THE INTERNATIONAL JAGUAR 'S'-TYPE REGISTER FORUM

Caroutfitter is not capable of testing anything & I would take their comments with a pinch of salt. They get paid for linking advertising to Amazon and get a commission on purchases made through their links.

As I said "Latest DOT 4 LV class 6 brake fluids can achieve slightly over 300C dry. (Super DOT 4)" The Motul product is a good example & you can give it a try. Motul is a reputable manufacturer.

I think from memory that the Eagle Speedster (E Type) uses AP Racing vented discs & calipers all round. It has lighter weight in it's favour. You might have to think seriously about fitting some ducting to the car to get cold air to the brakes. Some F1 style pods underslung on the front wheels would work. The rear is more of a challenge. Some flat ducting from ahead of the rear wheels at the skirt might work. There will be a high pressure spot on that sill somewhere but it will be trial & error.

Another alternative for the front would be to duct cold air from dummy horn grills where European cars have their fog lights mounted. It would require cutting holes in the mounting dishes but you are more than capable of doing that.

Yes I have been looking into some options for bigger calipers and larger truly vented rotors. Doug from the Jaguar Forums gave me this referral,
http://www.bgdevelopments.co.uk/
and I have sent them an email and awaiting a reply. Doug said he purchased their AP Racing larger 4 piston calipers with vented rotors. That looks like it might be a decent setup. I have been searching to see if anyone has done a 6 piston conversion but have yet to find that? so if that is not an option the larger AP Racing setup might be my next upgrade. I have other street high performance cars so I am familiar with using a more street friendly pad setup. I think if the rotors were vented and with larger calipers/pads the Jaguar should be able to just barely handle that level of abuse. I have done drives like that with my other Z cars with no problems but they have much larger rotors which are vented and more racing calipers with street pads but the other advantage is those cars can downshift and use the gearing to limit the reliance on the brakes compared to my Jaguar which is an automatic.

Glynn, so while the different types of fluids only have some increases based on the type, are there any brands or type you think are better to use? I saw this review https://www.caroutfitter.com/best-brake-fluid-reviews/
and they list a Motul 8060HL RBF600 Factory Line Racing brake fluid that claims a boiling point of 594 degrees or 312 Celsius ? I know the brake fluid will not solve my issue until I upgrade the calipers/rotors but this might be good to use right now and when I upgrade as it seems like that is higher than the chart you posted, any thoughts?

thanks in advance :)
Too bad I did not have a gopro camera as I think when you see how fast the big 3.8s Jag was able to go thru those mountains keeping up with much more serious cars is not bad for a car that is really more of a cruiser :) What I can say is with the current brake setup I have of the smaller Wilwood upgrade and larger rear later model Jaguar in board brakes and with 400+ HP the Jaguar can handle pretty darn good and go decently fast for about an hour or so then you will start to smell the brakes and another hour more and then it will be maxed out and fade... so for short racing the 3.8s can hold its own well and hopefully if I can get the larger brakes it can stay at that pace...

Exactly! e.g. Formula 1 carbon brakes operate in a temperature range from approx 400 degC to 1000 degC.

Below 400 degC their retardation is pathetic. No good for a road car.

I was going to say basically the same thing, you are looking to treat the symptom not the cause. For this it might be an idea to look to racing as most things have been encountered before and and a solution found. One problem with high end braking systems is that what works on a race track won't work on the road for everyday driving as to make the brakes work you need to get heat into them, too cold and you will sail through the first stop light you come to. Keep us posted on what you come up with.

Hi Primaz,
Here are the basic dry & wet boiling points of brake fluid types. Latest DOT 4 LV class 6 brake fluids can achieve slightly over 300C dry. (Super DOT 4)


[attachment=0]screen-shot-2014-12-15-at-10.27.18-am.jpg[/attachment]


The answer to your problem does not really lie in the fluid. It lies in the size of the brakes & as such their heat dissipation & cooling.

The solution to your question is to increase disc/rotor & caliper size so that they expose greater area to the air that cools them. Ventilate discs all round & duct air to the brakes.

Beyond this the answer lies in carbon ceramics etc. & exotic friction materials for the pads. Some ceramic etc. shielding of heat from the hydraulics can also help.

Brakes are all about size. Bigger disc & pad area, greater pressure & proper cooling.

Brakes turn kinetic energy into heat that must be dissipated.

[quote="Glyn Ruck" post_id=3128 time=1556418654 user_id=175]
Dot 4 Brake fluid is ideal for our S Types. They are polyglycol & polyglycol ether based. Brake fluid is hygroscopic & thus should be flushed approx every 2 years. Exotic brake fluids are not necessary & can give one elastomer compatibility issues. That is a neat little device Orlando shows if it is relatively accurate. As water level rises in the fluid so boiling point reduces leading to brake fade. At least we don't have ABS systems to worry about where corrosion byproducts can severely damage the system. Nevertheless as we have single circuit brakes with no backup other than the handbrake we should keep these systems in fine fettle & free of corrosion.

Buy brake fluid in small containers. Only unseal immediately before use. Never reuse brake fluid. Don't use brake fluid that has been stored for long periods after unsealing.


I have had all clutch & brake cylinders & calipers stainless sleeved with stainless pistons in the calipers on my car.
[/quote]

Glyn,

I know you are very knowledgeable on lubricants, etc. So even with extreme hard driving as I sometimes do, what would you recommend for brake fluid? The reason why I ask is that I recently went on a drive with a lot of more modern performance street cars and the drive was 118 miles of almost all 15-45 mile an hour curves where we were driving very fast on the limited straights and double the posted speed on the curves. My car with the V8 was able to accelerate hard but then I would use the brakes hard especially since my car is an auto and about 70% thru the almost 3 hour drive where we were averaging 50-90 mph my brakes faded and I had to back off and just let them go ahead and take my time; towards the end my pedal went down a lot more likely due to the fluid boiling over as after lunch the brakes were back to normal pressure. Many of the others even had their modern brakes smoke due to the abuse. I think I will take one of my sports car on their next run if the route has that many curves but the old Jag did hold its own at least during the first half against modified BMW M3 and M4's, modern modified Mustangs including a GT500 but it makes me want to look into what I can do to improve the brakes and what fluid might not boil over?

Thanks for the info and advice, Glyn.

Dot 4 Brake fluid is ideal for our S Types. They are polyglycol & polyglycol ether based. Brake fluid is hygroscopic & thus should be flushed approx every 2 years. Exotic brake fluids are not necessary & can give one elastomer compatibility issues. That is a neat little device Orlando shows if it is relatively accurate. As water level rises in the fluid so boiling point reduces leading to brake fade. At least we don't have ABS systems to worry about where corrosion byproducts can severely damage the system. Nevertheless as we have single circuit brakes with no backup other than the handbrake we should keep these systems in fine fettle & free of corrosion.

Buy brake fluid in small containers. Only unseal immediately before use. Never reuse brake fluid. Don't use brake fluid that has been stored for long periods after unsealing.


I have had all clutch & brake cylinders & calipers stainless sleeved with stainless pistons in the calipers on my car.

Thats a nice cheap tool for my tool kit Orlando. Will have to order one.

Yes Simon you can use Dot 4, the benefit over Dot 3 is the higher boiling point. If you want to go down the Dot 5 silicone route then it is best to install on a completely fresh brake system as any previous trapped fluid would would still give problems. I've been using silicone in my S Type since the 1970's with no problems.