I am still having issues with my 71 v12 brakes. Last month I wrote
about total brake failure after bleeding my brakes. Well, I decided
to re-bleed the front ones today. While bleeding them I noticed
that the hose coming off the reaction valve had come loose. I
re=attached it and re-bled them again, starting with the right one
then the left. No change. Should I assume the master cylinder is
gone? Before I started, I did notice that the fluid level in the
top reservoir was down about 2 inches. I did not see any fluid on
the ground or around the hoses or adjustment screw. Any info would
be appreciated. The bottom reservoir has stayed full’
Jeff–
Jeff 71 XKE V12 Coupe
Richmond/Virginia, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Jeffa sent Sun 24 Jul 2011:
Jeff,
I’m thinking you might find the missing brake fluid in the vacuum
tank…If both upper and lower MC’s haven’t been replaced or you
don’t know the history I’d replace them along with all suspect
hoses, vacuum and hydraulic.–
The original message included these comments:
then the left. No change. Should I assume the master cylinder is
gone? Before I started, I did notice that the fluid level in the
top reservoir was down about 2 inches. I did not see any fluid on
the ground or around the hoses or adjustment screw. Any info would
be appreciated. The bottom reservoir has stayed full’
Jeff 71 XKE V12 Coupe
Groan…
Well here is another one.
The below clue is the clue.
Almost certainly the fluid is being pulled into the bellows area of the booster. Good news is the aftermarket ones are of a better quality now than the ones on the market years ago.
LLoyd
My driveway is long enough that you can appreciate the conflict between the desire for privacy and the terror of being completely lost .----- Original Message -----
From: “Jeffa” jeffapp1@verizon.net
… Before I started, I did notice that the fluid level in the
top reservoir was down about 2 inches. I did not see any fluid on
the ground or around the hoses or adjustment screw. Any info would
be appreciated. The bottom reservoir has stayed full’
Jeff
In reply to a message from Jeffa sent Sun 24 Jul 2011:
Jeff,
My opinion regarding the brake system is to always replace
everything at once…If one part fails, the others aren’t far
behind, if they weren’t replaced already. I’d replace the upper MC
and the lower MC/Booster/Reaction/valve. Much better safe than
being in a potentially dangerous situation.–
The original message included these comments:
Matt, Thanks for the reply. Another post suggested it might be the
booster. What do you think?
Jeff 71 XKE V12 Coupe
Clean (flush) the master good, it may be ok, but booster and slave come together as a pair.
LLoyd
My driveway is long enough that you can appreciate the conflict between the desire for privacy and the terror of being completely lost .----- Original Message -----
From: “Jeffa” jeffapp1@verizon.net
To: e-type@jag-lovers.org
Sent: Sunday, July 24, 2011 6:48:52 PM
Subject: Re: [E-Type] brake problems-still-71 v-12
In reply to a message from @soothsayer1 sent Sun 24 Jul 2011:
Thanks for the info. Do you think the MAster Cylinders need to be
replaced or just the booster?
Hey Guys,When I read the posts here all offering advice for
diagnosing problems with the ‘‘E’’ SII/SIII braking system I wonder
why there are a variety of terms that are used which could be
somewhat confusing. Surely its best to stay with the jaguar wording
to avoid confusion. Please correct me if I am wrong, but we have
the master cylinder ( M/C ) which is fitted with a reaction valve,
and then the servo.–
1973 SIII Supra 5-Speed, 1970 SII OTS , Ontario, Canada
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
As I recall (?) the writer was distingwishing between the slave cylinder and bellows, which combine to make up the servo. So, John, you are correct.
LLoyd
My driveway is long enough that you can appreciate the conflict between the desire for privacy and the terror of being completely lost .----- Original Message -----
From: “john holmes” tcoholmes@shaw.ca
To: e-type@jag-lovers.org
Sent: Monday, July 25, 2011 6:25:53 AM
Subject: Re: [E-Type] brake problems-still-71 v-12
In reply to a message from @soothsayer1 sent Sun 24 Jul 2011:
Hey Guys,When I read the posts here all offering advice for
diagnosing problems with the ‘‘E’’ SII/SIII braking system I wonder
why there are a variety of terms that are used which could be
somewhat confusing. Surely its best to stay with the jaguar wording
to avoid confusion. Please correct me if I am wrong, but we have
the master cylinder ( M/C ) which is fitted with a reaction valve,
and then the servo.
In reply to a message from Jeffa sent Sun 24 Jul 2011:
A failed booster CANNOT cause fluid loss. If the master
cylinder has failed such that you lose fluid, you will end up
with brake fluid in the passenger compartment, likely UNDER
the carpet. If it’s dry there, then the servo cylinder has
failed, and you’ll find the missing fluid inside the booster
and the vacuum tank. As others have said, if EITHER master
cylinder has failed, the smart thing to do is rebuild/replace
them both - when one goes, the other one is usually not far
behind.–
The original message included these comments:
Thanks for the info. Do you think the MAster Cylinders need to be
replaced or just the booster?
Jeff
–
Ray Livingston - '64 OTS Santa Cruz, CA
Santa Cruz, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Jeffa sent Sun 24 Jul 2011:
I have no experience with the SIII brakes, except taking
them apart and being in the process of rebuilding.
However, I once had a Volvo P18oo with a similar problem.
The brake fluid disappeared. The brake booster was
defective and basically allowed the engine to suck the brake
fluid through the vacuum hose. A dead give away is if you
see excessive smoke from the exhaust when braking - engine
running off course.