For the love of God man, make it stop!

Some say he can fix a Mustang using just a banana..
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Spanner Monkey
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For the love of God man, make it stop!

Postby Spanner Monkey » Mon Jun 15, 2015 2:22 am

Brakes.
Or to be more specific, brake upgrades.
There are as many different opinions and upgrades with brakes as there are with the rest of the car. The following opinions are my own, things that I have known to work and (in most cases) used to good results.
Dealing initially here with just the front brakes. Rear brake upgrades are only really necessary with out-and-out race cars, and even then primarily with endurance cars. I’ll explain later.

Step 1:
Assuming a standard (ish) car with original master cylinder/brake booster.
If your car has front drum brakes, the first upgrade I’d recommend would be to fit discs. Drum brakes are extremely efficient and the leading shoes have self-servo action (Which effectively means they help to apply themselves). The downside with drums is that they retain heat, and the effect of that is in constant use they will cease to work efficiently. ‘Brake fade’ is a term we seldom hear now but in the age of drum brakes it’s what happened if they were pushed hard, or in some cases just going down a steep hill would do it.
If you already have disc brakes the first upgrade would be to a decent pad. Raybestos do a very good carbon-ceramic pad, and I’ve heard very good things about EBC pads. If you have never changed the pad material in your car do not underestimate the effect this will have.
At the same time, replace the brake fluid for a good silicone type fluid. The DOT3,4 and 5.1 fluids are hygroscopic, meaning they absorb water and therefore a)have a finite useful life, b)will promote corrosion internally, and c) have a lower boiling point which will decrease as more water is absorbed. Use a DOT5 fluid. Most manufacturers recommend changing the fluid every two years but few car owners ever do this. See it as an insurance policy, a few bucks spent every couple of years changing the fluid will save you a few hundred bucks when the calipers/wheel cylinders corrode.
Be careful when using brake fluid. I think everyone knows the paint removing properties, but not many realise how flammable it is. Get brake fluid on a hot exhaust or red-hot brakes and you will have a fire.

Step 2: Bigger is better.
Step 2 would be fitting bigger front discs and calipers.
Vented discs are better for cooling (obviously). Drilling and/or slotting discs will increase the surface area of the disc and therefore increase heat dissipation, but be careful when getting discs drilled as they do have a tendency to crack between the holes particularly if they are worked hard.
Bigger calipers give a larger surface area of piston, thereby increasing the hydraulic advantage of the braking system if the original master cylinder is used. In laymans terms it means more braking pressure (at caliper) for the same braking effort (at pedal). The only downside is that because you are moving more fluid you will get more pedal movement.
Leave the rear brakes alone (unless you are swapping discs for drums). Upgrade the friction material but don’t put bigger brakes on the rear at this stage. The only thing that will happen if you do is you will keep disappearing into the scenery backwards. Why do I say that? Imagine if your brakes are really good. Hit the brakes and the weight transference is all to the front to such an extent that the rear unloads and the tyres almost leave the ground (look at the MotoGP guys). At virtually every point during the braking process the rear brakes are already almost locking the wheels. Make the brakes more efficient and the brakes won’t be improved but the rear grip (and therefore car control) will be lost.
If, for some obscure reason you do put bigger rear brakes, you will need to restrict the pressure to them by using either a residual valve (pre-set pressure) or a proportioning valve (adjustable pressure).

Step 3: Cool it man.
The brake’s biggest enemy is heat, so if you can blow cold air over the calipers/discs it has to be a good thing. I won’t get into physical mechanics of it, but suffice to say if you can duct air from any external high-pressure area it will cool the brakes.
If you can keep free air around the brakes that will also help, but it may mean you need to go to larger diameter wheels.

Step 4: Rip it up and start again.
Having got your big brakes fitted and ducted, the next step is to make them fully adjustable.
Get rid of the brake booster and tandem master cylinder and fit completely separate systems for the front and rear, connected at pedal end by an adjustable bias bar. If you need to fit a brake booster you will need to fit a remote one to each of the systems. Fitting different diameter master cylinders (larger on rear) will give the brakes a ‘natural’ bias and help with pedal feel.
Then go out and test. Get the brakes up to operating temperature and start to brake progressively harder. When you feel the rear brakes lock-up, adjust the bias bar more towards the front. Keep testing until the brakes are perfectly balanced (which will change with temperature, humidity, track surface etc.). No one ever said this would be easy!

Heat cycling. When you get to this level of braking system you will need to heat-cycle the components before leaning on them too hard. Usually this will consist of a few gradual to hard operations followed by a cooling down period and then repeat. Individual manufacturers have their own heat-cycle ideas – follow them, it will increase the longevity of the components and prevent the discs from warping.

Discuss….

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Re: For the love of God man, make it stop!

Postby bigkeeko » Tue Jun 16, 2015 1:48 pm

My last wagon had 380mm disc and huge brembo calipers. The previous owner had put EBC yellow pads on and the brake dust was crazy. The discs were due for renewal so I bought basic EBC discs (good job) but not the high performance ones or the pads as I couldn`t handle the dust. I bought (on recommendation) a set of basic Mintex pads to go with the new discs.

Brilliant. No squeal, no fade, no dust. The basic option appealed more than the drilled/grooved/performance pad set up.


Then again, I`m never on a track.

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Re: For the love of God man, make it stop!

Postby Spanner Monkey » Thu Jun 18, 2015 8:52 am

bigkeeko wrote:My last wagon had 380mm disc and huge brembo calipers. The previous owner had put EBC yellow pads on and the brake dust was crazy. The discs were due for renewal so I bought basic EBC discs (good job) but not the high performance ones or the pads as I couldn`t handle the dust. I bought (on recommendation) a set of basic Mintex pads to go with the new discs.

Brilliant. No squeal, no fade, no dust. The basic option appealed more than the drilled/grooved/performance pad set up.


Then again, I`m never on a track.


I applaud you. I always promote the 'think about how you want to use your car when you are planning modifications' philosophy, and you have obviously done exactly that and are happy with the results.
Hopefully many will learn by your example!

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Re: For the love of God man, make it stop!

Postby jainser » Tue Jun 23, 2015 3:35 pm

Thank you for this - very useful

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Re: For the love of God man, make it stop!

Postby mattmoxon » Tue Jun 23, 2015 5:18 pm

Spanner Monkey wrote:
bigkeeko wrote:My last wagon had 380mm disc and huge brembo calipers. The previous owner had put EBC yellow pads on and the brake dust was crazy. The discs were due for renewal so I bought basic EBC discs (good job) but not the high performance ones or the pads as I couldn`t handle the dust. I bought (on recommendation) a set of basic Mintex pads to go with the new discs.

Brilliant. No squeal, no fade, no dust. The basic option appealed more than the drilled/grooved/performance pad set up.


Then again, I`m never on a track.


I applaud you. I always promote the 'think about how you want to use your car when you are planning modifications' philosophy, and you have obviously done exactly that and are happy with the results.
Hopefully many will learn by your example!


I took the same decision when I was looking at a brake upgrade (the OEM ones were wearing out) it was a case of go bigger or keep the stock size and upgrade the rotors and pads. In the end after thinking it through upgrading the disks and pads (I'd already replaced the rubber hoses with braided ones and put better than stock brake fluid in) was the best choice, I only need normal road stopping power and I have plenty of shut down room at the drag strip so going bigger, even if I supercharge in the future is unnecessary.

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Re: For the love of God man, make it stop!

Postby Molehill_Mike » Wed Jun 24, 2015 10:15 am

Great reading! Makes me think about increasing airflow to the front.. hmmm...

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Re: For the love of God man, make it stop!

Postby bigkeeko » Wed Jun 24, 2015 4:15 pm

Molehill_Mike wrote:Great reading! Makes me think about increasing airflow to the front.. hmmm...




I`m increasing the beerflow to my front this weekend.

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Re: For the love of God man, make it stop!

Postby badhand » Wed Jun 24, 2015 5:39 pm

I'm increasing airflow to my rear.


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