[xk] New member - help with XK140 OTS brakes (long)

XK
1

Hello folks, I bought a ‘project’ XK140 a few years ago. I rebuilt
the engine & did lots of other mechanical repairs, including
rebuilding the braking system. I rebuilt master & wheel cylinders,
and replaced all the rubber hoses. Finally, I took my long-awaited
first drive, and here’s what happened. A few miles from home, the
brake pedal got extra firm. I could tell the front brakes were
beginning to bind up. The brake pedal was rock solid, so I turned
around and just barely made it home. I jacked up the front of the
car in my garage, and both wheels were locked tight. Also, the
drums were VERY hot. I turned the bleed screw, and hot brake fluid
sprayed out under pressure. Once the pressure was released, the
front wheels turned freely again.

I’ve gone through and rebuilt the master and front wheel cylinders
again since then, just to make sure it wasn’t something obvious.
Still, I always get the same result.

I thought maybe the adjuster bar was racheting the brakes too
tightly, so I removed the rachet springs trying to isolate the
problem. In other words, the brake shoes were free to expand and
retract all the way. Upon testing, I still had the same problem.

Today I’m studying my shop manual, and it occurs to me that I’ve
got a mismatch. The master cylinder is the ‘early Lockheed’ type
(single cylinder). The front and rear brake assemblies are
the ‘later Lockheed’ type (which normally runs off a twin-outlet
master cylinder). The mounting is pretty interchangeable for the
two different masters, so I figure someone along the last 47 years
swapped the two.

Do you think this would cause the brakes to lock up? Personally, I
think there’s something wrong with the ‘rubber cup © in the metal
body (B) that assembles on the larger end of the return spring
(D).’ This is a little valve that sits just behind where the banjo
union is attached. What is its purpose? I followed the (unlabelled)
diagram, and I’m sure it’s assembled properly.

I know the concept is that the master cylinder pushes the fluid
into the wheel cylinders, and the stiff brake springs push the
fluid back into the master cylinder. I don’t know what that little
valve does, do you?

Has anyone experienced (or fixed) a similar problem? I guess I
could buy a new master cylinder, but then I haven’t really learned
anything. Any advice or comments would be greatly appreciated.

Dave–
Dave Shaw
Orange/CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

2

Dave,

Sure, this kind of thing happens all the time. I can’t say for sure
about an XK 140, but on my 120 this symptom was caused by me. I had
adjusted the pedal free play according to my interpretation of the
words in the service manual. On my 120 that adjustment is made by
lengthening or shortening the rod that emerges from the master
cylinder…and free play is supposedly measured at the pedal.

My brakes tightened right up.

Eventually, I learned to “feel” the free play where the rod goes into
the master cylinder. You want to adjust the length of that rod allows
about 1/8" to 1/4" free play right at the master cylinder. In my case
that translates to about 2" at the pedal. maybe slightly less.

No more tightening brakes?

Ain’t it a drag to arrive home with smoking drums?

Like I say, this is for a 120. It may be the same on a 140, but I’m
not sure. Others can chime in here about 140’s.

By the way, my daughter will be attending Chapman this fall, majoring
in dance. I’ll be bringing her down around August 19. Are you near
the University?

Tom Carson
1954 XK 120SE OTS
1962 3.8 Mark 2 MOD, chrome wires
Juneau, AlaskaOn Sunday, July 13, 2003, at 08:40 PM, Dave Shaw wrote:

… A few miles from home, the
brake pedal got extra firm. I could tell the front brakes were
beginning to bind up. The brake pedal was rock solid, so I turned
around and just barely made it home. I jacked up the front of the
car in my garage, and both wheels were locked tight. Also, the
drums were VERY hot. I turned the bleed screw, and hot brake fluid
sprayed out under pressure. Once the pressure was released, the
front wheels turned freely again.

–
Dave Shaw
Orange/CA, United States

3

David S;
First off, Welcome and congratulations of taking that important
“First Drive”… It’s a good feeling, even if something minor does go wrong…
What you have experienced with your brakes is not an uncommon
problem when the “rod” that goes into the master cylinder (generally called
the brake pedal rod) is adjusted so the first seal in the M/C bore is
blocking the brake fluid relief hole… (generally, the rod is “in” too
deep… but can be “out” a bit too far, as well.
This hole is for the express purpose of allowing the hot,
expanding brake fluid a return path to the reservoir. The results, when
this hole is blocked, are exactly as you have described… Instant Stop,
without touching the brake pedal ;-}
Some have stated that the use of DOT 5 Brake Fluid can cause the
seals to swell and cause this same condition. especially if any previous DOT
3 or 4 was not thoroughly cleaned out of the system. In my opinion, good old
Castrol LMA Brake Fluid is the only stuff to use… You will find a number
of us are somewhat opinionated about various oils, fluids, etc., we use…
makes for lively discussions.
Additionally, I would question the use of the “Dual” system wheel
cylinders on a “single” Master Cylinder … The XK120 Parts Book shows the
wheel cylinders were different between the “early”(single) and “late” (dual)
systems…
The 140 is suppose to have the Single Stage M/C and wheel
cylinders, backing plates, etc. to match… not the Lockheed brake system
that was used on the later production ('53-'54) XK120’s. I suspect the PO
(Previous owner) changed all this for some reason, sometime in your 140’s
life… who knows why!!
A fellow by the name of John Elmgreen will post an on-list query to
you begging for your Jag’s “Numbers”… he use to be a “wine-o” begging for
quarters ;-}, but we’ve “retrained” him… so humor him and send him all the
info, history, previous owners (if knows), etc. on or about your 140… it
will make him happy. Please note that I am joking… John E. wasn’t a
wine-o… just an Aussie who writes an occasional book of Jaguar XK’s… He
is, however, documenting every XK ever built that is still surviving… a
daunting task, to say the least! Help him out all you can.
You can post a note to the XK-List, containing all the “numbers”,
information, etc. just use the Subject: “Numbers For John E” and he will
catch it…
Charles #677556.

Finally, I took my long-awaited----- Original Message -----
From: Dave Shaw

first drive, and here’s what happened. A few miles from home, the
brake pedal got extra firm. I could tell the front brakes were
beginning to bind up. The brake pedal was rock solid, so I turned
around and just barely made it home. I jacked up the front of the
car in my garage, and both wheels were locked tight. Also, the
drums were VERY hot. I turned the bleed screw, and hot brake fluid
sprayed out under pressure. Once the pressure was released, the
front wheels turned freely again.

4

Dave Shaw wrote:

I’ve gone through and rebuilt the master and front wheel cylinders
again since then, just to make sure it wasn’t something obvious.
Still, I always get the same result.

I thought maybe the adjuster bar was racheting the brakes too
tightly, so I removed the rachet springs trying to isolate the
problem. In other words, the brake shoes were free to expand and
retract all the way. Upon testing, I still had the same problem.

Dave

Dave Shaw
Orange/CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

do you have enough free travel at the master cylinder pushrod. With the
piston fully seated to the rear of the cylinder, the push rod should
have free travel at this point. I suspect you are not uncovering one of
the return ports in the master cylinder. try this first… then check
the brake hoses. Old ones develop little flaps inside the allow
pressure to go thru, but not back the other way. john shuck

5

This happened to me last year. After sitting (covered) in the weather
outside a local shop, my 140 OTS had immediate brake problems. Same
symptoms - exceedingly hot drums, rock hard pedal, wheels locked tight going
forward (but could creep in reverse) – I had to be hauled home on a flatbed
the first time out. Next day, all was well until two or three miles then one
could feel the wheels slowing, and the dash for home ensued.

I assumed that the sitting outside had caused accelerated aggravation to the
moving parts (maybe even rust). I wanted to avoid a disassembly, so I first
backed off the adjusters in the rear units. Then I spent a bit of time in
the driveway hard-stopping in reverse to get the front brakes moving. Being
determined to avoid having to adjust the brake pedal shaft, I made a point
of doing frequent evening rides with increasingly aggressive braking, when
the ambient temperature was helping, not hurting my efforts.

I think I have dodged the bullet. No real trouble since. Interestingly, last
month I swapped my knockoffs for some rechromed ones, and immediately
started getting a chirping from one of the front wheels – along with some
excess drum heat. Three whacks with a nice new lead hammer loosened the
knockoff a tad and the chirping and heat disappeared. There’s a discussion
point for the list: Can too-tight knockoffs force the drum inward and cause
shoe binding?

Bottom line - These brakes are happy if they are clean and used a lot.________________

Peter A. Thomas
Delmar, NY
1957 140 OTS

6

jeez… you poor people with the pesky drum brakes. I’m sure glad I’ve got
nice reliable, trouble free discs! (and no, it’s not because I have an XK
150 either!)

Brandon B. Shriver
Hazleton, PA
http://www.shriverperformance.com
The people who are crazy enough to think they can change the world… are
the ones who do.----- Original Message -----
From: “Tom Carson” tcarson@gci.net
To: xk@jag-lovers.org
Sent: Monday, July 14, 2003 1:06 AM
Subject: Re: [xk] New member - help with XK140 OTS brakes (long)

Dave,

Sure, this kind of thing happens all the time. I can’t say for sure
about an XK 140, but on my 120 this symptom was caused by me. I had
adjusted the pedal free play according to my interpretation of the
words in the service manual. On my 120 that adjustment is made by
lengthening or shortening the rod that emerges from the master
cylinder…and free play is supposedly measured at the pedal.

My brakes tightened right up.

Eventually, I learned to “feel” the free play where the rod goes into
the master cylinder. You want to adjust the length of that rod allows
about 1/8" to 1/4" free play right at the master cylinder. In my case
that translates to about 2" at the pedal. maybe slightly less.

No more tightening brakes?

Ain’t it a drag to arrive home with smoking drums?

Like I say, this is for a 120. It may be the same on a 140, but I’m
not sure. Others can chime in here about 140’s.

By the way, my daughter will be attending Chapman this fall, majoring
in dance. I’ll be bringing her down around August 19. Are you near
the University?

Tom Carson
1954 XK 120SE OTS
1962 3.8 Mark 2 MOD, chrome wires
Juneau, Alaska

On Sunday, July 13, 2003, at 08:40 PM, Dave Shaw wrote:

… A few miles from home, the
brake pedal got extra firm. I could tell the front brakes were
beginning to bind up. The brake pedal was rock solid, so I turned
around and just barely made it home. I jacked up the front of the
car in my garage, and both wheels were locked tight. Also, the
drums were VERY hot. I turned the bleed screw, and hot brake fluid
sprayed out under pressure. Once the pressure was released, the
front wheels turned freely again.

–
Dave Shaw
Orange/CA, United States

7

In reply to a message from Dave Shaw sent Mon 14 Jul 2003:

From one new guy(Lee)…to another(Dave),
John Shuck mentioned brake hoses…as well he should have. Many
times over the years, I’ve dealt with rotted, and therefore closed
(collapsed) brake hoses. These buggers will expand upon brake
application, allowing fluid to reach the wheel cylinders, but when
it comes time to reverse the flow, the brake springs are simply not
strong enough to overcome the flow restriction. That hot stream of
fluid out the bleeder, as you described, leads me to suspect those
hoses. A relatively simple, cheap and easy fix…IF the hoses are
the culprits.

Lee140FHC
Santa Ana, CA–
Lee140FHC
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

8

In reply to a message from Dave Shaw sent Mon 14 Jul 2003:

Thanks for the great responses � this forum is the BEST! I only had
a little time last night, so I crawled under the car, and found the
push rod adjusted too tight. I loosened a good 3/16� before I felt
any �play�, and kept going another 1/8� just for kicks. Now, when
the pedal is retracted, I can feel the push rod is definitely not
contacting the piston. Tonight, I�ll bleed the system, and take it
for a test drive. Obviously, I�m trying the easiest fix first. If
this doesn�t work, my next step will be to pull and inspect the
Master and make sure the recirculate hole is uncovered and clear of
obstructions when the piston is retracted. As stated previously,
I�ve already replaced all the rubber hoses, as I�d heard stories of
them plugging up / restricting. I�ll log the results post-drive
tonight, and thanks again for the great input.

Dave–
Dave Shaw
Orange/CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

9

Dave wrote:
“push rod adjusted too tight. I loosened a good 3/16” before I felt
any ‘play’, and kept going another 1/8" just for kicks. Now, when

the pedal is retracted, I can feel the push rod is definitely not
contacting the piston."

Dave…It would not suprise me at all this is your problem. On my XK
140FHC,
my brakes were grabbing too…after a short drive. Sure enough, the
push rod
was not totally free when the pedal was not pressed. My brake light
would
even come on. After adjustment, no more problems. The previous owner
had insalled a Mk V booster, & put disc on the front. The rear have
the
original drums. Let us know…
Richard Greene
1956 XK 140 FHC

10

Dave,
Very common for the recirculate hole to plug up. It’s very small and was
the source of the same problem for me.
I pulled the master as you suggested and found it completely blocked - had
to go by sectional drawing just to locate it!
Once cleared - problem solved.
Good luck - Brad Smith.
140FHC-----Original Message-----
From: owner-xk@jag-lovers.org [mailto:owner-xk@jag-lovers.org]On Behalf
Of Dave Shaw
Sent: Tuesday, July 15, 2003 12:48 PM
To: xk@jag-lovers.org
Subject: Re: [xk] New member - help with XK140 OTS brakes (long)

In reply to a message from Dave Shaw sent Mon 14 Jul 2003:

Thanks for the great responses � this forum is the BEST! I only had
a little time last night, so I crawled under the car, and found the
push rod adjusted too tight. I loosened a good 3/16� before I felt
any �play�, and kept going another 1/8� just for kicks. Now, when
the pedal is retracted, I can feel the push rod is definitely not
contacting the piston. Tonight, I�ll bleed the system, and take it
for a test drive. Obviously, I�m trying the easiest fix first. If
this doesn�t work, my next step will be to pull and inspect the
Master and make sure the recirculate hole is uncovered and clear of
obstructions when the piston is retracted. As stated previously,
I�ve already replaced all the rubber hoses, as I�d heard stories of
them plugging up / restricting. I�ll log the results post-drive
tonight, and thanks again for the great input.

Dave

Dave Shaw
Orange/CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

11

In reply to a message from Dave Shaw sent Tue 15 Jul 2003:

TEST DRIVE COMPLETED!!!

With new ‘loose’ push rod, I bled the brakes, and ventured forth. I
drove about 1/2 hour, and I think the lockup problem is solved! The
pedal remained the same throughout the trip.

Now, I’ve got to figure out how to adjust the brakes, because the
right front is locking up on me when I jump on the brakes. Yes, it
pulls terribly to the right. I’m thinking I should:

  1. Bleed the left front again, to ensure all air is removed.
  2. Pull the left drum, and inspect the adjusters. Possibly, I
    overtightened the ratchet bolts, and they’re not sliding easily
    enough. Loosen so I can just fit the cotter pin; no tighter. Then,
    maybe I’ll ratchet a notch manually & retest.

Hate to be a bother again, but how did you get your car to track
straight under braking?

Never satisfied…

Dave Shaw–
Dave Shaw
Orange/CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

12

Hate to be a bother again, but how did you get your car to track
straight under braking?

     Dave S;
     You mean, the XK is *Suppose* to track straight under braking??

Then what’s that big steering wheel for?? ;-}
Charles #677556.----- Original Message -----
From: Dave Shaw

13

In reply to a message from Dave Shaw sent Wed 16 Jul 2003:

Front brakes grabbing, commonly is caused by brake fluid that has
gotten on the linings from leaking cylinders. A good washing with
soap & water will remove most of the fluid & a couple of rapid
stops from 60 mph will drive off the rest.

I’ve rarely had my 120 stop in a perfecly straight line. It seems
that it adds to the interest level of driving, not knowing which
direction she’s gonna go when you apply the brakes. That said,
when all is in adjustment and clean, the XKs stop quite nicely and
with little fanfare. The initial leap to one side or another can
be laid to the self adjusters not being even. There’s little you
can do about that, save applying the brakes vigorously when you are
backing up periodically.
Welcome to the wonderful world of XKs and their unique ‘‘character’’!

Roger–
Roger, 1954 120 DHC BRG, S678300
Tamarac, South Fla., United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

14

Dave
I had the same problem with my 140 OTS after the brakes were completely
overhauled. After several cycles of bleeding, as well as disassembly and
careful reassembly none of which did solve the problem, a certain guru in
Rhode Island suggested that I round the leading edges slightly of the brake
linings.
Both front wheels were done and I can now take my hands off the wheel even
when braking hard.
I did not measure the radius but would guess about 1.5 mm.
Best of luck
Klaus W. Nielsen
812394----- Original Message -----
From: “Dave Shaw” davenlori@hotmail.com
To: xk@jag-lovers.org
Sent: Wednesday, July 16, 2003 12:01 AM
Subject: Re: [xk] New member - help with XK140 OTS brakes (long)

In reply to a message from Dave Shaw sent Tue 15 Jul 2003:

TEST DRIVE COMPLETED!!!

With new ‘loose’ push rod, I bled the brakes, and ventured forth. I
drove about 1/2 hour, and I think the lockup problem is solved! The
pedal remained the same throughout the trip.

Now, I’ve got to figure out how to adjust the brakes, because the
right front is locking up on me when I jump on the brakes. Yes, it
pulls terribly to the right. I’m thinking I should:

  1. Bleed the left front again, to ensure all air is removed.
  2. Pull the left drum, and inspect the adjusters. Possibly, I
    overtightened the ratchet bolts, and they’re not sliding easily
    enough. Loosen so I can just fit the cotter pin; no tighter. Then,
    maybe I’ll ratchet a notch manually & retest.

Hate to be a bother again, but how did you get your car to track
straight under braking?

Never satisfied…

Dave Shaw

Dave Shaw
Orange/CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

15

When I bought my XK 120, it was pretty much an unrestored mess, but the
brakes had been professionally restored with White Post components.
The fellow I bought the car from made a point of telling me the work
included having the shoes “radiused”. I assumed at the time it was a
process that matched the shape of the brake linings to the drums.
Klaus has finally illuminated the process for me.

I must say that my brakes have always worked extremely well except when
I have adjusted that master cylinder rod inappropriately. No pulling
one way or the other when the brakes are applied. I have also learned
the value of occasionally finding an empty parking lot and run the car
backwards a ways while pumping the brake pedal hard numerous times.
This procedure does seem to keep the front brakes nicely adjusted.

Radius those shoes!

Tom Carson
1954 XK 120SE OTS
1962 3.8 Mark 2 MOD, chrome wires
Juneau, AlaskaOn Wednesday, July 16, 2003, at 04:34 AM, Klaus Nielsen wrote:

… a certain guru in
Rhode Island suggested that I round the leading edges slightly of the
brake
linings.
Both front wheels were done and I can now take my hands off the wheel
even
when braking hard.
I did not measure the radius but would guess about 1.5 mm.
Best of luck
Klaus W. Nielsen
812394

…

Hate to be a bother again, but how did you get your car to track
straight under braking?

Never satisfied…

Dave Shaw

Dave Shaw
Orange/CA, United States

16

Radius those shoes!

      Tom C, et al;
     Brake shops use to routinely "radius" the brake shoes.. but, like

everything else, it has pretty much been dropped from the “Correct things to
do” list as companies who reline the shoes generally “radius” the edges of
the bonded/riveted shoes… many don’t.
Tom, you are correct, to correctly “radius” the shoes, they were
“matched” to the “arc” of the brake drums.
For those interested in having this procedure done, try to find an old
shop (with old mechanics) who still has an old style brake lathe… they
ought to have the equiptment to match the radius of the shoe to the drum.
You should be able to just take in your shoes and drums to have this done…
Charles #677556.----- Original Message -----
From: Tom Carson

17

Charles:
Most of those old shops threw out that equipment when OSHA got hard on
asbestos.
JUST TRY TO FIND someone NOW!!??
ML

18

Mad Ernie,
There is still someplace that has stuff like that–
bill----- Original Message -----
From: Fhc12001@aol.com
To: xk@jag-lovers.org
Sent: Wednesday, July 16, 2003 12:42 PM
Subject: Re: [xk] New member - help with XK140 OTS brakes (long)

Charles:
Most of those old shops threw out that equipment when OSHA got hard on
asbestos.
JUST TRY TO FIND someone NOW!!??
ML

19

In reply to a message from jagwillie@ids.net sent Wed 16 Jul 2003:

On Princeton Avenue in Trenton New Jersey, is a shop that really
does that kind of work. Trenton Brake is the name. It’s owner is
named Andruzewicz, (pronounced Andru-shevitz) He’s been around a
long time & has done my Jag, Velocette, Ducati’s, Triumphs, (both
two wheeled & 4), Early Alfa Romeo Giulietta with 3 leading shoes
in the front. All without any problems.

Roger–
Roger, 1954 120 DHC BRG, S678300
Tamarac, South Fla., United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

20

Thanks Bill Bassett. NOW, what don’t you have o/t than those clevis pins?
YOU seem to have EVERYTHING else a Jaguar owner might want?
Best regards,
Mad LUDWIG
Mad Ernie is my better looking, smarter, non Jaguar owning brother.
Appreciate your input!!!