Booster
and Twin Master Cylinder Upgrade For A MK3
By
Alan Martin
This
upgrade makes use of a LH Torana Booster and a HJ Holden Master Cylinder,
although most Holden and Ford Master Cylinders will bolt to this booster.
The
LH Torana booster is not only an ideal size unit but the bolt holes are almost
identical to the MKIII mounting bracket holes. A very minor bit of filling is
required for the MKIII bracket to bolt onto the new booster. The diameter of
the rod and inner diameter of the cylinder is also perfectly suited to the
application.
In
this instance I purchased a new Booster and Master as I use the car as a daily
driver and intend to do so for a long time to come, I hope. This cost $400aus
including the modification to the rod and having the bracket fitted, both of
which could be done at home.
Comparison between the 2 boosters. The
MKIII bracket has been fitted to the Torana Assembly and the rod has been
modified prior to me picking it up.
Shows
the modified rod assembly Both the MKIII rod and Torana rods were cut and
threaded to accept a threaded tube which now doubles as a pedal adjustment
point. Whilst I had this done for me I think any one with the right tools could
do it at home.
Of
the four bolts on the back of the Booster the top outer bolt prevents the
booster from fitting up to the firewall and needed to be shortened as shown.
The
Assembly is located in place as per a standard setup. I was concerned that the
new Master cylinder may not clear the bonnet, but it fits in without any
trouble at all. As an alternative the XA/XB master cylinder may be used as it
not only fits the Booster but is also a lower profile (around 25mm).
In
this setup I blocked the top hole on the T-piece with an old bleed nipple. This
needed to have the nipple end turned down and blocked as it is too long to
screw in enough. It may be better to source a bolt that will do the job.
I
then made up two new brake pipes.
1. A
complete pipe from the rear reservoir to the T piece for the front brakes.
Note: I found it easier to block the top one and use the lower hole as the pipe
had easier access.
2. A short
length down to a joiner for the rear brakes. As an alternative a complete new
pipe to the rear could be fitted but as I had only recently fitted a new rear
pipe I chose not to change it again.
Pipe
and joiners can be purchased from brake shops such as PBR (Aust).
Note: Just a tip I
also made up a Foam Ring to seal between the firewall and the centre of the
booster (see Pic 2 on the old booster) as it they do
let a bit of a breeze in without it.
This
conversion was extremely easy and the advantage of having a dual system and
easily accessible replacement parts makes it well worth the money.
Disclaimer:
The advice and guidelines given in these articles are given in good faith.
The owners and managers of the Galeforce Zephyr site will take no
responsibility for any injuries or loss sustained while carrying out the
described tasks and procedures or any consequences arising. Please read
the Safety First
Article
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