I have a '66 4.2 MKX wreck that has had the S1 XJ caliper conversion, and still has some of the old parts in the boot, so I can take some pics for you if you want?
( but please dont hold your breath lol…see my next post about tow bars! )
I got it for $300, minus engine & gearbox, it had a Ford V8 conversion removed,
made for a fairly easy tow home, paid for itself with a few parts
It would also have an LSD, which became non standard in 1967, so not on my 420G
My car is # 1D75725 and it appears to have the earlier Dunlop calipers by inspection, as it should by the book (my free downloaded parts manual is missing those pages - thanks for the reference - I have a print version on the way). There is no way I’m getting into those steering issues, as I have been there before. Thanks for the offer on the photos, but please don’t.
Would I need the 420G uprights as well as calipers and rotors to be able to bolt these on? It would be nice to source the parts, as the front end needs a rebuild anyway. There is an off-chance I might have the calipers, as I parted out a 420G 25 years ago. I will look and shoot a photo if I have them.
Many thanks,
Ron
No joy, no calipers.
Ok, a little confused here. Photos attached of my calipers, which are quite large, integral cup outboard, Dunlop bolt-on inboard, and clearly 1/2" rotors, which are minimally worn. I couldn’t find a casting #. Are these the early or later version? It is possible that the car has been previously upgraded…
not sure whether they are the same as mine, I will take a pic…it may be hard to tell the difference, I know the 3.8MKX had another different caliper and 3/8" disc
will take a pic in the next few days, and check a book I have “Thorleys MK7-420G”…buy this if you can get it used !
Its entirely possible the brakes have been upgraded, as the original owners of these cars were wealthy, and Jaguar would and could upgrade them if asked
I am 99.9% sure the upright is the same for a MKX and 420G
The Parts Manual for 420G is a separate publication called IPL4, and is a somewhat deficient and confusing document, but does generally show where Part nums are different between late MKX and 420G…if i see the part num is different, I will notify you by posting
FPM describes same part num for late 4.2 MKX as 420G
Thorley describes it as 2-1/4" piston Dunlop mark 3 made from cast instead of malleable iron
the only thing he mentions is a change of brake pad material for 4.2mkx…no caliper change
…so who knows…accurate info on these cars is very difficult, as even the official manuals are incorrect in places
The front brakes are the last part of my brakes still to be rebuilt…I have new pistons, seals, discs, (even NOS hubs & bearings if I want), and copper-nickel lines for the calipers
It appears that my Mk10 does have the same calipers as your 420G, so that’s good news. I do have the Thorley book, and was perusing it the other day, but didn’t think to check about the brake specifications - thanks much. I should probably rebuild the calipers when I have things apart. The other good news is that there is only one link component worn out in the front end, now that I have it up and unloaded, plus new boots needed on the ball joints and tie rod ends. I believe I’ll start looking for the brake master core, and the car should be pretty functional soon.
I think that obsolete booster will get you in the end…a failed booster will scare the pants off you, so therfore, imo, you need to look for a booster master combo from a later MKX, 420G S1/2 XJ
even though the earlier master cyl is rebuildable, it is not compatible at all with the later booster…I promise you nearly every supplier does not even know this basic but vital fact
direct bolt up to the pedal box. They are not impossible to find in specialist wreckers
If you look at the jaguar saloons.org site, it shows some MKX that have been upgraded to the later brake system, I understand Jaguar dealers did this when the P90 booster failed
P90 and its master was only on cars 66-67, and I dont think it was on any other Jaguar models of that era
(The 3.8 MKX have an even worse brake arrangement, but shares many parts with 3.8 E-types, so parts are available)
The later booster does not bolt right up to a 3.8
I think I might have one, if my friend decides to use the series 3 master on his XJC restomod. It seem that would be best for him considering the less obsolete nature of the S3. I think a previous post indicated that it works. If he doesn’t use the series 1 master, it should be available. But I’ll find one if not - there are quite a few cars still getting parted out, I think. The S1 booster seems readily available from the usual suppliers.
I did score on a Series 2 master and booster that came from a running car albeit now unused for several years. I’m going to try it as is after flushing some clean fluid through it. I think the pressure differential warning activator is probably best not used, but any comments would be helpful.
Tony, I can’t find the saloon.org site you mention. Is it still functional? I’m confused about some of the cooling components, reservoirs, etc. I need some good photos of the stock arrangement under the bonnet, and that site may help.
Thanks
the links to the site might be a bit fractured, but persist, its a goldmine
Thank you - that is a useful site - lot’s of photos there of the engine bay. It does seem that a complete original is a rare find.
this '66 looks original, has many pics
That’s a good one, but it appears that my car is actually a '65, titled as a '66. Unlike the survivor in the photos, mine has the header tank (currently leaking) on top of the radiator which appears to be an earlier feature. The cars near mine do not seem to have a separate burp tank, and you have pointed out that mine has been added. My car is missing the vacuum controlled water valve C24054. This appears to be unavailable, but a previous posting suggests an aftermarket solution, which I will investigate. None of the vacuum activated ventilation controls work on the car so that will be another problem to address.
http://www.saloondata.com/gallery/zoom/?id=224458
http://www.saloondata.com/gallery/zoom/?id=634727
some interesting detail in those 2 pics
the vacuum controlled heater valve is still available, or a substitute parts store one will get you out of trouble
The vacuum system is complex, but I have a good understanding of how it all works, or should I at least say, I have taken mine all apart, and it all works
I’ve got a universal on order ($17 on Amazon) until I find an original valve that works. The C24054 is not available from my usual suppliers, and the couple I’ve found are very expensive, like 200 pounds. Makes me mad, as I’ve parted two of these cars over the years and apparently didn’t save one. I’ve got two extra ventilation system air cans that live on the right inner fender if anyone wants to trade!
its the same as an XJ6 S1…at some time they reversed them so vacuum off stops the water flow, I cant even remember which way they are supposed to work, as I took mine off many years ago, and all used items I have come across allow hot water to bleed thru my heater core at all times. So I just bypassed it, as I would very rarely need a heater, and can put in a tap if I want. My dark blue car is very hot, the only time I would ever want a heater is mid-winter at night
I suspect if you want an item that works, and looks correct, you will have to pay big bucks for a brand new one
Here in the Pacific NW, a heater and especially a defroster, is a must in winter, but it will be some time before I get into that system. I’ll get back to you about how the universal works out - the car currently has a frozen manual valve letting hot water through. At least I can tell that the core is ok. I’m not too fixated on correctness where it doesn’t make sense. When I get a chance, I’ll post the fuel tank clean-out video - I think it will be entertaining.
unless you are an originality freak, I would stick with a substitute
One thing to be very aware on these cars is that tremendous rust can lurk in the base of the heater case and the panels underneath…in some cases destroying the car
its very hard to get the entire heater case out for a full inspection…in lieu of this, I suggest you unscrew the sheetmetal cover on the front, and check the base of the heater case is not rusted…if there is any rust at all, you must remove the heater case and make detailed quality repairs
Hmm. That sounds like potentially a lot of work. I’ll put pulling the panel on the to-do list. I suspect a rusty box could come from a leaking heater core (no evidence of that), leaking windshield (some rust there, but no sign of interior damage) or a leaking scuttle. It doesn’t appear that the scuttle has been open in decades, and it does not operate at this time. I was thinking of trying to manually open it, but haven’t investigated. Is that possible through the center drop down electric panel?
