Thread: brake upgrade

Originally Posted by Pedro_The_Swift

yea John,, the word better is a bit hard to quantify,, the difference between D1 and D2 brake pedal feel is huge, The D1 is like a brick wall and the D2 is a lot softer with longer travel but stops just as well if not a tad better.
go figure.

how about "more effective"?

the car pulls up faster, for longer, with the same pedal pressure.

"more effective" is no more definitive than better! How fast the car pulls up is, for any modern car, ultimately dependent on tyres, to a lesser extent on ABS system and front/rear proportioning. If you want it to pull up faster for the same pedal pressure, this is a function of linings, cylinder diameters, pedal geometry and the (often ignored) vacuum level - but only up to the level of adhesion. For longer, i.e. less fade, is dependent on linings, discs, wheel ventilation, fluid. But you have left out progressive application, pedal travel as factors.

I have actually never encountered brake fade since the seventies, but that may be that since I learnt to drive on cars prone to fade I drive to avoid it (saves fuel too). The best brakes I have encountered are those on my Citroen (which is a 1950s design) - light pedal, zero pedal travel, zero fade from inboard front brakes with cooling ducts, braking proportioned to actual instantaneous load distribution.

But I am still interested in trying to find out what people mean when they look for better brakes.

John

British four wheel drive sell the spacer kits, and you can fit the slotted and vented DBA rotors. We just did a D1 V8 last month , was an easy job with good results.

Check Alans website for further info regarding $$$

JC

Good point about just what do I mean by better brakes?

To pull up in a shorter distance with the same level of pressure applied to be brake pedal.

disco standard tyres are 205 currently running 265 75 16 much larger and the breaking distance has increased proportionally to the larger diameter

I like the idea of larger discs and calipers etc but this apears a very expensive way to go, therefore braided lines first and see what that does. Then if that does not work to my very subjective satisfaction caliper spacer and vented discs with softer pads (softer pads first)

I am laid up at the moment so I will get to it in about a month or so I will post a break down of the results when I get to it.

Cheers Blythe

Originally Posted by blitz

Good point about just what do I mean by better brakes?

To pull up in a shorter distance with the same level of pressure applied to be brake pedal.

disco standard tyres are 205 currently running 265 75 16 much larger and the breaking distance has increased proportionally to the larger diameter

I like the idea of larger discs and calipers etc but this apears a very expensive way to go, therefore braided lines first and see what that does. Then if that does not work to my very subjective satisfaction caliper spacer and vented discs with softer pads (softer pads first)

I am laid up at the moment so I will get to it in about a month or so I will post a break down of the results when I get to it.

Cheers Blythe

What you have done is increase the leverage of the tyre by about 15% without changing the leverage of the brake caliper, giving a 15% increase in pedal pressure, everything else being equal. As you say, the best thing would be a 15% in the AVERAGE radius of the caliper leverage (NOTE: not the overall disc diameter!), which you probably can't fit inside the wheel - although getting as much increase in disc diameter as you can accommodate would be a start. But as you say, this is expensive. As to get back to the original braking effect you need a 15% increase in hydraulic pressure, it is just possible that the braided lines will have some effect, though I doubt it - and if it does improve it I woould suspect the fluid that you drained out while bleeding rather than the line.. The softer linings will undoubtedly work (and would be the first thing that I would do), but at the expense of more rapid wear. Vented discs will reduce fade, but of themselves will do nothing for pedal pressure.

The simple thing I would look at is put a gauge on your vacuum line , see what the level of vacuum is. Unless it is up around 12psi, consider a) whether there are vacuum leaks you can fix, or b) whether the vacuum pump is working properly, or c) can you get an alternative vacuum pump that works better than the standard one. Any increase in vacuum translates directly into a reduced pedal effort, and since these are rarely checked there is a good chance that there are problems.

John

I've just renewed my front and rear brakes with new standard discs and bendix pads and rebuilt the calipers but the one thing i didnt do and will have to now is replace the brake hoses as these are seeping and i cant get full pressure for long. I'll be going the braided route as these are generally protected by a hard plastic sleeve and i can get them made slightly longer for extra flex. Thats all im doing to my brakes and i think it will be sufficient as long as i dont ride the brakes down a hill like a moron

Well amongst a miriad of things done to the old girl I had vented discs and the adapters fitted which of course included new pads.

Possibly my original problem was that the old discs were buggered? the difference is huge, only trouble is the damn thing squeals like a stuck pig every time I brake - I got her back in feb so 9 months later it is still squealing. tool it back several times because I was not happy with it, they did fix everything in the end but it still cost and it still squeals

did I mention it bloody squeals like a stuck pig??

have you tried pulling the pads out and giving the whole area a drenching with brake cleaner then spray on stop squeal before reassembly?? worked for me on previous cars/trucks that have squealed

Originally Posted by nicho

have you tried pulling the pads out and giving the whole area a drenching with brake cleaner then spray on stop squeal before reassembly?? worked for me on previous cars/trucks that have squealed

a completely legitimate question - except after over 3k spent on the brakes I must admit to being a bit narky about having to do a damned thing to them. But yes eventually they will anoy me to the point where I will do just that.