Anyone have big rear brake for ae86?

[Tom86]

Has anyone done a rear brake upgrade for ae86? I'm currently running a Hopper kit with 280mm rotors and twin piston calipers in the front and using a standard disc in the rear. I want to improve braking power in the rear so I can have a better balance.

What combination of caliper/rotor size can I use for the rear to give a good balance? at the moment the front is just working too well the rear (I feel) doesn't do much. Without swapping a whole rear end has anyone manage to adapt a bigger rotor/caliper onto their 86?

Thanks

[MWP]

Are you overheating the rear brakes?
If not, then its not small brakes that are the problem, its just bias/proportioning.

Have a read of this:
http://www.toymods.net/forums/showthread.php?p=325679

[Tom86]

Are you overheating the rear brakes?
If not, then its not small brakes that are the problem, its just bias/proportioning.

No the rear brakes are not overheating. I get what you're trying to say about the bias/proportioning part. I don't have any problem with the rear locking up early as other people. The rear doesn't lock at all the front does easily.

So far, In an attempt to make the rear work harder I've gutted the proportioning valve i.e remove all the springs etc so now there is no restriction to the rear brake line(100% fluid to the rear). I'm still not happy with the front rear bias I just think the front are way too powerful. Hence my reason for wanting a bigger more powerful rear brake so I can have better front rear bias.

[wilbo666]

Is your rear master circuit working?

Cheers
Wilbo

[takai]

Is your rear master circuit working?

Cheers
Wilbo

Very true. Usually when you have big brakes on the front and tiny ones on the rear you will lock up the rears VERY easily.

[Tom86]

Is your rear master circuit working?

Appear to be working fine, I had the rear wheel up in the air with the engine running I can easily stall the engine with the rear brake. Also when I bleed the brake I do get a nice stream of brake fluid coming out the rear line. I tested all that. I'm open to any suggestion

Very true. Usually when you have big brakes on the front and tiny ones on the rear you will lock up the rears VERY easily.

Shouldn't it be the other way around? bigger brake more surface area, bigger pad area more friction so more braking power. So the front should lock before the rear?

[MR22ZZ]

a bigger piston area requires a greater fluid volume to move, hence why the smaller ones (that use less volume) lock first, if they are not proportioned correctly.

[Chrisso]

If you're using a disk brake T series rear end, the only bolt up change I've come across is MA45 rears. These are a 10" disk I believe, but good luck finding them. Your best bet would be NZ paddocks from what I hear.

Sounds like you might be better off with a bias proportioning box. Otherwise, there was a post (possibly by cruzida) on adapting brake calipers/brackets.

Chris

[Billzilla]

I'm getting bigger rear discs fitted to my Sprinter right now in fact.

Here's a (poor) photo of what's going onto it ->



It's a racing disc, I can't remember the part number sorry, and it'll be still using the stock caliper so I keep the handbrake and brake lines & so on all stock.

[The Real Roadrunner]

how are you planning on using the stock caliper with such a big difference in swept area and internal arc of caliper? it will get very messy with the top of the pad overhanging the disc by 5mm or more.

cheers
linden

[Billzilla]

A new mounting bracket, of course.

[MWP]

Who supplies disks like that in Aus?
Seems its an easier way of upgrading brake size...

[Billzilla]

Brake Distributors Australia.
Trevor - 0414-868555

[Tom86]

Billzilla would going to a bigger diameter disc without upgrading the caliper make a significant different to the stopping power? what size disc is that 280mm? I'm really interested in the result of this upgrade please let us know when you finish the upgrade

I've found an article that confirm my suspicion about the rear brake not doing enough work when you have big brake at the front.
CLICK HERE

[Billzilla]

Billzilla would going to a bigger diameter disc without upgrading the caliper make a significant different to the stopping power? what size disc is that 280mm? I'm really interested in the result of this upgrade please let us know when you finish the upgrade

Yep - For example if the disc is twice the diameter then you have twice the stopping power even with the same caliper. The reason is simple leverage.
That disc is something like 315mm, so about 70mm larger than the stock Toyota one, so I'll have something like 30% more stopping power on the rear.
The car also has a brake bias adjuster, and that'll let me fiddle to get it where I want it.