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PostPosted: Tue Oct 14, 2008 7:57 pm 
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I was planning to upgrade the sports850's brakes from the standard single leading shoe ones to twin leading shoes (have reco'd backing plates ready to swap over) but then started wondering if there was any way of improving them while keeping their appearance as standard . Is there any benefit in fitting a different wheel cylinder (if possible/availible) or anything else that would improve them ? If not I'll just go with the swap and keep the original backing plates for later but thought I'd throw the question out there anyway .

Also if anyone has some non spacered mini-fin's I'd like to chat to you ....

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PostPosted: Tue Oct 14, 2008 8:00 pm 
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Back in the day, they used harder material shoes and a servo to work em... :lol:

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PostPosted: Tue Oct 14, 2008 8:01 pm 
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I had thought of harder shoes , but last I checked there was only one grade availible unles they are custom made :( Still an option though I guess .

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PostPosted: Tue Oct 14, 2008 8:22 pm 
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is it possible to get a different size cylinder in there? would that work? just a thought. other wise yeah what doc said is the only thing i've heard of

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PostPosted: Tue Oct 14, 2008 8:28 pm 
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I was wondering about the non-spacered minifins as well, I haven't been able to find any non-spacered versions floating about... So I was thinking is it possible to get the spacered ones and skim them down to a suitable thickness. This would allow a small "spacer" to be put in as well ie. if I wanted to have a 3mm spacer them I'd just have 3mm less skimmed off.

I would imagine that skimming a set could become a pretty costly exercise as well.


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PostPosted: Tue Oct 14, 2008 8:33 pm 
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Also I thought I would add that I had a chat to a guy that does racing brakes and he said that they can fit better material linings to old shoes. I will be looking into this very soon for myself...
Other ways to improve drum brakes are to 'vent' them by making holes through the backing plates to get the air through them.
Also I have heard that some people drill holes around the perimeter of the drum, sort of like drilled rotors on disk brakes.


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PostPosted: Tue Oct 14, 2008 9:12 pm 
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I would be very wary about drilling holes through the outside of the drum, they are thin grey cast iron- just add some heat, a stress raising hole or 12, expansion from the shoes, then crrrrrrrrrraaaaaaaack.... :cry:
If you must drill things, do the backplates. :lol:

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PostPosted: Wed Oct 15, 2008 12:53 am 
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Discs :-)

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PostPosted: Wed Oct 15, 2008 4:56 am 
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my old 850 had a booster fitted under the rear parcel shelf, i.e. in the boot. It seemed to work pretty well with the single leading shoes.

Of cousre when one of the ball joint threads snapped off the hub and I had to source a new hub, it was easier just to reco a full set of twin leading shoe front hubs that are on the car now (ask serenity how the brakes are now as he is the new owner)

cheers
michael

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PostPosted: Wed Oct 15, 2008 8:26 am 
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Ian, last time I checked it wasn't too expensive to get new linings bonded onto your old shoes. I currently run with shoes that have undergone this procedure.

Word of warning though - my front drums leave brake dust on the wheels like disc's. Many people have just assumed I run discs and are amazed when I tell them I only washed my car a week ago and it has that much brake dust :lol:

I think these really soft shoes are one of the reasons my drums work so well (compared to other drum braked mini's).

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PostPosted: Wed Oct 15, 2008 10:29 am 
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I might get a couple of new wheel cylinders and give them another go as single leading shoe brakes , will look at shoe compounds too . I thought you would have to go harder though Nick rather than softer for them to work better and not fade as quick ?

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PostPosted: Wed Oct 15, 2008 10:36 am 
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Hey Nick can you post the place that you had the new shoes rebonded at please :)

Also I believe that brake fade is mainly to do with the heat dissipation effectiveness as opposed to the material, but that said I'm sure a good lining compound also helps... I would have a chat to the blokes rebonding the shoes as to what compound is the best choice...


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PostPosted: Wed Oct 15, 2008 11:05 am 
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Just another thought if you can't drill the drums then what about 'slotting' by putting some grooves in them to get rid of the worn off material?
Like the below picture :)
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PostPosted: Wed Oct 15, 2008 11:16 am 
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I had thought of something similar before (not as steep an angle though)but not sure of the strength of it all , remembering that if the drum is really hot and a chunk lets go from the drum the shoe could get jammed and lock one wheel . Not really a pretty thought at speed .

The idea itself isn't bad though as it would clean the dust out of the way and possibly slightly aid cooling (???) . I know people have drilled entry and exit holes in the backing plates and also put a tiny scoop in front of the entry hole to aid cooling but not sure what else .

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PostPosted: Wed Oct 15, 2008 11:24 am 
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My concern with drilling holes in the backing plates is water entry, as with standard drums there is no way to get the water out again...
However with drilled drums or some sort of slot (as above) it would get forced out centrifugally.
The best modification would have to be minifins though, does anyone have any thoughts of skimming the offset ones down?
It would be good to see a side on picture of one of them to show how much 'fin' would be left after a skim...


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