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Upgrading the brakes of a standard 350i - Everything you wanted to know but were afraid to ask! Article by: Mike Hurley The standard brakes
on the 'stock' 350 do exactly what they should do, they stop the car (eventually!!).
In all seriousness providing that the discs and pads are in fine shape
then the standard brakes are ok for normal run of the mill use, the trouble
is we don’t own a Wedge because we couldn’t afford the beige
automatic Nissan Micra at the local dealer so the brakes can get well
used and lets face it they have been around on your car for at least 11
years now. If money is no object
then book the car into one of several firms that will do the work for
you, but if like me you only have beer money then I believe for a modest
outlay you can improve the brakes tremendously. Providing of course that
you are competent in mechanics. So as such I am not going to detail the
work by a blow by blow account as if you need that then you shouldn’t
be doing it!! If you are in any doubt at all about your ability to undertake
such an important project then please, please let somebody else handle
the work for you - you have been warned. The essence of the
conversion is to fit 4 pot callipers and ventilated discs, similar to
that a la 400/450SE’s. But before going any further I must stress
that in the last few months since I obtained my callipers the market has
dissapeared a bit so before commencing on the project start by soucing
your calipers first, an alternative is available, see parts listing at
the end of this article. I carried out this conversion in 2 stages. The
1st stage was to fit the 4 pot callipers with the standard solid discs
and then later I upgraded to ventilated discs. I did it this way as I
was feeling my way and didn’t want to end up spending lots of dosh
on a load of tosh as they say in all the best circles. I will list all the items required at the end of this article along with contact numbers and approximate costs.
Picture 1 (above)
shows the standard calliper and disc we all have come to love. As you
probably all know these parts are sourced from Ford. They come from the
Granada saloon / Estate made from 1972 to 1984. For the conversion
the first thing you require will be new callipers. These are sourced from
the Austin Princess (A.P.) range circular 1979 to 1984, the only type
of calliper fitted to this range as far as I am aware. I bought mine 2
years ago as exchange items but not having any to hand back I had to pay
a small excess charge. I rang several companies before making my final
choice, some firms required the physical handing over of old callipers
before supplying replacements others just a deposit and this varied from
firm to firm. These callipers are widely used on the club racing circuit
scene so there is always a one way demand for them so they can be hard
to source. The A.P. callipers bolt straight onto the existing stub axle carrier mounting points that the standard calliper uses so they can be used with the solid discs with out modification. You will need to provide an additional hydraulic feed to the callipers as there are 2 circuits per calliper, one for the top 2 pistons 1 for the bottom 2. You will need to purchase a "T" piece with all female connections, shown on the right hand side in picture 3, for it to mate with the existing flexible hydraulic hose, as well as 2 new short brake pipes, male connections both ends required. Thread sizes for the
flexible hose, both the calliper inlet ports and all the calliper bleed
nipples are the same thread size so getting the correct size T piece and
brake pipe connections is just a question of taking one of the A.P. bleed
nipples with you to confirm thread size when sourceing the items. Having
got all these bits together its just a question of unbolting the old Granada
calliper, bolting on the A.P. calliper, fitting the new "T"
pieces and brake pipes, installing new brake pads and bleeding the system. When buying the pads
for the first time don’t forget to request the fitting kit as well,
anti rattle shims and pad retaining split pins, only required if not fitting
ventilated discs. The new pads will overhang the standard disc by about
2mm. Although some efficiency is no doubt lost the benefits of the new
calliper outweighs the negatives. Some concern is expressed that the pads
could wear leaving an outside ridge on each pad making contact with themselves
thus preventing the pads from being squashed against the disc, this ridge
will just crumble away when pressed against itself but as with all things
concerning brakes regular checks need to be undertaken. That then is the first part of the upgrade I undertook....We now move into the ventilated disc conversion.
The ventilated disc
is again sourced from the Ford Granada 2.8 circular 1972 to 1984. The
disc diameter is 262mm. The post 1984 disc, now the round shaped Granada,
although far cheaper is no use at all as it is of a different design and
only 260mm diameter. Picture 2 (above) shows the ventilated disc, A.P. calliper and brake pads.
In order for the A.P. calliper to fit the ventilated disc it must be widened as the solid disc is approx. 13mm thick where as the ventilated disc is 24mm thick. This is achieved by obtaining the kit from Rallydesign. Picture 3 shows on the left hand side the parts from the kit that are needed for 1 calliper. Note however that the 2 large 5mm thick washers, intended to fit between the A.P. calliper and the stub axle carrier are not required as the inside face of the ventilated disc is in the same plain as the solid disc. The A.P. calliper is now split by undoing the 4 bolts, these bolts are discarded as new longer ones are supplied in the kit. Picture 4 shows the 2 halves of the calliper and the 4 pistons can clearly be seen hence the term 4 pot calliper. Each calliper is then
rebuilt by inserting the spacers along with new "O" rings and
then the longer bolts to hold them together. Utmost cleanliness is required
when undertaking this operation as any contamination could cause failed
seals leading to loss of braking!!! The Ventilated disc
is a straight swap with the solid disc, of course you will have had to
remove the old calliper first. It is now just a question of fitting the
widened calliper to the stub axle carrier and hooking up the hydraulics
as described above. Fit the brake pads and the longer pad retaining split
pins, included with the calliper widening kit, before bleeding the system.
At the moment I have not sourced the kit for the anti rattle springs so
I am using them with out. To date I have not experienced any problems.
Don’t use the standard anti rattle springs as they are not wide enough
and could jam between the pads causing loss of braking. One tip when bleeding the brakes. I use a pressure system first to remove all the air, don’t forget there are 3 bleed nipples per side, and bleed everything at least twice. When I think all is OK I get an assistant to sit in the car and press the brake peddle hard. I then go around each bleed nipple again giving each one a quick loosen which allows a blast of fluid to be ejected and quite often a trapped bubble or two of air. As each nipple is
released the brake peddle will be floored so don’t forget to tighten
each bleed nipple up before telling the assistant to release the peddle,
after which you can then move onto the next nipple. All the while keep
an eye on the fluid in the brake resivor.
Picture 5 (above)
shows the final installation just to prove that it does all fit !! You will now have
a braking system far superior to the original system producing quicker
stopping distances with less peddle effort not to mention fade from overheating
a thing of the past. To get the best out of the system refer to Steves
Heath's book about adjusting the rod between the brake master cylinder
and the servo to eliminate unwanted play, it makes quite a difference. You may of course
wish to go from standard set up to 4 pot calliper and ventilated disc
in one go. There is no problem with that but obviously some of the above
procedures will need to be changed, but source the callipers first. Parts
required
Just to confirm that I have no involvement with any of the above mamed companies and before carrying out any work or buying any items you must satisfy yourself that they are suitable for your intended use and that you are skilled / confident enough to undertake the project. Cheers Mike Hurley Important Article Update: Further to my article above about the brake upgrade, I have had an E-Mail from a chap who is in the process of doing the conversion but on receipt of the Rallydesign spacer kit it appears that the spacers are only 8mm wide and not 10mm as in my case. He has contacted Rallydesign again to confirm and it seems that they have standardised at 10mm spacers but when they run low on these they supply 8mm from an old batch, Rallydesign have suggested that when ordering you must state that 10mm spacers are required as you are doing the AP/TVR upgrade. This will hopefully ensure that the correct thickness spacers are supplied. Also could it be noted that the anti-rattle / retaining clips for the pads can be obtained from Rimmer Bros, tel 01522 568000, at a cost of £1.53 each, 4 required. Not a straight fit as a couple of millimeters needs to be clipped off each one for them to fit snuggly. Thanks to Mike Hurley for submitting this article. |
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