Technical Disc Brake Mod??

[the hobbler]

I seem to remember(from my Radbourne days) the 850 front uprights and hub units, including the discs that went with them, could be made to fit a 500. Trouble is, even in those days there were very few 850 coupe/spiders on the road, so the chance of finding a 850 coupe/spider scrapper these days is very, very slim---and if you do, they are so rare that it is probably worth restoring! I have noted Peter's (Bigvtwin996) comments, but will continue to find an available caliper that is of a more compatible size for the 500s than the normal Punto/Cinquecento/Cicento variety which to be honest, are a tad OTT.

 

[Bleeding Knuckles]

Greetings, MOT time again, so I got the chance of some pic's of the inside of the disc brakes and wheels with the car sitting on the rubber. All please note that my wheels are Alloy Minilite style and 5J x 12H size with 165/60 x 12 Yokohama tyres. I have the later 126 front upright with X 1/9 (1300cc) callipers and Bendix 48mm single pistons. The caliper body has been ground away and now gives a 24mm gap between it and the inside of the wheel. The problem area for my set up is that the wheel rim has a slight chamfer where the inside surfaces meet - the distance is no more than 10mm from the caliper rear outside edge. As far as I car determine the caliper does not need to be ground away on the outside surface and only slightly on the rear to give good clearance. I will be obtaining new caliper piston frames to assess this further. MOT was a pass
pics have all come out lying on their sides !!!!!
Ian.

 

[the hobbler]

I have done a bit more research with regard to calipers that might be used to put discs inside 12inch wheels. The front calipers from the "Daihatsu Cuore" might do the job---211mm discs (10mm thick) and quite small calipers. Anybody out there run such a vehicle or can lay their hands on one of these calipers?---even just 1 used caliper (and its support bracket) would enable me to see if these would do the job.

 

[Bigvtwin996]

"Daihatsu Cuore".

looked at these..... single floating calipers and hard to get in the UK,
went out of production in 2003... and disks will not slip over a 126 hub

Also looked at Bedford Rascal and Suzuki Carry.....

All hard to find with a regular supply

 

[the hobbler]

There are a number of the Cuore front calipers for sale on e-bay--both new and used. The caliper mounting frames are also still available. The trouble with the Suzuki/Honda/Vauxhall micro-van/pick-ups is that they tended to use 18mm vented discs--small in diameter, but vented to dissipate heat. The problem with using (even big) bike calipers is that they are used on thin (5mm, or even thinner) discs.
Ian (bleeding knuckles) has ordered a pair of Fiat X19 calipers--it will be interesting to see where the calipers currently on his 500 (which are also off a Fiat X19) differ in order to get the clearance for use in 12inch wheels.

 

[Bleeding Knuckles]

Greetings, A quick update, the front right caliper (offside) has arrived, the nearside item should be with me today or tomorrow. When I get the time I'll get back with details
Ian.

 

[Bigvtwin996]

The trouble with the Suzuki/Honda/Vauxhall micro-van/pick-ups is that they tended to use 18mm vented discs--small in diameter, but vented to dissipate heat. The problem with using (even big) bike calipers is that they are used on thin (5mm, or even thinner) discs.

not quite correct, certain Bedford Rascal, Suzuki etc etc use a 213 mm solid disks, with a center bore that will allow a custom hub to pass through and use std Fiat bearings... but not quite enough offset without a completely ne off hub to permit a dual piston caliper...

 

[the hobbler]

I stand corrected! The trouble is trying to remember/find all the options that can be investigated, so any input is appreciated. "Rascal" calipers (and holders) are available, new and used. Just for interest, what have you got against 'floating' calipers? yes, they are (relatively) cheap, but they are available and, if well maintained, pretty fault-free.

 

[Bigvtwin996]

Perhaps I am a brake snob.....
but floating calipers are designed to be cheap for mass production...
however there can also be problematic...
the slider pins are only protected by rubber sleeves and as an example... I had to replace the rear calipers on my shogun as they had seized.... whilst the calipers themselves were about £100 each the various pins clips carriers sliders etc came to almost the same, if not more as all were unusable being more exposed...
There are many more components in a floating caliper and I perhaps refer the simplicity of twin piston calipers and they are less likely to produce uneven pressure on the pads/disk ... I could say.... you don't see many top end cars with floating piston calipers...

My main idea was to be able to use relatively off the shelf parts, retaining 500 bearings and the caliper I am working with uses std Classic Mini pads available in a variety of compounds and an off the shelf disk that costs less than £12 and are easily obtainable without any modification. this would mean no need to have to search for difficult to obtain service parts in the future.
I have had custom hubs machined up to test and experimented with clearances with all sorts of setups...
but each has a problem... the solution I like however uses calipers that cost me £105 each,,,,
but it could be a solution that costs sub £350 using all new components and is relatively future proofed
My philosophy is if you are going to do something do it once and do it the best way possible.

 

[Bleeding Knuckles]

Greetings All, I have just managed - amongst other things! to make a comparison between modified and non modified (original) front callipers you can see that the outer shoulder of the caliper has been ground away and a small chamfer added above and below this area too. Measuring from the inside brake pad face to the outer shoulder of the original I get 21.41mm. With the modified part the shoulder has been reduced to 11.04mm There are two 5mm spacers each side that assist with clearance. The outer area of the modified caliper is in excess of 20mm from the inside face of the 5J x 12 Minilite alloy.
BUT at the rear of the caliper at the chamfered area this clearance reduces to 5mm maximum. So I can say that my brake wheel combination has been heavily modified to fit and as the arches are standard the wheels rub on full lock!!!!!

Ian.