when I was enthusiastic on some long downhill twisty sections of roads.

A used disc brake setup off a herald or spitfire should not be too expensive, assuming it is a fairly simple swap.

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11 hours ago, Clive said:

I suspect finding a disc brake conversion will be easier, and is probably a well trodden path. Rear brakes will be fine as they are, the car is light and the last thing you want/need is too much braking at the rear.

One of the biggest issues is friction material. The usual "white box" (or stuff bearing the name of a company that used to make quality stuff) is not very good at all. I have found NOS asbestos pads/shoes to be much much better. Mintex 1144 are probably as close as you can get to those but in asbestos free material. 

Of course, it is well worth trying the brakes as they are, but checked over, adjusted and so on. But I do remember my first car (avenger) and that had drums all round. I experienced brake fade many times, but always when I was enthusiastic on some long downhill twisty sections of roads.

A used disc brake setup off a herald or spitfire should not be too expensive, assuming it is a fairly simple swap.

It’s so cheap it’s almost worth buying the stuff new…

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Only cheap if it fits! Online it says the Standard 8 front suspension was double wishbone with coil over damper which sounds hopeful but on it and the steering there were '21 greasing points to be done every 1000 miles'. This is rather more than a Herald/Spitfire has so really need to get to a meet and compare cars side by side👍  

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I've used Mintex 1155 for ages.   But now that "Racing" range  has been superceded by MRM 1801 (for 1144), MRM 1802 (for 1155) and 1805 (for 1166).  They seem similar, but not identical, see:  Racing Compounds – Mintex

Being honest, even drum brakes are perfectly good when adjusted correctly and will stop you just as quickly as all-round carbon-fibre discs, unless you get them hot, by pass-storming or track work.   The critical factor is adhesion, and good tyres and a well made road surface are just as important, so unless you believe that the original, rock-hard tyres are appropriate or go gravel road rallying, think hard before you go to all this trouble.

I have Ford Capri discs on the front of SofS, matched to Austin Princess 4-pots but those were really a youthful excess.    4-pots allow larger pads, but the pressure per unit area on the disc goes down, so larger pads produce the same friction as smaller ones!    Multi-pot calipers do work if they enable wider discs (longer moment of leverage) but then you need bigger wheels which don't work with Standard Triumph  suspension.

It also has rear discs that came with the MGF rear uprights, but that was for a different reason than better braking, stronger half shafts.     No need to go to rear discs IMHO.

Good luck!

John                             

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Totally agree re tyres and road adhesion !! Also with sticking with drums on the rear… 

 

I’ve got the princess calipers and discs on my sprint, I also went up slightly on the master cyl but as you rightly point out it’s all about the larger swept area and heat dissipation…

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Hi,

Increasing the master cylinder bore will make the pedal travel less, but you pay the price with a harder pedal. The larger piston displaces more fluid. But the advantage of a small master cylinder is that the same pressure on the smaller piston area makes the total force on the master cylinder piston less. The pistons at the wheels all see the same pressure as the master cylinder piston unless the system is boosted. If the wheels have double the piston area they have double the force on them, but only move half as far. The area ratio is normally much more than 2:1. This is why proper adjustment of drum brakes is so important. It minimizes lost motion before the shoes reach the drum.

Cheers,

Paul

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4 hours ago, drofgum said:

Hi,

Increasing the master cylinder bore will make the pedal travel less, but you pay the price with a harder pedal. The larger piston displaces more fluid. But the advantage of a small master cylinder is that the same pressure on the smaller piston area makes the total force on the master cylinder piston less. The pistons at the wheels all see the same pressure as the master cylinder piston unless the system is boosted. If the wheels have double the piston area they have double the force on them, but only move half as far. The area ratio is normally much more than 2:1. This is why proper adjustment of drum brakes is so important. It minimizes lost motion before the shoes reach the drum.

Cheers,

Paul

Absolutely true, the bore size of the master cylinder determines the pressure achieved however, if you upgrade to 4-piston callipers, you also have to factor in the travel length of the piston in the master cylinder to match the additional pistons in the calipers.

 

A 1” master cylinder creates 127.4 PSI as compared to a 7/8” master cylinder which is 166.7 PSI based on your foot making 100 pounds of force at the master cylinder. 

 

The smaller cylinder makes more pressure but the smaller bore will move less fluid. More travel will be needed to make up for the reduction in fluid moved by a 7/8” master cylinder as compared to the larger 1”

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Hi to everyone who have given their thoughts.

I knew there would be people on the Forum who would have the information and ideas I needed.

Its obvious that lateral thinking and experience are still the ways to go, you have all helped a lot, and your advice, knowledge and information are gold dust - the only trouble I have now is to find and get the bits fitted.

When I was a teenager I had access to a community who had bits or knew where to get them, sadly nowadays the supply chain is usually the bugbear.

Thanks again - progress is being made.
 

Rick

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To 65redspit Thanks for your reply, sorry for no reply before today.

Could you send me links to the brake parts you purchased. It would be good to see where the parts from - I think as a hobby people need to be talking to each other about using none standard parts - thanks for your help.

As an aside my first car was a 1965 Spitfire, she was white with a cherry red hard top, the car was then 8 years old when I got her and I paid a garage £250. The car needed a huge amount of TLC and a lot of bodywork and chassis repairs. Sadly we had to part after less than two years due to a truck reversed over the front end.

Eric

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