Hilux brake mods yet again!

Hugh Myers said:
The Hilux 4 pot caliper/Peugeot vented disc arrangement works well enough for rallying on gravel or tarmac. The big pads dissipate the heat well and there are lots of pad materials available as they are pretty much the same as the Group N Subaru Imprezas. Best we used was Mintex F4R which cope with the heat of tarmac stages without eating the discs!
The problem then becomes getting enough braking on the back. Again vented discs and 4 pot calipers are they way to go and are historic legal, if that bothers you. The 280ZX solid disc/little caliper set up is probably little better than drums.
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Hugh, which Impreza?
 
Ok i read somwhere here about removing the splash/dust shield, good idea or not ?

I like the idea, what do you big brake boys do ?

Sean good point brake bias valve, probably a beter mod than rear disk upgrade if your sensible
 
tel240z said:
Ok i read somewhere here about removing the splash/dust shield, good idea or not ?

I like the idea, what do you big brake boys do
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I've keep the splash guards myself, I just had to cut a bit off to clear the new calipers...




Rob
 
tel240z said:
Ok i read somwhere here about removing the splash/dust shield, good idea or not ?

I like the idea, what do you big brake boys do ?

Sean good point brake bias valve, probably a beter mod than rear disk upgrade if your sensible
Click to expand...

No dust shields on our rally car.

The standard car has a pressure regulating valve (actually a cut-off valve, I believe) in the rear system, the object of which is to prevent the rears locking before the fronts, maintaining directional stability.

(If the fronts lock first the car goes straight on, which is safest for a production car. If the rears lock first, the car is directionally unstable until you get off the brakes!)

For competition use, the standard rear drums + valve system gives a great lack of rear braking, even with the best competition linings, especially if the fronts have been upgraded in any way. The solution is decent rear discs and a system which gives you the ability to adjust the balance between front and rear, to suit the circumstances eg pad material, weight distribution and road surface.


The brake balance can be regulated with a twin master cylinder pedal box and balance bar, or with an adjustable pressure regulating valve in the rear hydraulics, or both.

Our car has vented discs and 4 pot calipers front and rear, and an adjustable pressure regulating valve in the rear system. In fact, we found we almost always have the valve adjusted to give full pressure to the back because of the difference in the coefficient of friction of the two pad materials that we use in the front calipers, and also because of my liking for more rear bias on gravel.

Anyone find this interesting?:lol:
 
Hugh Myers said:
Anyone find this interesting?:lol:
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Actually I found quite interesting :thumbs:.

I'm having a set of custom disc's made for the rear at the moment and I'm trying to make my mind up whether to have them drilled or left plain, So any feed back from people who have a rear disc set up is of interest....



Rob
 
vpulsar said:
Actually I found quite interesting :thumbs:.

I'm having a set of custom disc's made for the rear at the moment and I'm trying to make my mind up whether to have them drilled or left plain, So any feed back from people who have a rear disc set up is of interest....



Rob
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Drilled will eat your pads up - no ? For a road car - don't bother it's all look !
 
Brakes are like many upgrades (especially suspension mods) it's more involved that you might think.

From my experience there are two good ways of modifying a car:

1/ go to someone who has trusted previous experience and tell them what you WILL be using the car for. Then take their advice or let them modify it (some comeback then too). This has been my route with my engine.

2/ USE the car as intended and upgrade as you find the weaknesses. Time consuming but satisfying. This has been my route with brakes/suspension.

Hugh knows what works for him and Sean knows what works for him, both have great cars. Don't just go out and buy big fancy expensive components until you know that you need them and that they are compatible with each other. Small things like pad material, brake fluid etc have significant impact on performance.

I haven't got my braking or suspension right yet but it's a lot better than when I started track days. The problem is as you improve things you go quicker and then need to upgrade again - the same with most sports/hobbies I suppose.

For info I use a DJ rear disc setup but it gets too hot so I need a balance bar (but you need to understand those too e.g. cylinder bore size re pressures, bleeding) or regulator. My rear drums appeared to do nothing and I never needed new linings!

Range Rover front calipers - I thought this was going to be simple but by the time I had sorted piping (dual system) spacers (for vented dics not solid RR) Mintex pads etc it got a bit involved. They work with Pug discs but I really need a slightly bigger dia disc to use all the pad. No splash shields, not drilling of discs. Calipers are big and heavy but they seem to cope with short track sessions ok (until I get more braking to the front). I feel I now need a decent lightweight set-up though.

Ducting would seem a good idea but not needed for a road car. Be careful on a road car to ensure your brakes are getting warm enough to work with your pads/linings. What a race car needs will be very different from a road or sprint car. And rally cars have their own specific requirements.

As always what are you going to use it for?
 
Rob - Brian Morris was advertiing a balance bar/twin mastercylinder setup in the classifieds a while ago. It fixes straight onto the std servo but the inner wing may need a bash to clear it!
Balance bars work fine, although a friend of ours did have a problem on his rally TR7 when something went wrong with his system. The balance bar then jammed and he had NO BRAKES or on another occasion brakes stuck fully on! I hope he has fixed it now!
We use a normal tandem mastercylinder - actually I think it may be a 260 one. At least this means that if one system fails, due to a broken pipe or caliper or whatever, you do get braking at the other end, albeit with long pedal travel. Of course, with discs on the back you get much better braking than drums if the front system fails!
 
Yes Hugh I have been in touch with Brian a while ago (decent chap) the more I read about things though the more I realise how much I don't know. I don't want to give myself too much aggro. a limiter may be enough.
 
In my experience getting the brakes right can be a long drawn out affair, I found with my last car that just fitting a nice big set of AP discs and calipers wasn't all it was cracked up to be, I then needed to upgrade the rear discs and pads because it was a bit over braked at the front end, And then of cause fitting braided hoses and in my case racing blue brake fluid also made a big improvement, I finally got the whole thing right with the removal of the ABS system which on my pulsar it didn't like the big AP's on the front.

To be honest the main reason I'm changing to rear discs is I hate working on drum brakes, Always did even back when I had my first cars, Plus I've quite enjoyed the challenge of making all the parts work together and finding people to machine the brackets and make new disc's.

But once the car is finally on the road I do expect to have to do a lot more tinkering with things like rear bias, But at least everything will be brand new and easy to work on lol....



Rob
 
So we all know what brake fade is right ?

jump into a standard braked Z use the brakes hard for 5 mins around some nice lanes and hey presto it don't stop yes ?

So are we talking good brakes here with little pedal pressure, or good brakes for an hour of fast driving, is it all about cooling quickly ? I can lock the front wheels up no problem running 235/17s, just not for long :eek: I'm asking this because i have a set of 4 pots waiting to go on the front of mine and want to keep them cool:bow: not for track days but as some of you know theres a nice 2 mile private road near me which is great on sundays :devil:
 
tel240z said:
So we all know what brake fade is right ?
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I think most of us would of experienced that moment when you push down hard on the middle pedal only to find theirs nothing there mate :(.

You know from what I can remember of my old Z all be it 25 years ago I don't remember having many problems with the brakes on that car, Apart from the fact it used to like to lock up the fronts quite easily in the wet, But I put that down to the silly 235 tyres I had fitted to the front more than the brakes themselves.

On this car I've gone for what I think are sensible brake upgrades with out having to spend silly money like I did on my last project, OK if I decide in the future that I want 500 bhp again then I'll have to look at the brakes again, But I doubt very much that I'll be going down that road again. Hopefully for road use and the odd track day blast I'm hoping the set up I've gone for will be adequate for my needs.

It's good to see how many people have done different things though, As the old saying goes "theirs more than one way to skin a cat" ;):D.



Rob
 
Brake fade is usually due to pad material. The better performance materials keep their coefficient of friction up at higher temperatures. Standard 240Z size pads get very hot with repeated braking even if spaced out for vented discs, so get some good Mintex pads - say 1166 or something like that.
The main advantage of 4 pot calipers is that the much bigger pad area dissipates the heat much better.
Using better quality fluid also makes a big difference but we have always used the AP Racing 551 so have not had a problem with fluid temperature. If you change fluid, make sure the new one is compatible with what was in the system before unless you have 100% new components.
Bleed at least the contents of the calipers out of the system after hard (eg competition or track day) use as it has been well cooked!
 
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I've gone for 280zx vented disk and caliper because it must be better than the standard solid disks and I already had them, which means its a free upgrade. They have been fine for the last couple of years and been no problem at all. The car has been off the road and on axle stands for the last 5 years though so that could be the reason.
 
Rob Gaskin said:
Brakes are like many upgrades (especially suspension mods) it's more involved that you might think.

From my experience there are two good ways of modifying a car:

1/ go to someone who has trusted previous experience and tell them what you WILL be using the car for. Then take their advice or let them modify it (some comeback then too). This has been my route with my engine.

2/ USE the car as intended and upgrade as you find the weaknesses. Time consuming but satisfying. This has been my route with brakes/suspension.

Hugh knows what works for him and Sean knows what works for him, both have great cars. Don't just go out and buy big fancy expensive components until you know that you need them and that they are compatible with each other. Small things like pad material, brake fluid etc have significant impact on performance.

I haven't got my braking or suspension right yet but it's a lot better than when I started track days. The problem is as you improve things you go quicker and then need to upgrade again - the same with most sports/hobbies I suppose.

For info I use a DJ rear disc setup but it gets too hot so I need a balance bar (but you need to understand those too e.g. cylinder bore size re pressures, bleeding) or regulator. My rear drums appeared to do nothing and I never needed new linings!

Range Rover front calipers - I thought this was going to be simple but by the time I had sorted piping (dual system) spacers (for vented dics not solid RR) Mintex pads etc it got a bit involved. They work with Pug discs but I really need a slightly bigger dia disc to use all the pad. No splash shields, not drilling of discs. Calipers are big and heavy but they seem to cope with short track sessions ok (until I get more braking to the front). I feel I now need a decent lightweight set-up though.

Ducting would seem a good idea but not needed for a road car. Be careful on a road car to ensure your brakes are getting warm enough to work with your pads/linings. What a race car needs will be very different from a road or sprint car. And rally cars have their own specific requirements.

As always what are you going to use it for?
Click to expand...

Wise words - especially this bit :

"The problem is as you improve things you go quicker and then need to upgrade again - the same with most sports/hobbies I suppose."

Bigger pads will just create more heat - they're not the answer :

better pad material - yes of course, better hoses, fluid, a 280ZX master cylinder but vented discs and the more performance required, the bigger the vented discs should be.

I had a 280ZX 'kit' on the front of my green/silver Z running about 180bhp - it was just about capable.

With what I have now and I've driven hard, non-stop for over 2 hrs on a fast circuit - no problems at all, I even watched as the other three Zs peeled off into the pits with no brakes - after 1/2 an hour I was alone on the track.

I restate my belief that the 280ZX upgrade is for a standard car, the other two spoken of here are good for up to 200bhp and reasonable track use.

Anything above that, go for some serious kit 'cos it's you and you cars' life at stake.

Braking should always be more than you need - never have brakes on the limit of you and your cars' performance !
 
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