Which Discs and Pads are best for 4.0 V8

[Gary220262]

Hi Jeff, surprised or not i can only speak as i find and compared to my XJ8 its definately different !. To be fair i am getting more used to it and it it does handle better (or feels better) at high speed, a lot more planted and less 'wallowey' (for want of a proper word !). Doesnt like our local speed bumps though. Needs new discs & pads on front if anyones got any experience of what works best, enthusiastic but not reckless use (except when wifes in car then its nice & gentle ). Thanks, Gary

[J44EAG]

I have cross drilled and grooved discs on my 4 litre, Gary.

On the early cars before the MY52 plate models, front brake disc diameter is 300mm. Later cars have 326mm discs which helps slightly with brake improvement but in actual fact the increase is more to do with high brake pad wear rates which can be quite heavy on the early models.

Sadly the later larger diameter discs cannot be fitted to early cars. One of the additional problems with the small disc models is that the discs are prone to warping due to elevated temperatures generated during hard braking hence the rapid wear rate of the pads and also the front discs. What can be done to improve the situation then?

Knowing that I could not upgrade disc size due to design changes embodied on later cars, I recognised that I had to attempt to lower disc running temperatures and fitted a full car set of budget priced drilled and grooved discs which I bought via ebay from JAP Parts in Manchester.

There are many after market discs available for the early cars and prices vary widely depending upon materials and heat treatments applied by the manufacturers. Terox, Black Diamond and EBC products are well worth viewing. Prices will be rather higher than standard spec discs. With brakes, you get what you pay for in direct proportion to cash expended. However you can achieve a good result at a reasonable price as long as you accept budget discs will tend to wear faster that one of the top name brands.

Brake pad material also influences braking efficiency. EBC Red Stuff is well regarded as being resistive to fad at elevated temperatures, is relatively dust free compared to standard material and gives improved braking efficiency. However, the material again comes at a higher price than standard pad material but is known to last longer than a standard material. Is it worth the extra cost? I think that is down to how often you wish to change pad material, how hard you use the brakes and whether the extra cost is worth it to you personally.

So I have the JAP drilled and grooved discs running with standard Mintex pad material which for road going use, I find quite adequate for my braking style. Frankly, I`m not heavy on brakes, preferring to save fuel and brake material by driving intelligently. If I do need to push the brakes hard occasionally, I have no issue with their performance. I can with careful buying source a full set of pads for around £37 on the internet. Red Stuff is considerably more expensive and I really don`t see the need for me personally needing to fit the material.

Fitting drilled and grooved discs certainly eradicated the feeling of slight brake fade I used to experience with standard discs but then mine were well worn when replaced. Be aware that initially new grooved discs can produce a turbine like noise under moderate to hard braking. The noise in my experience decreases as discs settle down. I believe that the advantages of drilled and grooved discs are worth having in that they do contribute to helping reduce disc temperature which helps maintain reliable braking and that needs to happen on the early small disc equipped S-type models.

One hint with any car equipped with disc brakes. if you have driven the car fairly briskly and used the brakes hard then find yourself in stationary traffic, avoid sitting there with your foot on the brake pedal. If you have hot discs and then apply the foot brake without moving the car forward, you are likely to locally cool an area of brake disc at at different rate to the remaining exposed part of the disc. This can lead to disc warp due to differential cooling and cause a pulsing brake pedal under braking conditions. In stationary traffic, I just nip the gear selector into neutral thus stopping the car creeping forward and allowing me to take my foot off the brake pedal.

I know what you men about the early S-types competence to deal with speed bumps in a civilised manner. In my opinion early model suspension is far from good as the car appears to bounce, bang and crash in such situations. Stiffer springs and top notch dampers cure the issue but that will set you back around £700 decent Bilstein uprated gas dampers all round and around another £270 for an Adamesh type uprated spring set.

Mike

[Gary220262]

Hi Mike, thanks for an informative and interesting post, ive looked at a set of EBC drilled & grooved front disc's at £170 a pair on E bay (dont know if thats a decent price or not ?) and will have at look at the discs you mention at JAP, the current discs are well worn and warped so need replacing asap, as for the suspension parts, they will have to wait until my credit rating with the wife improves or maybe santa will fetch me some if im lucky !. I take it they are no differant to normal disc and pad changes and nothing to be wary of.
thanks, Gary

[J44EAG]

A perfectly straight forward fit with no mods needed.

You will need a Laser1314 or similar brake rewind tool for the back brake calliper pistons. Remember one piston has a right hand thread, the other side has a left hander. Tool available from eBay or Halfords etc at around £16. Denoted as suitable for Ford cars but also suitable for S-type, X-type and X350 Jaguars.

The hand brake mechanism is within the calliper as a ball and ramp type. When you have the rear callipers off, ensure that the hand brake arm moves without sticking. Lubricate and ensure full and free action before fitting new discs and pads. Once all back on the car, work the hand brake to settle everything in. Ensure the hand brake works and then check to see that it releases correctly. Drive the car and then feel the front faces of the wheel rims to ensure that brakes are not jamming or dragging and generating heat within the hub and brake mechanism. Use copper grease during pad installation on pad calliper running surfaces and on the thrust face of the calliper pistons.

EBC is premium grade equipment so should give a good long service life.

Mike

[Montana5]

EBC dimpled and grooved Discs tend to cause a bit of noise even with EBC pads and have been known to produce extra dust, my next job over the winter will be to fit EBC Red Stuff pads to the rear and new discs, probably OE.

Doug.