Since my Master Cylinder change a few months ago, I have had less
boost to the brakes, although the car stops fine. Just too much
pressure needed. Other Jaguar owners who have driven the car
confirm this.
It is theorized that in replacing the MC, the booster nipple and
seal was bumped, banged or other wise disturbed. The seal, being
original, must have shrunk/distorted/hardened over time, so this
sounds a reasonable cause for some vacuum leak.
My question is, as I have a spare new one on hand, has anyone out
there replaced this nipple before? I know it is a very tight fit,
and getting the old one out seems like it would be difficult based
on the design of the unit.
So, looking for any advice/assistance so I don’t botch this job 
Thanks in advance–
Larry Karpman '88 V12 SIII, '94 MX-5
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
===================================================
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Larry,
I pulled the old nipple out of my brake booster without much drama. I placed
some thick cardboard padding against the body of the booster to prevent
damage, then used two flat bladed screwdrivers to lever the nipple out,
starting in one spot and slowly working around, using the first screwdriver
to keep the nipple from popping back in while the other pried at a different
spot. It is a tight fit, but it did come out without too much difficulty.
The shaft of the nipple is ribbed. I’m still waiting to receive the new
nipple, so can’t yet advise on the replacement.
Doug Ingram
Victoria BC Canada
1987 Jaguar Series III XJ6 VdP----- Original Message -----
From: “Larry Karpman” lkarpman@comcast.net
To: xj@jag-lovers.org
Sent: Sunday, July 11, 2004 10:35 AM
Subject: [xj] Brake Booster Nipple
Since my Master Cylinder change a few months ago, I have had less
boost to the brakes, although the car stops fine. Just too much
pressure needed. Other Jaguar owners who have driven the car
confirm this.
It is theorized that in replacing the MC, the booster nipple and
seal was bumped, banged or other wise disturbed. The seal, being
original, must have shrunk/distorted/hardened over time, so this
sounds a reasonable cause for some vacuum leak.
My question is, as I have a spare new one on hand, has anyone out
there replaced this nipple before? I know it is a very tight fit,
and getting the old one out seems like it would be difficult based
on the design of the unit.
So, looking for any advice/assistance so I don’t botch this job 
Thanks in advance
Larry
===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html
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// please trim quoted text to context only
In reply to a message from Doug Ingram sent Sun 11 Jul 2004:
Thanks Doug. I will eagerly await your further instructions once
you have installed the new one, if you would be so kind to post the
successful procedure.
Cheers–
The original message included these comments:
I pulled the old nipple out of my brake booster without much drama. I placed
some thick cardboard padding against the body of the booster to prevent
damage, then used two flat bladed screwdrivers to lever the nipple out,
starting in one spot and slowly working around, using the first screwdriver
to keep the nipple from popping back in while the other pried at a different
spot. It is a tight fit, but it did come out without too much difficulty.
The shaft of the nipple is ribbed. I’m still waiting to receive the new
nipple, so can’t yet advise on the replacement.
Doug Ingram
–
Larry Karpman '88 V12 SIII, '94 MX-5
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html
To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.
// please trim quoted text to context only
In reply to a message from Larry Karpman sent Sun 11 Jul 2004:
Check also that the vacuum pipe from the manifold hasn’t collapsed
internally & that the inline non return valve is not gummed up,
wash in fuel usually frees it up if not a new valve.–
Keith Turner '79 XJ6 based Aristocat, , '81 3.4 XJ6
Swansea, United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
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In reply to a message from Keith Turner sent Sun 11 Jul 2004:
Thanks Keith: I was looking for the inline non return valve, but
darned if I can find it on the '88V12 engine. I see nothing
visable inline with the metal pipe and rubber hoses.
Cheers–
The original message included these comments:
Check also that the vacuum pipe from the manifold hasn’t collapsed
internally & that the inline non return valve is not gummed up,
wash in fuel usually frees it up if not a new valve.
Keith Turner '79 XJ6 based Aristocat, , '81 3.4 XJ6
–
Larry Karpman '88 V12 SIII, '94 MX-5
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html
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// please trim quoted text to context only
In reply to a message from Keith Turner sent Sun 11 Jul 2004:
Keith: Please disregard my last post.I believe I have located the
brake system non return valve.
Thanks–
Larry Karpman '88 V12 SIII, '94 MX-5
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html
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// please trim quoted text to context only
In reply to a message from Larry Karpman sent Mon 12 Jul 2004:
Forgot to ask, what is the test for this non return valve once
pulled? I’m not sure how it is supposed to operate. Should I be
able to blow/suck in one direction only, or what?
Thanks in advance–
The original message included these comments:
Keith: Please disregard my last post.I believe I have located the
brake system non return valve.
Thanks
–
Larry Karpman '88 V12 SIII, '94 MX-5
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html
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// please trim quoted text to context only
That’s it Larry - air should pass through freely in one direction, and not
pass at all in the other.
Doug Ingram----- Original Message -----
From: “Larry Karpman” lkarpman@comcast.net
To: xj@jag-lovers.org
Sent: Sunday, July 11, 2004 7:49 PM
Subject: Re: [xj] Brake Booster Nipple
In reply to a message from Larry Karpman sent Mon 12 Jul 2004:
Forgot to ask, what is the test for this non return valve once
pulled? I’m not sure how it is supposed to operate. Should I be
able to blow/suck in one direction only, or what?
===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html
To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.
// please trim quoted text to context only