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67 Jaguar 420 Brakes and Carb Problems?

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PlaidMan

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I'm helping a friend work on a 67 Jag 420 Brakes and Carb problem. We don't have a manual, is there somewhere online that we could view the Brake system? The car tries to start but feels like there is too much choke, can this be adjusted and what is the little black electrical solenoid between the carbs?

Thanks, Charlie
 
The solonoid is the "starting carb". It is controlled by a temp sensor in the water rail near the thermostat. When it is cold, the switch trips and opens the air passage in the starting carb, and fuel and air in a nice rich mixture is introduced. Often the switch in the fuel rail is bypassed in favor of a switch in the dash.Check the float levels in both carbs, as this also controls the level in the starting carb, and too high a level will cause rich running.

What is wrong with the brakes? The fronts are 3 piston calipers, and the rears are inboard as on 3.8s models, and similar to approximately the same year Etype.
 
Thanks for the info Jesse, the brake pedal goes completely to the floor, the rear reservoir was almost empty, filled it with fluid but not sure how to approach the bleeding procedure. Also there appears to be a second master cylinder next to the front driver side fenderwell, tried pumping the pedal but it does not seem to build any pressure at the brake pedal.

Thanks, Charlie
 
Bleed as older car brakes. Start Right Rear to left rear to right fron to left front. Might bleed master cylinder at lines first to remove air at M/C. Is the second cylinder the booster? This will be your vacuum source unless there are lines to it as a n E-type then you will need to line bleed it also. If system has been dry or low for some time figure on rebuilds. May need engine running to build vacuum.

Carb starting solenoid may need a switch as Jesse mentioned.

Scematics and diagrams on JCNA site and Jag-lovers. Keep us informed.

Or get the Jag 420 CD from XKs or Welsh E, if in no hurry can copy and send this weekend. The CD is a 95/98 format and I have to search on my computer till I find it.
 
Larry, the vacuum unit is on the MC next to the firewall and from what I could see there are only lines running to the unit by the firewall. I'll try the bleeding procedure tomorrow but I'm sure certain items will need to be replaced as you mentioned.

Thanks again, Charlie
 
Two good sources from Exotexs!
 
Found the brake fluid leak today. After bleeding the Master Cylinder, it had a substantial pedal with just a few pumps and then saw fluid leaking from the front wheel brake hose. As Jesse mentioned the starting solenoid has been previously wired to a switch but am not sure if the solenoid works because the engine was already warmed up when I traced the wires back to the switch under the dash. Is there a way to test this solenoid, it definitely has voltage running to it but after the engine was warmed up I flicked the toggle switch to on but there was no difference in the way the engine ran, I would think it would be running rich with the switch on. I will try the switch tomorrow morning and see if it is easier to start when cold, starts fine when hot.

Thanks , Charlie
 
thanks LarryK.

Charlie, the switch keeps the Auxiliary Starting Carb (or the "solenoid" as you call it), OFF.

Normally the ASC or "solenoid" is activated by the "otter" switch, located on top of the thermostat housing under a triangular-shape fitting fastened by 3 small bolts. The "otter" switch" is a thermal sensor which senses the coolant temperature and activates the solenoid. (that's the theory but the reality is another, so people install an under-dash switch to prevent the otter switch from activating the ASC when the engine is warm, that's all it does).

the ASC is also known as an Automatic Choke. Most all Jaguars had it until around 1970. You can order a rebuild kit.

so turn the switch to ON when the engine is cold.

here's a link to the ASC:

https://www.jag-lovers.org/ebooks/view.php?Vbook=Saloons&Vsection=4.5


here's a link to the Saloon's e-book index at Jag Lovers:

https://www.jag-lovers.org/ebooks/bookindex.php?Vbook=Saloons

Ex
1965 S type
1984 XJ-6
 
The ASC definitely works, makes all the difference in cold starting. Vacuumed the AC today and charged it, works great but I had to raise the idle a little to compensate but when I turned the engine off it would tend to run on so put the idle back, runs about 550 rpms with the AC on. Is that about right? Brakes now work after changing front brake hoses but did notice the pads were completely worn on one side of the caliper(Driver side). Engine runs fairly well but does miss a beat every now and then on the passanger side exhaust(not sure which cylinders that would be). Did not overhaul carburetors but just added oil to the dashpots. I'm really enjoying learning about this Jaguar.

Thanks , Charlie
 
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