480 vented brakes

[foggyjames]

You don't have a boat anchor in the front

cheers

James

[MJ]

Well, not sure waht to say. Luckilly I've never really had the need to do an emengency stop, and tend to treat the old girl gently to save fuel and reduce the chance of breaking ort.

But when I was learing to drive my instructer had a Renult Megane *don't tease me * and having been driving the 340, I hated the breaks. I'd press gently and be flung foward in the seat. Great for an old granny, but it was a pain and I only just mastered them before the test. So either, yes the 340 breaks are under assisted, or the Megane is over assisted, I vote the latter, I like a bit of feel.

[SteveP]

I like a bit of feel.

Don't we all

[Chris_C]

Ahh.. now this is the bit I don't get..... Kar feels like the brakes are a lot sharper than anything else I drive. I physically have to stand on Mums mondeo estate, and me mates cars. Maybe Kar's just spethcial

[Damir130]

Maybe a lot of people still driving around with worn master cylinders or old braking fluid? I really don't get everyones problem with the brakes..My brake pedal is rock hard and the brakes are a breeze to apply. They hold up to whole days at the racetrack with no trouble at all.

When I see what most of you guys are running for tires/wheels, then I seriously doubt whether those can handle extra braking capacity. Seems more like a theoretical discussion to me, then a solution to a real problem. First try and get the std. stuff into good shape.

[Just trying to get some discussion started]

[foggyjames]

Agreed on the condition of the stock system. I suspect my master cylinder might be 'tired' after 17 years.

What do you mean about the wheels?

cheers

James

[redline]

I guess he means that most 300's are running pretty much standard rims (steel or alloy )which are of a fairly "closed "design to say the least . these dont help very much with brake heat dispertion , the more open or spoked designs you and I have mean far more cold air circulating around the brakes causing greater cooling to the brakes and therefore less brake fade.

[petefarrell360]

IMO the brakes on 360 GLT's are fine, not had the experience of 340's yet. I'd go as far as to say they can be a bit too good at times, needing to be cautious in the wet.
Pete

[foggyjames]

Regarding the efficiency of my cars brakes...I have no real desire to uprate them for my regular motoring, but I can see that they'd be insufficient for heavy towing or prolonged competition use.

cheers

James

[jtbo]

I have new master cylinder and new brakefluid waiting, weather is just cold and soon rainy, so maybe it will take some time to do that fix.

My brake fluid has gone black, so it is dead now, was good and fresh at last spring, but I pushed brakes too hard I think.

[classicswede]

I've got a pair of struts from a 340 i scraped and one disc is like new and the other has worn down to between 4-5mm The brakes must have been crap.
I must admit when I fitted new discs and pads to mine ( did this within a few weeks of owning the car as always) it made a noticable difference. The old discs were not badle worn but groved.

I can see the need to uprate the brakes for heavy use.
Even on 240's you notice the difference between vented and no vented but they are both very good even so.

Dai

[Damir130]

Ok, I don't know how much all of you know, so I'll just try and put down all I can Think off. Sorry if I'm stating the obvious...

Braking potential is limited by two things:

1. The amount of friction that can be develloped between the braking mediums (e.g. pad and disk)
2. The amount of friction that can be develloped between the tire and the roadsurface.

Number one is seldom a problem, I have yet to find a reasonably modern car that could not lock its tires through use of the brakes. Number two therefore is the biggest limiting factor in most cars braking performance. When I see what most people here are running with regard to wheels and tires, then I have a hard time imagining them upgrading their braking through bigger brakes. Take it from me, the best way of upgrading your brakes is going out and buying a decent set of tires (something very little people are willing to do somehow..who here runs Bridgestone SO3 pp's or similar tires?)

Ok, so now we now whether we have enough braking power or not. The second problem that you run into is the amount of time that you have this power available to you. Brake systems heat up and you start to experience a phenomenon called "fading". IE: I could lock up the brakes earlier, but can't do so after a prolonged duration.

Fading can be divided into two different categories:

1. Pad Fade
2. Fluid fade

Pad fade devellops whenever the brakepads are heated to beyond their max.temp and they start rapidly producing gas and other deposits. The end result is less braking power, glazed over pad surface and a phenomenon that most people call "warped" discs. In reality the discs are just fine. What you are feeling are irregular deposits of pad material onto the disc.

Solution:
The solution is easy. Use a appropriate pad for the sorts of conditions and temp ranges that you are expecting. For street the best choice is still a stock pad. For the track use something with a higher heatrange (and thus often poor cold performance) like ferodo's DSXXXX or mintex pads.

Fluid fade devellops whenever the brakingfluid is heated so much (usually in the calliper), that the fluid starts to boil, leaving compressible air bubbles in the fluid. The pedal will feel very spongy.

Solutions: There are more solutions thinkable for this problem. I'll name a few. Almost all of them have some relation with heat management.

Use proper fluids!!! For street use, pick a DOT5.1 fluid, for racing pick a DOT5.1 or high temp DOT4 fluid. Fluid that has boiled never regains its full heat capacity. For racing it is vital that u change it often. I change the brake fluid before every event (more if I experience heavy fading during a day.) I cannot emphesize this enough!

Provide better cooling...Be creative: airducts (to the calliper, it needs it the most) provide surprisingly good results. Vented discs have a similar effect. Who knows, rig up some sort of brake light actuated water spray system.
This is also where a nice open rim design pays dividents.

Create a better heat sink capacity. This means that you try and divide the heat created by braking over a larger mass of steel. Easy fixes are perfectly flat wheel/hub mating surfaces (perhaps even some sort of heat transfer paste) that allow the brake disc to transfer heat to the wheels.
The most popular solution is using bigger brake discs that have more mass (and the added benefit of a better calliper clamping torque arm, but thats usually not a problem to begin with.

In my experience, a well maintained stock 360 brake system, using proper track pads and fresh DOT 5.1 fluid is more then up to the task of serious track use. I have done so many times, often outbraking many other dedicated racing cars. I run Advan AO32R ss slick tires and have not once had a problem with locking them up whenever I wish so.

[jtbo]

Good post there

I have experienced both 1.pad fade and 2.Fluid fade

Braking from 150kph to 0kph is good test, last 40kph it does not make big difference if I do press brake pedal or not, pads are not gripping to disk, this is with Fedoro DS2500 pads.

Reasons for this are:
-My wheels are not open at all, more like solid
-My brake disks are not new anymore, surface is not smooth at all

Also I can't push pedal enough hard to experience wheel lock from 150kph, I think that from 80kph that may be possible, but at least from 60kph I have locked wheels several times. This could be partly because pads are not new anymore either, those have got some serious heating.

Also sometimes left side front brake is not as efficent as right side.

But I don't see reason to buy new stock parts and install them as I can with almost same work install ventilated discs

Last time on track I experienced also number 2. Also my brake fluid decided to change colour then, I think. I think that there was water in fluid for some reason. Also I did push pedal much harder and later, not sure what is reason and it is not important. I just need to fix everything from my brakes before next season.

Oh yes, when I returned home from track I needed to push pedal very hard to make car even stop. That has cured a bit since then.

Maybe I just weight too much, lol.

[Damir130]

JTBO.
1. You need to change your fluid much more often..could be a large part of the problem.
2. Changing to vented discs when for example the BMC is leaky will solve nothing.
3. DS2500 pads should be more then able to lock your tires, I suggest taking a good look at the BMC (check for bubbles in reservoir).
4. Difference in braking performance could very well be the tie-rods. The bushings desintegrate and often the metal bracket that holds them is rusted away. Parts can be ordered from volvo for 50E or so.
5. Stock discs can be found very cheaply..payed like 20E for mine. (unsure whether this also holds for vented discs..guess so.) Other then that I replaced all rubber hoses and rebuilt the callipers.

In the end I wouldn't trust my life to an inferior braking system. They are the single most important part of the car on track. So far, the volvo has proven itself absolutely flawless.

[Carl]

When I had my last 360, I renewed all the fluid with dot5.1 and used mintex M1144 pads, which in previous experience (on other cars) were very very good. I was running Uniroyal Rallye 550 tyres, which were also very good. After a few hours of a road rally the fronts had faded badly and were barely working and the rears had completely overheated and had locked on, with smoke pouring out from the back wheels. After stopping, letting things cool down and loosening the rear brakes the car was driveable again.

When I got home and took the wheels off I found the front discs grooved, the front pads cooked and crumbling on the edges. The rear brake cylinders were weeping fluid, the rubber seals had melted, and the shoes were crumbling to pieces. I've got some pics somewhere of them. Admittadly I was quite hard on the brakes and the night did involve a fair bit of turning on the handbrake, which doesnt help, but all in all I found the brakes completely inadequate.

This is why I sold my 360. This time round I'm determined to fix this problem which is why I want a vented setup at the front, along with some more open alloys and some air ducting. The rears will remain standard except maybe trying to route some cooling ducts too hte back of the drums, using the same sort of system of the autos do for the transmission