X350R, STR, XKR 4.2R (Brembo) Disc and pads.

[J44EAG]

On the internet again yesterday having a look at prices for discs and pads for my 350R on Vin No G33305. This is an early model which ran up to G49700. Models after G49700 use different discs and pads to the early model.

Here are the part numbers for consumable brake parts on the early 350 model. I noted they were also listed as suitable for S-type R and also XKR models of the 03>06 period. Please check suitability and part numbers before ordering.

OE parts from the Berkshire Jaguar Components site.
Front brake discs, 365mm. OE Jaguar C2C8355 £113.28
Rear brake discs. 330mm?. OE Jaguar C2C8356 £68.40
Front pads (Brembo calipers) OE Jaguar C2C24018 £40.32
Rear pads (Brembo) OE Jaguar C2C24016 £39.17

OE Mintex parts from Premier-Factors ebay site.
Front pads OE Mintex MDC2220 £15.48 on clearance offer.
Rear pads OE Mintex MDC2221 £20.56 moderately discounted.

As you can see there is quite a difference in pricing. I bought Mintex F&R pad sets for just £36 inc P&P. A good saving when compared to the OE Jaguar marketed items at around £80 excluding P&P.

I understand that Jaguar used Mintex pads and discs during original manufacture and that Brembo didn`t make either discs or pads themselves....only the 4 pot calipers. Can anyone confirm?

Mike

[J44EAG]

A link here to Loc8apart here. The site harvests the ads on other sites and puts them all together making it quite quick and easy to find the parts you need at best prices.

Best prices for Mintex discs for my early model X350R appear currently to be £79.08 for a pair of MDC2207 front discs with MDC2206 rears coming in at £52.85. This is for plain disc types. Drilled and grooved are a bit more.

Also worth seeing are the MTec range of up-rated parts which appear at very competitive prices. EBC, Delphi and Brembo appear to be the premium type products which are very much more expensive than standard OE.

https://www.google.co.uk/url?sa=t&rct=j ... n6mEpqAAgA

Always check your own disc diameters before placing an order. Differences in listed parts can only sometimes be a few mm. ie 326mm or 330 mm for rear discs and 355mm or 365mm for fronts.

Mike K

[J44EAG]

Lets go a bit further.

Brake disc selection is not always easy.... especially where there is a break point with later models in the range.

I`ll look here at the early model X350R. The VIN range in this case finishes at G49700 for this early type. These have the Jaguar Sport, so called four pot Brembo calipers. Front discs are 365mm diameter with the the rears at 330mm diameter. (Later cars saw the front discs reduce to 355mm. Not sure about the rears. From G49700 the brake manufacturer was to my knowledge changed to Teves.)

Lets look at performance discs now rather than OE. EBC are rather expensive options with Mtec being next in the pecking order. I`ve been talking to Mtec in Londonderry from which I`ve gleaned the following info. If you go to their site for the early model XJR 350, you will find their parts listing inaccurate. Ros, their sales guy helped me to clear through the mire. Their site gives the Teves sized discs as applicable to the early XJR. Always check before buying. O800 410 1910 gets you through to Ross. Top guy!

OK, so what is needed for the early XJR performance disc wise is a pair of 5086 for the fronts and a pair of 5087 for the rear. £189.99 and £164.99 respectively. The four discs would total £354.98 less £10% discount which works out at around £320 for a complete disc set. Compare that to my OE Mintex best prices of £132 on the internet. The difference in cost amounts to an extra £188 being needed for the Mtec products. Various options are available, ie drilled only, drilled and grooved, dimpled and grooved or C-hook patterns. Ross recommended dimpled and grooved for best road car applications. Drilled tend to block with brake dust which has to regularly have to be poked out with a coat hanger wire or similar object. Grooved, I know from personal experience are rather noisy and pad and discs wear rapidly.

Is it worth the extra cost? Perhaps not if you are happy with the OE brakes. I`ve no real issues with mine except for a slight front brake judder at around 50-55mph when slowing down quickly. My old discs will need replacing shortly, hence my looking around at costs and options.

Mike

[SCUTHY2002]

Interesting topic Mike. I have had 4 Jaguars with Brembo Brakes and every one has been prone to warping the front discs on a regular basis. I tried all the things that my dealer and other specialists suggested regarding bedding in new discs and not holding the car on the foot brake whilst stationery in traffic {to avoid hot spots} but they continued to warp on a regular basis. One Jaguar Technician suggested to me that the size and thickness of the standard hubs used with the massive Brembo discs was not up to the job.
I would be interested to know if vented and drilled discs may assist the cooling process and hence help prevent this warping problem that Jaguar have always been aware of but seem to deny any knowledge of.
I think I will try some of the MTEC discs when they next need replacement.

[J44EAG]

The best advice is always to get the foot off the brake once stopped after a fast deceleration. That helps the disc cool in a uniform fashion to hopefully but not always control warping.....This despite the fact that we have a twin disc arrangement with vents already in place.

Drilling only really helps reduce gassing when brakes are applied. Great in practice but at least a once a month clearance session needed with a coat hanger wire to keep clear of pad dust.

The early models, STR, X350R and XKR, all appear to share the 365mm diameter option on front discs. These appear massive when compared to the diminutive cross sectional thickness. When I first acquired my car, my training and pedantic engineering bent caused me to question the wisdom of Jaguar/Brembo putting such thin discs on such a large diameter rotor. Warping appears to be a very common occurrence and I`m not surprised to see the issue on my car. At 78k, the discs had a 1mm lip apparent on each side of the discs, so during my overhaul, I machined that off with a grinder and flappy wheel. I also removed a few high spots. To my astonishment the discs gave no vibration issues following the work. Eight thousand miles on, I`m beginning to get a bit of vibration from 60mph down to about 50mph. Another lip has begun to be seen which implies I could do with a new set of discs. I suspect that when measured with a vernier caliper, I`ll be down to the minimum limit.

It is interesting to note that the later cars from G49700 went to the Teves system with discs receiving a down size of 10mm across the diameter. I`d suspect that Jaguar recognised the problem and changed components to try to combat the warping issue.

The frustrating thing is that many owners replace discs only to find the warping and run out issues can occur again with only four thousand or so miles being run with new discs.

EBC, Torox and MTec seem to be the premium brands as far as my internet and other research indicates. Only when pushed into service are we likely to know whether spending extra on these after-market rotors are likely to prove any better than OE Jaguar/Mintex. Some how, I think the sheer diameter size and lack of cross sectional area on V8R model discs is always going to be a problem area whatever we might otherwise fit. I wonder if a carbon fibre set up might have increased longevity?

Mike K

[oldtimer]

After fitment of new discs a "runout" check should be carried out measured with a DTI. This should be within the tolerance of Zero - 40 microns. Failure to follow this procedure is likely to cause brake judder after a short period of time.

Reference to this procedure is rarely, if ever referred to on this forum.

In view of the tolerances required it is essential that wheel bearings and hubs are also in perfect condition.

The asbestos free discs pads are sadly not as forgiving as the asbestos pads used to be

Oldtimer

[J44EAG]

I belted the hell out of my brakes today on the A3. I drove them extremely hard and got them very hot indeed.

Result....no more brake judder! I bet it comes back again!!

Mike

[J44EAG]

Just arrived are a pair of OE Mintex front discs for the early X350R using 365mm units. These are quite massive at 14.3" diameter. Compare that to your dinner plate! Weight of each disc is 11.8Kg!!

These discs came from Premier on ebay at £79.08 delivered. Its a lot of disc for the money!

Now I have to find the enthusiasm to fit them.

Mike

[BrizzleJag]

Very nice and a great price for Mintex quality.

[J44EAG]

Two sets of pads, two front discs and two rear discs came from four different suppliers, all on ebay.

The total cost was just under £169 delivered. The same parts if bought from an independent supplier such as Berkshire Jaguar Components would have come to £261 delivered. So I`ve made a saving of £98! No doubt the cost would be even higher if sourced from a Main Dealer even with JEC discount or other negotiation on the day of collection.

Now awaiting delivery of the rear discs.

Had I decided on MTec uprated discs, the package cost would have multiplied by about 230%.

The OE plain discs are more than good enough for road going use. If I were going to do a track day, then I`d be tempted to put the old discs back on again and wreck those instead of the new ones. It is such a shame these discs are so prone to warping even in road use.

Mike

[BrizzleJag]

Do you put the warping down to poor heat dispersal, or a more fundamental design issue? I kept the OEM's on the rear of my XKR (standard not Brembo's) but changed the fronts to EBC grooved discs and green stuff pads, big improvement. What do you think about braided hoses? I like a really solid positive brake pedal feel, I'm thinking braided hoses might help? Sorry for going slightly off topic.

[J44EAG]

Warping issues. The air is known not to be well directed onto the vented discs on big brake models. I`m looking to see whether I can improve on that.

Drilled and grooved discs I have found effective in the past although I found both discs and pads wore at a terrific rate.

I`ve now fitted new front discs and pads. Would you believe that each front disc new weighs in at 11.8Kg! By comparison, the old discs with about 3mm wear, have each lost nearly three quarters of a Kg in weight!

I had noticed a small wheel vibration on the XJR prior to the disc change. I had the wheels balanced but there was still some cruising vibration present. I put that down to tyre carcass issues and intended changing to new tyres shortly. Now, with new discs fitted, the braking has changed character completely and the cruising vibes have gone. This now leads me to think that the worn discs were also out of balance, ie, wear had taken its toll and unbalanced the discs. The general mass and distance from the centre line of the hub is around six inches.That is a fair distance to have all that weight spinning around at high speed. I consider that out of balance forces are more of an issue than brake run out of which I could find no evidence. A feeler gauge slipped behind the pad and disc before removal gave no indication of anything that could be construed as warping.

The new front brakes have about forty miles on them now. Hugely improved feel, softer, less effort needed, very nice indeed.

I`ve braided hoses all round on the XJR. Having climbed out of my old V8 S-type and straight into the XJR and subsequently repeating that for six weeks, I`d say the braided application provides a more immediate feel, especially when braking hard. Normal un-braided flexi pipes will tend to expand slightly in heavy use and perhaps not be so re-assuring compared to the braided types. I like the idea of braided hoses as they also give some protection from flying object attack!

Hope that covers things.

Mike

[BrizzleJag]

Thanks Mike, I really appreciate your response, it's good to have advice from someone who clearly knows their stuff.
I'm interested to see how you will modify the cooling to the brakes. If you were doing a race car you'd cut holes in the front valance and duct air to the brakes but you probably don't want to make those kind of cosmetic changes to your road car?
My thinking on grooved discs are that pads are relatively cheap and worth the sacrifice for better braking. Thanks for the comments on braided hoses it's a cheap and fairly simple upgrade so no real reason not to do that. Interestingly I think my S Type has pretty standard set up on brakes but they feel more positive (less soft pedal) than the XKR. Everything I've done so far with the XKR brakes has made an improvement, EBC grooved discs, green stuff pads, new dot 4 fluid (the water content was fairly high when I bought the car), so I think braided hoses are next. The car stops really quickly but it's more about the pedal feel.
Thanks for your input really appreciated.

[J44EAG]

I`ve seen that Goodrich make braided hoses for S-types. I never got around to doing that on my old early model 4 litre V8!

Yesterday, I prepared the new rear discs. Thoroughly cleaned of packing protective oil, exposed top hat sections abraded to accept cold spray zinc galvanising paint, masked up with sticky back plastic and painted. Now back in their boxes as I`ve had quick look at the existing rear disc condition. I fitted new pads eighteen months ago and found the discs in seemingly good condition at that time. The discs still look very good so for the time being, I`ll continue to run with the existing rear pads and discs and take another look at them next year. I suspect that the set up is probably good for another 15k miles of use before a rebuild will be needed. My annual mileage is only about 7k, so I believe this set up will probably work well for a couple more years yet. In the meantime, I`ll hide the discs and pads behind the fridge and forget all about the job for the time being. I`m not one for doing jobs before it is necessary.

A "front brake" rebuild article and images have been sent off to Nigel yesterday for future inclusion at some point in the magazine. A second article has also been completed about tackling the rear brakes which includes the EPB service mode, reset and calibration requirement. As I`ve already been involved with the rear EPB units and rear main caliper pad reline last year, I`ve used that experience for the text for the second "rear brake" article. I need to take some more photographs to support that article before I send that one off as well.

Glad to be able to offer an opinion.

Mike

[BrizzleJag]

Look forward to seeing the articles in the magazine.