Brakes, was Re: [xj] Fitting ABS to a SII

Eric, here’s my take on pads, having first started with them in '69 by
switching a '67 Sprite disc front end with our '61 Sprite’s drums. Pads that
grip well are easy to come by and dust should not be a concern – either you
wash your car every week, as some do, or you wash it every year, as I do. In
either case, pad dust is a non issue.

Discs that aren’t warped will last a long time, unless you like full hard
stops at most every light or on downhill freeway exits. I’ve replaced one set
of discs in 30 years. – never had a drilled set and don’t see why ordinary
driving would call for them. My current cars all have discs up front, and 3
have them at the rear. I think each pad lasts over 30kmi on our Hondas, and I
expect about that on our Jags. I say “each” pad, because I rotate them, just
like tires & replace only when they’re down to metal. I just replaced one pad
on our '86 Accord because it was down to its steel (I run them for a day after
the grinding is noticeable, because it grinds off the inevitable lip at the
rim of the disc) – ahhh, I can sense the raised eyebrows out there. :]

Other than regrinding/replacing discs only when you have to, and rotating pads
from one side of a caliper to the other every time you rotate tires, I just
suggest greasing all steel edges/faces of pads that rub or touch anything.
This lets them float properly in the caliper and avoids squealing (grease the
backing plate added to most pads too). Moly-sulfide grease is fine, although
most pad kits come with packets of hi-temp grease for the purpose.

Flush the brake fluid every few years and use the stuff marked “DOT 3/4”,
unless you have a thing for a complete flush, even with solvent, so you can
convert to silicone. Hoses will last a long time with good behavior on the
flush side, but our cars may not have been treated so well, so the rubber
brake hoses do need some inspection to see if their insides are coming apart,
etc. Other than these things and checking the master cylinder, the Jags’
brakes are very, very good (ignoring the hand brake).On tires, our SII will just accept 225/70-15s, but our SIII won’t up front. So I guess 65 series tires would be ok, if you want a little more width. Alex 79xj6L SII (BRG + wires) 86xj6 SIII (Black) 61 Sprite MkII (Red) Menlo Park, Calif. Eric318 wrote:

In reply to a message from Alex Cannara sent Thu 11 Nov 2004:

This is all very interesting, also the other thread started by
Arnoud. This is enough to make me shelf the ABS retrofit idea (and
yes I did also had a bad dream about Airbags in a SII… I should
really stop eating those funny mushrooms…).

Having been part and witness in two serious crashes that created
hurt and cost, my driving style has changed enormously, for the
better (I would hope). Safety distances, speed limits and road
surfaces have become primary parameters in my equations as I have
becopme less bothered with the hypothetical 2 and a half minutes
gained on journey time through burning more fuel and rubber. This
would probably mean that I am not necessarily a driver that would
greatly benefit from ABS. The cost of retrofitting/maintaining
would then outweigh the benefit.

So now, how does one improve the braking system on a SII. Vented
disks, ‘‘greenpads’’ etc ? The idea here in my case is simply to
shorten braking distance in normal use + avoid wheel lock on less
than perfect surfaces.

  • Good wide tyres for grip seem compelling to start with right?
  • New Master Cylinder, always a good thing to have
  • Replace braking fluid (keep to DOT 4?), of course (now I am
    curious to hear how many of us actually get this done regularly…
    every two years?)
  • Replace brake hoses (with braided ones? Is that worth it?)
  • Vented disks at the front (is that really useful in normal road
    use, or just a vanity ‘‘a la Schumacher’’ thing?)
  • New disks at the back (I have just done that actually, and
    together with new callipers I am happy to report that I now have an
    operational braking system at the back… what an improvement! with
    handbrake and all!)
  • high quality pads? I currently have the standard �14 a box pads
    on and I wonder if the higher quality advertised ones are worth the
    extra money…

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// please trim quoted text to context only

Nah, not at all. After your confession about reusing cotter pins, Alex,
nothing surprises us any more :slight_smile:

Doug Dwyer
Longview, Washington USA
1987 Ser III XJ6
1988 XJS V12

(I run them for a day after
the grinding is noticeable, because it grinds off the inevitable lip at
theFrom: “Cannara” cannara@attglobal.net
rim of the disc) – ahhh, I can sense the raised eyebrows out there. :]

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// please trim quoted text to context only

What about when the cotter pin finally goes and I use a nail? :]—
Alex
79xj6L SII (BRG + wires)
86xj6 SIII (Black)
61 Sprite MkII (Red)
Menlo Park, Calif.

Doug Dwyer wrote:

Nah, not at all. After your confession about reusing cotter pins, Alex,
nothing surprises us any more :slight_smile:

Doug Dwyer
Longview, Washington USA
1987 Ser III XJ6
1988 XJS V12

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// please trim quoted text to context only

In reply to a message from Cannara sent Fri 12 Nov 2004:

all very good, so that brings us to the question of number of
pistons (pots?) in the front callipers.

I read above that this number changed over time during the
production life of the SII. When did that actually happen? Was the
change from 2 to 3 pots?

Is it good to retroswitch from 2 pots to 3 pots?

What about the 4 pots callipers that one reads about in the Jag
press? Racing only probably.

Thanks–
1975 XJ6C - LHD
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

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// please trim quoted text to context only

G’day Eric,

My SII (1976) has four pot front calipers and vented discs as do all SIII’s.
Best stoppers on any car I’ve driven.

Regards,
Jeff Watson.
Sydney, Oz.Subject: Re: Brakes, was Re: [xj] Fitting ABS to a SII

In reply to a message from Cannara sent Fri 12 Nov 2004:

all very good, so that brings us to the question of number of
pistons (pots?) in the front callipers.

I read above that this number changed over time during the
production life of the SII. When did that actually happen? Was the
change from 2 to 3 pots?

Is it good to retroswitch from 2 pots to 3 pots?

What about the 4 pots callipers that one reads about in the Jag
press? Racing only probably.

Thanks

1975 XJ6C - LHD

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// please trim quoted text to context only

Silly question perhaps but does improving the front not upset the brake
balance?
Did you modify the rear as well?

Rgds Louis>My SII (1976) has four pot front calipers and vented discs as do all SIII’s.

Best stoppers on any car I’ve driven.

Regards,
Jeff Watson.
Sydney, Oz.

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// please trim quoted text to context only

Louis Mossou wrote:

Silly question perhaps but does improving the front not upset the
brake balance?
Did you modify the rear as well?

As long as the total piston area remains constant, the number of pistons
is basically immaterial, Louis…

Frank
xj6 85 Sov Europe (UK/NZ)===================================================
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