F series rear end disc brake upgrades

[TurboRA28]

Hi all, i've done some searching around but can't find a definitive thread on this topic..

What options are there for disc brake upgrades that will suit a F series diff housing (in a ra28).

I currently have the Corona ST141 disc brakes on it, but would like something more substantial but also cost effective..

What options are out there?

Thanks
Joel

[Norbie]

Have you looked into the MA70 upgrade for Hilux axles? I'm not sure how much similarity there is between F and G series axles but it might be worth looking at. I mention this because I'm thinking there probably won't be many "big" brakes available for 4-stud axles, and you might have to look at re-drilling 5-stud stuff.

[The Witzl]

upgrade to a Volvo diff
Comes with twin-piston large disc brakes.

Otherwise i know nussing

[gianttomato]

Having done this years ago on an MS112 F series diff with disc brakes, the easiest options were ventilated MA61 discs with spaced out rear calipers or 300mm 500 SEC Merc discs, caliper bracket and whatever two spot you wanted to use. Just had to radius grind the internal handbrake drum shoes.

You're probably have a Corona Mk2 diff with the whole ST141 shebang bolted up. I would use the backing plate/internal drum mech as a starting point and work from there.

[timbosaurus]

Are you actually having issues with the rear brakes Joel? Or just logic saying bigger will be better?

[TurboRA28]

Few reasons..
Ive always felt it lacking in rear braking performance.
Since Winton a rear axle seal has gone, and rear pads are down and rotors should be replaced also.. So it all has to come apart..

So just thinking now is the time to change if there are better options..

[old_school_jap1]

The st141 items are pretty much the biggest you can go on a mx13 housing without making brackets for another caliper. The st141 brakes are 280mm and are the same piston as up to vr commonwhore, so they aint exactly small. The ms112 setup gt is talking about is 260mm and single piston and is not compatible with the mx13 diff.

[timbosaurus]

Fair enough. And have you got an adjustable bias valve yet? I found my brakes sooooo much better once biased correctly. Obviously, better bias does actually stop you quicker.

off topic, but I can't beleive the amount of posts I read that say i've just fitted xyz brand pads (or bigger calipers etc), and now my silvia stop heaps quicker. I don't think they realise that the limit is with the tyres ability, not the brake pads. Better brakes only helps prevent fade etc.

[gianttomato]

Joel do you have a pic of the ST141 backing plate/caliper bracket? I looked at one millions of years ago and I remember it being aluminium? Is that right?

[TurboRA28]

I haven't got an adjustable bias.. I gutted the factory ra28 item so somewhat equal pressure to front and rear.. But still feels like too much front not enough rear..
I thought if I put a bias valve in I can only restrict the rear.. Where I need to increase the rear, obviously without decreasing the front..

[old_school_jap1]

ST141 backings are aluminium

[TurboRA28]

Yes, aluminium thats correct.. I'll grab a pic shortly.

[gianttomato]

Just find a rear rotor with similar hat height and identical internal drum diameter and make up a caliper bracket for the two spot you want to use.

[roadkill]

Hi,

what master cylinder have you got and what brakes have you got upfront? My 28 had standard upront but has the hilux rear end. It felt like the rear did nothing and the front did everything because the calipers were so small upfront.

bEn

[WDE_BDY]

I'm currently looking at an upgrade for the MS112 disc brake diff using Estima parts, mainly to eliminate issues with the Crown handbrake. Looks like the setup will need to be swapped left to right and mounted upside down to get it to work as I need it to. That doesn't help you of course, as the bolt pattern on the end of the housings is different.
For simplicity in your case I would probably ditch the whole internal drum setup (I presume it runs internal?) and just get a disc to suit and make a bracket for a caliper with built in handbrake.

Callum