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Hydraulic Clutch (MC rebuild --kinda long)
Ref: Your note of Tue, 20 Jan 1998 21:06:44 =0600 (attached)
Bob and all,
I have an '87, and recently rebuilt the clutch MC (at 239k).
In my case, when the clutch pedal was depressed, it would stay at the
floor, also fluid could be observed being circulated back into the
reservoir as it went down.
Your case may be different. From the symptoms it could just need to be
bled. Might be worth a try unless the car is leaving home again soon.
On mine, a chunk was torn out of the master cylinder piston seal lip
(how's that for a mouthful). This was due to horribly contaminated and
gritty fluid and some slight corrosion on the cylinder walls near the
reservoir port inlet (probably having nearly a quarter million miles on
it had something to do with it too). Lots of things were well cared
for on this car, but the hydraulics weren't one of them.
The rebuild kit was $16, and the job was straightforward:
remove kick panel,
remove two nuts (inside car) holding MC to firewall,
remove clip and clevis pin at pedal,
remove hydraulic line to slave,
remove reservoir tube at reservior (plug or catch draining fluid),
pull out MC including actuating rod and boot.
Dissasemble, clean, inspect, and hone MC as needed. A new hone was
about $12, a generally useful tool if you do brakes and clutches
(my old one was stolen --dang, there's always something the insurance
co. gets out of paying for).
My rebuild kit had two main seals of differing thickness, I used the
6mm one, plus the rear seal, c-clip, washer, spring retainer and boot.
When reassembling, keep everything scrupulously clean and make sure to
lubricate everything with lots of new brake fluid.
Go easy as you insert the piston into the bore so as not to damage the
seals as they pass over the c-clip groove. Someone here suggested a
"shoe horn" made with a short piece 3/4" copper water tube, but I did
not find such necessary. Put the feed tube back on the MC before re-
installing on car, and fill the MC completely after re-assembling it
(tap and pump to remove all air). I trimmed the end of the feed tube
slightly to get down to an unused section so to have a tighter fit
on the reservoir.
Assembly of remainder is the reverse of disassembly. I later found a
small plastic bushing on the drivers floor mat. I assume it goes on the
clevis pin. Does anybody know for sure, it is not shown in Bentley.
I pumped the pedal a few times with the hydraulic line threaded only one
turn in, just to get last air out. I did not pressure bleed the system
yet, it has been fine. I plan to do the slave soon, and have the parts
to do a pressure bleeder then: regulated air supply, spare reservoir
cap, schrader valve and fittings, and seals. I'll let y'all know how
it goes when I get to it.
----------------------------- Note follows ------------------------------
Date: Tue, 20 Jan 1998 21:06:44 =0600
From: "R. Cummings" <email@example.com>
Subject: Hydraulic Clutch
I think I sent this message to the wrong address, so I will try again.
1987 Coupe GT 113k
I have been off the list for awhile since my daughter had the Coupe and out
of sight is out of mind. It's back with the following problem. Often when
you first get in the car, you put your foot on the clutch and the pedal
sinks to the floor. You pull it back up and push it down and it works fine.
This also occurs sometimes while driving.
If you disengage the clutch in gear, it will hold and does not seem to leak
My first thought is to replace both the master and slave cylinder but I
have two questions. First, do the symptoms indicate which is the problem?
Second, my Haynes manual doesn't admit the existance of a hydraulic clutch
and I am too cheap for a Bentley but, both cylinders look buried. Does
someone have a procedure for removing them or at least how one might get at
Thanks in advance = Bob Cummings 87 Coupe GT 113 K, Bedford, TX