wilwood spot caliper on mini discs heeeeeeeeeeeelp please

[lizardking]

Hiya all,
quick question for all techies and trikers,I've got a manual mini/metro trike and i'm gonna somehow convert the rear brakes to discs i have the mini discs bearings driveshaft ends and calipers ,i've also chucked some of my hard earned at a wilwood spot caliper on frirst impressions it looks nasty and cheap but i'm nearly out of cash so i wanna make it fit.
has anyone done this before and can help me with the bracket design to make it fit?
i think i'm limited on what i can weld to cos the bearing carrier looks to be cast
can cast be tig welded with any success?
any info appreciated

[Sir Ewok]

Not an expert at TIG, but cast iron is difficult to weld, due to the brittleness of the parent metal. The weld tends to be harder and breaks away from the parent metal, like a weld failing at the root. I believe that you have to pre heat the parts to be welded, do your weld and then bury it all in a sandbox to cool down over a long period (possibly 12 hours or more) to redistribute all the stresses imposed by the welding operation. I am sure if I am wrong, somebody with more experience will put you right. Having MIGged tubing onto cast clamp handles to extend them, I know that it isn't as straightforward as some peeps think.

Cast Aluminium can be welded with TIG (not an inverter), but must be pre-heated and sandbox cooled.

[noizy git]

Sir Ewok is right about castings being difficult to weld to.There is a method called thermit welding which is used on castings but it's pretty specialised so it may be hard to find someone who can do it.
Given how nasty it could be if the weld broke you might be better looking at another way of attaching the caliper.

[Blackjack]

The other thing is that your uprights aren't cast iron, they're cast steel......

TIG isn't a good idea for big lumps of stuff like that, Stick works better, with MIG being my personal second choice.

BE WARNED, welded repairs to suspension components are an MOT failure. Strictly speaking what you're talking about is a modification, but if the tester decides it's a welded repair........

Do your Mini uprights have two threaded lugs for the caliper, or does the caliper bolt to a steel plate which bolts to the upright with 4 bolts?

If you've got the later type with the two lugs cast into the upright, a 1/4" plate bracket that goes under the caliper bolt heads and provides a mount for the small caliper is a thought.

If it's the type where the caliper mounts to a plate which then mounts to the upright, just make new plates, or weld a bit to the existing plate.

[guydewdney]

or go to the scrappy and buy a pair of volvo 440 / 460 back brake calipers - and a small bit of 1/2" plate.

make two kidney shaped plates up with 4 holes - two for the mini, two for the volvo.

1/2" plate spaces the calipers out just right, and volvo back discs are the same (+/- 5mm) diameter and the same thickness as mini fronts - so the caliper fits very nicely.

I would post a picture of this - but its the GFs trike and its at sootys customs being 'finished'

[lizardking]

cheers dude i think i'm gonna scrap the wilwood idea and go for the volvo option.......................anybody want a cheap wilwood spot caliper?