(AE101) for ya'll planning to swap to rear discs... - Toyota Nation Forum : Toyota Car and Truck Forums

VooDoo · 11-06-2005, 10:28 AM

if you have a 4AFE or a 7AFE engine, ya might want to plan out how you're gonna do your rear disc conversion...

as it turns out, its not as simple as bolting on rear discs from a Trueno/Levin...

the 4AGE brake booster is a lot thicker and has twice as many vacuum hoses...

94_Rolla_Guy · 11-06-2005, 01:11 PM

great reasource! is it available over the net or do you work at Grupo?

Im gonna take a guess on why its bigger, id bet the 4age has less manifold vacuum at idle which is why it would be bigger????,

Id be really interested about the master cylinders and proportioning valves and what the differences are

Ive been trying to figure out how to use AE92 GTS brakes on my AE102 i figure the only way i can make it work is to make a caliper braket that goes between the hub and axle carrier just haven't had the time or money to mess with it. Also i don't wanna go to all that work to discover that the master cylinder or proportioning valve is all wrong for the GTS system

Flashmn · 11-06-2005, 01:21 PM

Quote:

the 4AGE brake booster is a lot thicker and has twice as many vacuum hoses...

No its not... both are 9" in diameter 4A-F/FE and GE.
Plus that diagram is a RHD car, they have some diffrences, because the vacuum is taken from another place. It doesnt matter how many vacuum ports you have in the brake booster, you still get the same vacuum in there.

punter · 11-06-2005, 03:05 PM

From what i've seen (JDM cars only) the master cylinders are the same FE to GE only the proportioning valve is different

Flashmn · 11-06-2005, 03:42 PM

Guess what... the proportioning valve... its the same wether or not you have disks or drums, my pal took two of them and compared them. Part number changes but the valve is identical, so I wonder what the difference is in them

RedAE102 · 11-06-2005, 05:22 PM

The valves are the same on the outside because they're interchangeable... On brake boosters.... even on U.S. E10s, they differ depending on whether or not the car is equipped with anti-skid brakes (ABS).. the non-ABS cars (like mine) use a 9" brake booster, while the ABS-equipped cars use tandem 7" brake boosters (still in a single housing). I now run an AE92 GT-S proportioning valve (one of the late ones with the 258 mm front rotors, 242 mm rear rotors) on my '93 AE102 with 255 mm front/266 mm rear disk brakes. There really wasn't anything wrong with the basics of the factory disk/drum brake setup, it just was horribly proportioned... it didn't send anywhere near enough braking power to the rear. A good braking system should lock the rear brakes up just ahead of the front, which means that under panic braking, all four contact patches are being put to their maximum use.

That said, the handbrake on the rear disks leaves a lot to be desired. It takes considerably more effort on the lever to set the parking brake solidly. Any of you who do handbraked turns will also be displeased with the performance of the handbrake on the disks. Unlike many cars with rear disks that use drum-in-hat type parking brakes, which incorporate a separate drum in the rotor for the handbrake, the Corolla uses the type that uses a lever to push the caliper piston out.

punter · 11-06-2005, 05:25 PM

Quote:

Originally Posted by Flashmn

Guess what... the proportioning valve... its the same wether or not you have disks or drums, my pal took two of them and compared them. Part number changes but the valve is identical, so I wonder what the difference is in them

You sure there the same? They should look the same but the spring inside should be a different rate.

Would make life easy if they were the same

Dr Tweak · 11-06-2005, 07:05 PM

The rear disc setup from a Levin does bolt right on, you don't need to worry about the brake booster at all. I've done it myself. I also have put together rear disc conversions using Celica parts, I usually sell a complete bolt-on setup for $500 shipped. I recommend that a proportioning valve from a Celica GT with rear disc be used and they can be had pretty easily.

-Doc

Flashmn · 11-06-2005, 11:41 PM

Quote:

A good braking system should lock the rear brakes up just ahead of the front, which means that under panic braking, all four contact patches are being put to their maximum use.

Heck no. Rears ALWAYS get less power than the fronts, if the rears lock before the fronts you lose control, period. It would be the same as pulling up the handbrake and locking the rears.

Yeah the handbrake sucks on the disks, then again, making hydraulic handbrake is one option.

VooDoo · 11-06-2005, 11:42 PM

yes the do bolt up and work. not sure if we're getting the most out of the brakes though if we stick with the OEM brake hoses and proportioning valve, booster, etc...

Flashmn · 11-07-2005, 06:17 AM

well, the brakes arent that great to begin with so yeah I'd say you'd be pretty much in the green. Then again if you have 4 pot hilux brakes that you're considering putting onto a corolla with a ~300mm disk, then you have some added braking power.

RedAE102 · 11-07-2005, 03:06 PM

Quote:

Originally Posted by Flashmn

Heck no. Rears ALWAYS get less power than the fronts, if the rears lock before the fronts you lose control, period. It would be the same as pulling up the handbrake and locking the rears.

Yeah the handbrake sucks on the disks, then again, making hydraulic handbrake is one option.

I never said the rears would get more power than the front; that would be ridiculous. The right braking system puts just enough braking force to the rear to get all four at the point of locking up at roughly the same time... The factory brakes do not do that. Not even close. I only said the rear brakes would lock at about the same threshold as the fronts, not that they would use the same pressure to do so.

Flashmn · 11-07-2005, 03:34 PM

You'd always want the fronts to lock and rears well.. they wouldnt really have to lock up, infact you wouldnt really want to lock up any tire as a locked wheel actually brakes worse than a slightly rolling tire. Plus you have control of the car.
Even in racing front biased brakes are used to have a predictable car during braking. Notice for example F1 cars, theres alot more smoke coming out from the front than back during braking.

thespud · 11-08-2005, 09:19 AM

OK, just to clear this up. I have a booster off a GT-Apex in my shed and the OEM (Aussie made) booster in the car atm. Both are identical in both size, shape and vacum lines. The booster doesnt change. Its when it hits the ABS controller that the vacum lines and brake lines get tricky.

But then, the Aussie built E10's all came with the option of ABS and 4 wheel discs. It may be different in NA.

RedAE102 · 11-09-2005, 02:43 PM

In response to Flashmn: Yes, that's what I'm saying... you want all four wheels to lockup at the same time, so that when you get one to the lockup threshhold, all four of them are just short of locking up, and thus the four contact patches are being utilised to their fullest.

And to thespud: Yes, ABS was an option on all E10s in the U.S., whether they were built in Toyota, Japan at the Takaoka plant, in Fremont, California, US at NUMMI, or in Cambridge, Ontario, Canada at TMMC. However, no E10s were ever sold in the U.S. with rear discs; all of the U.S. models came with rear drum brakes. Everywhere else in the world (Aussie included), being an AE102 (with the 1.8 7A-FE) automatically meant that it came with factory 4-wheel discs (255 mm rotors at the front, 266 mm at the rear). Then there are the Super Strut brakes, which, as you well know, are another matter altogether, with 275 mm front rotors and twin pot front calipers. Everything I've been able to find has indicated that the Aussie AE101s came with rear drum brakes and smaller front rotors (to fit underneath 13-inch wheels), but actually being there, you'd know better than I do!