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Basil

Basil

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Ok, so I admit it was 114 years ago that I took my EType apart, and now I'm finally getting to the brakes. I was doing a survey of my parts for the brake servo and master cyl and, by comparing the parts in my baggies, with the pictures in my <u>Complete Official Jaguar "E"</u> workshop manual, I was able to figure out how everything went back together, except for one thing!

There was, among the parts that came from my brake servo/ slave cyl, a small spring that is about 3/4" in diameter and 1/2" high. The picture of the servo/slave cyl rebuild kit shown in the XK's unlimited parts catalog shows a similar looking spring, so I am 90 percent sure this goes somewhere in the servo or attached brake slave cyl BUT, in the parts breakdown in my manual, it does NOT show this little bugger.

Here is a picture of the spring in question:

spring.jpg


And here is a scan from my manual showing the Servo.

servo.jpg


Can anyone tell me where this little spring goes?

Thanks,
Basil
 
Is that not the diaphragm return spring for the vacuum/air valve? The "top hat" thingie with the pin on the bottom into the cylinder? The device not shown in your "explosive view" above.

Just my guess.
 
[ QUOTE ]
Is that not the diaphragm return spring for the vacuum/air valve? The "top hat" thingie with the pin on the bottom into the cylinder? The device not shown in your "explosive view" above.

Just my guess.

[/ QUOTE ]

Are you talking about the vacuum valve that sits on the end of the Master Cyl? (The diagram above shows the Slave cyl that sits on the end of the bellows. The Master Cyl is attached to the pedal box and has a vacuum valve on the end of it. Anyway, if that's what you are talking about, I dont think this spring belongs there because when I took all this stuff apart I kept parts for each item separate.

Here is a diagram of the vacuum valve and Master Cyl:

vacuum.jpg


I don't see any springs like the one pictured in this diagram either, but a picture of a Servo rebuild kit in my XK's Unlimited catalog shows a spring that looks very much like the one pictured above so I am pretty sure it belongs somewhere in the servo/slave cyl assembly.

Basil /ubbthreads/images/graemlins/frown.gif
 
Hmmm. That is what I was thinking about: #38 in the master cyl. illustration above, but I thought yours mounted at an angle on top. Obviously the #38 spring here is smaller than what you got. Check valve on master cyl (#7 above) has a smaller dia. spring too... rats.

Disregard! It's been a few years since I had one opened up.

Sorry Baz. John F should be along to set us both straight /ubbthreads/images/graemlins/wink.gif
 
Basil,

Its been about 5 years since I built the brakes on my E but I remember a short spring like that, best I can remember it was the # 38 item. Travel is short, so spring is suited to that area.
 
Thanks for your confidence but for this situation involving small (but important) parts, that is why I farm out assemblies like the E type brake cylinders to Apple Hydraulics that work with these cylinders on a frequent basis. I am now 72 years old and do not trust my memory of a small spring placement such as this. I also hate to install a complex assembly only to find that it is not correct and it is my fault!! Forgive my conservative approach: I know British carburetors and ignition systems like the back of my hand but E type brake cylinders are not my bag. Best regards, Jack Farrington
 
basil,

The drawing isn't very clear but it appears to me that there is a spring under part #29 in the 1st drawing (fig.2 Exploded veiw of remote servo). It would appear to be about the right size.
 
[ QUOTE ]
basil,

The drawing isn't very clear but it appears to me that there is a spring under part #29 in the 1st drawing (fig.2 Exploded veiw of remote servo). It would appear to be about the right size.

[/ QUOTE ]

A friend sent me a scan of a Lockheed diagram of a similar servo (Lockheed made the one in my Jag) and in that diagram it shows a spring between items 19 and 20 on my first diagram. So, I tried that and lo and behold, the spring just fits over the spacer and then the rubber part (19) fits snuggly over the whole thing. If this is correct then the spring doesn really serve as a spring but just as a means to secure the other two parts together.

I've decided I am taking the whole thing to a Jag mechanic in town and ask him for his opinion just to be on the safe side.

Basil
 
I showed the whole assembly to a friend in town who is a Jag mechanic and he suggested, while he's not certain its original, it may have been added after the fact because the seal (item 19 in the first picture) often leaks. The spring fits pefectly over the extrusion in part 20 (plastic spacer), then the rubber seal fits nicely over the whole thing and the spring serves "expand" the rubber seal somewhat and would reduce the likelyhood of its leaking. Since the rubber seal just sits in the back end on the slave cyl assembly and does not move back and forth like the seals on the inner piston, he suggested I include the spring on reassembly (and someone sent me a diagram of a similar Lockheed servo/slave cyl and it does show such a spring between the two parts). Without the spring, the rubber seal is very loose on the plastic spacer, so in tearms of helping the assembly seal properly in the backend of the slave cyl, it does seem to make sense.

Basil

Lockheed drawing of similar servo/slave cyl assembly showing spring (#31) just forward of seal:

Servo3a.jpg
 
ehhr, cough, cough, the XK's Unltd. and other companies' Cat-A-Logs explain that these rebuild kits include parts for a number of other models, not just your particular year/model, in the interest of efficiency and to keep prices low, (yeahh, right), so your kit might have parts required in another year or model Jaguar. That might explain the mistery spring, or any seals or parts that do not apply. Unfortunately, they do not tell you this with a note inside the package. So the part about "efficiency" is lost too.
/ubbthreads/images/graemlins/jester.gif
 
[ QUOTE ]
so your kit might have parts required in another year or model Jaguar. That might explain the mistery spring,

[/ QUOTE ]

Well, perhaps, but I have owned this car for 25 years + and I am fairly certain the Servo is original as are all the parts inside. This spring definitley came out of this Servo. I am now pretty sure that it fits on the spacer, then the rubber cup fits over the whole thing and then the spacer/rubber seal up the rear end of teh slave cyl. I think the spring is just to fill space between the spacer and the rubber seal since without the srping in place, the rubber fits very loosly over the spacer, but with teh spring (which happens to be exactly the correct size for the spacer) the rubber seal is much snugger.

Basil
 
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