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MG MGB Technical - Uprated breaks the choice

Im in the middle of up rating the suspension system and breaks but the choice is really winding me up im running a 130 bhp engine, ive tried getting v8 breaks but the servos are hard to get get hold of.
four pots are lots and lots of money and again i need a larger servo.

What are the options for breaks everyone as the a different opinion.

Ontop of that should i go the hole honk and buy an uprated pedle box and start matching the servo to the calipers? Failing that is there a similar breaking system that will fit straight into a MGB Gt 78

seb

SGE Granville

Seb

Tyres stop the car but if you wish to prevent fade these are available

http://www.powerstop.co.uk/uploaded_Files/Visual5.pdf

Servos just helps the leg and doubtful if of any value with a B.
Paul Wiley

I don't know from personal experience but try searching under Vovle 240 disc brakes. I think there is a thread in the archives
Frank Baker

Paul,

It wasn't clear to me. Wouldn't the uprated 25% larger pads require new calipers?

Philip, New York
Philip

Philip

V8 pads will fit, not sure what % additional. You could question pad stability and perhaps a move to 4 pots, but adds to expensive. Uprating pads only is cheapest option as dimples holes and even grooves for a road car are more design than function.
Paul Wiley

Running standard, but good condition discs, and Mintex M171 (no longer available) pads V8 size, standard Servo, Dot5 fluid and Goodridge hoses, I have never experienced brake fade even on the race track during competition or track days. As Paul says, the tyres are what stop you. Press the brakes hard and the wheels lock, so I don't see the point in uprated brakes - the wheels will lock sooner, that's all.

The Mintex pads created a lot of dust and wore out quite quickly. Now running 'Greenstuff', V8 size. Not so good as the Mintex for fade.

Neil
Neil Lock

Bendix D81 for a TR8 fit right in and offer 20% more pad area.


FWIW

Bruce

P.S.

Do we have spell checker with the BBS now? Every time I type in a wrongly typed word it is underlined with red

Cool
Bruce Mills

Seb-
Today's brake pads and shoes are available in a wide variety of materials. Materials intended for racing applications are unsuitable for street use as they perform well only when hot. At the temperatures incurred outside of a race track their performance is actually inferior to that of materials intended for street use. Rather than use racing brake material, install a set of MGB GT V8 brake pads in the calipers. They will fit without modification and, due to their larger surface area dissipating heat more easily, are more fade-resistant. Avoid the use of pads made of the Original Equipment organic compounds as they are the least heat resistant, have the poorest coefficient of friction of .32mu, and produce more brake dust.
There are essentially three options for high performance brake friction material. The first and perhaps the most commonly available material marketed for a high performance street application are the Carbon Metallic compounds such as those marketed by Hawk. These seem to come in two categories: those suitable only for racing and those suitable for only street use. Those suitable for street use have a coefficient of friction of .36mu, which is too small an increase in performance (11%) over that of stock materials to make them worth the additional expense. The second choice is the Semi-Organic/Semi-Metallic type. Being more heat resistant than organic compounds, they also have a superior coefficient of friction of .48 mu, a fifty percent improvement over that of stock materials. These are available from Carbotech Engineering. They have a website at http://www.carbotecheng.com . While these may be popular, there is another material which has an equivalent coefficient of friction but yet an even greater resistance to heat: the Carbon Kevlar type (F 1,050). These are available from TSI Automotive (Pads- Part # CKPMGA/B, Shoes- Part # CKSMGA/B). They have a website at http://www.tsimportedautomotive.com . Be advised that whatever material that you choose for the front brakes should also be used on the rear brakes as well so that the coefficients of friction will be equal, otherwise one pair will prematurely lock up under heavy braking.
Steve S.

I can lock up all four wheels with the stock brakes. Therefore I see no advantage to stronger ones. Hotter pads for racing, sure. But I don't see a need more stopping power when I already have more than 195-width tires can handle in the stock setup.
Steve Simmons

The speed of the vehicle squared is proportional to the temperature rise in the brakes

At 60 mph you travel 88 feet per second. If your brakes reached peak torque .1 seconds faster, then you just reached limit braking 8.8 feet sooner.

Hawk squeal too mich for my liking for road use but Greenstuff are .45 cof and OK for road, Mintex also have good road pads. Although Cof of grip does not increase/decrease with friction area it does change dramatically with temperature so larger pads help with temp. An upggrade of brake material will help with both the above without too much expense.
Paul Wiley

I haven't noticed any real difference in cold/hot performance with the Mintex M171 or Greenstuff pads. Everyone is using Greenstuff, they are cheap and available even in Halfords. V8 size is the same as a Transit I think, but you would need to check.

V8 discs are thicker, hence the calipers are different (bigger gap between them). I think they use one side of a MGB caliper and one side of another caliper (Triumph 2.5?). The thickness will help with fade as it will take the disc longer to get hot. But if you use modern anti-fade pads you'll get the same/better effect at much less cost.

I seem to remember the calculations for disc brake performance to be a bit more complicated - the friction force being generated is a function of force and friction coefficient, but the resultant torque is a function of diameter. So bigger diameter discs and pads will give you more stopping power. For example, the pads on my big heavy diesel Mondeo estate are tiny, but they do their job way better than the brakes on the MGB.

Anyway, stand on the brakes on an MGB GT and you'll lock the front wheels pretty much immediately, so stopping distance is more about your braking skills and the tyres than the brakes themselves. Race cars are running wide slicks so you can apply more brake force before they lock.

Be careful about uprating the rear brakes as suggested in case you find the rear brakes locking first which is not a nice place to be.

Neil
Neil Lock

Neil

Agreed bigger diameter discs will give you more brake torque but this is limited to type of wheels we run.

Agreed rear brakes locking first is not a nice place to be - which is why often a lower cof is run on rears, getting the brake balance right depends on a number of other factors.
Paul Wiley

Uprating the fronts by allowing them to lock at a lower hydraulic pressure can *reduce* overall retardation, as it results in less retardation from the rear.

Banging the brakes on will cause the fronts to lock sooner, and hence give significantly less retardation, than if you brake progressively, which gives times for the weight transfer to press the front tyres down harder onto the road which means they can take more hydraulic pressure before they lock.

"Do we have spell checker with the BBS now?" I wish there was! 'Breaks' instead of 'brakes' is one of the most frequent. Maybe your browser.
Paul Hunt 2

I have tried EBC Greenstuff pads and didn't care for them. They require more pedal effort for the same braing power. The upside to them is that they create very little brake dust.
Steve Simmons

Someone at my brake place told me once the Greenstuff pads don't actually generate less dust. Just the dust they do produce is less 'sticky' so you gte less stuck to the wheels. I have them on my car but alas I am still nowhere near being on the road yet to comment on how they work (and it is damn frustrating)!

Simon
Simon Jansen

Since installing the upgraded engine, I've been using Mintex 1144 pads and shoes (standard size!) and have been very pleased with them. I believe these replace the 171s?
They work very well from cold and they make the car stop a lot better. I'd been looking at 4-pot and V8 brakes conversions before, but the Mintex' do their job perfectly.
Alexander M

My car stops very well and has excelent pedal "feel" and quite light pedal pressures as well. I run a non servo system with braided stainless flexis and greenstuff front pads. I think a standard system in good condition is enough for the road, my car was measured at 93 BHP at the back wheels to calibrate these comments. We were out on a run today and I was surprised at how much black dust the car got on the front wheels, it covered about 100 miles today and 10 on Monday after the last 2 hours spent with a flexihead toothbrush and a bottle of washing up liquid. I did have to stand it on it's nose about 3 times to avoid 4x4s driven by the insouciant. The Mintex DS11s made a lot less dust, but then never actually retarded the car very much on the road as they were never up to temperature.
Stan Best

Common Simon, get that car going!! :)

As far as the spell checker goes, it's definitely a feature of Firefox 2, if you've just upgraded.
Curtis Walker

ditto the comments on greenstuff and brakedust - recently used greenstuff for the first time, bedded them in as per instructions etc - very dusty as compared to my old pads (bog standard 10 quid jobs) - front wheels now permanently covered in black dust between cleans, and to be honest i am not sure that they are any better as regards braking - perhaps less fade, but i never found that to be that much of an issue before either, but each to their own i guess. next time around i will be back to standard pads though.
mick
m rae

I'm running the Mintex V8 pads on a non-servo single circuit '67 B. The extra stopping power is quite noticable with very little pedal pressure. However, they do leave a large amount of residue on my wire wheels. Ray
RAY

I run stock pads and Shoes on my 70 B GT with a 3.1 liter V6 and Auto Trans. I have put 23000 mi on it in 18 mo. I have not had to lock up the brakes. It does stop well. Brake dust is noticable. I run 205 75 14 tires.
The only track use it gets is the standing start mile at Maxton, NC. I usually run between 107 and 112. It stops just fine from those speeds. It does have plenty of time to cool before the next run.
I see no reason to spend big bucks to up grade the brakes.

Steve
Steve

A lot of enthusiasts (including myself) have needlessly spent their money on brake upgrades that are not necessarily needed, especially for the combinatation of their car/driving habits.

I have to agree with Steve Simmons on this one.

I did, however, put GreenStuff disc pads on my 1969 MGC.

FWIW - YOMV

rick
1978 MGB
1969 MGC
1974.5 MGB/GT V8 Conversion
1968 MGC
rick ingram

Greenstuff pads are definitely dusty. I don't know if they are more or less dusty than the M171s. I think pads in general (whether on your MGB or your Mondeo) have become more dusty since asbestos was outlawed.

A pad with a higher friction coefficient will require less pedal force for the same retardation - that's physics. The greenstuff pads don't seem to need warming up, they are pretty much okay from the off. The M171s weren't a problem either (except for lasting less than 3,000m). I had DS11s on a Mk2 Mexico - that was scary until the brakes warmed up, in fact I used to drive with the brakes on a bit until they did!

Greenstuff, M171s, etc fade less than standard pads. That's not an issue if you don't drive fast and use the brakes a lot. The original question related to a car with 130bhp and uprated suspension - there's not much point in uprating the engine, suspension and brakes if you are not going to drive faster...

Neil
Neil Lock

My experience with the Hawk ferro carbon pads (about $50) is silent brakes, lots more cf (friction) i.e. lot's less pedal pressure, and virtually no dust.

The rotor looks nice and shiny and is not showing signs of wear.

The increase in cf from a regular brake pad is a lot more than 11%. I would estimate the pedal pressure needed for a stop compared to the old stock style pads is 1/3 to 1/2 less.

Because of the increased front end braking power, I changed the rear brake cylinders in my '67 GT to the large diameter type to get more rear braking power. The front still does most of the braking. The front end will lock up before the rear.

Barry
Barry Parkinson

This thread was discussed between 27/10/2006 and 01/11/2006

MG MGB Technical index

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